SOLAR PV GRID INTERCONNECTION CODE FOR LEBANON. Recommendations And Guidelines

Transcription

1 SOLAR PV GRID INTERCONNECTION CODE FOR LEBANON Recommendations And Guidelines

2 Authors: ProfEC: Basem Idlbi and Andreas Jansen Zakaria Rammal, National Energy Consultant Reviewers: UNDP DREG and CEDRO IV Projects, Lebanon Copyright UNDP / CEDRO and DREG 2016 Reproduction is authorized provided the source is acknowledged and provided repro-duction is not sold. The United Nations Development Programme (UNDP) is the UN s principle provider of development, advice advocacy and grant support. With 170 coun-try offices, it has long enjoyed the trust and confidence of government and NGOs in many parts of the developing as well as the developed world. It is typically regarded as a part-ner rather than as an adversary, and its commitment to universal presence proved espe-cially useful in post conflict situations and with states that have been otherwise isolat-ed from the international community. For further information: United Nations Development Programme, DREG, CEDRO, Note: The information contained within this document has been developed within a spe-cific scope, and might be updated in the future. Acknowledgement The UNDP would like to thank both the Global Environment Facility and the European Union for the donation of funds that enabled this study through the DREG and the CEDRO IV projects. The UNDP extends its gratitude to all the stakeholders involved in this study, namely the Ministry of Energy and Water, Electricity of Lebanon (EDL), the Lebanese Center for En-ergy Conservation (LCEC), and the grid code committee.

3 CONTENTS Abbreviations I. Executive Summary II. Background III. Methodology Review Of Other Guidelines Consideration Of Derived Recommendations In The Project Consideration Of Stakeholders Feedback IV. Recommendations And Guidelines For Grid Interconnection Of Large Pv Plants Applicability Of The Guidelines Preconditions Of Installation Submission Of Relevant Documents Start-Up Principles For The Determination Of The Grid Connection Point Allowable Voltage Change Due To Grid Connection Active Power Reduction Based On Grid Operator s Command Characteristics Of Active Power Output (Frequency Control) Steady State Voltage Control Dynamic Voltage Support Auxiliary Support Remote Control Other Guidelines Related Points V. Overview Of Planned And On-Going Re Projects In Lebanon Appendix Checklist Proposed For Edl For Grid Interconnection Of Re Plants Summary Of Other International Guidelines Related Points Pv Parameters Of The Uk As Defined By Steca Service Manual For The Compliance For The Case Of The Uk As Defined By Sma Data Assessment Report Abbreviations Executive Summary Background Methodology Summary Of The Received Data Assessment Of Received Data Assessment Of Grid Situation Evaluation Of The Data And Measurement Availability Conclusions And Recommendations Appendix A: Required And Requested Data Appendix B: High Level 220 Kv Analysis For The Network Grid References

4 LIST OF FIGURES Figure 1: Methodological structure of the project Figure 2: Active power output due to over frequency Figure 3: Example of Q(U) characteristics Figure 4: Example of cos φ (P) characteristics Figure 5: Fault ride through of the PV plant Figure 6: Methodological structure of the project as presented in the Inception Report in Chapter 8 Figure 7: Map of Lebanon showing the transmission system as well as the locations of installed and expected large RE projects Figure 8: Statistical illustration of exemplary voltage measurements of some stations at the level of 11 kv level. 70 measurements are taken at each station in the time from till Data number 9 in Table 6. Figure 9: Statistical illustration of exemplary voltage measurements of some stations at the level of 15 kv level. 70 measurements are taken at each station in the time from till Data number 9 in Table 6. Figure 10: Statistical illustration of exemplary voltage measurements of some stations at the level of 15 kv level. 70 measurements are taken at each station in the time from till Data number 9 in Table 6. Figure 11: Measured exemplary frequency variations with the time at the household level. The measurements have 1 minute resolution and are performed on Data number 7 in Table 6. Figure 12: Measured exemplary voltage variations with the time at the household level (level of 230 V). The measurements have 1 minute resolution and are performed on Data number 8 in Table 6. Figure 13: Measured exemplary frequency variations with the time at the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. Figure 14: Measured exemplary voltage at the PCC of the BRSS. The measurements have 5 minutes resolution and are performed between and The measurements are taken at the PCC of the plant at the LV level (400 V side). Data number 10 in Table

5 Figure 15: Measured exemplary output power of the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. Figure 16: Measured exemplary frequency, voltage and output power at the PCC of the BRSS. The measurements have 5 minutes resolution and are performed on Data number 10 in Table 6. Figure 17: Ramp rate of measured exemplary frequency at the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. Figure 18: Ramp rate of measured exemplary voltage at the PCC of the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. Figure 19: Flicker values at the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. Figure 20: Statistical illustration of exemplary voltage and frequency measurements at the station of Nabatieh at the level of 15 kv. The measurements have 1 minute resolution and are taken between and Data number 15 in Table 6. Figure 21: Statistical illustration of exemplary voltage and frequency measurements at the station of Sour at the level of 15 kv. The measurements have 1 minute resolution and are taken between and Data number 24 in Table 6. Figure 22: Statistical illustration of exemplary voltage and frequency measurements at the household level in Zahle (level of 230 V). The measurements have 1 minute resolution and are taken between and Data number 25 in Table 6. Figure 23: Measured exemplary frequency, voltage and output power at the PCC of a test micro PV inverter (250 W) installed at the household level in Zahle (level of 230 V). The measurements have 1 minute resolution and are taken between and Data number 25 in Table 6. Figure 24: Statistical illustration of exemplary voltage and frequency measurements at the station of Kobayyat at the level of 15 kv. The measurements have 1 minute resolution and are taken between and Data number 26 in Table

6 LIST OF TABLES Table 1: Max observed voltage and frequency deviations in normal operation (Assessment Report) Table 2: Recommended settings for grid-tied grid-dependent (B1) and gridtied dual mode (back-up) (B2) for Lebanon (Source: UNDP-CEDRO project) Table 3: Active power in relation to grid frequency Table 4: List of RE projects in Lebanon until the date of submitting this report Table 5: Country-specific parameters of the UK for PV inverters as defined by Steca. Source: Table 6: Illustration of the collected data Table 7: Illustration of the received data from the UNDP (i.e., Jil Amine) Table 8: Summary of illustrated measurements Table 9: Outline of the required data for Evaluation of grid stability and the framework in the present Table 10: Outline of the required data for Evaluation of Grid situation in future scenarios Table 11: Outline of the required data for evaluation of preparation for future grid planning and monitoring subject

7 ABBREVIATIONS AC BRSS CDR CEDRO DREG EDF EDL EDZ EIA EPSS FRT GEF GoL IEEE IPP LCEC LENCC LV NEEREA NERA MoEW MV PCC PV RE SLD ZOI Alternating Current Beirut River Solar Snake Council for Development and Reconstruction Community Energy Efficiency and Renewable Energy Demonstration Project for Lebanon Small Decentralized Renewable Energy Power Generation Project Électricité de France Électricité de Liban Électricité de Zahle Environmental Impact Assessment Electrical Power Supply Systems Fault Ride Through Global Environment Facility Government of Lebanon Institute of Electrical and Electronics Engineers Independent Power Producers Lebanese Center for Energy Conservation Lebanese Electrical National Control Center Low Voltage National Energy Efficiency and Renewable Energy Action National Electricity Regulation Authority Ministry of Energy and Water Medium Voltage Point of Common Coupling Photovoltaic Renewable Energy Single Line Diagram Zahrani Oil Installations 7

8 I EXECUTIVE SUMMARY This document is submitted within the framework of the projects: The Small Decentralized Renewable Energy Power Generation (DREG) and CEDRO IV Technical Study and Development of a Solar PV Grid Interconnection Code for Lebanon. This report provides a set of guidelines and recommendations mainly in relation to the interconnection of large-scale PV plants in Lebanon (i.e. larger than 1 MWp), in addition to other large-scale renewable energy generators that should take into consideration the mentioned guidelines and recommendations. The assessment performed is mainly based on recent and locally collected data, which was presented in details within the Grid Code Data Assessment Report. In addition, the information requested and received from relevant technical companies and international manufacturers of PV inverters was also assessed, evaluated, and considered, knowing that it would not make sense to establish grid code recommendations where manufacturers in the market cannot comply with. This document has a special focus on presenting guidelines that consider the critical frequency and voltage deviations in the Lebanese grid; regarding these parameters, solid measurement data were accessible in acceptable quality. Given the weak data availability in general, the assessments may have some gaps in terms of representation, and these gaps were indicated in the Data Assessment Report. The adoption of these guidelines and their applicability in Lebanon should go through several iterations of discussions between the stakeholders and relevant authorities. New data that may be raised during this process could contribute in a beneficial way to these proceedings. Since there is a critical deficit between electricity generation and demand in Lebanon, the grid is susceptible to various problems, such as high deviations in voltage and frequency as well as regular outages due to load shedding. Therefore, the targeted guidelines aim for increasing the harness of renewable energy and to avoid possible power curtailment due to critical frequency and voltage deviations. In other words, the guidelines are suggested in order to avoid the possible frequent disconnection and/or curtailment of PV and RE plants, which can lead to inefficient or non-economic operation of the plants. On the other hand, the international standards and codes in countries, whose grids are more stable, aim for neutralizing the possible negative effects of the intermittent RE plants, such as over-voltage or over-loading problems. This contrast between the aim of these guidelines for Lebanon and the aim of other (international) standards should be taken into consideration during further development and adoption of a final grid interconnection code for Lebanon in the future. 8

