WECC Criterion – TPL-001-WECC-CRT-3Page 1 of 17
Criterion Development
This section is maintained by the drafting team during the development of the document and will be removed when the document is approved by the WECC Board of Directors (Board).
Document Scope
This document is designed to address the substance of TPL-001-WECC-CRT-2.1 (TPL), Requirement WR3 and the requirements imposed by NERC TPL-001-4, Requirements R5 and R6. Standard Authorization Request (SAR) WECC-0100 also provides for review and disposition of Table W-1 associated with the WECC TPL. Once the Requirements of this document are more fully developed the drafting team will revisit the need to edit, modify, or delete the table.
Procedural Background
On September 5, 2012, the WECC Board of Directors (Board) adopted a recommendation by the Regional Criteria Work Group (RCWG) changing the designation of this document from a WECC Criterion (CRT) to a WECC Regional Business Practice (RBP). On June 24, 2014, the Board reversed that decision and designated this document as a CRT.
In further keeping with the September 5, 2012 recommendation, on November 28, 2012, a Standard Authorization Request (SAR) was submitted to evaluate whether this document should be drafted as a WECC Regional Reliability Standard (RRS).
On December 19, 2012, the WECC Standards Committee (WSC) accepted the SAR as drafted with specific approval to assign an evaluation team to review the subject matter and return a recommendation to the WSC as to whether the document should be redrafted as an RRS.
On June 26, 2013, the WSC approved the evaluation team’s recommendation to ballot the retirement of TPL-001-WECC-RBP-2.1, WR1, WR2, WR4 and WR5. If approved the retirement would become effective coincident with the Effective Date of NERC’s TPL-001-4, because the content of the WECC Requirements will be resident in the NERC TPL-001-4.
On August 8, 2013, the WSC assigned the original drafting team, augmenting the team during later weeks.
On October 8, 2013, a WECC Ballot Pool voted to retire TPL-(012 through 014)-WECC-RBP-2.1, WR1, WR2, WR4 and WR5 of the Effective Date of NERC TPL-001-4. (The Effective Date is projected for approximately January 1, 2016. It should be noted that the TPL has a staggered Effective Date.)
On November 1, 2013, the WECC-0100 Drafting Team (DT):
- Reported completion of the tasks assigned in the WECC-0100 Standard Authorization Request (SAR);
- Requested the WECC Standards Committee (WSC) deem the WECC-0100 SAR complete; and,
- Requested the WSC accept the DT’s recommendation to proceed with informal drafting in support of an iterative SAR tailored to the remedial needs of TPL-001-WECC-RBP-2.1, System Performance, WR3 as well as a more granular implementation plan of TPL-001-4, Transmission System Planning Performance Requirements Requirement R5 and R6.
The WSC agreed to expand the WECC-0100 drafting team to include the entire Reliability Subcommittee, and accept the drafting team’s recommendation that further drafting continue on remedial language for:
- TPL-001-WECC-RBP-2.1. WR3;
- Table W-1; and,
- TPL-001-4, Requirements R5 and R6.
On December 5, 2013, the Board approved the decision to retire portions of the WECC TPL upon the Effective Date of the NERC TPL.
During June 2014, the Planning Coordinating Committee (PCC) conducted a straw poll concluding the most appropriate document categorization for this document should be that of a WECC Regional Criterion.
On June 24, 2014, the Board changed the designation of this document from that of a RBP to that of CRT.
Completed Actions / Date- SAR Filed.
- Review Team files Preliminary Recommendation.
- WSC approves ballot to retire WR1, WR2, WR4 and WR5.
- Notice of Joint Session to discuss retirement.
- Ballot Pool open asking for retirement of WR1, WR2, WR4 and WR5.
- WSC approves Drafting Team.
- Ballot Pool closed asking for retirement of WR1, WR2, WR4 and WR5.
- Joint Session to discuss retirement.
- Ballot open asking for retirement of WR1, WR2, WR4 and WR5.
- Drafting Team – First Meeting – Orientation.
