PRODUCTION, DISTRIBUTION AND SUPPLY OF ELECTRICITY IN KOSOVO FOR THE PERIOD

Transcription

1 International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 3, March 2018, pp , Article ID: IJCIET_09_03_102 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed PRODUCTION, DISTRIBUTION AND SUPPLY OF ELECTRICITY IN KOSOVO FOR THE PERIOD Avni Alidemaj Kosovo Electricity Distribution and Supply, KEDS Kosovo Ahmet Shala * University of Prishtina, Faculty of Mechanical Engineering, Prishtina, Kosovo *Corresponding author ABSTRACT Kosovo s energy sector, particularly the electricity generation, in the period from 2000 to 2015 had faced multifaceted problems causing thus serious problems for the overall development of the country. Customers, both household and commercial, suffered from unstable electricity supply, which became a barrier to economic development. In absence of insufficient generation of electricity and constant growing demand, Kosovo was heavily dependent from the unscheduled importing of electricity in the region. Furthermore, often the real demand for electricity in Kosovo has been higher than the energy available. Consequently, customers in Kosovo were subject to daily load shedding, both planned and unplanned. These load shedding were carried out according to the so-called ABC Plan, where customers are categorized into one of the categories A, B or C, based on the level of payment and commercial losses in their 10 kv feeder. Keywords: Technical losses, non-technical losses, Thermo power plants (TPP), hydropower plants (HPP), power system, Kosovo A, Kosovo B, ABC plan, consumption. Cite this Article: Avni Alidemaj and Ahmet Shala, Production, Distribution and Supply of Electricity in Kosovo for the period , International Journal of Civil Engineering and Technology, 9(3), 2018, pp editor@iaeme.com

2 Production, Distribution and Supply of Electricity in Kosovo for the period INTRODUCTION Economic development and improving the living standards of the population of each country is closely linked with the level of electricity use. The energy system of a country is not an easy system to understand and manage. The complexity of technology used today represents real challenge for proper execution of the works in this system. Apart from the conventional technical nature, Kosovo's power system has long been and still remains specific, given the background over the period During the mentioned period, the system has been utilized without any criterion with lack of necessary investments and maintenance. In order for any power sector to be successful, four components need to be in place and functional, which are indeed closely connected with each other: Sufficient and permanent generation of electricity (certainly also the fuel for electricity generation). Adequate power facilities and fully functional for the transmission and distribution of electricity from the point of production to the final customer. Operation, maintenance and development of Kosovo's distribution system to improve performance and to move forward in meeting the Standards of Quality. Secure delivery of all the electricity produced in the country at reasonable prices that reflect the cost of the regional and local market. 2. PRODUCTION OF ELECTRICITY Electricity is produced at power plants using different types of energy. According to the type of energy used, the power plants are divided into: Thermo plants Hydro plants Nuclear power plants, Power plants that use the renewable sources, etc. In most countries, the majority part of the power plants consists of thermal power plants (TPP) and hydropower plants (HPP), which are built near the raw materials, i.e. near fuels and water resources. In recent years a greater importance was given on electricity production from the renewable energy such as wind, solar etc. The benefits of a country depend on the available energy resources. Most of western counties are widely focused on increasing the renewable energy sources. Similarly, as a European country, Kosovo is working very hard to increase its renewable energy sources. However, Kosovo has large reserves of coal and no rivers with large amount of water, thus producing electricity has been always concentrated on thermal power plants based on lignite coal exploitation. Kosovo gets the bulk of power supply from two power plants, Kosovo A and Kosovo B, at 97%. Both of these power plants use coal as a source for electricity generation. Kosovo A has five units: A1, A2, A3, A4 and A5, two of which are no longer operational (A1 and A2). Three other units (A3, A4 and A5), constructed between 1970 and 1975, have an installed capacity of 200 MW, 200 MW and 210 MW (Kosovo A, 2015). Kosovo B operates two units B1 and B2 which have an installed capacity of 339 MW each, which entered into operation in 1983 and 1984, respectively. Both units have a net capacity of 280 MW, (Kosovo B, 2015). Electricity generation from hydro plants is about 3%, and the most important Hydropower is Ujmani hydro plant with a capacity of 35 MW (2 X 17.5 MW = 35 MW), then the hydro editor@iaeme.com