9 II BACKGROUND The United Nations Development Programme (UNDP), in partnership with the Ministry of Energy and Water, has initiated the fourth phase of the CEDRO (Community Energy Efficiency and Renewable Energy Demonstration Project for Lebanon) Programme (CEDRO 4) funded by the European Union. The CEDRO 4 project includes several sustainable energy projects that are designed to promote related renewable and energy efficiency systems. In parallel, another nationally executed project has been initiated in this field with the Ministry of Energy and Water (MoEW) in coordination with the Lebanese Center for Energy Conservation (LCEC): the Small Decentralized Renewable Energy Power Generation Project, or DREG, funded by the Global Environment Facility (GEF). Both projects are collaborating with MoEW and LCEC to undertake the required assessments of renewable energy sources in order to support the Government of Lebanon s pledge to reach 12% renewable energy targets by The LCEC is a governmental organization affiliated with the MoEW. LCEC supports the Government of Lebanon in developing and implementing national strategies that promote the development of efficient and rational uses of energy and the use of renewable energy at the consumer level. This work is the first step in assessing the baseline existing conditions of the Lebanese grid and its ability to reliably absorb RE sources (mainly large-scale PV) in the areas where they are expected to be installed, and recommendations on the necessary next steps with respect to actions and reinforcement of the national grid are to be detailed in order to save them as guidelines and recommendations regarding the establishment of a national approved grid code. It should be taken into consideration that Lebanon does not have a published RErelated grid code yet. But such a grid code is needed to facilitate the optimized implementation of a national RE strategy and also to create an enabling environment for IPPs (Independent Power Producers) that could generate electricity from renewable energies or fossil fuels. Renewable energy related codes should be developed and implemented considering the existing grid codes in the country, its market structure and the country s context. Grid codes provide the rules for the electrical system and energy market operation, ensuring operational stability, security of supply and wellefficient market segments (traders, wholesale, transmission, distribution, etc). A set of grid codes should at least include (but are not limited to): interconnection codes, operating codes, planning codes, and market codes. In the absence of such national RE-related grid codes, the applicability and enforceability of any RE policy and its objectives is limited or sub-optimal. 9

10 III METHODOLOGY The methodology utilized for the development of this Grid Code is presented in the schematic illustration depicted in Figure 1 below where the section highlighted in blue represents the content of this report, whereas the two previous sections are covered in the Grid Code Data Assessment Report. Assessment of the Current Situation of the Grid Listing the required data for the present Data collection with Coordinating Expert Evaluation of data and present RE project Recommendations for the present situation Assessment of the Future Situation of the Grid Listing the required data for the future Data collection with Coordinating Expert Evaluation of data and future RE project Recommendations for the future situation Develop recommendations and guidelines for PV interconnection Review of other codes in the same region Consideration of derived recommendations Consideration of stakeholders feedback Consideration of manufacturers feedback Figure 1: Methodological structure of the project REVIEW OF OTHER GUIDELINES The development of grid interconnection guidelines has been ongoing for many years in several countries, especially industrialized countries such as Germany, where the share of RE in the grid is comparatively high 1. Most such countries have rather complex infrastructures, but still very stable grids that are achieved by operating and maintaining very well-defined, and within narrow margins, grid codes and grid connection appraisal procedures. On the other hand, the Lebanese grid has several flaws and regular load shedding causing high dynamic grid characteristics. In this section, some guidelines and standards will be presented, referring to cases with more stable grids but higher sophistication of grid infrastructure: 1 About %47 of installed capacity is from renewable energy, generating about %26 of the electricity: Strommarkt-der-Zukunft/zahlen-fakten.html ( ) 10

11 Guidelines of Some Neighboring Countries to Lebanon In the Middle East, the development of interconnection guidelines is still under process and development in several countries neighboring Lebanon. The Technical Consultant has contacted some experts in Jordan and Egypt to get up-to-date with the development of their guidelines. An agreement has been reached with an expert in Egypt to receive the guideline document for the interconnection of PV plants in Egypt for the MV level as soon as it is published. Right now the guidelines are still under discussion, and until the date of submission of this document, they have not been published yet. In the case of Jordan, a guideline document for the interconnection of large PV plants is still also under development, therefore it has not been published yet. The Technical Consultant met an expert from Jordan and discussed some points in the draft guideline document. The draft document in Jordan is relatively similar to the international guidelines (e.g. same voltage and frequency tolerance bands). However, because the grid in Jordan is more sophisticated and more stable than Lebanon s, it cannot be compared to the Lebanese case. The main reason for the Jordanian grid s good performance is that the installed generation capacity is sufficient enough to always meet the energy demand and cover the consumption (according to the Jordanian expert) and the generation and load capacities are well managed, among others based on compliance to relevant standards. EN The European norm EN is adopted for the European interconnected grid. The EN defines the tolerance band for the frequency deviation by ±1% for 99.5% of the time during the course of the year. Grid operators, who should comply with this norm, must configure their grid, so that the frequency deviation never exceeds ±1%. In addition, EN defines the tolerance band for the steady-state voltage deviation at the end-user (i.e. LV level) by ±10% for 95% of the 10-minute average values along the year. Grid operators, who should comply with this norm, must configure their grid, so that the voltage deviation never exceeds ±10% for the whole year. Most grid operators in Europe reserve ±5% for the deviations in the LV level, so that the tolerance band to the MV level is usually ±5%. German Guidelines [1]: In Germany, there are several guidelines presented by different standardization organizations. However, all guidelines have to comply with the EN 50160, thus they have similar definitions regarding voltage and frequency issues. It should be taken into consideration that the large PV plants (i.e. > 1 MWp) are usually connected to the grid at the medium voltage (MV) level through MV/LV transformers. Therefore, the Technical Guideline for Generating Plants Connected to the Medium-Voltage Network, which was introduced by the Federal Association for Energy and Water (BDEW), is considered as a good example for international guidelines. The guideline document was published in 2008, which is during the beginning phase of high RE installations in Germany. Since Lebanon is also in the beginning phase for the installation of large PV plants, this guideline document is considered as a good basis for development of guidelines in Lebanon. Another important international standard is the IEEE P1547 IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems. However, most important points in P1547 in relation to the focus of these guidelines are also included in the German guidelines. 11

12 CONSIDERATION OF DERIVED RECOMMENDATIONS IN THE PROJECT Based on the available measurements in Lebanon, the grid situation was analyzed as part of the Assessment Report. Three main topics were discussed in this report: frequency stability, voltage stability, and power quality of the installed large PV plant. In general, the operating conditions in Lebanon are critical in comparison to the international standards such as EN The analyzed frequency measurements in Lebanon show obvious deviations that can sometimes exceed 2%. It is also found that the grid operator, EDL, set up the frequency set-point in the control systems to a higher value than the nominal frequency (i.e. 50 Hz) in order to limit the expected under-frequency deviations due to excessive consumption. This exceptional frequency setting in Lebanon should be taken into consideration when future PV plants are designed and installed. The analyzed voltage measurements in Lebanon show high deviations that can exceed 13% at the MV level. In addition, the observed voltage deviation is usually a voltage drop that can be caused by excessive consumption at certain nodes. Since the feed-in of PV plants can compensate for the excessive consumption, they can play a positive role in reducing the under-voltage deviations. In addition, reactive power compensation can be considered for future RE plants to further support the voltage (e.g. reactive power provision by the PV inverter or by installing capacitor banks). It is anticipated that the target of the stakeholders in Lebanon through RE installations is the maximal exploitation of RE power in order to cover the deficit in generation compared to the increasing consumption, regardless of the deviations in the grid. The probability of power curtailment due to critical deviations in the grid should be further analyzed and discussed with the plant designers and manufacturers of inverters. Furthermore, it is recommended to measure the output power of the BRSS plant for one year, and then compare the actual accumulated energy versus the expected yield energy, which can be forecasted from the recorded weather conditions. This comparison can provide a rough estimation for the potential power curtailment due to critical voltage or frequency deviations in Lebanon. Such power curtailment should be taken into consideration by the investors and designers of future PV plants. However, such estimation is still rough and optimistic, considering that the BRSS is located in Beirut where grid operation is relatively stable (and close to nominal values) compared to remote areas. In addition, before installing an RE plant with high capacity, it is recommended to perform several load flow calculations with suitable grid modelling and analysis in order to assess whether grid reinforcement should be undertaken to avoid any potential overloading problems in the grid. Table 1: Max observed voltage and frequency deviations in normal operation (Assessment Report) Voltage deviation at MV level 13% Frequency deviation 2% 12