- Ballot closed asking for retirement of WR1, WR2, WR4 and WR5. Retirement approved.
- Posting 1 - Open 45-day
- Posting 1 – Closed
- Posting 1 – Response to Comments Posted
15. Posting 2 – Open 30-day / February 4, 2015
16. Posting 2 – Closed / March 6, 2015
17. Posting 2 – Response to Comments Posted / March 17, 2015
18. Posting 3 – Open 30-day / July 24, 2015
19. Posting 3 - Closed / August 24, 2015
20. Posting 3 – Response to Comments Posted
Anticipated Actions / Date
- Version 4 Posted – Open 30-Day Comment Period
- Version 4 Posted – Closed
- DT meets for final Comments / Forward to WSC
- WSC Meets
- Open Ballot Pool
- Joint Session – Notice
- Close Ballot Pool
- Joint Session
- Open Ballot
- Ballot Closed
- WSC Meets
- Notice to WECC Board of Directors
- Board
Implementation Plan
Approvals Required
TPL-001-WECC-CRT-3, Transmission System Planning Performance
A WECC Criterion
Prerequisite Approvals
- WECC Ballot Pool
- WECC Standards Committee
- WECC Board of Directors
Applicable Entities
Planning Coordinator
Transmission Planner
Conforming Changes to Other Standards
None required.
Effective Date
The Effective Date is the later of January 1, 2016 or the Effective Date of TPL-001-4, Transmission System Planning Performance, Requirements R2-R6 and R8.
Justification
The effective date is targeted to coincide with the effective date of TPL-001-4, Transmission System Planning Performance.
Consideration of Early Compliance
The DT foresees no reliability-related issues if an entity chooses to implement the document early; however, entities should continue to adhere to approved WECC Criteria until they are retired.
Retirements
This document will replace TPL-001-WECC-CRT-“2” that is to be retired as of the Effective Date of this project.
New or Modified Term(s) Used in the WECC Glossary for WECC Criteria and Naming Conventions (WECC Glossary).
This section includes all new or modified terms used in the proposed criterion that will be included in the WECC Glossary upon applicable approval. The new or revised terms listed below will be presented for approval with the proposed document. Upon WECC Board of Director (Board) adoption, this section will be removed and the approved terms will be moved to the WECC Glossary.
Term(s): None proposed
A. Introduction
1. Title:Transmission System Planning Performance
2. Number:TPL-001-WECC-CRT-3
3. Purpose:To facilitate coordinated transmission planning for the Western Interconnection, and to facilitate the exchange of the associated planning information for normal and abnormal conditions.
4. Applicability:
4.1. Functional Entities:
4.1.1. Planning Coordinator
4.1.2. Transmission Planner
4.2. Facilities:
4.2.1. This document applies to studies conducted in both the near-term and the long-term planning horizons.
4.2.2. This document applies only to Bulk-Electric System (BES) substations buses.
4.2.3. This document applies to all transmission planning studies conducted at the Western Interconnection level.
4.2.4. Each of the following elements is specifically excluded from this Criterion:
4.2.4.1. Line side series capacitor buses
4.2.4.2. Line side series reactor buses
4.2.4.3. Shunt capacitor buses
4.2.4.4. Shunt reactor buses
4.2.4.5. Metering, fictitious, or other points of interconnection modeled solely for measuring electrical quantities; and,
4.2.4.6. Other buses specifically excluded by each Planning Coordinator or Transmission Planner internal to their system.
5. Effective Date:The Effective Date is the later of January 1, 2016 or the Effective Date of TPL-001-4, Transmission System Planning Performance, Requirements R2-R6 and R8.
B. Requirements and Measures
Rationale Blocks will be relocated to the Guidance section when the project is complete.
Rationale for Requirement WR1:In the context of Requirement WR1, the word “nominal” carries its common definition and could be, for example, either the base voltage or the operating voltage as established in the entity’s Planning Assessment. This voltage will vary from entity to entity.
Requirement WR1.1.2, refers to the post automatic equipment adjustment effect prior to manual adjustment.
