PO-KO-006 METERING CODE. ver. 1.1 faqe 1 nga 42 METERING CODE

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1 METERING CODE Prepared by Controlled by Approved by Name of Company KOSTT KOSTT ERO Date

2 TABLE OF CONTENTS 1 Preface Glossary and Definitions General Conditions Terminology Unforeseen Circumstances In this Metering Code Affecting the ability of Parties to Comply with this Code Management of the Metering Code Disputes General Disputes Procedure Introduction Objectives Scope Responsibilities for Metering Systems Installation and Protection of Metering Equipment Derogations and Planned Upgrade of Metering Systems General Registration of Metering Systems not fully Compliant Upgrade periods Estimation during Upgrade Periods Exemptions Metering Systems Minimum Metering Requirements Capacity and Energy Measurements Technical Specification of Metering Equipment Existing Measurement Transformers Metering Equipment Overall Accuracy...20

3 8.3.2 Metering Equipment Accuracy Class Interval Meter Data Requirements Data Storage Timekeeping Monitoring Facilities Communications Equipment Local Interrogation Remote Interrogation Metering Data and Remote Data Collection Metering Database Security of Metering Systems Equipment location Sealing of Metering Equipment General Form of Seal Control of Sealing Tools Microprocessor Equipment Password Protection Level Level Level Level Security of Metering Database Failure Restoration Requirements Testing of Metering Systems General Type Approval Calibration and Verification Periodic Calibration and Re-furbishment Routine Testing at Connections with Large Transfer Capacities Measurement Transformers...36

4 General Initial calibration Periodic testing Data Concentrators General Initial calibration Periodic testing Payment for Metering Systems Resources and Documents...38

5 1 Preface The metering code has a key role in setting out the requirements for commercial metering in order to facility the operation of the electricity market. It is one of a series of technical codes that are designed to ensure a level playing field for all parties who are operating in competitive energy and ancillary service markets by setting conditions for non-discriminatory and transparent use of networks The metering code establishes clear rules for the installation and use of metering to ensure that production, transfer and consumption data is available to support the efficient settlement of electricity transactions In accordance with the law on energy, the TSMO is responsible for the administration of all technical codes for electricity including the metering code and they are subject to the approval of the Regulator prior to their implementation The drafting of this metering code has taken place prior to the establishment of market rules clearly defining the manner in which the market is to operate in Kosovo. To allow this to happen, certain assumptions have had to be made: any eligible customer who wishes to purchase energy from a supplier of their choice must first install metering capable of measuring their energy consumption to full settlement requirements. any generator wishing to be paid for energy transferred to the transmission or distribution system must first install metering capable of measuring their energy transfer to full settlement requirements. the market rules will establish that, where there are any differences between the settlement requirements within Kosovo and in the regional market, any party trading on the regional market via the transmission or distribution system in Kosovo must install metering capable of meeting that ever are the more onerous of the Kosovo and regional market requirements in each case. neither the TSMO nor the distribution system operator will be required to calculate the energy transfers for which they are due to receive network access payments. All such calculations will be carried out within the settlement process.

6 As drafted, this metering code addresses the metering requirements of a fully competitive market rather than only the transmission metering requirements. 2 Glossary and Definitions In this Metering Code, the following definitions apply: Term Acronym Definition Active Energy Wh A measure of electrical energy flow, being the time integral of the product of voltage and the in-phase component of current kwh flow across a connection point, expressed in Watthours and MWh multiples thereof. Connection The interconnection of two systems. Connection Agreement Connection Point A bilateral agreement between a network operator and a user that details the conditions for connection to the network. The agreed point of supply established between a network operator and another party. Current Transformer CT A transformer for use with meters and/or protection devices in which the current in the secondary winding is, within prescribed error limits, proportional to and in phase with the current in the primary winding. Data Concentrator De-energise Distribution System Distribution System Operator Eligible Customer DSO A device that collects energy data, packages it into intervals, holds a minimum of 45 days of data, and is capable of being accessed electronically by the TSMO, via a communication link. This device may be a separate item of equipment, or combined with the energy measuring components within one physical device. To remove voltage from an electrical installation by opening the final switch or removing a cut-out fuse. De-energised, deenergisation etc shall be construed accordingly. Is as defined in the Law on Electricity (a combination of electricity power lines and electricity units of medium and low voltage to serve the distribution of electricity) An electricity enterprise responsible for operating, ensuring the maintenance of and, if necessary, developing the distribution system in a given area and, where applicable, its interconnections with other systems and for ensuring the long-term ability of the system to meet reasonable demands for the distribution of electricity. The DSO is also responsible for customer meters. Is a customer who is free to purchase electricity from the supplier of their choice as defined in the Law on Electricity