13 CONSIDERATION OF STAKEHOLDERS FEEDBACK On May 10, 2016 a workshop was organized through the UNDP for the consultation of different stakeholders in Lebanon. Many stakeholders participated in the workshop, such as representatives of EDL, UNDP, LCEC, CEDRO, DREG, MoEW, BRSS, Local installers and others. Based on the discussions in the workshop, some feedback and recommendations can be summarized as follows: It is recommended that EDL have a third party (e.g. consultant), in addition to the installer and EDL, for the installation of any RE plant. The third party should be responsible to check the compliance of the installers to the agreed interconnection requirements (technically and legally), the agreement of the relevant authority (e.g. MoEW/LCEC) and also the submission of the required documents (e.g. environmental assessment or other technical reports). Thereafter, the third party should provide a conformity letter, which will certify the plant and its capability to be connected to EDL s grid. It is recommended that EDL implement a frequency control system to mitigate the critical frequency deviations in the Lebanese grid since EDL is operating the grid without any kind of automatic frequency regulations till now. It was mentioned in the workshop that a 3 MWp PV plant is in the planning phase, but the location of the plant is still under discussion. It was mentioned in the workshop that a 40 MVA biomass plant is in the planning phase, but the location of the plant is still under discussion. The voltage control strategies presented in Section 4.9 were discussed in the workshop and it was agreed that the suggested strategy by the Technical Consultant is reasonable. However, the control strategy is related to the need for voltage support, which is dependant on the location of the grid connection point. A question about the feed-in of RE plants in relation to the outages in the grid was addressed. It was discussed that in case of outages caused by faults, the RE plants should be disconnected as per Section However, in case load shedding causes the outage, RE plants should not be disconnected. Therefore, the connection of RE plants should be planned to a grid point that is not susceptible to outages due to load shedding. For example, connecting RE plants to higher voltage levels than the levels that are susceptible to outages because of load shedding will serve that purpose. It was discussed, but not agreed on, that the parameterization of Figure 2 can be modified, especially the higher frequency limit of 52 Hz to be reduced to 51.5 Hz. However, the value of 52 Hz was suggested by the Technical Consultant based the assessed measurements in the Assessment Report, but it can be modified if agreed upon by the stakeholders in the future. One of the local installers who uses the Steca inverters said that they use the Australian code for the case of Lebanon and not the one for UK (as in Section Error! Reference source not found.) since the Australian code is more flexible. 13 The required measured data and the quality (e.g. resolution and time window) of measurements, which should be available for the planning of future RE plants, should be agreed on with EDL in the future.

14 EDL suggested modifying the text in Section 4.2 so that EDL still has the right to reject the connection to the grid in some special cases. The Technical Consultant has already modified the text, but further feedback for modification of Section 4.2 can be later included if required by the stakeholders in the future. EDL suggested having the right to visit the plant at any time to check compliance to the agreed requirements. EDL suggested having access to the monitoring and control systems of the RE plants. It was suggested that EDL have the right to ask for additional documents, such as: An assessment report for measurements collected at the connection location. An assessment for the potential feed-in energy of the plant. A grid impact study in coordination with EDL. It should be taken into consideration that a set of adapted settings to the Lebanese grid have been proposed by the UNDP-CEDRO project and are shown in Table 2. However, these settings are further adjusted within the more detailed assessment associated for large plants in this report. Table 2: Recommended settings for grid-tied grid-dependent (B1) and grid-tied dual mode (back-up) (B2) for Lebanon (Source: UNDP-CEDRO project) 14

15 IV RECOMMENDATIONS AND GUIDELINES FOR GRID INTERCONNECTION OF LARGE PV PLANTS Since there is a critical lack of generation compared to demand in Lebanon, the grid is susceptible to various problems such as high deviations in voltage and frequency, as well as regular outages due to load shedding. Therefore, the targeted guidelines aim for increasing the harness of renewable energy and avoiding possible power curtailment due to critical frequency and voltage deviations. In other words, the guidelines are suggested in order to avoid the possible frequent disconnection and/or curtailment of PV plants, which can then lead to inefficient operation of the plant, and consequently unfeasible investments. On the other hand, the international standards and guidelines in countries whose grids are more stable aim for neutralizing the possible negative effects of the intermittent RE plants. In those countries, generating RE plants supplying the grid (e.g. MV level) will have to make a contribution to grid support (i.e. mainly during normal operation and possibly during non-typical conditions). This contrast between the aim of the guidelines in Lebanon and the aim of other international guidelines should be taken into consideration in the development and adoption of the planned interconnection code for Lebanon in future. The aimed guidelines summarize the essential aspects that have to be taken into consideration for the connection of generating plants to the grid. Thus, they shall serve as a basis for the grid operator and for the installer in the planning and decisionmaking process and provide important information about the plant s operation. The guidelines are presented point-by-point hereinafter. APPLICABILITY OF THE GUIDELINES The presented guidelines are mainly based on the available data, which are collected or measured by the Coordinating Expert, and then assessed by the Technical Consultant in the Assessment Report submitted already to the UNDP. However, this assessed data can have some gaps in terms of representativeness, as indicated in the Assessment Report. The adoption of these guidelines and their applicability in Lebanon can go through several iterations of discussions between stakeholders and relevant authorities. In general, RE power plants can be classified according to size (i.e. nominal power), whether they are very large plants to be connected to the transmission system or smaller plants to be connected to the distribution system (or even off-grid). RE plants can also be classified according to their output characteristics, whether they are stochastic (variable) such as wind and PV, or deterministic (firm) like, for instance, waste-to-energy, hydro, biomass, and geothermal. These presented guidelines can apply to the planning, construction, operation, and modification of generating PV plants (> 1 MWp) that are connected to the Lebanese grid (e.g. MV distribution level), however, other large-scale RE plants should take into consideration the mentioned guidelines and recommendations. 15 PRECONDITIONS OF INSTALLATION Regarding the general terms, a standardized grid connection appraisal procedure should be developed so that it contains a well-defined set of standards to comply with and information to be handed in by the applicant requesting a grid connection permit. If this appraisal procedure is successfully passed, there are no grounds to refuse granting grid connection.

16 Furthermore, connection to the grid should be agreed on with the grid operator (i.e. EDL) on a case-by-case basis during the planning phase prior to equipment purchasing. Appropriate specialist firms shall carry out planning, construction, and connection of the generating plant to the system operator s grid. The system operator may demand modifications and completions to existing plants or to those under construction as far as this is required for secure operation and to comply with the requirements set forth within the grid appraisal procedure. However, the grid operator should not have the right to reject a grid connection petition of an applicant that fulfills the technical criteria of the appraisal procedure, but the grid operator can still reject the connection in some special cases, which should be specified in the planning phase. SUBMISSION OF RELEVANT DOCUMENTS During the inquiry, the technical examination and the elaboration of the connection offer, relevant documents about the generating plant shall be submitted to both the grid operator (i.e. EDL) and the MoEW/LCEC (for the creation of the national register to be used in future power forecasting), for instance: Site plan showing the location and streets, the designation and borderlines of the site as well as the place (geographical location according to the World Geodetic System 1984 as a degree in decimals) where the connection facility and the generating units are to be installed. Proposed grid connection point. Data sheet with the technical specifications of the generating plant and its components, and relevant certificates. The installed capacity, inclination angle(s) and orientation(s) for each generator. Single-line diagram of the plant. Estimated date of initial start-up and date of decommissioning. Data on whether the generated power is used on location or exclusively fed into the grid. Verification of the electric characteristics of the generator (certificates in accordance to standards, e.g. ISO / IEC / IEEE, provided by the manufacturer of the gen-set unit(s)). In the stakeholder consultation workshop that took place on May 10, 2015, it was recommended that EDL have a third party (e.g. consultant) in addition to the installer and EDL for the installation of any RE plant. The third party should be responsible of checking the compliance of the installers to the agreed interconnection requirements (technically and legally), the agreement of the relevant authority (e.g. MoEW/LCEC) and also the submission of the required documents (e.g. environmental impact assessment or other technical reports). Thereafter, the third party should provide a conformity letter, which will certify the plant and its capability can be connected to EDL s grid. It was also suggested in the workshop that EDL can ask for these additional documents: - An assessment report for measurements collected at the connection location. - An assessment for the potential feed-in energy of the plant. - A grid impact study in coordination with the EDL. Other documents the grid operator requires. START-UP After the necessary documents are available by the grid operator, the plant installer and grid operator shall agree on the date of initial start-up of initial parallel operation. Initial start-up of the generating units shall be implemented by the plant operator. The grid operator will decide whether his presence is required for this purpose. However, initial start-up shall be documented in a report by the plant operator. Functional tests and acceptances for plant components and functions concerning the connection shall be implemented according to the grid operator s requirements. These include, for instance: 16

