Reliability Performance Evaluation Work Group

Transcription

1 Reliability Performance Evaluation Work Group Phase I Probabilistic Based Reliability Criteria Evaluation of Exceptions List Facilities February 2, 2001

2 Phase I Probabilistic Based Reliability Criteria Evaluation of Exceptions List Facilities Purpose The purpose of this report is to document and present to PCC the Reliability Performance Work Group (RPEWG) evaluation of the Criteria Exceptions List facilities using the Phase I Probabilistic based Reliability Criteria (PBRC) as required by the RPEWG s work scope. Criteria Exceptions List A list contain the exception facilities and their descriptions as provided in the original TSS documentation (Criteria Exceptions List, January 1996.) is given in Attachment 1. Two categories of exceptions are identified: (1) disturbances declared noncredible, and (2) credible disturbances that have been granted exceptions to the criteria. An Exceptions List developed for the Phase I PBRC test period application is given in Table 1 below. This list was developed using Attachment 1. In developing this list several considerations were made: Develop more encompassing description of the exceptions, provide appropriate means for collocating sufficient data to assess outage frequencies, and combine the two categories of the original exception lists since their outage credibility will be re-evaluated using Phase I PBRC. Exceptions List Outage Data The RPEWG requested outage data of all Exceptions List facilities and provided outage data submittal templates. Transmission facility multiple element outage data resulting form simultaneous outages of dependent events are considered. Outages or system impacts caused due to RAS failure or system wide disturbance that are caused outside the facility are not subject for performance evaluation by the RPEWG. The utilities that submitted outage data associated with the Exceptions List are indicated in Table 1. Data for all of the Exceptions List items except No. 2 and 3 have been provided. MJB 2/2/01 1

3 Table 1: Exception List Facilities for Phase 1 PBRC Evaluation (The description of the Exceptions List Facilities is given in Attachment 1.) No. Description RAS Available Data Submitted Data Submitted by 1 Laramie River fault with loss of 2 circuits No Yes WAPA & BEPC 2 NE/SE Separation Scheme Misoperation Yes No 3 Bridger fault with loss of 2 circuits and RAS failure Yes No 4 Taft fault with loss of 2 circuits and RAS failure Yes Yes BPA 5 Navajo fault with loss of 1 circuit with 1 circuit already out and system unadjusted 6 Malin fault with loss of 2 circuits and RAS failure 7 Ingledow fault with loss of 2 circuits and RAS failure No Yes APS Yes Yes PG&E Yes Yes BCH 8 IPP Bipole outage and RAS failure Yes Yes LADWP 9 Palo Verde fault with loss of 2 circuits No Yes APS 10 Navajo fault with loss of 2 circuits No Yes APS 11 Lugo fault with loss of 2 circuits No Yes SCE 12 a) Navajo fault with loss of 2 circuits No Yes APS b) Eldorado fault with loss of 2 circuits No Yes APS WSCC Reliability Criteria for Transmission Planning Application To perform reliability performance evaluation of the Exceptions List facilities, general reliability criteria principles with regard to the application of the WSCC Disturbance Table, and definitions of the multiple element outages, two circuit outages, and Remedial Action Scheme are utilized. Some of the pertinent requirements and definitions from the WSCC criteria are given in Attachment 2. MJB 2/2/01 2

4 Phase I PBRC Performance Table and Data Interpretation Given below are the Phase I PBRC Performance Table and some conceptual diagrams for interpretations of the criteria. Performance Level Disturbance Outage Class Outage Frequency (outages/year) Mean-Time- Between-Failure (year) V 1 (%) t (cycle) V 2 (%) f min (Hz) A Single Element >0 B Bus Section >0 C Two Element >0 D More than Two NO CASCADING PERMITTED Elements (I)* E More than Two Elements (II)** < < EVALUATE FOR RISKS & CONSEQUENCES * Three or more circuits on common ROW ** Other multi-circuit outages identified in the March 1999 Reliability Criteria. Damp. (%) Probability of Occurrence A B/C D E V V = Variance Logarithmic Scale MTBF, years A B C D E Logarithmic Scale MTBF, years MJB 2/2/01 3