3 Avni Alidemaj and Ahmet Shala plant Lumbardhi with capacity 8.3 MW, hydro plant Dikance with capacity 1.8 MW, hydro plant Radavci with capacity 0.8 MW, Hydro plant Burimi with capacity 0.8 MW, (Ujmani, Dikance, Radavci and Burimi, 2015) Import of Electricity In Kosovo, starting from 2000, consumption has been higher than production (Table 1). The balance between demand (consumption) and supply has been supplemented by import of electricity (in the year about 10%), and for a better supply of electricity to the customer, import of electricity is been need. Import is made through the interconnection lines 400 kv and 220 kv Kosovo B, and along the 400 kv network in SS Peja 3 and through Prizren 2 TS 220 kv and SS 220 kv Podujeva, ( The 110 kv network level, which belongs to the transmission, serves as the main backbone for the power supply of 7 districts of Kosovo. Table 1 Consumption, production and import of electricity in MWh, from Year Consumption in MWh Production in MWh Import in MWh This table shows that electricity demand exceeds the production capacity of thermal plants and hydro plants, therefore the country is obliged to import electricity. From this table it is seen that the import requirements in 2000 were very large, but over years this demand was being improved. By 2015, the domestic generation has covered almost entire consumer demand, with little difference. Districts use the 35 kv and 10 kv systems to distribute energy in localities, by supplying customers through transformers 10/0.4 kv, 10 kv level network features over 600 feeders 10 kv and 6600 transformers 10/0.4 kv. Losses in the distribution network calculated in the network of medium level are around 8-9%. With the total number of approximately customers it is not surprising that the technical losses in the distribution network below the 10 kv are rated about 8-10%, (KEK, 2016). The price of imported energy was 75.9 / MWh, while the average price of electricity in Kosovo in 2009 was / MWh, ( editor@iaeme.com

4 Production, Distribution and Supply of Electricity in Kosovo for the period THE PRODUCTION CAPACITY OF ELECTRICITY The production capacity of electricity in our country is mainly based on lignite-fired TPP s, which in fact cover 97% of total production, while the rest of the production of HPP Gazivoda and several small hydro power plants connected to the distribution network. Electricity in Kosovo is produced in two relatively large TPP: TPP Kosovo A and TPP Kosovo B. Both stations use the coal-lignite as a fuel. Lignite is currently taken from the Sibovc southwest mine. The Mirash and Bardh mines, which supplied Kosovo A and Kosovo B, were exhausted in 2010 and 2012, respectively. The open cast mines Bardh and Mirash covered an area of about 14.5 km. In the near future it is planned to expand the Sibovc Field in the South. Energy value of Kosovo lignite is about 7800 kj / kg with larger values Sibovc s digs (8100 kj / kg). So we can say that Kosovo's lignite has an average value from the average value of sulfur content and high level of ash compared to lignite in the world Description of Property of Kosovo Transmission and distribution network Transmission Network in Kosovo consists of transmission lines and substations of high voltage 400 kv, 220 kv and 110 kv, as well as other equipment for surveillance, command, control the transmission system. Kosovo's transmission system at the state level has an installed capacity of 1,824 MW, while the peak load for 2013 was 1,168 MW. Below is given a brief description of the property and the age of the equipment. The capacity of the transmission lines are shown in the following table. Table 2 Length of transmission lines Overhead lines Total length km 400kV kV kV Number of sub-stations (SS) and transformers (Tr) according to the voltage level transformation in transmission network of the level 400/220 kv, 400/110 kv, 220/110 kv, 110/35/10kV and 110/10kV for the year 2013 is shown below in the table (Table 3), ( Table 3 Number of substations and number of transformers with transforming level Transformation Owner Nr. SS Nr. of Tr Sinst MVA 400/220 KOSTT 1 3 1, /110 KOSTT /110 KOSTT 3 8 1, /35/10(20) KOSTT /10(20) KOSTT /35/10(20) KOSTT /10(20) KOSTT /35 KOSTT /10 KOSTT Kosovo Distribution Network (KEDS) contains HV power lines and substations of the level 35kV, 10 kv i 0.4 kv editor@iaeme.com