17 Inspection of the plant. Access to commissioning and test reports. Comparison of the plant construction with the planning scheme. Comparison of the structure of the measuring device for accounting purposes with the contractual and technical requirements, and commissioning test of measuring devices. Functional tests of the short-circuit protection and protective disconnection equipment. Check-up the technical installation for the reduction of power injections. Check-up the installation for monitoring of the agreed power injections. PRINCIPLES FOR THE DETERMINATION OF THE GRID CONNECTION POINT Generating plants shall be connected to the grid at an appropriate point (i.e. the grid connection point, or sometimes called point of common coupling). The grid operator shall determine the appropriate point of connection which ensures secure grid operation, taking the generating plant into consideration, and at which the requested power can be received and transferred. The criteria for the decision of the grid operator should be based on the feed-in power of the plant and the examinations for possible problems in the grid related to the plant connection. As indicated in the Assessment Report, the installation of high PV capacity can lead to excessive reverse power flows that can lead to overloading problems especially during peak feed-in hours. Such a problem can occur in some sections of distribution grids if the hosting capacity of the grid for distributed generation is exceeded. Therefore, the grid operator should perform several load flow calculations with suitable grid modelling and analysis in order to assess whether grid reinforcement should be undertaken to avoid any potential overloading problems when defining the connection point. Grid operators usually perform a test called worst-case analysis, which represents load flow calculations with the appropriated grid modelling (e.g. PowerFactory or other software). For this analysis the grid model is parameterized as follows: - Maximum feed-in of all RE plant (i.e. peak AC power of PV plants) - Minimum load consumption With this parameterization, the maximum reverse power flows caused by PV feed-in can be assessed. Therefore, the grid operator can require a suitable model for the PV plant from the plant installer in order to perform this analysis. It should be taken into consideration that the installer of the PV plant should be responsible for the connection facility to the grid (e.g. from the cost and technical point of view). For example, if the plant location is far from the grid node, the plant installer installs the suitable line in agreement with the grid operator. This is possible in case of a medium voltage connection. For higher voltage connections that possibly require expropriation of lands, the grid operator is responsible to ensure the expropriation decrees, whereas the plant installer is responsible for building the corresponding overhead line. In addition, in case the grid needs reinforcement measures (e.g. adding new lines, replacing lines or transformers) after the connection of the RE-generator, the grid operator will then be responsible for installing the required measures. In addition, the grid operator should be in charge of any grid reinforcements and upgrades (not extensions) to enable RE-operators to connect at a given PCC subject to a successful grid connection appraisal procedure. 17

18 ALLOWABLE VOLTAGE CHANGE DUE TO GRID CONNECTION As indicated in the Assessment Report, the power injection at certain nodes in the grid leads to local voltage increases at these nodes. Under normal operating conditions of the grid, the magnitude of the voltage changes caused by the PV plant at a point of connection to the grid must not exceed a value of 2% as compared to the voltage without a PV plant. Voltage changes shall be determined preferably by means of suitable load-flow calculations (e.g. worst-case analysis). This point should be further discussed with the grid operator based on a case-by-case assessment since voltage increases, in many cases, are not a problem in Lebanon while voltage drop is a problem in Lebanon based on excessive demand at some nodes. For example, the voltage in Beirut, or close to Beirut, is expected to be close to the nominal values whereas it can have critical deviations at remote areas. Therefore, this condition only can be required at some locations based on the evaluation of the grid operator. ACTIVE POWER REDUCTION BASED ON GRID OPERATOR S COMMAND For secured and efficient grid-connected operation, it must be possible to operate the generating facility at reduced power output. In the cases listed below, the grid operator is entitled to require a temporary limitation of the power feed-in or disconnection of the plant: Potential danger to secure system operation. Congestion or risk of overload on the operator s grid. Risk of islanding. Risk to the steady-state or dynamic grid stability. Rise in frequency endangering the system stability. Repairs or implementation of construction measures. Within the scope of generation management/feed-in management/grid security management. The PV plants must be capable of reducing their active power in any operating condition and from any operating point to a target value given by the grid operator. This target value is normally preset without steps or in steps, and corresponds to a percentage value related to the agreed active connection power PAV (e.g. 60%, 30%, 0%). The grid operator can agree with the plant operator on signalling and time delay for the power reduction (e.g. maximum one minute). A reduction to the target value of 10% must be possible without disconnection from the grid; below 10% of the agreed active connection power PAV, the generating facility may disconnect from the grid. The grid operator, whose grid may not be capable enough to absorb the power while maintaining and warranting grid stability, may need to reimburse the RE-plant operator for the losses accordingly. Therefore, a legal framework for the metering of RE energy and reimbursement of RE power losses should be agreed on in the planning phase of each plant. CHARACTERISTICS OF ACTIVE POWER OUTPUT (FREQUENCY CONTROL) Since PV plants are supposed to support the grid operation, or at least not affect it negatively, PV plants must reduce their power output, while in operation, at a frequency higher than 51 Hz. This power reduction can limit the over-frequency deviations in future scenarios of high PV installations. 51 Hz represents the 2% deviation from the 18

19 nominal frequency, which was observed in normal operation conditions in Lebanon (Assessment Report). It is anticipated that the grid operator (i.e. EDL) set up the frequency set-point in the control systems to a higher value than the nominal frequency (i.e. 50 Hz) in order to limit the expected under-frequency deviations due to excessive consumption. Therefore, the power reduction characteristics are illustrated in Figure 2 and Table 3 as a function of frequency. Active power as percentage to available output 100% 80% 60% 40% 20% 0% Disconnected Frequency in Hz Disconnected Figure 2: Active power output due to over frequency Table 3: Active power in relation to grid frequency No reduction in output power P=25 P_m (51 Hz - f_grid)/(50 Hz) Plant is disconnected 47 Hz < f grid < 51 Hz 51 Hz < f grid < 52 Hz f grid < 47 Hz or fgrid > 52 Hz P m is the instantaneously available power ΔP is the power reduction f grid is the grid frequency STEADY STATE VOLTAGE CONTROL During grid feed-in, generating plants must be capable of participating in voltage control. Steady-state voltage control means voltage control within the grid under normal operating conditions where slow voltage changes in the distribution grid are kept within acceptable limits. If required by the grid operator and to meet grid requirements, PV plants must participate in steady-state voltage control within the grid they are connected to. The voltage control is usually based on reactive power provision by the PV inverters [2]. With active power output, it must be possible to operate the PV plant in any operating point with at least a reactive power output corresponding to a power factor at the grid connection point of: cos φ = 0.95 underexcited to 0.95 overexcited These values are defined in most international standards, thus most PV inverters are able to provide the corresponding reactive power values. However, the provision of higher reactive power than the value corresponding to cos φ=0.95 can be discussed 19

20 with the plant installer if the voltage at the planned connection point needs more voltage support. If the grid operator agreed with the plant installer on deviating from the above values, it must be agreed upon by contract. With active power output, either a fixed target value for reactive power provision or a target value variably adjustable by remote control (or other control technologies) will be specified by the grid operator. The setting value in relation to voltage control can be one of the following: Fixed active factor cos φ: In this strategy, the reactive power will be always proportional to the active power output (i.e. Q = P tan φ). Fixed reactive power in Mvar Here, the reactive power will be fixed while the power factor is varying. Reactive power/voltage characteristic Q(U). Figure 3: Example of Q(U) characteristics Active power factor cos φ (P): 20 Figure 4: Example of cos φ (P) characteristics

21 The reactive power of the generating plant must be adjustable according to the specified characteristics by the grid operator. Not only should a voltage control approach of the PV plant be agreed on with the grid operator, but its parameterization, which can be based on the location of the plant, must also be agreed on. The time delay for the adjustment can be agreed upon between the plant operator and the grid operator. In many standards, the time delay should be between 10 seconds and 1 minute. It is recommended for the Lebanese case, but should later be discussed, to implement a fixed reactive power provision (i.e. overexcited) by the plant, which is connected to a node having under-voltage violation. Since under-voltage violations are often observed in Lebanon due to excessive demand compared to generation, such an approach is suitable in order to support its voltage at the connection point of the PV plant for the entire day. This also includes the reactive power provision when the RE active power is not available (i.e. at night for PV plants). Some manufacturers of inverters can configure their products to provide this service and they refer to it as Q at night. However, the grid operator should have sufficient voltage measurements from the candidate connection point before the installation of the PV plant in order to evaluate the required voltage control approach. DYNAMIC VOLTAGE SUPPORT Dynamic grid support means voltage control in the event of voltage drops within the grid with a view to avoid unintentional disconnections of large feed-in power, and thus grid collapse. Usually the short-term voltage drop is caused by faults especially in high voltage levels. In this case, the grid support is labelled as fault ride through (FRT). In future high RE installations connected to the grid scenarios, the integration of these plants into the dynamic grid support scheme will become ever more important. Consequently, these RE plants must generally participate in a dynamic grid support, especially if required by the grid operator at the time of the plant s connection to the grid. That means that generating plants must be able in technical terms: Not to disconnect from the grid in the event of grid faults. To support the grid voltage during a grid fault by feeding a reactive current into the grid. The suggested characteristics for Lebanon are illustrated in Figure 5 and can be described as follows: If the voltage drastically drops with duration of less than 150 ms, the PV must not be disconnected from the grid. If the voltage drop and its duration are located in the blue area (Area 1), there are no requirements that generating plants have to remain connected to the grid. If the voltage drop and its duration are located in the red area (Area 2), the PV plant can be disconnected from the grid, unless the grid operator asked to keep it connected in future scenarios. If the voltage drop and its duration are located outside Area 1 and Area 2, it must not lead to unstable operation of the PV plant and the plant must not be disconnected from the grid. It is permissible to shift the borderlines if the plant operator agrees with the grid operator. After neutralizing the fault, the PV plant can be synchronized and connected to the grid in two seconds. The suggested support is mainly for symmetrical faults. However, for unsymmetrical faults, the symmetrical voltage support of the PV plant might increase the voltage at 21