5 Remedial Action Scheme Issues The Exceptions List facilities that contain RAS are indicated in Table 1. Six out of the twelve Exceptions List facilities include RAS failures. RPEWG is not mandated to evaluate the reliability of these RASs or the credibility of their failures. Only the outage data related to the transmission equipment is analyzed. Information on RAS failures that are obtained during the performance evaluation will be forwarded to the WSCC Remedial Action Scheme Reliability Task Force (RASRTF) for their review and consideration. Criteria Exception in the PBRC Table By definition, the WSCC Criteria Exceptions List facilities are not required to meet any of the WSCC Criteria. (See Attachment 1 and 2.) From the PBRC application, the criteria for the Exception List facilities is Level E or better with MTBF greater than 300 years, or outage frequency of less than outages per year. Performance Evaluation Considerations As outlined in the Phase I PBRC report of June 25, 2000: Performance level evaluation (PLE) includes event probability assessment of facility taking into consideration the facility s physical characteristics, design considerations, operational history, geographic location, environmental surrounding, or other appropriate factors. (Section 4.1) A facility in the Exceptions List that is projected to have higher outage frequency than the class in which it is placed due to the exception may be downgraded 1 in its performance level following PLE. (Section 4.1) When considering performance level upgrade or downgrade of a facility, the facility s outage impact should be part of the consideration. (Section 4.1) To be consistent, as much as practicable, with the requirements of the new NERC Planning Standards and existing WSCC Reliability Criteria, no cascading or voltage collapse will be allowed for "loss of a single component" or "single system element disturbances," respectively 2. Outside the existing NERC and WSCC criteria, planned loss of load or loss of generation may be allowed for single element outage disturbance for less probable outages. (Section 4.1) 1 Downgrade = Making the performance level requirement more stringent; for example changing requirement from Level D to C, or B to A. 2 NERC Planning Standards, Page 14, Table I, Column 1; WSCC Reliability Criteria for Transmission System Planning Page 2, Paragraph 5. MJB 2/2/01 4

6 [R]PEWG may reasonably request additional information or data associated with its performance level evaluation and determination and the entity(s) involved should furnish the data to the extent it is available. (Section 4.3.5) Upon consensus agreement by [R]PEWG members, performance level adjustment recommendations are made to the appropriate WSCC group or committee for consideration and further actions. (Section 4.3.5) RPEWG Evaluation Guideline In evaluation of outage data, one outage occurrence is considered statistically insignificant regardless of the outage data time period. However, two or more are considered significant and are used in the reliability performance evaluation. Outage data time period should cover not less than ten years. If data greater than 10 year is available, it can be used in the evaluation at the facility owner s discretion. For facilities that has been in operation less than ten years, data for the operational period will be used. For Performance Level C, D and E, forced automatic 3 common-mode 4 outages are considered in outage counting. This will include: 1. Right-of-way or corridor outages. 2. Relay or other failures of unknown nature. 3. Human or relay failures that cause system outages. For Performance Level A and B, all forced automatic outages are considered in outage counting. Outages not considered in the counting include: 1. System wide outages that are initiated outside the facility in question. 2. Scheduled outages. 3. Major natural disasters or malicious misconduct such as earthquakes or sabotage. Only outage event probabilities are considered in the RPEWG evaluations of the Exceptions List facilities. Outage impacts or the overall performance risk due to outages are not considerations in this RPEWG evaluation. (This is in contrary to the recommendation of Phase I PBRC implementation plan Section 4.1.) Until the WSCC Reliability Subcommittee (RS) develops impact probabilities (Phase II PBRC), RS will be assisting RPEWG in the evaluation of facility outage impacts. As a general guide, RPEWG recommends that a single outage occurrence that results in cascading system impact is sufficient to disqualify an Exceptions List facility. 3 An outage which results from automatic operation of switching devices. 4 A related multiple outage event consisting of two or more primary outage occurrences initiated by a single incident where the outage occurrences are not consequences of each other. MJB 2/2/01 5