7 Term Acronym Definition Energise To apply voltage to an electrical installation by closing the final switch or inserting a cut-out fuse. Energised, energisation etc shall be construed accordingly. Energy Regulatory ERO Is the independent regulatory body established by the Law on Office the Energy Regulator. See regulator Force Majeure Is in relation to any Party any event or circumstances beyond the reasonable control of such Party and which results in or causes the failure of that Party to perform any of its obligations under the this metering code including, but not solely limited to any one or more of the following acts: Acts or restraints of governments or public authorities; war, revolution, riot or civil commotion; strikes, lock-outs or other industrial action; blockage or embargo; failure of supplies of power, fuel, transport, equipment or other goods or services; damage to the premises or storage facilities by explosion, fire, corrosion, ionizing radiation, radioactive contamination, flood, natural disaster, or negligent act of others or accident; and breakdown or failure of equipment whether of the Party s or others Generating Unit A physical unit located within Kosovo for the production of electricity operated by a Generator. Generator An electricity enterprise with a generation licence or a natural or legal person exempt from holding a licence in accordance with the Law on the Energy Regulator who engages in the activity of owning, controlling, or operating generating units and who generates electricity. Genset See generating unit Interval Meter Metering equipment that integrates energy over defined periods and stores it in those periods. Law on Energy Is law number 2004/8 approved by the Assembly of Kosovo Law on the Energy Regulator and promulgated by regulation UNMIK/REG/2004/21. Is law number 2004/9 approved by the Assembly of Kosovo and promulgated by regulation UNMIK/REG/2004/20. Law on Electricity Is law number 2004/10 approved by the Assembly of Kosovo and promulgated by regulation UNMIK/REG/2004/22. Licence An authorization issued by the Energy Regulatory Office that allows the holder to perform an activity in the energy sector for which a Licence is required according to its provisions as established by the Law on the Energy Regulator Market Operator MO A legal person responsible for the organization and administration of trade in electricity and payment settlements among producers, suppliers and customers;

8 Term Acronym Definition Market Rules The set of rules governing trade in electrical energy between the market operator and market participants and the interaction between these parties and the TSMO for the purposes of maintaining the physical balance of the market. Measurement The generic name that embraces both current transformers Transformer (CT) and voltage transformers (VT). Meter A device that measures and records the production or consumption of electrical energy. Metering Code Is this code, which has been prepared by the TSMO and approved by the Energy Regulatory Office as established by Article 38.7 of the Law on Electricity Metering Data Is meter readings provided to the Market Operator from a Metering System by the relevant Party who will be either the TSMO or the Distribution System Operator Metering Equipment Is the equipment and installations in a Metering System as specified in this Metering Code that is sufficient to provide the Metering Data required under the Market Rules Metering System A registered aggregation of meters treated as a single installation providing a single reading or related group of readings for Settlement Ministry Ministry of Industry and Energy of Kosovo Network Access An arrangement in terms of which the NOs agree to provide the use of their transmission system or distribution Network Access Charges system to any market participant. The tariff established by the network operator and approved by the regulator which is used to charge system users for their use of the network of a network operator. Network Operator NO A company which owns or operates the transmission system or a distribution system to which the networks of system users are connected. Non-interval Meter Operational Codes Governance Committee Party OCGC Metering equipment that simply integrates energy and stores it. The committee established in accordance with the provisions of the rule on governance procedures for technical/operational codes to oversee the operation of technical and operational codes. Someone who operates in the organized electricity market of Kosovo or provides services to enable the market to operate. Reactive Energy VArh A measure, in varhours of the alternating exchange of stored energy in inductors and capacitors, which is the time-integral of the product of voltage and the out-of-phase component of current flow across a connection point.