22 non-faulty phases. Therefore, the plant should be disconnected in unsymmetrical faults. PV plants turning into isolated operation in the event of a fault in order to cover the customer s own energy demand must participate in grid support until they are disconnected from the system operator s grid. Isolated operation scheduled by the customer has to be agreed through a contract with the grid operator. Figure 5: Fault ride through of the PV plant AUXILIARY SUPPORT In case the agreed connection point of the PV plant is susceptible to critical voltage deviations (e.g. based on voltage measurements), the grid operator might require the implementation of voltage support by the PV inverter through reactive power provisions as indicated in Section 4.9. Another option that can be agreed upon between the PV installer and the grid operator to support the voltage is the installation of reactive power compensators (e.g. capacitor bank). However, this should be discussed in the early phases of the planning for the PV plant and possibly documented in the contract. REMOTE CONTROL For secure grid operation, the grid operator can ask for including the generating plant into the grid operator s remote control scheme, such as control of the circuit breaker (in particular opening of the circuit breaker in case of critical grid conditions remote switch-off ), limitation of active power production, and provision of reactive power. This concept can be especially relevant for large plants (e.g. > 25 MW). On the basis of the grid operator s applicable remote control concepts, the necessary data and information required for system operation management shall be made available. 22 OTHER GUIDELINES RELATED POINTS Some points, other than the point mentioned in this report, are usually included in international guidelines and standards, such as harmonics, short circuit, flicker, etc. However, these points were not investigated in the framework of this project due to the limitation of collected information and time constraints. In neighboring countries, these points are adopted similar to international standards and guidelines. These points are summarized in Section A.2 of the Appendix, though, without examining if they are valid for the Lebanese case.

23 V Overview of Planned and On-Going RE Projects in Lebanon A list of the operating plants and planned RE projects is depicted in Table 4. The presented RE installations do not represent a significant fraction of the gap between generation and consumption (i.e. ca. 1.3 GW). In addition, several studies in the literature show that the installation of renewable energy plants does not support grid stability since they provide intermittent power to the grid based on the weather conditions. Therefore, in the forecasted scenario, it is not expected to have considerable grid support by RE plants to reduce the frequency deviations in the grid, unless grid codes and regulations enforce subjects and remedies as highlighted in the previous Chapter 4. Nevertheless, the RE plants could more substantially support the voltage compliance at their point of common coupling (PCC) to the grid especially if the reactive power provision is considered in the design. However, power curtailment of the RE feed-in due to critical fluctuations in the grid must be taken into consideration, and should be assessed carefully. Table 4: List of RE projects in Lebanon until the date of submitting this report Project Type Capacity Location Comments BRSS (In service) PV 1 MWp Beirut There are no critical issues/ flaws reported until this report s submission since the plant is well parameterized to the Lebanese grid and also located in Beirut where voltage has no critical deviations. Zahrani (In planning) Choukine plant (In planning) PV 1 MWp South, close to Saida PV 1 MWp South, close to Nabatieh It is recommended to parameterize the plant according to the voltage and frequency measurements at the planned PCC in order to avoid unnecessary power curtailment and other problems due to critical deviations. The presented guidelines in this report should be taken into consideration. It is recommended to parameterize the plant according to the voltage and frequency measurements at the planned PCC in order to avoid unnecessary power curtailment and other problems due to critical deviations. It should be taken into account that the measured voltage deviations in Nabatieh are found to be critical in the Assessment Report. The presented guidelines in this report should be taken into consideration. 23

24 Kobayyat Wind farm (In planning) wind 60 to 117 MW North, close to Akkar It is recommended to parameterize the plant according to the voltage and frequency measurements at the planned PCC in order to avoid unnecessary power curtailment and other problems due to critical deviations. It should be taken into account that the measured voltage deviations in Kobayyat are found to be critical in the Assessment Report. The presented guidelines in this report should be taken into consideration. PV plant (In planning) Biomass generator (In planning) PV 3 MWp under discussion Biomass 40 MW under discussion It is recommended to parameterize the plant according to the voltage and frequency measurements at the planned PCC in order to avoid unnecessary power curtailment and other problems due to critical deviations. The presented guidelines in this report should be taken into consideration. This type of RE plants has stable and controllable output and is similar to conventional fossil fuel plants, thus it is less susceptible to flaws due to critical deviation in the grid. However, the presented guidelines in this report should be taken into consideration. 24

25 APPENDIX CHECKLIST PROPOSED FOR EDL FOR GRID INTERCONNECTION OF RE PLANTS Project name: Date of submission (dd / mm / yyyy): Proposed in-service date (dd / mm / yyyy): Energy type (PV/wind/biomass/others): Project size as nameplate capacity in kw and in kva: Project net annual energy generation expected in kwh: Project net plant capacity factor in -%: Project location (site name and address): Project location (UTM WGS84 coordinates and GEO WGS84 coordinates): Project Contact Information: Company Name Contact Person Post Address Telephone Cell Phone Fax Address Plant Operator Mandatory Plant Owner Mandatory Consultant Optional Voltage level of the PCC in the EDL s grid in kv: Connection to EDL s grid: On a map, provide the location of the plant with proposed line routings for connection to the grid. It should identify the Point of Common Coupling of the plant (PCC), the station to which the plant is connected, and the location of new lines between the plant and the station. Drawing received Drawing reviewed Distance from the PCC to the station to which the plant is connected in km: 25 Electrical characteristics at the PCC: Active nominal power in kw: Maximum apparent power in kva: Reactive power capability at the PCC: a plot of generator capability curve (kw output vs kvar): Received Reviewed Frequency operation band in Hz: Voltage operation band in V: Compliance to the agreed operation limits (voltage and frequency): Yes No Compliance to the agreed fault ride through characteristics: Yes No

26 Fault contribution from plant s facilities, with the fault location at the pcc: Three-phase short circuit in kva: One-phase short circuit in kva: Reactive power provision: Reactive power auto-control: Yes No Characterization of reactive power control: Single line diagram: Provide an SLD of the plant s facilities including the PCC. It needs to include information about transformer(s), conductor lengths, switchgear, compensation, meter location and overview of protection system including settings. Drawing received Drawing reviewed Characteristics of generating units: Type of generating units (PV with inverter/ synchronous generator/ induction generator/ doubly-fed induction generator/ etc.): Number of generator units: Manufacturer / type or model no: Rated power of each unit: Number of inverter units: Manufacturer / type or model no: Rated power of each unit: Rated frequency of each unit in Hz: Rated voltage of each unit in V: Starting inrush current in p.u.: Generator terminal connection (star/delta): Neutral grounding method of star connected generator (solid/ impedance/ ungrounded): Data sheets of the facility: Received Reviewed Simulation model: Received Reviewed Diurnal average power in kw or kvar / hour: Received Reviewed Annual average power in kw or kvar / month: Received Reviewed Plant s transformer characteristics: Transformer ownership (plant owner/edl): Transformer rating in kva: Data sheets of the transformer: Received Reviewed Self load information: Maximum load of the facility in kvar and in kw: Maximum inrush current to loads in p.u.: Conformity letter from moew/lcec (or agreed third party): Received Reviewed 26

27 Attached documents: Item-no Description Number of documents Number of pages SUMMARY OF OTHER INTERNATIONAL GUIDELINES RELATED POINTS As mentioned in Section 4.13 some points and technical parameters are not standardized in the framework of the project due to limitation of collected information and time constraints, such as harmonics, short circuit, flicker, etc. In neighboring countries, these points are adopted as in international standards and guidelines. Based on the UNDP request, the main points are summarized from [1] and presented hereinafter. Long-Term Flicker For the assessment of the connection of one or several generating plants at a junction point, the following long-term flicker strength has to be observed at the junction point with regard to flicker-effective voltage fluctuations due to operational reasons: P lt 0.46 The long-term flicker strength Plt of a generating unit can be estimated by means of its flicker coefficient c at: P lt =c S re /S kv where S re is rated apparent power of the generating unit and c is flicker coefficient. In the case of a generating plant with several generating units, P lti has to be calculated separately for each generating unit; on this basis, a resulting value has to be determined for the flicker interference factor at the junction point according to the following formula: For a generating plant consisting of n equal generating units, the resulting value of the flicker interference factor is as follows: Harmonics and Inter-Harmonics If there is only one junction point to the grid (e.g. MV level), the harmonic currents totally admissible at this junction point are obtained from the related harmonic currents iν zul multiplied by the short-circuit power at the junction point: I v zul = i v zul S kv If several plants are connected to this junction point, the following formula shall be used for the calculation of the admissible harmonic currents: 27

