Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Stakeholder Comment and Reply Matrix AESO AUTHORITATIVE DOCUMENT PROCESS Proposed New ISO Rules Section 502.3 Interconnected Electric System Protection Requirements (“New ISO Rules Section 502.3”) Date of Request for Comment [yyyy/mm/dd]: Period of Consultation [yyyy/mm/dd]: 2012/08/14 2012/08/14 through 2012/09/14 1. ISO Rules (a) Purpose of Proposed New ISO Rules Section 502.3 Proposed New ISO Rules Section 502.3 sets out the minimum technical protection system requirements for the interconnected electric system. In developing the New ISO Rules Section 502.3 the AESO has redrafted and relocated content from the current AESO Protection Standard. In addition, in developing New ISO Rules Section 502.3 the AESO is proposing changes as outlined below, as a result of the review performed with the industry workgroup. In the AESO’s opinion, these proposed changes improve the protection systems on the Alberta interconnected electric system and ultimately the safe reliability operation of the system. The AESO is specifically seeking comments from stakeholders with respect to these key changes. Please provide comments on : 1) Do you agree or disagree that the AESO has clearly and adequately represented the key changes in proposed New ISO Rules Section 502.3? If you disagree please provide your reasons and suggestions for improvement. Stakeholder Comments and/or Alternate Proposal AESO Replies EDTI 1. With regards to Subsection 15, EDTI requests clarification as to whether there are any timing (speed) requirements, similar to those provided in Subsection 8, with isolating faults with 5 ohms ground fault resistance. EDTI has a number of very short lines (2-10 ohms line impedance) and in some cases 5 ohms arc resistance can only be detected by distance protection with zone 2 and using communications. Alternatively the same fault can be tripped by the line differential relay. 1. In the AESO’s opinion, draft Information Document # 2012-004R Protection System information (“ID 2012-004R”) provides the clarification that EDTI is seeking. Specifically, Section 8.1 in draft ID# 2012-004R states: “For further clarity, the required protection relay operate times identified in subsection 7 are not intended to be applied in conjunction with the five (5) ohm impedance. Slower clearing times for ground faults are acceptable as they do not cause stability issues.” In addition, proposed New ISO Rules Section 502.3 applies to new facilities as referenced in future project specification and is not intended to apply retroactively. Accordingly, the AESO has not amended final proposed New ISO Rules Section 502.3 to provide further clarification. AESO Replies to Stakeholder Comments: 2012-10-23 Page 1 of 10 2. In Subsection 16(1)(b), EDTI believes the correct wording should read “not allow for more than one (1) attempt at each end of the line to auto-reclose the bulk transmission line” 2. The AESO agrees with EDTI’s suggestion, and accordingly, has amended final proposed New ISO Rules Section 502.3. In addition, AESO review identified that Section 8.2 of ID# 2012-004R, incorrectly referenced subsection 17 of proposed New ISO Rules Section 502.3. Accordingly, the AESO amended Section 8.2 of draft ID# 2012-004R to correctly reference subsection 16 of proposed New ISO Rules Section 502.3. 3. With regards to Subsection 21(2), EDTI would like to comment that upon communications failure, the line differential function must be blocked. For the relay to still detect and trip, the relay should be of a hybrid design, and the trip is done by distance element without communications. EDTI believes it would be adequate to include this information in the Information Document. 4. EDTI recommends that Subsection 29(1)(a) should read, “one(1) independent overcurrent protection system installed on the high voltage side;” If the high voltage side is not mentioned, some entities may install one overcurrent on the low voltage side and the transformer will have no redundant protection against internal faults. 3. The AESO agrees with EDTI’s suggestion and has amended draft ID# 2012-004R accordingly. 4. The AESO agrees with EDTI’s suggestion for transformers less than 25MVA in size as the overcurrent is intended to provide redundant protection. For larger transformers the location of the overcurrent protection is not as important as the transformer is protected by redundant differential protections. Accordingly, the AESO has amended final proposed New ISO Rules Section 502.3 subsection 29. 5. Transformers must be protected against (1) internal faults, (2) dangerous through current in case of external faults and (3) overload conditions. For internal faults a differential protection and an overcurrent protection (50/51) installed on the high voltage winding are usually used. If strong infeed 5. For larger transformers two differentials are required to ensure all internal transformer faults are cleared high speed. The overcurrent element was intended to provide backup coverage for external faults. As written 29(2)(b) indicates the overcurrent should be on AESO Replies to Stakeholder Comments: 2012-10-23 Page 2 of 10 exist from the low voltage side one directional overcurrent (67) relay connected to the low voltage winding is used. the secondary side and is only needed to detect overloads. The use of directional overcurrent would also meet the intent of this requirement. For dangerous through faults an overcurrent protection (51) installed on the high voltage winding or a low voltage overcurrent protection (51) installed on the low voltage winding are used. Accordingly, subsection 29 of final proposed New ISO Rules Section 502.3, has been amended to allow overcurrent on either the high or low voltage side for large transformers and will be broadened to cover through faults other than overloads. The low voltage (51) is not design to detect internal faults. 