9 Term Acronym Definition Reasonable and Prudent Operator Remote Data Centre Regulator Rule on Dispute Settlement Procedures Rule on General Conditions of Energy Supply RDC An operator of an electricity undertaking seeking in good faith to perform its obligations and, in the conduct of its undertaking, exercising that degree of skill, diligence, prudence and foresight which could reasonably be expected from a skilled and experienced operator with sufficient financial resources complying with the relevant law Licences, market rules and this metering code and any reference to the standard of a Reasonable and Prudent Operator shall be a reference to such degree of skill, diligence, prudence and foresight as aforesaid. The central data centre established by the TSMO for the purpose of remotely reading metering systems which are microprocessor based and can be interrogated via a communications link. Is the Energy Regulatory Office (ERO), the independent regulatory body established by the Law on the Energy Regulator. A rule on dispute settlement procedure established by regulator in accordance with article 17.1 of the law on the energy regulator for the resolution of disputes in the power market. A rule on general conditions of energy supply issued by the regulator in accordance with article 9.1(f) of the law on the energy regulator. Rule on Governance Procedures for Technical/Operational Code Settlement Settlement Day Settlement Period Supplier A rule on governance procedures for technical and operational codes issued by the regulator in accordance with article 9.1(f) of the law on the energy regulator. Is the collective name for processes used to determine usage of the system by each Party and the financial liabilities and subsequent payments derived from this Is the Business Day on which the Market Operator will undertake Settlement calculations in respect of any specified Settlement Period Is the interval established in the market rules (or, in the case of energy trades beyond the boundary of Kosovo, by SETSO) over which energy delivery and contract delivery are measured with the first settlement period of each day starting at midnight. Entities whose main activity is selling electric energy produced or bought by them to other parties.

10 Term Acronym Definition Supply point SP The physical location at which the overall accuracy requirements as stated in the market rules or this metering code are to be met. These locations are fully defined in the relevant Connection Agreements. System User A system user is a natural or legal person who uses the transmission system of the TSMO or the distribution system of a DSO, as appropriate, including: - large consumers whose equipment is connected to the transmission system, - generators whose equipment is connected to the transmission system or is eligible to trade in the wholesale market, - other transmission system operators whose networks interconnect with that of the TSMO, - distribution system operators whose networks interconnect with the network of the TSMO or another DSO, and - electricity customers. Transmission Activities pertaining to a transmission system including the conveyance of electricity, and providing a physical connection to it. Transmission System TSMO Based on Article 12.1 of Chapter 4 and Article 27.1 of and Market Operator Chapter 8 of the Law on Electricity the regulator had licensed TRANSMISSION SYSTEM AND MARKET OPERATOR JSC, Transmission System Operator and Market Operator. Transmission System The electricity system owned by the TSMO. Universal Time Coordinated UTC Has the same meaning as in the document Standard Frequency and Time Signal Emission, International Telecommunication Union (CRTF.4609ISBN ) Voltage Transformer VT A transformer for use with meters and/or protection devices in which the voltage across the terminals of the secondary winding is, within prescribed error limits, proportional to and in phase with the voltage applied to the terminals of the primary winding. Working day WD Any day other than Saturdays, Sundays and the holidays normally observed in Kosovo

11 3 General Conditions 3.1 Terminology In addition to special meanings contained in the Glossary and Definitions above, within this document certain words and phrases have the following meanings: References to the masculine shall include the feminine and references in the singular shall include references in the plural and vice versa, Where this metering code specifies written information or written confirmation to be given then any other suitable means of electronic transfer that enables the recipient to retain the information such as electronic mail or FAX - fulfils this requirement, Except where explicitly stated otherwise all references to section shall be a reference to a section in this metering code, All clock times or other references to time, shall refer to the standard time in Kosovo, which is one hour in advance of Universal Time Co-ordinated (UTC), Any reference to a law or regulation shall be a reference to that law or regulation applicable in Kosovo or, following the replacement of that law or regulation the new law or regulation from the date it comes into force. 3.2 Unforeseen Circumstances In this Metering Code If circumstances arise that the provisions of this metering code could not reasonably have foreseen, the TSMO shall, to the extent reasonably practicable in the circumstances, consult promptly with all affected parties and the operational codes governance committee (OCGC) in an effort to reach agreement as to what actions, if any, should be taken. If agreement between the TSMO and those parties cannot be reached in the time available, the TSMO acting as a reasonable and prudent operator shall determine what actions, if any, should be taken. The TSMO shall notify the parties and the regulator of its decision and the reasons for it as soon as practicable.

