Operating Security Standards

Transcription

1 Version 1.1 Prishtina December 2009

2 TABLE OF CONTENTS 1 Introduction Definitions General Kosovo Transmission System Circuit The N-1 Criterion Normal System Conditions Adverse Weather Conditions Unacceptable Voltage Condition Step Change in Voltage Unacceptable Overloading of Equipment General Information Operating the Kosovo Transmission System General Policy Normal Operational Criteria 400kV and 220kV System General Principles Inability to meet N-1 Criterion Normal Operational Criteria 110kV System General Principles Inability to Meet N-1 Criterion Overloading of Plant Post-fault Restoration of System Security Outage Conditions kV System kV System kV System Operating Under Outage Conditions System Restoration Grid Code Requirements...7 i

3 3.7.2 Permanent Faults Dealing with Adverse Weather Operating Constraints Voltage Limits General Exceptional Limits Normal Limits Failure to Meet Voltage Limits Busbar Arrangements General General Conditions Disputes Procedure Amendments to the Unforeseen Circumstances Appendix 1 Single Radial Circuits Appendix 2 Specific 220kV elements Appendix 3 Winter Season Limitations Appendix 4 Summer Season Limitations Appendix 5 Voltage Limits Exceeded ii

4 1 Introduction The Transmission System Operator (TSO) license requires KOSTT as licensee to..comply with all Articles and conditions stipulated in this license for carrying out the licensed activity, and with the requirements of all relevant legislation and directions of ERO This document is produced pursuant to Article 15 of the Transmission System Operator License with Conditions granted to KOSTT Transmission System and Market Operator J.S.C. It should be read in conjunction with the Grid Code and the Transmission System Security and Planning Standards This document sets out a set of criteria and methodologies that the TSMO should adopt in the operation of the Kosovo transmission system. These include cost-benefit techniques and weather related operation and the need for services to be provided for voltage and reactive power control. 2 Definitions 2.1 General In this document the defined terms used have the meanings contained within the glossary of the Kosovo grid code except where they are specifically defined below. The defined terms are shown in bold type Kosovo Transmission System For the purposes of this document the Kosovo transmission system consists of the following: The 400kV, 220kV and 110kV lines, the 400/220kV and 220/110kV transformers and associated plant and apparatus within Kosovo that are owned by KOSTT; The 110kV busbar and 110kV line circuit breakers and associated plant and apparatus at Sharri; 1

5 The 110kV busbar including the bus coupler and the 110kV line circuit breakers and associated plant and apparatus at Trepça; Circuit A circuit is that part of the system between two or more circuit breakers inclusive. It may include transformers, series reactors, underground cables and overhead lines. Shunt reactors and capacitors and busbars are not regarded as circuits. Guidelines for shunt reactors and capacitors are dealt with in section Guidelines for busbar arrangements are set out in section The N-1 Criterion The N-1 criterion is a rule according to which elements remaining in operation after failure of a single network element (such as a transmission line, transformer or generating unit, or in certain instances a busbar) must be capable of accommodating the change of flows in the network caused by that single failure Normal System Conditions The situation when the Kosovo transmission system is being operated with no system outages, either planned or fault Adverse Weather Conditions Weather conditions that significantly increase the risk of system faults (eg due to high lightning risk or other severe weather conditions) Unacceptable Voltage Condition A voltage outside the ranges for normal circumstances or exceptional circumstances, as appropriate, as specified in the balancing code of the grid code Step Change in Voltage The voltage change experienced at a transmission substation about [one] second after the occurrence of an outage, after any severe transients due to a fault have died away and any generator voltage regulator action has taken place Unacceptable Overloading of Equipment The overloading of any piece of electrical equipment beyond its specified time-related capability. Due allowance shall be made for agreed time and pre-fault dependent 2