WR1.Each Transmission Planner and Planning Coordinator shall use the following base criteria in its Planning Assessment, unless otherwise specified in accordance with Requirements WR2 and WR3: [Addresses NERC TPL R5 and R6]
1.1. Steady-state voltages at all applicable Bulk-Electric System (BES) buses shall stay within each of the following limits:
1.1.195 percent to 105 percent of nominal for P0[1] event (system normal),
1.1.2 90 percent to 105 percent of nominal for P1-P7[2] events (post-contingency).
Rationale for Requirement WR1.2:Requirement WR1.2 establishes a target that could be met by each entity without incurring costs that would outweigh the benefits. Many legacy systems were not designed to meet a more stringent threshold. The eight percent target of Requirement WR1.2 is established not by a technical study; rather, it is established based on sound engineering judgment. Further, certain entities are bound by state tariffs that establish the percentage rate specifically at eight percent.
By default, only automatic post-contingency actions including capacitor y or reactor switching are considered when calculating voltage deviation.
For P1 there is no high voltage deviation requirement. For P2-P7, there is no low or high voltage deviation requirement.
1.2. Post-Contingency steady-state low voltage deviation at each applicable BES bus serving load (having no intermediate connection) shall not exceed eight percent for P1 events. [Addressing TPL R5]
1.3. Transient stability voltage response at applicable BES buses serving load (having no intermediate connection) shall recover to at least 80 percent of pre-contingency voltage within 10 seconds of the initiating event for all P1-P7 category events[s1].
1.4 For voltage swings subsequent to fault clearing and the first voltage recovery above 80%, voltage dips at each applicable BES bus serving load (having no intermediate buses) shall not dip below 70% of pre-contingency voltage for more than 30 cycles or remain below 80% of pre-contingency voltage for more than two seconds for all P1-P7 category events.
1.5 For Contingencies without a fault (P2.1 category event), voltage dips at each applicable BES bus serving load (having no intermediate buses) shall not dip below 70% of pre-contingency voltage for more than 30 cycles or remain below 80% of pre-contingency voltage for more than two seconds.
Rationale for Requirement WR1.5Requirement 1.5 is not intended to require that transient stability simulations be run out to 30-seconds all the time in order to ensure the system is stable and positively damped. Shorter runs are permissible[s2].
Rationale for Requirement WR1.6:
For purposes of Requirement WR1.6, positive damping in stability analysis is demonstrated by showing that the amplitude of power angle or voltage magnitude oscillations after a minimum of 10 seconds is less than the initial post-contingency amplitude. In any case, results that do not show positive damping within a 30-second time frame are considered to be undamped.
1.6Oscillations that do not show positive damping within a 30-second time frame shall be deemed unacceptable.
WM1.Each Transmission Planner and Planning Coordinator will have evidence that it used the base criteria in its Planning Assessment specified in Requirement WR1, unless otherwise allowed in accordance with Requirements WR2 and WR3.
Rationale for Requirement WR2:Planning Assessment is a NERC defined term. For purposes of Requirement R2, the requirement applies to all planning studies applied at the Western Interconnection level.
The rationale for Requirement R2 is to ensure that planning entities do not impose more stringent requirements on systems other than their own. It may use more stringent criteria on its own system but may not impose more stringent criteria on others.
Transmission Planners and Planning Coordinators may mutually agree to use study criteria that is more stringent than that described in this document.
WR2. Each TP and PC that uses more stringent criteria in its Planning Assessment than that stated in Requirement WR1 shall apply that criteria only to its own system, except where otherwise agreed upon by all planning entities included in the Planning Assessment.
WM2. Each TP and PC that uses more stringent criteria in its Planning Assessment than that stated in Requirement WR1 will have evidence that it applied those criteria only to its own system, except where otherwise agreed upon by all planning entities included in the Planning Assessment.
Rationale for Requirement WR3:The rationale is to ensure equity between planning entities. (Availability of differing criteria is addressed in Requirement WR6.)