12 Whenever the TSMO makes a decision, it shall do so having regard, wherever possible, to the views expressed by the other parties and, in any event, to what is reasonable in all the circumstances After the event the TSMO shall promptly refer all such unforeseen circumstances and any such decisions to the operational codes governance committee for consideration in accordance with section Affecting the ability of Parties to Comply with this Code Where a party is unable to comply with its obligations under this code for a force majeure event, it may send a notice to all affected parties and to the regulator detailing the reasons for it being unable to meet its obligations, why it believes these reasons are a force majeure event and the time during which the force majeure event will last During the period of force majeure, the party s obligations shall be suspended If any party believes that the declaration of force majeure is unreasonable, he may refer the matter to the regulator for review and the decision of the regulator shall be final. In the event that the regulator determines that the reasons for non compliance were not a force majeure event, then the obligations of the party claiming force majeure will not be considered to have been suspended Management of the Metering Code This metering code is prepared by the TSMO in accordance with its obligations under article 38.7 of the law on electricity and approved by the regulator. It lays down the conditions that have to be met by all parties in the circumstances covered by this code Revisions to this metering code will be undertaken by the operational codes governance committee established in accordance with the rule on governance procedures for technical/operational codes approved by the regulator. The TSMO shall take responsibility for incorporating any amendments that are agreed by the OCGC and approved by the regulator and will issue amended versions of the code as required.

13 3.3 Disputes General The provisions of this metering code are mandatory and are generally specific covering most of the situations that are likely to arise in the areas covered by the metering code. All parties should in the implementation of the code act at all times in good faith. The aim should be to try, as far as is possible, to ensure that disputes do not occur Disputes Procedure Disputes arising from the operation of this metering code shall be dealt with in accordance with the rule on dispute settlement procedures approved by the regulator as a means for resolving disputes arising between parties in the power market. 4 Introduction This metering code is intended to form the basis for the commercial metering of energy in the electricity market in Kosovo Accurate metering data is crucial for the settlement function and to ensure non discriminatory access to distribution systems. This metering code describes the rights and obligations of the parties with regard to the metering of electrical energy measurement to ensure that metering data can be obtained so that all market participants can have equal rights. 5 Objectives This metering code describes the metering facilities required at all connection points between networks, between networks and generating units and at the supply points of customers. It defines the rights and obligations that each of the parties have, especially those of the network operators, and including those of the regulator. It covers issues regarding the security of systems and the confidentiality data This metering code details the minimum standards for the measurement and recording of electricity metered quantities that will be used for settling electricity sales and purchases in the electricity market including those necessary for trades that originate or terminate outside Kosovo. It sets out the provisions relating to the installation, testing, maintenance and operation of metering systems including the associated communication links. It defines the accuracy requirements, the parameters to be measured and the maintenance and testing requirements.

14 6 Scope This metering code sets out the facilities that shall be provided and the procedures that shall be followed for the measurement and recording of energy transfers for settlement purposes within the electricity network of Kosovo The provisions of this metering code shall apply to all network connections where such connections are: Interconnection points between the transmission system and a distribution system, Interconnection points between distribution systems belonging to different distribution system operators, Connections where electricity generation enters the network of the TSMO or that of a DSO from the network of a system user, (generation connections) Connections where an energy supply is taken by a system user from the network of the TSMO or that of a DSO (supply connections), and Connections where energy is provided to the network of a DSO from the network of a customer who receives energy from the transmission system The provisions of this metering code shall apply to all legal or natural persons who are: Holders of a licence to undertake any of the licensed activities associated with the electricity industry in Kosovo, Consumers of electrical energy whether eligible to choose their supplier or not, and Owners or operators of any electrical network that is connected to the network of a licensed NO.

15 7 Responsibilities for Metering Systems 7.1 Installation and Protection of Metering Equipment As established by the law on electricity and, where appropriate, the rule on general conditions of energy supply, metering devices shall be provided by the NO onto whose network a connection is made The NO shall determine the place where metering equipment shall be installed taking account of the requirements of this metering code and all relevant regulations Following commissioning of the metering system, the system user shall report any suspected problems with the equipment to the NO The system user shall ensue that the chosen location remains a suitable location for metering equipment taking particular account of the requirements for access to and the security of equipment outlined in section Where the system user believes that it the location chosen by the NO is an unreasonable position for the metering equipment to be installed, the system user may refer the issue to the disputes procedure Obligations for maintenance, control and reading of metering point: For metering at the boundary between Transmission System and Distribution System, generators, direct customers responsible for metering system is TSMO; Boundary between network of a consumer who receives energy from the Transmission System and Distribution System of a DSO shall be corresponding connection point with corresponding system. The responsible for metering between customer and Transmission System is TSMO whereas between customer and Distribution System is TSMO, whereas between customer and Distribution System is DSO.; Where energy is provided by consumer s network for Distribution System, shall be considered as connection between Transmission System and network of a DSO, therefore DSO shall be responsible for metering system, whereas