7 Exception List Facilities Evaluation and Recommendations Detailed evaluation sheet for each of the Exceptions List facilities is given in Attachment 3. The assessment is strictly based on the data submitted by the facility owners/operators as indicated in Table 1. If different data are made available in the future, the evaluations may be different. Some of the key considerations used in the reliability performance evaluation of the Exceptions List facilities included: Whether the facility is equipped with RAS or not? Whether the outage statistics show one or more outages in ten years? Based on the ten-year data submitted. Is there sufficient data to make the proper evaluation and reliability determination? Conclusions and recommendations are given below: RAS Equipped Facilities: Four facilities (No. 4, 6, 7 and 8) were assessed and the data of each of these facilities did indicate proper operation of their respective RASs. Because, the facilities are equipped with RAS, and the RASs were found to operate properly, these facility are recommend for maintaining their Exceptions status. Facilities Recommended for Keeping their Exceptions Status: Six Exceptions List items (No. 1, 5, 9, 10, 11 and 12) were assessed and found to meet the requirement for keeping their Exceptions status. According to the data submitted, in all of these cases except item 11, the facilities did not experience any outages in the ten-year evaluation period, and the two circuits under evaluation do not have common mode failure conditions. For Exception List Item 11, there was one multi-circuit outage (caused by a plan hitting the lines) that resulted in loss of load in areas outside the initiating utility. Nevertheless, according to the RPEWG Evaluation Guideline, the single event is considered statistically insignificant and thus not counted in the determination of evaluation performance. Furthermore, since the impact did not result in cascading outage, there is no compelling evidence to disqualify the facility from the Exception List. Facilities that have not Provided Data: Evaluation of two Exceptions List items (No. 2 and 3) was not done because no data was provided. Exceptions List No 2, is related with RAS only and no transmission line equipment is involved. Thus, it is recommended that no further evaluation is needed. Exceptions List facility No. 3 is also equipped with RAS. However, it is recommended that the owners of the facilities provide the necessary information to complete the assessment. Mo Beshir MJB 2/2/01 6

8 2/2/01 MJB 2/2/01 7

9 ATTACHMENT 1 Excerpts from: Criteria Exceptions List By System Review Work Group January DISTURBANCE DECLARED NON-CREDIBLE The following is a list of disturbances declared non-credible by the TSS. If any of these outages occur in real life, the subject of their credibility will be re-evaluated by the TSS. Until that time, they will not be formally studied by the WSCC staff as part of the Annual Study Program. DISTURBANCE D2.1: Laramie River 345-kV three-phase fault, loss of the Laramie River-Ault and Laramie River-Beaver Creek 345-kV lines. DISTURBANCE D2.2: False operation of the NE/SE separation scheme RAS malfunction. DISTURBANCE D2.3: Bridger 345-kV three-phase fault, loss of the Bridger-Borah and Bridger-Kinport 345-kV lines with failure of Bridger generator tripping RAS malfunction. DISTURBANCE D2.4: Taft 500-kV three-phase fault, loss of both Taft-Garrison 500- kv lines with total failure of Colstrip generator tripping RAS malfunction. DISTURBANCE D2.5: Navajo 500-kV three-phase fault, loss of the Navajo- McCullough 500-kV line, prior outage of the Navajo-Meonkopi 500-kV line with system unadjusted. DISTURBANCE D2.6: Malin 500-kV three-phase fault, loss of both Malin-Round Mountain 500-kV lines with failure of Chief Joseph brake insertion and Northwest generator tripping remedial action RAS malfunction. DISTURBANCE D2.7: Ingledow 500-kV three-phase fault, loss of both Ingledow- Custer 500-kV lines with failure of Mica generator tripping remedial action RAS malfunction. DISTURBANCE D2.8: Bipole loss of the Intermountain-Adelanto 500-kV DC line, with failure of one of the two Intermountain generators to trip RAS malfunction. MJB 2/2/01 8