1. Clarified applicability and the relationship of proposed New ISO Rules Section 502.3 to a project’s Functional Specification will be provided. Subsections 1 to 5 AltaLink Management Ltd 6. AltaLink supports with language suggestions. 6. AltaLink recommends that the wording “functional specification” be adjusted to “initial (i.e., first issue) functional specification” in section 2 and subsection 3(1) to provide further clarity. The AESO disagrees with AltaLink’s language suggestions. As projects are developed revisions to functional specifications are made. The final functional specification issued supercedes earlier versions. Accordingly, the AESO has not amended final proposed ISO Rules Section 502.3. 7. AltaLink recommends that more details be provided regarding the application of the Rule on existing facilities. Although the application of the Rule on existing facilities is discussed in the Information Document, it is not clear how the AESO will define in the functional specification (as it is not clear in the Rule) when existing facilities need to meet the requirements of the new Rule. 7. The AESO disagrees with AltaLink that more details are required regarding the application of proposed ISO Rules Section 502.3 on existing facilities. The AESO’s project functional specifications are typically for the addition of new facilities and will reference final proposed ISO Rules Section 502.3 that need to be complied with by these new facilities. For new standalone “green field” facilities, all such facilities need to meet final proposed ISO Rules Section 502.3. For the addition of new facilities in existing substations, these new facilities will need to meet final proposed ISO Rules Section 502.3. However, integrating the new facilities into the existing substation may require changes to existing protection systems. Consistent with current practices, modifications to existing AESO Replies to Stakeholder Comments: 2012-10-23 Page 3 of 10 facilities will be determined on a case-by-case basis and if modifications to existing facilities are required the AESO will indicate this in the functional specification. Accordingly, the AESO has not amended final proposed ISO Rules Section 502.3. 8. Subsection 1(c) states that the rule applies to “the legal owner of a transmission facility with a rated voltage equal to or greater than one hundred (100) kV;…” However, the rule does not indicate if it only applies to facilities connected at 100 kV or higher? AltaLink recommends that the rule include a statement that indicates that it applies to transmission facilities with a rated voltage equal to or greater than one hundred (100) kV. 8. The AESO disagrees with AltaLink’s language suggestions. The “applicability” section in proposed ISO Rules Section 502.3 is consistent with drafting of applicability sections in other ISO rules and Alberta Reliability Standards. Some examples include: 1. ISO Rules Section 502.2 Bulk Transmission Line Technical Requirements 2. Alberta Reliability Standard PRC–021–AB–1 Under Voltage Load Shedding Program 3. Alberta Reliability Standard VAR-501-WECCAB-1 Power System Stabilizer 4. Alberta Reliability Standard VAR-002-AB-1.1b Generator Operation for Maintaining Network Voltages The examples listed above have been consulted on with industry and to date no market participant has expressed concern that the applicability subsections are unclear. For greater certainty, with respect to proposed New ISO Rules Section 502.3, the AESO will not be monitoring the requirements of these rules for a generating unit directly connected to the Alberta interconnected electric system with a maximum authorized real power rating equal to AESO Replies to Stakeholder Comments: 2012-10-23 Page 4 of 10 or less than eighteen (18) MW, or an aggregated generating unit directly connected to the Alberta interconnected electric system with a maximum authorized real power rating equal to or less than sixty seven point five (67.5) MW, or the legal owner of a transmission facility with a rated voltage less than 100 kV. Accordingly, the AESO has not amended final proposed ISO Rules Section 502.3. 2. Requirements for two protection systems and subcomponents will be clarified. Subsection 7 AltaLink Management Ltd 3. Maximum protection relay operate times will be provided to ensure transmission grade relays are utilized for new facilities. Total clearing times will be addressed in the AESO’s upcoming revision to the Planning Criteria. Subsection 8 AltaLink Management Ltd AltaLink supports this ISO requirement and has no comment 9. AltaLink supports with language suggestions. AltaLink recommends that the wording in subsection 8(1), 8(2), 8(3), 8(4) be adjusted to “… the primary protection relay must be specified such that the operate times…do not exceed…” to more closely align with section 7.1 of ID 2012-004R. No reply required. 