6 loading cycles of equipment and, where applicable, for the relief obtainable from agreed procedures. 2.2 General Information In addition to special meanings detailed above, 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 code of practice 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 document, 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 Operating the Kosovo Transmission System 3.1 General Policy In principle the Kosovo transmission system will be operated at all times under normal conditions to satisfy the N-1 criterion. However this will not apply to specific 110kV elements where the system design does not permit this. These are detailed in Appendix With the exceptional supply shortage circumstances in Kosovo there will be numerous occasions over and above those referred to in paragraph when the N-1 criterion cannot be fulfilled under normal operation. These situations are dealt with in the following sections of this document and are detailed in the Appendices. 3

7 3.2 Normal Operational Criteria 400kV and 220kV System General Principles The 400kV and 220kV transmission system shall be operated under the prevailing normal system conditions so that in the event of a fault outage in Kosovo or in the neighbouring UCTE systems of any of the following single items: An overhead or underground transmission line, a transformer or a reactive compensator; The loss of a generating unit or a power infeed; There shall not be any of the following: System instability that could cause a widespread blackout; A loss of supply capacity; Unacceptable overloading of any primary transmission equipment; Unacceptable voltage conditions; Inability to meet N-1 Criterion With the limited capacity of the Kosovo transmission system there are a number of situations under normal operation when the N-1 criterion cannot be satisfied on the 220kV system during the winter season. Appendix 3 lists the transmission network elements that are affected. 3.3 Normal Operational Criteria 110kV System General Principles Except as detailed in section the 110kV transmission system shall be operated under the prevailing normal system conditions so that in the event of a fault outage of any of the following single items: An overhead or underground transmission line; The loss of a generating unit or a power infeed: There shall not be any of the following: 4

8 A loss of supply capacity except as specified in Appendix 1; Unacceptable overloading of any primary transmission equipment; Unacceptable voltage conditions; System instability: Inability to Meet N-1 Criterion With the limited capacity of the Kosovo transmission system there will be numerous occasions under normal operation when not only the N-1 criterion cannot be satisfied but that all demands can also not be met. Under these circumstances the TSMO shall operate the situation with the following priorities: Ensuring the safety of staff and other people; Ensuring that plant is not operated in a manner that would damage it; Ensuring that a single additional event does not lead to a widespread blackout in Kosovo; Satisfy as far as is possible system demands; Maintain the system voltage within the limits specified in the grid code; Operate to satisfy the N-1 criterion: Appendix 1 lists the 110kV elements where the substations are supplied by a single radial line and a single outage under all normal operating conditions will result in a loss of supply Appendix 3 lists the transmission network elements where the N-1 criterion cannot be met during the winter season Appendix 4 lists the transmission network elements where the N-1 criterion cannot be met during the summer season. 5

9 3.4 Overloading of Plant Overloading of plant is permitted, so long as it is within the plant s short term rating and where the overload can be removed by manual switching within the allowable time of the plant short term rating. 3.5 Post-fault Restoration of System Security Following the occurrence of a permanent fault outage the TSMO shall take measures in line with its obligation under the grid code to restore the system to the above operational criteria as soon as is reasonably practicable. To this end the TSMO should have plans in place in order to facilitate the speedy restoration of system security. 3.6 Outage Conditions kV System Pre-arranged outages on the 400kV system shall be planned so that the 400kV system can be operated to satisfy the N-1 criterion and meet the requirements of paragraphs and For the 400kV network the outages of transmission lines that are interstate interconnectors and all other 400kV outages must be coordinated with the other parties in line with the appropriate interconnection agreement and the operational planning code of the grid code kV System Pre-arranged outages on the 220kV system shall be planned so that the 220kV system can be operated as far as it is possible to satisfy the N-1 criterion and meet the requirements of paragraphs and Appendix 2 lists the circuits where due to circuit design this requirement cannot be met For the 220kV network the outages of transmission lines that are interstate interconnectors and all other 220kV outages must be coordinated with the other parties in line with the appropriate interconnection agreement and the operational planning code of the grid code. 6