10 3.0 CREDIBLE EXCEPTIONS TO THE WSCC RELIABILITY CRITERIA FOR TRANSMISSION SYSTEM PLANNING The following is a list of disturbances found credible by the Reliability Subcommittee but later declared exceptions to the WSCC Reliability Criteria for Transmission system Planning by the Planning Coordination Committee and the Executive Committee. DISTURBANCE D3.1: Palo Verde 500-kV three-phase fault, loss of the Palo Verde- Devers and Palo Verde-North Gila 500-kV lines. DISTURBANCE D3.2: Navajo 500-kV three-phase fault, loss of the Navajo-Moenkopi and Navajo-Westwing 500-kV lines. DISTURBANCE D3.3: Lugo 500-kV three-phase fault, loss of the Lugo-Eldorado and Lugo-Mohave 500 kv lines. DISTURBANCE D3.4: Loss of the Navajo-McCullough and Moenkopi-Eldorado 500- kv lines. MJB 2/2/01 9

11 ATTACHMENT 2 Excerpts from: Western Systems Coordinating Council Reliability Criteria for Transmission System Planning March APPLICATION TO MULTIPLE ELEMENT OUTAGES When experience proves that an outage involving multiple system elements, AC or DC, occurs more than once during the previous three years (sliding three-year scale) and causes (on another system) loss of load or loss of a thermal unit rated greater than 100 MW, then the intent of the Criteria is not achieved. In such event, the owner(s) of the facilities experiencing the disturbance should take the following actions expeditiously: 1. Implement measures to reduce the frequency of occurrence of the disturbance to meet the Criteria, and/or 2. Take steps to reduce the effects of the disturbance; specifically, the owner(s) should make all reasonable efforts to insure that loss of load or loss of a thermal unit rated greater than 100 MW are confined to their own system(s). Historical records of all multiple system element outages are to be maintained by the owners of the facilities experiencing the outages regardless of the effects of the outages. This information is to be made available to other WSCC members upon request. 7.0 APPLICATION TO REMEDIAL ACTION AND SPECIAL CONTROL SCHEMES Remedial Action Schemes (RAS) are allowed as a way to comply with the WSCC Reliability Criteria For Transmission System Planning. If studies show that the RAS failure (i.e., operation when not required or non-operation when required) will result in voltage collapse or cascading, then the RAS failure must be proven to be a non-credible event to the WSCC. Such RAS reliability determinations are made by the WSCC Remedial Action Scheme Reliability Task Force. If RAS failure occurs, the failure is considered credible until the owners of the facilities have demonstrated that the cause of the failure has been corrected and it is no longer credible. The Performance Level associated with accidental RAS operation is the more stringent Performance Level of the following: (1) the disturbance that would correctly initiate RAS operation or (2) the action initiated by the RAS. For example, if the RAS is intended to operate for a double-line outage and the remedial action initiated is the tripping of a single generator, then its accidental operation would be required to meet Performance Level A. However, if the RAS is intended to operate for a double-line outage and the remedial action initiated is the tripping of six lines, then its accidental operation would be required to meet Performance Level C. In general, high-speed control systems, such as MJB 2/2/01 10

12 used in a DC link, DC line, or a Static Var Control system, are not considered to be RAS. However, they are subject to the reliability philosophies contained in these criteria as is any other proposed or existing facility. If a control malfunction does not directly result in removal from service of the controlled facility, it should not expose other systems to loss of load, generation, or equipment damage or line outages. TERMS USED IN THE DISTURBANCE-PERFORMANCE TABLE Three or More Circuits in a Right-of-Way In the application of the Disturbance-Performance Table, this category is intended to cover those situations where the separation between circuits is such that a common mode failure could result in the simultaneous outage of multiple circuits. The credibility of such an outage depends on the credibility of the common mode failure. Considerations in the determination of credibility should include line design; length; location, whether forested, agricultural, mountainous, etc.; outage history; operational guidelines; and separation between circuits. For example, some organizations use separation by more than the span length as adequate to designate the circuits as being in separate corridors. Two Circuits In the application of the Disturbance-Performance Table, this category is intended to cover those situations where a common mode failure could result in the simultaneous loss of two circuits. The credibility of such an outage depends upon the credibility of the common mode failure. The credible outage of two circuits could result from a lightning storm or forest fire. Loss of two circuits does not require the same tower or right-of-way to be credible. Considerations in the determination of credibility should include line design; length; location, whether forested, agricultural, mountainous, etc.; outage history; operational guidelines; and separation between circuits. Common mode failures of substation terminal equipment, such as a breaker failure, are covered under the Bus Section category in the Disturbance-Performance Table. MJB 2/2/01 11