5 Avni Alidemaj and Ahmet Shala The table below shows total length in km according to the voltage level, number of substations of the voltage level 35/10 kv and number of transformers with transforming level 35/10 kv, 35/6 kv, 35/0.4 kv, 10/0.4 kv and 6/0.4 kv, (Annual report 2015). Table 4 Length of distribution lines Overhead lines Total length km 35kV (20)kV kV kV 50 3kV 4 0.4kV Table 5 Number of substations and number of transformers with transforming level Transformation Owner Nr. SS Nr. of Tr Sinst MVA 35/10 KEDS /6 PRIVATE /0.4 PRIVATE (20)/0.4 KEDS (20)/0.4 PRIVATE /0.4 KEDS /0.4 PRIVATE /0.4 PRIVATE Consumption Consumption of electricity in Kosovo is grown strongly since 2000 (2936 GWh) by the year 2007 (4855 GWh). The latest data show that consumption continues to rise up to 5590 GWh in and has reached 5610 GWh in Energy Strategy predicts that energy demand will increase from its current level (estimated) between 1400 and 1500 ktoe / year (in thousand tons of oil equivalent / year), up between 1900 and 2200 ktoe / year in During the same period, demand for electricity is projected to grow to about 7500 GWh in 2018 and 8,000 GWh in The increasing consumption is planned to be covered with the construction of new capacities in Kosovo B power plant (2 X 300 MW known as "Thermo plant Kosova e Re" - KNPP). For this purpose up to now there have been drafted several projects by the Government of Kosovo, but so far has not been realized in the absence of funds and donors. In the figure 1 is given Kosovo electricity production, import, export, consumption and load shedding editor@iaeme.com

6 Production, Distribution and Supply of Electricity in Kosovo for the period Figure 1 Kosovo electricity production, import, export, consumption and load shedding Electricity Shortages Energy resources mentioned before are insufficient to cover the growing consumption, especially in the hours of maximum loads (peak) and during the winter season. This is more pronounced especially in the winter months, taking into account that the electricity is mainly used for heating and misuse of power in this period is at a higher level. Even energy imports have often been limited, either because of insufficient financial resources for electricity imports, either due to lack of electricity generation in the region, [4], [5], and [6]. However, even if the customer demands for electricity are met, yet the limited capacity of lines or transformers prohibits to deliver that energy to the final customer. Therefore, the distribution company is forced to apply load shedding, particularly during the winter months. Hence, there is a plan in place which is implemented through a methodology known as ABC Plan for load shedding, which is explained further below. 4. METODOLOGY OF ABC PLAN In order to maintain the balance of power system and interconnection compliance with rules relating to deviations in the system, since 2006 has started to apply the policy "ABC" for load minimization, load reduction respectively. This was done so that each 10kV feeder is categorized into one of the categories A, B or C, using software called "ABC Module", prepared only for this issue. This has to be done especially in winter time when the load is too high and shutting down of one aggregate cause disturbances on the system, so, in these cases the ABC module has to be applied. Category A includes customers who pay electricity and have small commercial losses, while in category B and category C especially, are part of consumers who have low paying rate or not paying at all. In this case the technical losses are not taken into account because that issues belongs to the distribution company. In order to work and understand easier this process, it would have useful if the codes were placed beforehand. Every customer is coded with 13 digit code at KEDS network editor@iaeme.com

7 Avni Alidemaj and Ahmet Shala The first three digits represent 110 kv substation code, the second three digits represent MV/MV substation code. The eight digit present the 10 kv feeder code. Digit nine, ten and eleven represent SS MV/LV kv and the last two digits identify the customer. Meters with remote reading capability exist in all incoming and outgoing feeders from SS HV/MV kv and SS MV/MV kv. Also, those remote reading meters are installed at secondary side of the distribution transformers MV/LV kv. In the figure 2 is given an example. Year Table 6 Load shed of electricity Consumption in MWh Production and import in MWh Load shed in MWh Figure 2 The way of generate code for consumer From Figure 2, we can see that we have metering at all voltage levels whereas every node or point have its own code and by using the current applications we could know the billed, loosed and collected electricity for every SS 10/0.4kV, 10kV feeder, SS 35/10kV and SS 110/10 or 110/35kV. During the implementation of ABC all customers of the same category are treated equally and not discriminatory. This is achieved by implementing load shedding rotating system. In table VI are given load shedding in the period editor@iaeme.com