28 where: S A = apparent connection power; S Gesamt = total connectable or scheduled feed-in power; For generating plants consisting of generating units of the same type, the following equation can be used: S A = ΣS re. In the case of generating units of different types, this statement represents only a rough upper estimate. With several junction points in to the grid (e.g., MV level), it is indispensable for the assessment of the conditions at one junction point to take all other junction points into consideration as well. Consequently, the conditions in a MV grid are to be considered admissible if the harmonic current fed-in at every junction point does not exceed the following value: The following formula shall apply to harmonics above the 13 th order and to interharmonics: where S Gesamt represents the sum of apparent feed-in power of all generating plants connected to this junction point and S Netz is the capacity of the feeding transformer within the grid operator s transformer substation. For inverters with intermediate direct current link and pulse frequencies of above 1 khz, the formula (I v u zul ) shall apply to harmonics above the 2 nd order. If the calculation shows that the admissible harmonic currents are exceeded, remedial measures need to be taken unless more precise calculations according to the Technical Rules for the Assessment of Network Disturbances allow and show that the admissible harmonic voltages in the grid are not exceeded. Particular situations, such as the consideration of resonances, should be subject to a special analysis. Harmonic currents shall be measured in accordance with EN Note: The following approaches determined in the standard EN shall be applied: In the case of harmonics: rms values of harmonic subgroups. In the case of inter-harmonics: rms values of inter-harmonic centred subgroups. Harmonic currents which flow into the generating plant (e.g. into filter circuits) due to a distorted grid voltage, are not assigned to the generating plant. The same shall apply if the generating plant works as an active harmonics filter and, due to its operating mode, brings about a continuous reduction of harmonic voltages existing in the grid voltage. 28

29 Maximum Admissible Short-Circuit Current Due to the operation of a generating plant, the grid s short-circuit current is increased by the generating plant s short-circuit current, particularly in the vicinity of the grid connection point. To determine a generating plant s short-circuit current contribution, the following rough values can be assumed: For synchronous generators: eight times the rated current For asynchronous generators and double-fed asynchronous generators: six times the rated current For generators with inverters: one time the rated current. To ensure correct calculations, the impedances between the generator and the grid connection point (customer transformer, lines, etc.) need to be taken into consideration. Protection Equipment General Protection equipment is of considerable importance for secure and reliable operation of grid, connection facilities and generating plants. The plants shall be protected against short-circuit, earth fault and overload protection, protection from electric shock, etc. Thus, the plant operator must install an adequate amount of protection equipment. Concepts and protection settings at the interfaces between the grid operator and the plant operator/connection owner shall be implemented in such a way that a danger to adjoining grids and plants can be excluded. The setting values for protective disconnection devices are reference values. It can be assumed that the sum of the inherent response time of the protection device and the switching device does not exceed 100 ms. Where applicable, it may be necessary to make an adjustment. Therefore, these values shall then be specified by the grid operator according to the plant requirements. Essential modifications to the protection equipment (protective disconnection devices, short-circuit protection device at the transfer point) or their set point shall be agreed in due time between the grid operator and the plant operator. The grid operator shall determine whether and which protection devices are to be sealed or otherwise protected against alterations. The grid operator is entitled to install or have installed devices at the transfer point which automatically disconnect the generating plant from the grid if the predetermined limits compatible with the grid (such as the agreed connection power SAV or the maximum apparent power of a generating plant SAmax) are exceeded in steadystate operation. To ensure continuous secure operation, protection systems shall be inspected prior to commissioning and at regular intervals. It must be possible to make the adjusted values easily readable without using any additional means. This also applies to protection functions integrated into the plant control system. Voltage protection devices for the protection against disconnection must be carried out in a three-phase design. For measurements at the MV level, the voltage shall be measured between the outer conductors. This ensures that the generating plant is not disconnected by the protection equipment in the case of a stationary earth fault 29

30 in an isolated or resonant-earthed MV grid. For measurements at the LV level, the measurement shall be carried out between the outer conductor and the neutral point in the case of D-y generator transformers, and between the outer conductors in the case of Y-d generator transformers. The three measuring elements of a voltage protection device shall be linked through a logical OR connection. Logical OR connection means that If the response value is exceeded in one measuring voltage, this leads to the response of the rise-in-voltage protection relays; If the response value is undershot in one measuring voltage, this leads to the response of the under-voltage protection relays. On the other hand, the three measuring elements of the reactive power under-voltage protection Q & U< shall be linked through a logical AND connection. That means for the under-voltage protection relay that all measuring voltages have to be below the response value to activate the response of the relay. If there is no logical connection of the three measuring elements given in the text below, the connection in question is always a logical OR function. The reset ratio of the rise-in-voltage protection devices must not fall below 0.98 p.u. that of the under-voltage protection devices must not exceed a value of 1.02 p.u. (These values should be adapted for the Lebanese case as in Figure 5). Voltage protection devices for protection against disconnection should analyze the half oscillation rms value, the analysis of the 50 Hz fundamental oscillation being sufficient. Fall-in-frequency and rise-in-frequency protection relays may be designed as singlephase equipment. The voltage between two outer conductors shall be selected as a measuring variable. At frequencies between the minimum and maximum frequency limits (see Figure 2), automatic disconnection from the grid is not permissible due to the frequency deviation. However, if the frequency exceeds the minimum and maximum frequency limits, the unit must be immediately disconnected automatically from the grid. After clearing of a fault in the grid or in the case of automatic reclosure, the plant operator must be prepared that the recovery voltage at the grid connection point may be asynchronous to the voltage of the generating plant. The plant operator himself must take care that switching operations, voltage fluctuations, automatic reclosure, or other processes taking place in the grid do not cause damage to his facilities. Protective Disconnection Devices The function of protective disconnection devices described here is to disconnect the generating plant or units from the grid in the event of disturbed operating conditions in order to protect the generating plant and other customer facilities connected to the grid. Examples are grid faults, islanding, or a slow build-up of the grid voltage after a fault in the transmission system. Protective disconnection can be realized within a self-sufficient device and within the control system of the generating unit. The loss of the auxiliary voltage of the protection equipment or of the plant s control system must lead to an instantaneous tripping of the switch. Tripping through integrated protection relays must not be inadmissibly delayed by other functions of the control system. 30

31 Protective disconnection devices are installed at the transfer point and/or at the generating units. The protective disconnection devices at the generating units can be connected on the high or on the low-voltage side of the generator transformer. The following functions of the protective disconnection equipment shall be realized: 1. Under-voltage protection U< and U<< 2. Rise-in-voltage protection U> and U>> 3. Under-frequency protection f< 4. Rise-in-frequency protection f> 5. Reactive power under-voltage protection Q & U< Through the reactive power under-voltage protection (Q & U<) the generating plant is disconnected from the grid after 0.5 seconds, if all three line-to-line voltages at the grid point of connection are below 0.85 Uc (logical AND connection) and if the generating plant simultaneously extracts inductive reactive power from the grid (These values should be adapted for the Lebanese case as in Figure 5.). Connection of a Generating Plant to the Bus-Bar of a Transformer Station Short- Circuit Protection Short-circuit protection of the generating plant is required for clearing short-circuits in the connection facility. In addition, it serves as back-up protection in the event of faults within the generating units and in the grid. A distance relay with V-I starting function or a definite time-delay over-current protection relay shall be provided as short-circuit protection. The short-circuit protection devices of the plant operator must be integrated into the overall protection concept of the grid operator. For this reason, the protection scheme shall be agreed with the grid operator at the planning stage. The protection equipment settings are specified by the grid operator so long as they have an impact on his grid. The short-circuit protection devices act upon the circuit breaker at the transfer point. Short-Circuit Protection The connection of generating plants to the MV grid is implemented either by means of circuit breakers or through an on-load-switch-fuse combination, depending on grid conditions and the number and size of generating units. Generating plants connected through a circuit breaker shall be equipped at least with over current time protection as short-circuit protection. Short-circuit protection of generating plants connected by means of a combined on-load-switch-fuse is ensured by the fuse. 31

32 The installation of a distance relay and the relevant voltage transformers is to be taken into consideration in the conceptual design, and has to be realized at the grid operator s request. The distance protection device must then act upon the circuit breaker at the transfer point or, in the case of an on-load-switch-fuse combination, upon the generator-side circuit breaker. PV PARAMETERS OF THE UK AS DEFINED BY STECA Table 5: Country-specific parameters of the UK for PV inverters as defined by Steca. Source: 32