13 ATTACHMENT 3 Detailed Reliability Performance Evaluation of the Exceptions List Facilities MJB 2/2/01 12

14 1. Laramie River fault with loss of 2 circuits WAPA & BEPC Discussion: On the initial data request, both WAPA and Basin Electric had reported on this Exceptions List item. The data submitted were inconsistent and also some key information was missing. Both WAPA and Basin Electric subsequently provided clarifications. Based on the clarifications, there was no countable multi-element outage on the last 10 years. Assumptions: None Performance Evaluation: Facility: Laramie River Station (LRS) Ault, and LRS Story; the lines do not share common corridor Facility Outage Class: More than two elements Criteria Performance Level Specified: C Class Outage Frequency: outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.0 outages/year Criteria Performance Level based on Outage History: C System Impact of Reported Outage(s): Not Applicable Remedial Action: None Recommended Performance Level Adjustment: None Reason for the Recommendation: There were no multi-circuit outages in the facilities in the last ten years. MJB 2/2/01 13

15 4. Taft fault with loss of 2 circuits and RAS failure - BPA Discussion: PBA data clearly shows that there were four multi-element outages in the last 10 years. This results in outage frequency of 0.4 outages/year or MTBF = 2.5 years. The Phase I PBRC Performance Table specifies Level A performance for facilities with outage history grater or equal to 0.33 outages per year. Assumptions: None Performance Evaluation: Facility: Taft-Garrison lines 1 and 2 sharing the common corridor Facility Outage Class: Two elements Criteria Performance Level Specified: C Class Outage Frequency: outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.40 outages/year Criteria Performance Level based on Outage History: A System Impact of Reported Outage(s): No adverse effect Remedial Action: Yes (not armed, would not activate for momentary, no action) Recommended Performance Level Adjustment: none Reason for the Recommendation: The Phase I PBRC Performance Table is not applicable when the facility is equipped with RAS that mitigates the otherwise adverse impact of the disturbances. Furthermore, the RAS worked as designed and no information will be forwarded to the RASRTF for the RAS reliability evaluation. MJB 2/2/01 14

16 5. Navajo fault with loss of 1 circuit with 1 circuit already out & system unadjusted; 10. Navajo fault with loss of 2 circuits; and 12 (a). Navajo fault with loss of 2 circuits 12 (b). Eldorado fault with loss of 2 circuits APS Discussion: There was no multi-circuit outage reported. Assumptions: None Performance Evaluation: Facility: Navajo-Crystal (McCullough) and Navajo-Moenkopi lines (no common corridor), Navajo-Moenkopi and Navajo-Westwing (with common corridor), Navajo- Crystal (McCullough) and Navajo-Moenkopi lines (no common corridor), or Eldorado-Moenkopi and Crystal (McCullough)-Navajo (no common corridor) Facility Outage Class: Two elements (with or without common mode) Criteria Performance Level Specified: C or E Class Outage Frequency: or < outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.00 outages/year Criteria Performance Level based on Outage History: E System Impact of Reported Outage(s): Not Applicable Remedial Action: None Recommended Performance Level Adjustment: none Reason for the Recommendation: There were no multi-circuit outages in the facilities in the last ten years. MJB 2/2/01 15

17 6. Malin fault with loss of 2 circuits and RAS failure PG&E Discussion: PG&E data clearly shows that there were three multi-element outages in the last ten years. The outages frequency is 0.3 outages/year or MTBF = 3.33 years. This indicates a Performance Level C event. Assumptions: None Performance Evaluation: Facility: Malin-Round Mountain lines 1 and 2 sharing the common corridor Facility Outage Class: Two elements Criteria Performance Level Specified: C Class Outage Frequency: outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.30 outages/year Criteria Performance Level based on Outage History: C System Impact: Loss of interconnections Remedial Action of Reported Outage(s): Yes (not armed, no action) Recommended Performance Level Adjustment: none Reason for the Recommendation: The Phase I PBRC Performance Table is not applicable when the facility is equipped with RAS that mitigates the otherwise adverse impact of the disturbances. Furthermore, the RAS worked as designed and no information will be forwarded to the RASRTF for the RAS reliability evaluation. MJB 2/2/01 16