8 Production, Distribution and Supply of Electricity in Kosovo for the period Module ABC Module ABC is one module which was constructed in that form so it can make incorporation of data from Network Division and Supply Division by collecting them, processing in automatic method the data and in the end calculation of scheme ABC. All collected data he process them automatically and there is no possibility that someone interferes but naturally this work the Module performs based on data which are basic to function as module Requests and formula used for module ABC The data needed for module ABC are: 1. Data from Network Division: Energy input of the feeder 10kV in MW/h, Calculated technical losses in MW/h, for medium and low voltage Energy delivered to customer also in MW/h 2. The data from Supply Division: Energy billed in MW/h (these data Module ABC takes from CCP) Energy collected in Euro per feeder, Energy billed in Euro per feeder. Initially, all 10kV feeder readings are transported to ABC module. These readings provided by AMR. Then, the technical losses shall be inserted into this module for each 10kV feeder. These data are calculated by the Department of Technical Losses. After calculations will be obtained categorization for each category based on readings, technical losses, energy billed in MWh, energy billed in (euro) and collection in (euro), ( ), ( Used formulas for this module are as follow: (1) Where: E f -Energy measured in 10 kv feeder in MWh. E TL - Technical losses in 10 kv in MWh E dc - Energy delivered to customer in MWh CCP-Energy billed for customers of respective feeder in MWh. E b %-energy billed in %. C l -Commercial losses of the feeder in MWh C l %- commercial losses in % of 10 kv feeder. (2) (3) (4) *100 (5) E b euro-energy billed in Euro for respective month for customers that are supplied from 10 kv feeder in MWh. (6) editor@iaeme.com

9 Feeder Code Name 10kV Feeder Energy 10kV Feeder Technical losses 10kV MWh Technical losses 10kV % Energy without T.L. MWh CCP MWh Billed energy % Commercial loss MWh Commercial loss % Billed energy Euro Collection Euro Collection % ABC % ABC Avni Alidemaj and Ahmet Shala In Table 7 is given in tabular form the categorization of some 10 kv feeders. Number of 10 kv feeders for each category is defined on the basis of the categorization limits, and 1/3 of all feeders will be categorized as category A, 1/3 of all feeders category B and 1/3 of all feeders as category C. In Table 8 are given the categorization limits for the categorization given in table 7, data in table 7 are from December 2013, ( Table 7 Parameters and Categorization of feeders J A J A J J C J B J C J A From the table 7 above it can be seen how for example Feeder with the name J16 is loaded with 673.3MWh, technical loses are 121.4MW, so the total energy that will arrive to the costumer is 551.8MWh. From this amount of the energy the part that will be invoiced is just 381.8MWh or 69.1%. Commercial losses in this case are MWh. If we convert that in money, it means that there is invoiced just 27,582.4euro, but collected only 2,964 euro or 83.2%. To find the category of the costumer in this feeder according with the ABC plan for this feeder we have: ABC J16 =69.1*83.2=57.2% (7) So, this costumer belongs to the worst category (C) in which the load shedding is exercised more than at two others. These calculations are made every month and there is possibility that next month to change the category. This application enters in force for execution every month on the date first. Note: In case that any commercial costumer has the physical possibility to possess its own feeder and in this feeder there are no commercial losses but the such costumer in fact pays regularly its invoice then such costumer has special status of the category which is called A+ and in this feeder the load shedding will not apply. Usually these cases are advanced businesses or factories. Based on the formula (6) and the table 7, the border of the categories A, B and C will be like in bellow table A editor@iaeme.com