33 33 SERVICE MANUAL FOR THE COMPLIANCE FOR THE CASE OF THE UK AS DEFINED BY SMA

34 34

35 35

36 DATA ASSESSMENT REPORT ABBREVIATIONS BDL BRSS CDR CEDRO DREG EDF EDL EDZ EIA EIE EPSS GEF GoL LCEC LENCC LV NEEREA NERA MoEW MV ONL PCC PV RCREEE RE SLD SS ZOI Banque du Liban Beirut River Solar Snake Council for Development and Reconstruction Community Energy Efficiency and Renewable Energy Demonstration Project for Lebanon Small Decentralized Renewable Energy Power Generation Project Électricité de France Électricité du Liban Électricité de Zahle Environmental Impact Assessment Environmental Initial Examination Electrical Power Supply Systems Global Environment Facility Government of Lebanon Lebanese Center for Energy Conservation Lebanese Electrical National Control Center Low Voltage National Energy Efficiency and Renewable Energy Action National Electricity Regulation Authority Ministry of Energy and Water Medium Voltage Office National Litani Point of Common Coupling Photovoltaic Regional Center for Renewable Energy and Energy Efficiency Renewable Energy Single Line Diagram Substation Zahrani Oil Installations 36

37 EXECUTIVE SUMMARY This document provides a detailed assessment of the grid-related collected data in cooperation with the stakeholders in Lebanon. The document provides several conclusions and recommendations, which will mainly lead in the next stage, to a set of guidelines for the interconnection of large-scale PV plants (i.e., larger than 1 MWp). In addition, the document provides an evaluation for the availability and quality of received data and measurements. Moreover, it provides some recommendations for the future data collection that will be needed to for further assessments. Three main topics, which play the essential role in the operation of PV plants, are discussed in this assessment. These topics are the frequency stability and voltage stability, as they are crucial for the proper grid integration of PV plants. In addition, the power quality of the output of PV plants is discussed based on the available data. The assessed measurements show that the grid in Lebanon has critical conditions in relation to high frequency and voltage deviations, which should be considered in the settings of the PV plants. Some measurements show that the output power of a micro PV inverter is curtailed due to critical deviations in the grid. However, the measurements at the BRSS plant do not show any curtailment. BACKGROUND The United Nations Development Programme, in partnership with the Ministry of Energy and Water, has initiated the fourth phase of the CEDRO (Community Energy Efficiency and Renewable Energy Demonstration Project for Lebanon) Programme (CEDRO 4) funded by the European Union. The CEDRO 4 project includes several sustainable energy projects that are designed to promote related renewable and energy efficiency systems. In parallel, another nationally executed project has been initiated in this field with the Ministry of Energy and Water (MoEW) in coordination with the Lebanese Center for Energy Conservation (LCEC): the Small Decentralized Renewable Energy Power Generation Project, or DREG, is funded by the Global Environment Facility (GEF). Both projects are collaborating with MoEW and LCEC to undertake the needed assessments of renewable energy sources in order to support the Government of Lebanon s pledge to reach 12% renewable energy targets by The LCEC supports the Government of Lebanon to develop and implement national strategies that promote the development of efficient and rational uses of energy and the use of renewable energy at the consumer level. This work is the first step in assessing the baseline existing conditions of the Lebanese network and its ability to reliably absorb RE sources (mainly large scale PV) in the areas they are expected to be installed, and recommendations on the necessary next steps with respect to actions and reinforcement of the national grid are to be detailed in order to save them as guidelines and recommendations regarding the establishment of a national approved grid code. METHODOLOGY The methodology utilized for the development of this Grid Code is presented in the schematic illustration depicted in Figure 1 below where the sections highlighted in blue represent the content of this report. 37

38 Assessment of the Current Situation of the Grid Listing the required data for the present Data collection with Coordinating Expert Evaluation of data and present RE project Recommendations for the present situation Assessment of the Future Situation of the Grid Listing the required data for the future Data collection with Coordinating Expert Evaluation of data and future RE project Recommendations for the future situation Develop recommendations and guidelines for PV interconnection Review of other codes in the same region Consideration of derived recommendations Consideration of stakeholders feedback Consideration of manufacturers feedback Figure 6: Methodological structure of the project as presented in the Inception Report in Chapter 8 38

39 SUMMARY OF THE RECEIVED DATA In this chapter, all the data received are listed and described in Table 66 and Table 7. In addition, this received data is classified according to the categories of the tables of the required data as shown in the Appendix A. Table 6: Illustration of the collected data 39 Date of receiving Description of data as presented by the Coordinating Expert 1- Grid operation policy report prepared by AZOROM in However EDL does not operate as per this policy as the current electricity situation is critical. 2- EU report Paving the Way for the Mediterranean Solar Plan. 3- CDR report EDL System Operation Policies and Procedures. 4- Latest Master Plan prepared by EDF and approved by EDL. Unfortunately it is in French language, but the Coordinating Expert prepared a summary in English that details the most important projects (i.e. Appendix B). 5- Single line diagram for the transmission network including one 400 kv S/S, 220 kv, 66 kv and 33 kv. 6- A schematic drawing of the transmission network along with Lebanon map. 7- Frequency measurements at the household level taken by the Coordinating Expert. 8- Voltage measurements at the household level taken by the Coordinating Expert. 9- Voltage measurements at numerous MV nodes. 10- Measurements taken at the BRSS (the already installed PV), including frequency, voltage, active power, energy, harmonics, flicker, power factor and currents. Measurements taken from 03/09/2015 till 22/12/ A document related to hydropower was prepared by Mr. Karim Osseiran. 12- A document of the conclusions of the Coordinating Expert related to hydropower. 13- The presentation held by Sogreah in relation to hydropower. 14- The tender document for the new PV solar in LOI Zahrani. 15- Measurements collected from the incoming feeder on the 15 kv in Nabatieh SS. This file should help in analysing the behaviour of the network in this area. 16- The latest document published by CEDRO UNDP on their field study for 3 PVs (rooftop systems) installed in Lebanon on 29/12/ Data collected from the power plant in Beddawi (Deir Ammar) north of Lebanon. It shows the Gas turbine 1, and 2 generation along with frequency variation. 18- Request for Proposal of the BRSS project. This project was executed and it is functioning today. 19- Technical specs required for BRSS. 20- Single-line diagram (SLD) for Zahrani PV plant. Important to note that coupling will take place in 4 different points and on low voltage side. As well, the 60 Hz is due probably because Zahrani facilities were previously built by TapLine Company which is an American company. 21- Another SLD of Zahrani plant.

40 The environmental impact assessment (EIA) decree 8633 in Arabic and non official translation in English (Decree 8633 dated 2012). 23- The comments of the Coordinating Expert in English translation (which is not official). - It provides a list of project types requiring an EIA to be conducted. - The MoE decides upon the conditions to be met and information to be provided by a project to receive a permit. - The EIA should contain at least the following sections: Institutional framework, description of the project, description of the environment, impact assessment, mitigation measures and environmental monitoring plan. - The EIA is to be presented to the institution in charge of granting a permit to the project; depending on the type of the project. A copy of the EIA is sent by the institutions to the MoE for consultative and revision purposes. 24- Data downloaded from one 15 kv feeder in Sour SS used for water pumping. The SS is located in south of Lebanon. It is fed directly from Zahrani power plant through 220 kv line, and it is connected to a local generation plan on 66 kv (the open cycle plant in Sour does not run usually except for peak demand). The 15 kv feeder is used for water pumping and hence is not overloaded. 25- Data received from Zahle area in Bekaa Valley. Zahleh is exceptional case study because it is a distribution concession, for around 11 villages (80000 subscribers). Electricity de Zahle (EDZ) delivers electricity to the subscribers 24/24 hour: from EDL and from its own generators. The Coordinating Expert put one micro inverter 250 W on the roof of one subscriber and received the data for around one week. The inverter is a single phase so only U1 P1 Q1 etc are valid. The P1 is negative because the inverter is producing energy towards the grid in a life condition. 26- Data for Kobayyat SS, located in North of Lebanon. This SS is chosen for two major criteria: - It is located in the far north of Lebanon. It is the furthest SS in the north, just in proximity of Syrian boarders. - It is forecasted to have a wind farm in this area ranging from 50 to 100 MW. The analyzer was connected to the incoming of the transformer from the 15 kv side. The developer of the farm wind had not decided yet if they would connect to the medium voltage or to the 66 kv side. The Coordinating Expert did not connect it to the 66 kv side, because currently the Ministry of Energy and Water is executing a 66 kv line that will cross Kobayyat SS. So we would expect better voltage on 66 kv side. To be noted that it is forecasted as well to install capacitor banks inside this SS on the MV side. So, the voltage of the MV is expected to get better. 27- Documents received from EDL. These data belong to Zahrani power plant located in south area. It is a 450 MW combined cycle power plant. 28- A draft of the request for proposal of the 1 MWp grid connected photovoltaic turnkey project of MEDRAR Medical Center in Choukine.