18 7. Ingledow fault with loss of 2 circuits and RAS failure - BCH Discussion: There was no multi-circuit outage reported. Assumptions: None Performance Evaluation: Facility: Ingledow-Custer line 1 and 2 sharing common corridor Facility Outage Class: Two elements Criteria Performance Level Specified: C Class Outage Frequency: outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.00 outages/year Criteria Performance Level based on Outage History: E System Impact of Reported Outage(s): Not applicable Remedial Action: Yes (not armed, would not activate for momentary, no action) Recommended Performance Level Adjustment: none Reason for the Recommendation: The Phase I PBRC Performance Table is not applicable when the facility is equipped with RAS that mitigates the otherwise adverse impact of the disturbances. Furthermore, the RAS worked as designed and no information will be forwarded to the RASRTF for the RAS reliability evaluation. (The reason that there were no multi-circuit outages in the last ten years in the facility provides additional support to the recommendation.) MJB 2/2/01 17

19 8. Intermountain Power Project (IPP) Bipole outage with RAS failure - LADWP Discussion: There was one bipole (multi-circuit) outage reported. Assumptions: None Performance Evaluation: Facility: IPP bipole pole 1 and 2 sharing common corridor (tower) Facility Outage Class: Two elements Criteria Performance Level Specified: C Class Outage Frequency: outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.10 outages/year Criteria Performance Level based on Outage History: C System Impact of Reported Outage(s): No adverse effect Remedial Action: Yes (was armed and activated correctly and tripped an IPP unit) Recommended Performance Level Adjustment: none Reason for the Recommendation: The Phase I PBRC Performance Table is not applicable when the facility is equipped with RAS that mitigates the otherwise adverse impact of the disturbances. Furthermore, the RAS worked as designed and no information will be forwarded to the RASRTF for the RAS reliability evaluation. MJB 2/2/01 18

20 9. Palo Verde fault with loss of 2 circuits - APS Discussion: There was no multi-circuit outage reported. Assumptions: None Performance Evaluation: Facility: Palo Verde-Davers and Palo Verde-North Gila lines (no common corridor) Facility Outage Class: Two elements (with or without common mode) Criteria Performance Level Specified: C or E Class Outage Frequency: or < outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.00 outages/year Criteria Performance Level based on Outage History: E System Impact of Reported Outage(s): Not applicable Remedial Action: None Recommended Performance Level Adjustment: none Reason for the Recommendation: There were no multi-circuit outages in the facility in the ten years evaluation period. MJB 2/2/01 19

21 11. Lugo fault with loss of 2 circuit - SCE Discussion: In the initial data request, SCE had reported data on five multi-circuit corridor facilities and several lines with line crossing exposures. Three of the multicircuit corridors from Lugo are 500 kv systems. One multi-element outage on each of these three different 500 kv corridors were reported. According to the original 10 year data, the frequency of multi-element outage on each of the three corridors is 1 in 10 years (i.e., f = 0.1 outage/year or MTBF of 1 in 10 years). Additional clarifications were subsequently provided by SCE where they recommended to disregard all other data and only to consider the corridor outage data of Lugo-Eldorado and Lugo-Mojave lines. There is no RAS consideration with this facility. The Lugo-Eldorado and Lugo-Mojave outage event resulted in loss of load. Assumptions: None Performance Evaluation: Facility: Lugo-Eldorado and Lugo-Mohave lines (sharing the same corridor) Facility Outage Class: Two elements Criteria Performance Level Specified: C Class Outage Frequency: outages/year Criteria Performance Level Granted: E or higher (Exceptions List) Historical Performance: 0.10 outages/year Criteria Performance Level based on Outage History: C System Impact of Reported Outage(s): Loss of load Remedial Action: None Recommended Performance Level Adjustment: None Reason for the Recommendation: According to the RPEWG Evaluation Guideline, the following issues are taking into consideration: (1) One event does not constitute statistically significant event, thus it is not used in the reliability performance determination of a facility. (2) The impact of the event did not result in cascading outage, thus does not warrant RS review of the impact. Mo Beshir MJB 2/2/01 20

22 February 2, 2001 MJB 2/2/01 21