16 TSMO shall perform periodical reading for Market Operator s requirements in order of settlement For metering at the boundary of two or more DSO-s, the DSO whose network is electrically closer to the transmission system shall be responsible for the metering system For metering at the boundary between the electricity network of Kosovo and any other electricity network it shall be the responsibility of the NO that holds a licence approved by the regulator of Kosovo to ensure that the metering system meets the requirements of all relevant laws and regulations of Kosovo, including this code and the relevant interstate agreement In the substations and facilities that are TSMO property, for metering of self expenses of substations/facilities of TSMO that are supplied by DSO network, responsible for metering system is DSO. Accuracy level of meters shall be 0.5 (for active) and 1.0 or 2.0 (for reactive). It is sufficient that for these metering points to install only one meter and that the main one. 7.2 Derogations and Planned Upgrade of Metering Systems General Where metering systems that are currently in service do not meet the requirements of this code and/or of other current regulations their continued use will be permitted in accordance with the following arrangements until the metering systems can be upgraded in a planned manner. No derogations shall be permitted for metering systems commissioned after the date this metering code is approved unless the metering system fails to comply with the provisions of an amendment to this metering code that comes into force after the date of commissioning of the metering system. In that case it shall be permitted to issue a derogation in respect of that amendment and any other subsequent amendment The principles for the continued use of such metering equipment are: That the system user should not be disadvantaged by the NO being unable to upgrade the metering equipment.

17 That the system user should be able to request a change in metering equipment in accordance with the provisions of article 33.3 of the law on electricity and the conditions for connection established by the rule on general conditions of electricity supply and expect that change to take place within a reasonable period. That a NO should expect a reasonable return from its investment in the installation of metering equipment as determined by the regulator in the network access tariff and that the NO and system users generally should be protected from having to pay for frequent changes to the metering equipment installed at the premises of any one system user Registration of Metering Systems not fully Compliant The NO shall maintain a register of all metering systems that are not fully compliant with the requirements of this code, other regulations and the tariff requirements of the system user. This register shall include details of all metering system deficiencies By 1 February in each year a report detailing all metering system deficiencies shall be prepared by the NO and submitted to the market operator who will make recommendations regarding the continuation in service of the deficient metering systems to the regulator. The regulator will review the report and determine whether the continued use of the metering system should be permitted beyond 1 February of the following year The regulator shall instruct the market operator and the NO accordingly So that metering systems are brought up to the standard required by this code and other regulations in a phased manner, the NO shall establish a metering upgrade programme to ensure: In the case of metering systems that did not comply with the requirements of the applicable rules and regulations on the date of their first installation, that they shall meet the required standards within one year of the deficiency becoming apparent. In the case of metering systems that did comply with the requirements of the applicable rules and regulations on the date of their first installation, that they shall meet the required standards within the periods established in section

18 Where eligible customers are obliged by the certificate of eligibility issued by the regulator to install a metering system or metering systems compliant with the requirements of this code they must be installed within the timescale established in the certificate of eligibility issued by the Regulator Upgrade periods All meters that do not comply with the requirements of this code or other current regulations but that did comply with the requirements in force on the date of their first commissioning must be replaced by compliant meters at the end of their verification period If, on the date on which this code is approved by the regulator, meters that did comply with the requirements in force on the date of their first commissioning are already non-compliant and outside their verification period, then they must be replaced by compliant meters within a period of five years. The NO is required to agree a phased correction programme with the regulator such that an approximately equal number of metering systems will be installed in each year of the upgrade period If meters do not exist then compliant meters must be installed within a period of one year If CTs or VTs do not meet the requirements of this code or other regulations but did comply with the requirements in force on the date of their first commissioning and their replacement will require the replacement of a significant item of main plant, then they may continue in use until such time as the item of main plant is replaced at which point the relevant CTs and VTs must be replaced with equipment that complies with this code If CTs or VTs do not meet the requirements of these rules or other regulations, but did comply with the requirements in force on the date of their first commissioning and their replacement will not require the replacement of a significant item of main plant, then they must be replaced by compliant metering equipment within a period not exceeding five years from the date on that this code is approved by the regulator. The NO is required to agree a phased correction programme with the regulator such that an approximately equal number of metering systems will become compliant by virtue of the replacement of their CTs or VTs in each year of the upgrade period.