9. The AESO agrees with AltaLink’s language suggestions. The intent of this requirement is to ensure that the relay is capable of operating in the specified time. As indicated in Section 7.2 of draft ID# 2012-004R, the use of manufacture specifications is acceptable. Relay test results would also be acceptable. Accordingly, the AESO has amended final proposed ISO Rules Section 502.3. 4. Event capture for new facilities and the need for GPS time synchronization will be provided. Subsection 14 AltaLink Management Ltd 10. AltaLink supports with language suggestions. AltaLink recommends that this requirement be amended to indicate “it applies only on the addition of new power system elements and not modifications or replacement of existing protection systems.” 10. The AESO disagrees with AltaLink’s language suggestions. As specified in proposed New ISO Rules Section 502.3, a functional specification issued on or after the effective date of proposed New ISO Rules Section 502.3 must meet the requirements of proposed New ISO Rules Section 502.3 for all new facilities identified in a project functional specification. If a market participant identifies that for minimal additional cost, the GPS signal could be added to other existing lines to provide accurate event records AESO Replies to Stakeholder Comments: 2012-10-23 Page 5 of 10 for those other lines, then the AESO may choose to add this additional scope of work to the project functional specification. Accordingly, the AESO has not amended final proposed ISO Rules Section 502.3. 11. AltaLink also recommends that the reference to a global positioning system clock be removed from 14(3). It is recommended that the requirement be amended to indicate accuracy to 1.0 ms of UTC. The method of achieving the accuracy should be left to the discretion of the legal owner of a transmission facility. 5. 6. Auto Reclosing – At 240kV and higher voltages, single pole trip and reclose will become the standard practice for new facilities. At 240kV and higher voltages, no three (3) pole trip and reclose will be required. The success rate for reclosing will be removed. Protection System Communications – For now the 99.99% availability will remain a requirement within proposed New ISO Rules Section 502.3 for new facilities. This requirement will be re-evaluated when the AESO develops its proposed Communication Rules. Subsections 16 and 17 AltaLink Management Ltd 12. AltaLink supports with language suggestions. AltaLink requests further clarity on why single pole trip and reclose will become the standard practice for new facilities. Single pole trip and reclose inherently adds cost and complexity, and likely does not help the power system in most cases. AltaLink recommends that the wording be adjusted to make three pole trip and reclose the standard practice for new facilities and define exceptions to this in functional specifications. Subsection 23 11. The AESO agrees with AltaLink’s language suggestion, and accordingly, has amended final proposed ISO Rules Section 502.3. 12. Over the past 2 years the AESO has been reviewing the use of single pole trip and reclose and is generally satisfied the benefit warrants the cost for most applications. The AESO intends to conclude its review and discuss these finding with the transmission facility owners in the near future. For now, the AESO will review and specify reclosing type for all line 240kV and above on a project basis. Accordingly, the AESO has amended subsection 16 of final proposed ISO Rules Section 502.3. AltaLink Management Ltd AltaLink supports this ISO requirement and has no comment No reply required. AESO Replies to Stakeholder Comments: 2012-10-23 Page 6 of 10 7. Three Terminal Lines – Specific requirements will be provided regarding the protection of new three (3) terminal lines. Subsection 24 AltaLink Management Ltd 13. AltaLink supports with language suggestions. AltaLink recommends that a statement be added to subsection 24(1) requirement should be adjusted to reflect, “No three (3) or more terminal lines shall be allowed unless agreed to by the AESO and TFO’s.” 14. AltaLink recommends subsection 24(2) specify the acceptable level of mis-coordination? 8. 9. 9. 500kV Protection System Setting Verification – Real time digital simulation will be required for all new 500kV protection systems. Subsection 28 AltaLink Management Ltd Transformer Protection – All new 25MVA and larger transformers will require redundant transformer differential protection. Subsection 29 AltaLink Management Ltd Bus Protection – New 144kV and lower voltage busses will require redundant differential protection or studies to show remote protections can provide adequate coverage. Subsections 30 to 32 AltaLink Management Ltd AltaLink supports this ISO requirement and has no comment AltaLink supports this ISO requirement and has no comment 15. AltaLink supports with language suggestions. AltaLink recommends further clarity be added in section 9.2 of ID#2012-004R which states “Slower clearing times than those specified in section 502.3 subsection 8 are acceptable.” Subsection 8 of 502.3 specifies protective relay operate times and not fault clearing times. 13. The AESO disagrees with AltaLink’s language suggestions. The AESO will address the application of three (3) terminal lines in its upcoming revision to the Planning Criteria or in the upcoming proposed Substation Rules to be developed. The scope of proposed ISO Rules Section 502.3.remains unchanged and has not been expanded as a result of this comment. 