10 kV System Pre-arranged outages on the 110kV system shall be planned so that the 110kV system can be operated as far as it is possible to satisfy the N-1 criterion and meet the requirements of paragraphs and For the 110kV network the outages of transmission lines that interconnect with other states and outages of other relevant circuits must be coordinated with the other parties in line with the appropriate interconnection agreement and the operational planning code of the grid code Operating Under Outage Conditions For most outage situations on the 110kV network and for the 220kV circuits listed in appendix 2 the N-1 criterion cannot be met during planned outages. Under these situations the system should be operated in order to satisfy the following criteria in this priority order: Ensuring the safety of staff and other people; Ensuring that plant is not operated in a manner that would damage it; Satisfy as far as is possible system demands; Maintain the system voltage within the limits specified in the grid code; Operate to satisfy the N-1 criterion: For a number of circuits particularly on the 220kV network the supply to certain substations under outage conditions can only be maintained via an interstate interconnector and therefore the outages must be co-ordinated with the other parties as per the interconnection agreement and the operational planning code of the grid code. 3.7 System Restoration Grid Code Requirements Every outage request should contain the information that is required by the grid code and this must include details of the emergency restoration time at various stages of the outage and confirmation that a contingency plan for emergency restoration is in place. 7

11 3.7.2 Permanent Faults In the event of a permanent fault that causes a loss of load the TSMO shall have in place plans and arrangements in order to enable as much of the demand as possible to be restored as soon as is reasonably practicable. The TSMO shall make best endeavours to restore the total demand as quickly as possible using all resources that are available to them. 3.8 Dealing with Adverse Weather Under adverse weather or forecast adverse weather conditions the TSMO shall take whatever actions he deems necessary in order to protect the integrity of the network and in the event of a permanent outage to restore it to its normal state as quickly as possible. This could include having staff readily available, support and co-ordination arrangements with neighbouring TSOs, restoring to service circuits that are out of service etc. 3.9 Operating Constraints The TSMO should operate the Kosovo transmission system in a secure, stable and safe manner as well as satisfying all user requirements both generation and demand and facilitating the electricity market However there may be situations when because of system constraints it will not be possible to facilitate the electricity market and achieve system security. Under these conditions system security must take priority over fulfilling all the requirements of the market participants Voltage Limits General At all times under both normal and outage conditions the Kosovo transmission system should be operated to satisfy the voltage limits specified in the balancing code of the grid code. Under both normal and outage conditions a single contingency including a fault outage of a circuit, generating unit, power infeed or shunt reactor or capacitor should not breach the requirements of sections and

12 Exceptional Limits The system should be operated so that any step change in voltage after a fault or other significant event should not exceed [10]% of the pre-fault steady state voltage and the voltage level should not be outside the limits for exceptional circumstances specified in the balancing code of the grid code Normal Limits After a step change in voltage as above manual and automatic actions should be taken to restore the voltage within [10] minutes to within the normal limits as specified in the balancing code of the grid code Failure to Meet Voltage Limits There are a number of locations on the 110kV network where the voltage limits for normal circumstances cannot be maintained at all times under normal system conditions. Under these situations the system shall be operated with the following priorities: Ensuring the safety of staff and other people; Ensuring that plant is not operated in a manner that would damage it; Ensuring that a single additional event does not lead to a widespread blackout in Kosovo; Satisfy as far as is possible system demands; 3.11 Busbar Arrangements General In selecting the best busbar arrangements for normal operation or during planned outage conditions it is necessary to consider the possible effects of any credible fault and to adopt the arrangement which provides the best overall system security while, if necessary, limiting system fault level Lines and transformers shall be distributed over the available busbars in such a way that the impact of a busbar failure will be as limited as possible The arrangement chosen should take into account the likelihood of faults. In the order of a circuit or a single generator, a single busbar section, two coincident faults or two sections of busbar. 9