19 7.2.4 Estimation during Upgrade Periods If it is necessary to estimate the energy consumption at a connection point that is subject to the planned upgrade provisions of section such estimate will be carried out in accordance with the market rules Exemptions Where the NO is able to demonstrate to the satisfaction of the regulator that a metering system that does not fully meet the requirements of this code but does meet the requirements of all other regulations and meets the requirements of sections and 10, the tariff requirements of the system user, and is within its verification period, then the metering system may remain in service without modification until the end of the verification period or until such time as significant work is undertaken on the metering system whichever is earlier. 8 Metering Systems 8.1 Minimum Metering Requirements All supply points shall require as a minimum to have a non-interval meter able to record active energy and incorporate a display showing the integrated total Where required to meet the requirements of the network access tariff applicable to the supply point, meters to record reactive energy shall also be installed Interval metering shall be installed at: the connections between transmission systems operated by different NOs and between the transmission system and distribution systems, the connections between distribution systems operated by different NOs,

20 the connection points of generating units where the generator wishes to be paid for the energy they transfer to the public electricity network, the supply points of eligible customers who choose their own supplier, and any other supply point where the regulator deems that interval metering shall be installed System users operating solely within Kosovo who are obliged to install interval metering must install metering where the interval is the settlement period established in the market rules. System users whose networks connect to other networks outside of Kosovo or trade energy with enterprises outside Kosovo must install metering where the interval is the shorter of the settlement period established in the market rules and the settlement period established by ETSO to meet settlement requirements in the regional market or, if no such period is defined, a period of 15 minutes Interval metering shall measure, record and store energy transfer information for each settlement period and be capable of being interrogated both remotely and locally. The data storage of interval meters must hold a minimum of 45 days of information for each settlement period. The mandatory requirements for different classes of connection are detailed in the following sections. This data may be held in a data concentrator that is within the same case as the meter or in a separate unit All metering equipment must be of a pattern approved by the ministry by the issuance of a type approval certificate in accordance with section All metering systems must be compliant with the relevant technical standards specified in section and meet the accuracy class requirements detailed in section Capacity and Energy Measurements The metering equipment installed at each connection point shall measure, record and store the capacity and energy measurements listed in the following table that are required for settlement and network access purposes. Capacity and Energy Measurements Import kw and kwh Export kw and kwh Reactive Energy (Lagging) kvar and kvarh Reactive Energy (Leading) kvar and kvarh Interval Meter

21 Capacity and Energy Measurements Import kw and kwh Export kw and kwh Reactive Energy (Lagging) kvar and kvarh Reactive Energy (Leading) kvar and kvarh Interval Meter Connections between the transmission system and other systems Connections between distribution systems Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Generating units Yes Yes Yes Yes Yes Supply Points of eligible customers and supply points where regulator determines that interval metering is required - 1MW and above Supply Points of eligible customers and supply points where regulator determines that interval metering is required - below 1MW Yes No Yes Yes Yes Yes No Yes * No Yes Other Supply Points Yes * No Yes * No No * in the case of these supply points, the measurement and recording of kw, kvar and kvarh is only necessary if required by the network access tariff appropriate to the supply point Metering equipment shall be installed at the point of connection between the networks of different NOs or at the connection point between the network of a NO and that of a system user Where it is not practicable to install metering equipment at the boundary between networks as detailed in section , the metering equipment shall be installed as close as is reasonably practicable to the network boundary and correction factors agreed between the parties responsible for the networks of either side of the connection point and the market operator. In the event that the parties cannot agree appropriate correction factors, the issue shall be referred to the dispute resolution process Where correction factors are applied they shall, wherever possible, be applied to the meters so that the data displayed on the meter register shall reflect the obligations of

22 the parties. Where it is not possible to apply correction factors at the meters, they may be applied to the metering data either in any data concentrator out station associated with the meter or by the RDC A regime using main and check meters for measuring active energy shall be employed to ensure that accurate metering data is available in the case of the most important data in respect of all connections where the energy transfer is large or of particular importance to the settlement process Main and check meters shall be installed as laid out in the following table that also shows where separate VTs and CTs should be provided to drive the main meter and the check meter: Use of Main and Check Meters Main meter Check meter Separate CTs Separate VTs Connections between the transmission system and other systems Yes Yes Yes Yes Connections between distribution systems Yes Yes Yes No Generating units Yes Yes Yes Yes Supply Points of eligible customers and supply points where regulator determines that interval metering is required - 1MW and above Supply Points of eligible customers and supply points where regulator determines that interval metering is required - below 1MW Yes Yes Yes No Yes No No No Other Supply Points Yes No No No Where separate CTs or VTs are required, it shall be sufficient to provide CTs or VTs with separate secondary windings but where the primary winding is shared Where more than one appropriate VT exists, a changeover arrangement should be installed so that a voltage reference is available in the event of loss of supply from one VT. Where separate VTs are required to comply with the requirements of section , the changeover arrangement for each of the main and check meters should be biased towards different VTs The VT reference for metering systems should be fused as close to the terminations of the secondary winding as is practicable. Where other burdens are