14. The AESO does not agree with AltaLink. Given the complexity of three (3) terminal lines the AESO intends to review the acceptable level of mis-coordination on a project basis. Accordingly, the AESO has not amended final proposed ISO Rules Section 502.3. No reply required. No reply required. 15. The AESO agrees with AltaLink’s with regard to allowing zone 2 clearing. The AESO has amended draft ID# 2012-004R accordingly. AESO Replies to Stakeholder Comments: 2012-10-23 Page 7 of 10 10. Breaker Failure Protection – Based on extensive input from the external technical workgroup clear requirements will be provided that manage system reliability and where possible allow for the lowest cost solutions. Subsection 35 AltaLink Management Ltd 16. AltaLink supports with language suggestions. AltaLink request further clarification if subsection 35(6) applies to contact based breaker failure schemes such as cooling system trips for Static Var Compensators where longer breaker failure delay times are typically used. 16. The AESO agrees with AltaLink’s language suggestions. The intention of this requirement is to ensure high voltage faults are cleared quickly such that system stability is maintained. Once a primary protection system initiates a breaker open signal, there should be no reason for the breaker to take a longer time than specified. However, for low level fault there is no stability concern and longer times can be tolerated. . Accordingly, the AESO has amended final proposed ISO Rules Section 35 to clarify that this requirement applies to solid single line to ground or three phase faults. 17. AltaLink recommends that subsection 35(7) be revised to state “For applications where free standing current transformers are used with livetank breakers, it is acceptable to have a breaker fail operation for faults located between the breaker and the current transformer.” 11. Generating Unit Protection – Minimum protection requirements will be provided such that system reliability is maintained. Any protection requirements beyond this will be left up to the discretion of the owner of the unit. Proposed Change Subsections 37 to 45 Reference to the Subsections in Proposed New ISO Rules Section 502.3 17. The AESO agrees with AltaLink’s suggestion. Accordingly the AESO has amended subsection 35(7) of final proposed ISO Rules Section 502.3. AltaLink Management Ltd AltaLink has no comment No reply required. Stakeholder Comments and/or Alternate Proposal AESO Replies AESO Replies to Stakeholder Comments: 2012-10-23 Page 8 of 10 (b) Subsections within Proposed New ISO Rules Section 502.3 AltaLink Management Ltd. 18. AltaLink supports with language suggestions. In the AESO’s opinion, other than the key changes identified in (a) above, no other substantive changes were made as the AESO redrafted and relocated requirements from the AESO Protection Standard to proposed New ISO Rules Section 502.3. As stakeholders review each subsection of New ISO Rules Section 502.3 please specifically comment on: 1) Are there any subsections where stakeholders feel that the language does not clearly articulate the requirement either for the AESO or a market participant? If yes, please indicate the subsection and suggest language that would more clearly articulate the requirement. AltaLink recommends that subsection 6(a) be adjusted to reflect the wording in section 15. AltaLink recommends that the existing subsection be revised to state “successfully detect all phaseto-ground faults with ground impedance less than 5 Ohms, phase-to-phase-to-ground with ground impedance less than 5 Ohms, phase-to-phase, and three (3) phase faults on the protected equipment within the zone of protection;” 18. The AESO agrees with AltaLink’s language suggestion. Accordingly, the AESO has amended subsection 6(a) of final proposed ISO Rules Section 502.3. 19. AltaLink recommends that subsection 11 be made generic to indicate alarming on loss of potential. Other equipment such as miniature circuit breakers may be used instead of fuses on voltage circuits. AltaLink recommends that the existing statement be revised to the following: “A voltage transformer used for protective purposes, including synchronism checking, must have a loss of potential alarm.” For Subsection 17(2): 19. The AESO agrees with AltaLink’s language suggestion. Accordingly, the AESO has amended subsection 11 of final proposed ISO Rules Section 502.3. 20. AltaLink recommends further clarity be added to subsection 17(2) to outline whether auto-reclosing is permitted on hybrid lines (cables + overhead). AltaLink also recommends that cables should be made more generic by removing the word “underground” as not all cables are installed underground. 20. The AESO agrees with AltaLink’s language suggestion. Accordingly, the AESO has amended subsection 17(2) of final proposed ISO Rules Section 502.3. 21. AltaLink recommends that the phrase “capacitor bank can” in subsection 33(3) be replaced with the word “element”. 21. The AESO agrees with AltaLink’s language suggestion. Accordingly, the AESO has amended subsection 33(3) of final proposed ISO Rules Section 502.3. AESO Replies to Stakeholder Comments: 2012-10-23 Page 9 of 10 AltaLink Management Ltd. 2) Are there any subsections where stakeholders feel that the requirement does not appropriately address system reliability concerns? Please provide an alternate proposal if possible. AltaLink supports this ISO requirement and has no comment No reply required. AESO Replies to Stakeholder Comments: 2012-10-23 Page 10 of 10