13 4 General Conditions 4.1 Disputes Procedure Disputes arising from the application of these operating security standards shall be dealt with in accordance with the provisions of the grid code and with the rule on dispute settlement procedures approved by the regulator as a means for resolving disputes arising between parties in the power market. 4.2 Amendments to the The transmission system operator is responsible for the administration of all technical codes and the relevant standards for electricity that required under the terms of its licence. This includes the operating security standards, which are subject to the approval of the regulator prior to their implementation Amendments to these operating security standards will be undertaken by the operation codes governance committee (OCGC) 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 for posting the amended document on their website The appendices to these operating security standards will be reviewed annually in [November] of each year. Any changes will be agreed by the TSMO and the regulator and the amended document will be posted by the TSMO on their website. 4.3 Unforeseen Circumstances The TSMO will operate the Kosovo transmission system in accordance with these operating security standards and other codes and standards. If a situation arises that could not have reasonably been foreseen then the TSMO will act as per the unforeseen circumstances provisions of the grid code. 10

14 5 Appendix 1 Single Radial Circuits This lists the 110kV elements where because of system design, where the substations are supplied by a single radial line, a single outage under all normal operating conditions will result in a loss of supply Type of Element Identification From To Overhead Line TL 1801 SS KOSOVA A SS BARDHI Overhead Line TL 1809 SS RAHOVEC SS PRIZRENI 2 Overhead Line TL 1213 SS PRISHTINA 4 SS LYPJAN Overhead Line TL 1800 SS VALLACI HPP UJMANI 11

15 6 Appendix 2 Specific 220kV elements This lists the 220kV elements where because of system design the N-1 criterion cannot be satisfied during the planned outage of a single element Type of Element out Element From To Element of Service that doesnt fullfill N-1 criteria Overhead Line TL 267 TL 2306 SS KOSOVA A SS KOSOVA B Overhead Line TL 2306 TL 267 SS KOSOVA A SS KOSOVA B Overhead Line TL 293/2 TL 2303* SS PRIZRENI 2 SS PRIZRENI 2* Overhead Line TL 2303 TL 293/2* SS PRIZRENI 2 SS PRIZRENI 2* S.G. DRENAS SS FIERZA SS FIERZA S.G. DRENAS Overhead Line TL 205/2 TL 205/1 SS BESIANA KRUSHEVCI Overhead Line TL 205/1 TL 205/2 SS BESIANA SS KOSOVA B Overhead Line TL 2304 TL 2305 SS PRISHTINA 4 Overhead Line TL 2305 TL 2304 SS PRISHTINA 4 SS KOSOVA B SS KOSOVA B Overhead Line TL 2299 TL 2300 S.G. DRENAS SS FERONIKELI Overhead Line TL 2300 TL 2299 S.G. DRENAS SS FERONIKELI 12

16 7 Appendix 3 Winter Season Limitations This lists the transmission network elements where the N-1 criterion cannot be met during the winter season. Type of Element out of From To Element Service 220kV Overhead Line TL 293/2 - S.G. DRENAS SS PRIZRENI 2 Autotransformer TR1 SS PEJA 3 Autotransformer TR1 or TR2 SS PRISHTINA 4 110kV Overhead Line TL 184 SS PRISHTINA 4 SS GJILAN Overhead Line TL 164/3 SS PRIZRENI 2 SS PRIZRENI 1 Overhead Line TL 164/1 SS GJAKOVA 1 SS GJAKOVA 2 Overhead Line TL 126/3 SS PEJA 1 SS PEJA 3 13

17 8 Appendix 4 Summer Season Limitations This lists the transmission network elements where the N-1 criterion cannot be met during the summer season. Type of Element Identification From To 220kV Overhead Line TL 293/2 S.G. DRENAS SS PRIZRENI 2 110kV None,except radial lines 14

18 9 Appendix 5 Voltage Limits Exceeded The following is a figure of the 110kV nodes where is shown the improvement of voltage levels after the 2009 enforcement in transmission network. All 110 kv nodes have voltage in allowed limit according the Grid Code. In the figure below is presented the development of transmission capacity versus load, where it can seen the improvement of network capacity. [End of Document] 15