23 applied to the secondary winding in accordance with the provisions of section , the metering and other burdens shall be separately fused Where the main and check meters share the same voltage reference and the cable run from the fuses mounted at the VT terminals to the meters is greater than 30 metres, the voltage reference for the main and check meters shall be separately fused as close to the VT terminals as is practicable The metering data recovered from main meters shall only be disregarded and the data recovered from check meters used in its place in those situations detailed in the market rules. Where there is a difference between the values recorded by the main and check meters beyond the normal limits of accuracy, the reason for these differences shall be investigated by the NO who will recommend the action to be taken in accordance with the market rules A system user shall have the right to request that an expert assigned by the regulator investigates the difference in values where the system user does not agree with the decision of the NO following any review undertaken in accordance with section Where it is not required that both physical meters record the same type of data it shall be permissible for data to be recorded by either the main or the check meter. Where it is practicable, metering data, the recording of which is not required to be duplicated should be split between the meters of the metering system so that the amount of data lost in the event of a single equipment failure is minimized Technical Specification of Metering Equipment The metering equipment shall be accurate within the prescribed limits for such metering equipment referred to or set out in this metering code All active energy meters shall meet the requirements of IEC or IEC and the relevant parts of IEC as appropriate All reactive energy meters shall meet the requirements of IEC and the relevant parts of IEC as appropriate All meters shall be labelled with a unique identifier and this information together with the technical details and specifications shall be recorded by the NO All voltage transformers (VTs) and current transformers (CTs) shall meet the requirements of the relevant parts of IEC

24 The total burden on the secondary winding of a VT or CT shall in no circumstances exceed the rated burden of that winding Where practicable, the secondary winding of VTs and CTs used for metering purposes should be exclusively used for metering purposes, however it shall be permissible to share the use of the winding with other equipment provided the requirements of sections , and 9 are met and the approval of the market operator has been obtained. Once approval of shared use has been given it shall not be permitted to change the burden on any CT or VT winding without again obtaining the approval of the market operator Existing Measurement Transformers Where circuits, other than those newly installed, are to be metered in compliance with the market rules and this metering code, and where the installed measurement transformers do not comply fully with the requirements of section and of section , then such measurement transformers may continue to be used providing the following requirements and those in sections and are met Where subsequently a significant alteration to the primary plant is carried out, new measurement transformers meeting the full requirements of this metering code shall be provided. 8.3 Metering Equipment Overall Accuracy The permissible error limits for metering systems recording active energy shall be: Overall Metering Accuracy Current (relative to rated current) Power Factor Error Limit 120% to 10% 1 ± 0.5% Connections between the transmission system and other Below 10% to 5% 1 ± 0.7% systems and Below 5% to 1% 1 ± 1.5% Generating units - 100MW and 0.8 lead ± 1.0% above 120% to 10% 0.5 lag ± 1.0% Connections between distribution systems, and 120% to 10% 1 ± 1.0.% Below 10% to 5% 1 ± 1.5%

25 Overall Metering Accuracy Current (relative to rated current) Power Factor Error Limit Generating units below 100MW Supply Points of eligible customers and supply points where regulator determines that interval metering is required - over 10MW Supply Points of eligible customers and supply points where regulator determines that interval metering is required - between 1MW and 10MW Below 5% to 1% 1 ± 2.5% 120% to 10% 0.8 lead ± 2.0] 0.5 lag ± 2.0% 120% to 10% 1 ± 1.5% Below 10% to 5% 1 ± 2.0% 120% to 10% 0.8 lead ± 2.5% 0.5 lag ± 2.5% 120% to 20% 1 ± 1.5% Supply Points of eligible customers and supply points where Below 20% to 5% 1 ± 2.5% regulator determines that interval 0.8 lead ± 2.5% metering is required - below 1MW 120% to 10% 0.5 lag ± 2.5% Other Supply Points 100% to 5% 1 ± 2.5% The permissible error limits for metering systems recording reactive energy shall be: Overall Metering Accuracy Current (relative to rated current) Power Factor Error Limit All connections between networks, Generating units, and 120% to 10% 0 ± 4.0% 0.87 lag ± 5.0% Supply Points of eligible customers and supply points where regulator determines that interval metering is required - 1MW and above 120% to 20% 0.87lead ± 5.0% 0.87 lead ± 5.0% Supply Points of eligible 100% to 20% 0 ± 5.0% customers and supply points where regulator determines that interval 100% to 20% 0.87 lag ± 5.0%