41 Table 7: Illustration of the received data from the UNDP (i.e., Jil Amine) National wind atlas for Lebanon. 30- CEDRO: Photovoltaic plants in Lebanon. 31- EDL: Lebanon Electricity Tariffs. 32- MEW: Policy Paper for the Electricity Sector. 33- CDR November 2013: Electricity. 34- A Net-metering document by EDL which lists some specifications at the end. 35- A document titled A Guideline on Technical Requirements to Integrating Renewable Energy Projects into Grids and developed by the Regional Center for Renewable Energy and Energy Efficiency (RCREEE). 36- Presentation by the LCEC concerning the National Renewable Energy Action Plan which identifies RE additions for the future. ASSESSMENT OF RECEIVED DATA In this chapter, the collected data until the submission date of this report is depicted and assessed. Three main topics, which play the essential role in the operation of PV plants, are discussed. These topics are frequency stability and voltage stability as they are crucial for the proper integration of PV plants. In addition, the power quality of the output of the already installed PV plant (i.e., BRSS plant) is also discussed. In order to perform a clear data assessment, the remarks hereinafter should be taken into consideration. 41 Remarks Regarding the Assessment 1. As numerous documents in relation to the renewable energy topic in Lebanon are available already and to avoid repetitions, the data assessment will focus on the collected measurements and their depictions. Based on the assessed data, the technical guidelines will be adopted in next stages. 2. The measured data mostly were taken by means of the data analyzer Power Analyser & Meter SMY 133 from KMB Systems. 3. The measured data often have gaps in the time series due to some failures by the utilized meters. To avoid intermittent curves in the depiction of the data, only sections from the measurement, which do not include gaps, are selected to be depicted as time series. 4. If a measured data has obvious gaps, the statistical depiction of boxplots is adopted, so that all the measured data are considered regardless of the gaps observed. 5. The boxplots are statistical illustrations that show the median value of the measurements, a box including 50% of the measurements, whiskers including 95% of the measurements and the outliers representing the 5% extreme measurements, which can be sometimes caused by wrong measurement. 6. For the data management and the depiction of the measurements, the programming language of Python and its tool Pandas for data analysis are utilized. 7. The frequency has a global value in the interconnected grid. Therefore, all grid nodes have the same amplitude of the frequency at the same time of measurement.

42 8. The voltage has local values at different grid nodes. Therefore, the voltage amplitude as well as its angle can vary for each grid node in relation to the impedance matrices (i.e., location in the grid). 9. Several studies in the literature (e.g., [1]) show that the installation of RE plants leads to reverse power flows in the distribution system. As a result, RE plants can lead to over-voltage deviations or reduce the under-voltage deviations, especially during the time of peak feed-in of the RE (e.g., around noon for a PV plant). 10. It should be taken into consideration that the large PV plants (i.e., > 1 MWp) are usually connected at the medium voltage (MV) level through MV/LV transformers. Therefore, the voltage measurements at the MV level are under the focus of this assessment. The MV level in Lebanon includes 11 kv, 15 kv, and 20 kv. 11. The voltage values will be depicted in per-unit [pu] to show the voltage deviations with comparable illustrations. 12. Tolerance bands for the voltage and frequency deviations are presented in several international norms. For example, the European norm EN 50160, which is currently adopted in the European interconnected grid, defines the maximal allowed steady state frequency deviation by ±1%. The tolerance band of steady state voltage deviation at the end-user (i.e. LV level) is defined by ±10%. Mostly grid operators reserve ±5% for the deviations in the LV level, so that the tolerance band to the MV level is usually ±5%. 13. The locations, or the grid connection points, of the installed PV plants as well as the expected ones are important for this assessment. Therefore, these locations are indicated in Figure 7. Figure 7: Map of Lebanon showing the transmission system as well as the locations of installed and expected large RE projects 42

43 Illustration Of Received Data 1. Some exemplary voltage measurements at 11 kv substations are illustrated in Figure 8. It shows that the voltage deviation is relatively high, especially at the substation of Joumhour, where the under-voltage deviation is around 9% while the deviation at the Choueifat SS is relatively low (i.e., less than 2%). Figure 8: Statistical illustration of exemplary voltage measurements of some stations at the level of 11 kv level. 70 measurements are taken at each station in the time from till Data number 9 in Table 6. 43

44 2. Some exemplary voltage measurements at 15 kv substations are illustrated in Figure 9 and Figure 10. They show that the voltage deviation is relatively high, especially at the SS of Nabatieh, Sultanieh and Marjeyoun, where the under-voltage deviation exceeds 10% while the voltage deviation at Aramoun is relatively low (i.e. less than 2%). Figure 9: Statistical illustration of exemplary voltage measurements of some stations at the level of 15 kv level. 70 measurements are taken at each station in the time from till Data number 9 in Table Figure 10: Statistical illustration of exemplary voltage measurements of some stations at the level of 15 kv level. 70 measurements are taken at each station in the time from till Data number 9 in Table 6.

45 3. Some frequency measurements at the household level in Beirut are illustrated in Figure 11. It shows that there is long-term over-frequency deviation that exceeds 1.5%. The frequency drops only for short-term probably because of some disturbances in the grid (e.g. around 17:00 and shortly before 18:00). Figure 11: Measured exemplary frequency variations with the time at the household level. The measurements have 1 minute resolution and are performed on Data number 7 in Table 6. 45

46 4. Some voltage measurements at the household level in Beirut are illustrated in Figure 12. It shows that the voltage at the measurement location has no critical deviations. The maximal voltage deviation here does not exceed 3.5%. Figure 12: Measured exemplary voltage variations with the time at the household level (level of 230 V). The measurements have 1 minute resolution and are performed on Data number 8 in Table 6. 46

47 5. Frequency measurements for four days at the PCC of the BRSS plant are illustrated in Figure 13. It shows that there is long-term over-frequency deviation that can exceed 1.5%. The frequency drops only for short-term probably because of some disturbances in the gird (e.g., the highest under-frequency deviation is on in the afternoon). The illustrated measurements for four days do not demonstrate that the deviation time can be predicted since the deviations can occur in any time in the day. Figure 13: Measured exemplary frequency variations with the time at the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. 47

48 6. Voltage measurements for four days at the PCC of the BRSS plant are illustrated in Figure 14. It shows that there are obvious over-voltage deviations that can exceed 9%. However, under-voltage deviations are not observed in the illustrated measurements. A short-term voltage drop is observed on in the morning which is probably because of some disturbances in the gird. The illustrated measurements for four days do not demonstrate that the deviation time can be predicted since the deviations can occur in any time in the day. Figure 14: Measured exemplary voltage at the PCC of the BRSS. The measurements have 5 minutes resolution and are performed between and The measurements are taken at the PCC of the plant at the LV level (400 V side). Data number 10 in Table 6. 48

49 7. The output power of the BRSS plant for four days is illustrated in Figure 15. It shows that the power feed-in can slightly exceed 600 kw, whereas the nominal power of the plant is 1.08 MWp. However, it is not clear if the feed-in power is limited because of the weather conditions (e.g., solar irradiations) or because of the frequency of voltage deviations. Figure 15: Measured exemplary output power of the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. 49

50 8. In order to further investigate the effect of the frequency and voltage deviations on the output power of the BRSS plant, the measurements of frequency, voltage, and output power on the are illustrated in Figure 16. The figure shows that there is no obvious correlation between the deviations of frequency and voltage and the deviations of the output power. The figure shows that the output power of the PV plant has high quality and it is also independent from the disturbance in the grid. In addition, there are no flaws or issues recorded in the plant until the submission of this report. Figure 16: Measured exemplary frequency, voltage and output power at the PCC of the BRSS. The measurements have 5 minutes resolution and are performed on Data number 10 in Table 6. 50

51 9. Not only the frequency amplitude but also the frequency change rate with the time (i.e., ramp rate) is important for the frequency stability. The illustrated measurements in Figure 13 are also utilized to illustrate the frequency ramp rate in Figure 17. It shows that the frequency in the grid can change relatively fast (about 0.25 Hz/min). Such change rate should be taken into consideration when setting up the PV inverters. However, since the time resolution of the measurements is 5 min, higher ramp rate can be expected in the actual frequency. Figure 17: Ramp rate of measured exemplary frequency at the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. 51

52 10. Similarly to frequency ramp rate, the voltage change rate with the time is important for the voltage stability. The illustrated measurements in Figure 14 are also utilized to illustrate the frequency ramp rate in Figure 18. It shows that the voltage in the grid can change with the rate of ca pu/min. Such change rate should be taken into consideration when setting up the PV inverters. However, since the time resolution of the measurements is 5 min, higher ramp rate can be expected in the actual voltage. Figure 18: Ramp rate of measured exemplary voltage at the PCC of the BRSS. The measurements have 5 minutes resolution and are performed between and Data number 10 in Table 6. 52