10 Production, Distribution and Supply of Electricity in Kosovo for the period Table 8 Limit of Categorization ABC [%] Min ( MW) Max ( MW) A B C ANALYSES AND DISCUSSION Existing production capacities in Kosovo A and Kosovo B are insufficient to meet the demand for energy supply to the costumers in Kosovo, and consequently, the so called ABC module established especially for this issue, is applied to select distribution feeders 10 kv (Calculation of categorisation is not done in level 0.4 kv because of technical conditions. First we don t have measurement in all feeders 0.4kV and second the manipulation (reduction) is very difficult to be realized because are needed many teams. In all feeders 10 kv we have measurement, we have identification code and manipulation (reduction) is done by operator which is located in substation so there is no need for additional engagement of teams) for load shedding of the costumers according with the category A, B, C. In order to do the selection of the costumers for category A, B and C, it is important to have in consideration the power, invoicing and revenue. Costumers of the category C are the costumers with highest commercial losses and bad revenue collection, so, they will met more load shedding compared with those of category A which have lower commercial losses and better revenue collection so accordingly, less load shedding, which will be applied rarely or not at all. In all these cases technical losses are not taken in consideration and are not calculated, so the feeder or customer is not to be punished because of that, since this issue depends on the investments. Every month the company calculates technical losses so from that can be defined commercial loses and where are higher in which region and which feeder. These kind of load shedding have not helped the network, because often they caused damages of the network assets because after reduction has finished and the feeder was brought back in operation, the engaged power was too high and in many cases it damaged cables or overhead conductor fell down and so in many cases it was necessary to change the low voltage fuses. Other additional expenses were caused from damages of the feeder circuit breakers which were damaged due to frequent operations. 6. CONCLUSIONS Kosovo as a new and poor country, with an old network in which no investments were made for a long period and with a fast growing energy consumption, with a low and limited budget for investments and which is more oriented in purchasing of the power, having high commercial losses, limited generating capacities, the situation in the transmission and distribution systems, have all caused very often the shutdowns of electricity, as well as planned disconnections during the pick of consumption and when the generators were shut down from the system. This imposed to the company to find any way to apply reduction of power with the aim to protect responsible costumers who pay the electricity on regular basis. After privatization in 2013, new operator started with big investments in order to reduce in parallel technical and commercial losses. A number projects started to be implemented, which are ongoing in all levels of voltages: improvement of 10 kv network and new investments on the 0.4 kv level, eliminating the bottle necks, new substations 10(20)/0.4 kv etc. These projects will have an impact in decreasing of technical losses. For decreasing of commercial losses there were other projects as for example replacing of energy meters and putting them out of the buildings of the editor@iaeme.com

11 Avni Alidemaj and Ahmet Shala customers. The same project also included the improvement of the existing network. This project decreased technical and commercial losses and had an impact on reducing of the load. All these projects are ongoing and will continue in the coming years. On the other side, the Transmission Operator had invested on new capacities of HV network, which also improved critical situation of the network. Technical and commercial losses have been reduced from 36.69% on2012 to 31.82% on All these mentioned projects have improved quality of supply with electricity, have reduced technical and commercial losses and made the application of module ABC to be always less and less, with the aim to use this module only for study cases and not for load shedding purposes. However, construction of new capacities remains the priority number one, while the existing capacities do not give reliability in electricity supply and very often due to failing of the generation in PP Kosova A and Kosova B the company is obliged to import electricity which in some cases this is associated with difficulties. The commencement of a cogeneration in Prishtina (central heating of the city from PP Kosova B) had impact in decreasing of the load and not using of electricity for heating. The decision of the Government of Kosovo for release of the public debts until 2008, with the conditions that customers would be paying for previous years through written agreements and begin to pay has made customers aware who have started to pay, and now they save more electricity. REFERENCES [1] The technical data from Thermo power plant (TPP) Kosovo A, [2] The technical data from Thermo power plant (TPP) Kosovo B, [3] Technical data from hydropower plants (HPP) Ujmani, Dikance, Radavci and Burimi, [4] The technical data from the department for calculation of technical and non-technical losses, KEK, [5] The technical data from the Department for Management of Capacity, KEK (Kosova Power Corporation, 2016). [6] Technical data from the Department of Operations and Maintenance, KEK. [7] Technical data from Transmission System and Market Operator J.S.C., KOSTT, [8] The technical data for Module ABC from Network and Supply Division, KEK, [9] Annual report 2012 [10] Annual report 2015 [11] Ahmet Shala and Mirlind Bruqi, Kinetostatic Analysis of Six-Bar Mechanism Using Vector Loops and the Verification of Results Using Working Model 2D, International Journal of Mechanical Engineering and Technology 8(8), 2017, pp editor@iaeme.com