26 Overall Metering Accuracy metering is required - below 1MW, and other Supply Points where required by network access tariff Current (relative to rated current) Power Factor Error Limit 0.87 lead ± 5.0% Metering Equipment Accuracy Class The accuracy class for installed metering equipment shall be: Metering Equipment Accuracy Active Meter Reactive Meter CTs VTs Connections between the transmission system and other systems and Generating units MW and above 0.2S S 0.2 Connections between distribution systems, Generating units below 100 MW and Supply Points of eligible customers and supply points where regulator determines that interval metering is required - 10MW and above] Supply Points of eligible customers and supply points where regulator determines that interval metering is required - 1MW and above Supply Points of eligible customers and supply points where regulator determines that interval metering is required - below 1MW, 0.2S S

27 Metering Equipment Accuracy Active Meter Reactive Meter CTs VTs other Supply Points Interval Meter Data Requirements Data Storage Metering data for interval meters shall be stored at the point of measurement as established in section The data transmitted by the data concentrator to the remote data centre (RDC) shall be to a format and protocol that is supported by the RDC The data concentrators will normally be interrogated and the metering data collected by the RDC on a daily basis. However repeat collections of metering data shall be possible throughout the data concentrator data storage period. No read operation shall delete or alter any stored metered data. A data concentrator shall provide any portion of the data stored upon request by the RDC The data concentrators shall provide an alarm output signal at the RDC in the event of a power supply failure. To cater for continuous supply failures, the clock, calendar and all data shall be supported for a period of 45 days without an external supply connected Timekeeping The timekeeping requirements of the RDC and the local metering systems shall be as detailed in the following paragraphs All measured settlement periods shall be related to the time point 00:00:00 in accordance with the national time standard Time synchronization of the RDC shall only be performed by means of an integrated receiver and synchronized radio signal and synchronization shall be undertaken every six hours Where portable equipment is used by the RDC to collect data from a data concentrator in the event of a communications failure, time synchronization of the portable equipment shall be performed by means of an integrated receiver and synchronized radio signal or by a synchronizing reference signal from the main

28 systems of the RDC. Time synchronization must be undertaken either immediately before and immediately after being taken to collect data or, if these events are separated by more than 24 hours, at least once every 24 hours Time synchronization of the data concentrator shall be performed by means of an integrated receiver and synchronized radio signal or by a synchronizing reference signal from the RDC. Facilities for time synchronization of the data concentrator by means of an integrated receiver and synchronized radio signal shall be provided at connection points on transmission systems and at generation connections points and may also be provided at other connection points On each occasion that the systems of the RDC interrogates a data concentrator, the time recorded by the data concentrator will be checked against the time recorded by the RDC systems and, if the difference is greater than 2 seconds and less than 10 minutes then the RDC systems shall correct the time registered by the data concentrator. Where the time difference is greater than 10 minutes the time recorded by the data concentrator shall not be corrected and any data collected shall not be processed until the cause of the discrepancy is investigated and the effect of the discrepancy on the collected data is understood Monitoring Facilities Monitoring facilities shall be provided for each of the following conditions: error in data concentrator functionality, reverse running of the meter (if available), battery monitoring and power supply monitoring, memory check, VT supply problem, local interrogation port access Any of the above failures shall be reported by, at a minimum, a common alarm indication when data is retrieved by the RDC and when the local interrogation port is accessed. The alarm should be tagged to the relevant settlement period.

29 8.4.4 Communications Equipment Each data concentrator shall accommodate both local and remote interrogation facilities from separate ports The metering equipment shall be installed such that both the reading and the reprogramming of metering data held in the metering system shall only be possible through access both locally and remotely at a suitable security level controlled by appropriate passwords Local Interrogation An interrogation port shall be provided for each data concentrator to enable a local data terminal such as a notebook PC to be connected for the following purposes: Commissioning, maintenance and fault finding, Transfer of metering data in the event of a communications failure, and Time setting when this cannot be done remotely or automatically Remote Interrogation Each data concentrator shall be equipped with an internal or external communications interface such as a modem or radio transmitter that supports the data exchange for local and remote interrogation according to IEC or the relevant parts of IEC A communication link shall be provided to enable the acquisition of the metering data by the RDC. This link may also be used by the NO for the normal purposes associated with commissioning, maintenance and fault investigation in respect of the metering system The communication link may be established using dedicated or dial-up circuits, but it is not permitted for metering data to pass through any IT system where data could be manipulated while in transit to the RDC.