WR3. Each Transmission Planner and Planning Coordinator that uses less stringent criteria in its Planning Assessment than that stated in Requirement WR1 shall allow other Transmission Planners and Planner Coordinators to have the same impact on that part of the system for the same category of planning events (e.g., P1, P2).
WM3. Each Transmission Planner and Planning Coordinator that uses less stringent criteria in its Planning Assessment than that stated in Requirement WR1 will have evidenced that it allowed other Transmission Planners and Planner Coordinators to have the same impact on that part of the system for the same category of planning events (e.g., P1, P2).
Rationale for Requirement WR4:- Requirement WR4 is designed to establish precautionary markers that when discovered warrant investigation. The Requirement is not intended to imply that the presence of any one of more of the bulleted conditions creates a de facto negative impact on reliability.
- The term “cascading” in Requirement WR4 is not used as the NERC defined term “Cascading.”
WR4. Each Transmission Planner and Planning Coordinator shall use the following indicators to identify the potential for cascading or uncontrolled islanding:
- When a post contingency analysis results in facility loading that is either in excess of a known BES facility trip setting, or exceeds 125% of the highest applicable facility rating for the BES facility studied.
- Transient stability voltage response at any applicable BES bus outside of the criteria that is defined in Requirement WR1.3 of this document.
- If either unrestrained successive load loss occurs or unrestrained successive generation loss occurs.
WM4. Each Transmission Planner and Planning Coordinator will have evidence that it used the indicators of Requirement WR4 to identify the potential for cascading or uncontrolled islanding.
Rationale for Requirement WR5:Requirement WR5 addresses “what” must be achieved and does not address “how” to do it.
For a review of “how” to achieve the goals, please refer to:
- The WECC Voltage Stability Assessment Methodology
- WECC Guide to WECC/NERC Planning Standards I.D: Voltage Support and Reactive Power, Prepared by: Reactive Reserve Working Group (RRWG), Under the auspices of Technical Studies Subcommittee (TSS); Approved by TSS, March 30, 2006
- Additional guidance is contained in Section 2.2 Voltage Stability of the Guide to WECC/NERC Planning Standards 1.D, Voltage Support and reactive Power, March 30, 2006.
Power flow solutions refer to post contingency conditions where the actions of reactive devices should be modeled for the appropriate time frame being studied.
There is a higher likelihood of occurrence of a P0 to P1 category event; therefore, a higher margin (105%) is used. For P2-P7, there is a lower likelihood of occurrence; therefore, the lower margin (102.5%) is used.
WR5. Each Transmission Planner and Planning Coordinator shall identify voltage stability by maintaining positive reactive power margin at the real power flow defined through the following minimum criteria:
5.1 All P0-P1 events shall demonstrate a positive reactive power margin at a minimum of 105 percent of transfer path flow.
5.2 All P0-P1 events shall demonstrate a positive reactive power margin at a minimum of 105 percent of forecasted peak load.
5.3 All P2-P7 events shall demonstrate a positive reactive power margin at a minimum of 102.5 percent of transfer path flow.
5.4 All P2-P7 events shall demonstrate a positive reactive power margin at a minimum of 102.5 percent of forecasted peak load.
WM5. Each Transmission Planner and Planning Coordinator will have evidenced that it used the minimum criteria identified in Requirement WR5 to identify voltage stability.
Rationale for Requirement WR6:Requirement WR6 ensures the free flow of information between entities.
WR6. Each Transmission Planner and Planning Coordinator that uses study criteria different from the base criteria in Requirement WR1 shall make its criteria available upon request.
WM6. Each Transmission Planner and Planning Coordinator that uses study criteria different from the base criteria in Requirement WR1 will have evidence that it made its criteria available upon request, as required in Requirement WR6.
Version History
Version / Date / Action / Change Tracking1 / March 6, 2008 / WECC Planning Coordination Committee (PCC) approved TPL-(001 thru 004)-WECC-1-CR. / Reliability Subcommittee translates existing WECC components of NERC/WECC Planning Standards into a CRT.
1 / April 16, 2008 / WECC Board of Directors (Board) approved / No substantive changes
2 / October 13, 2011 / PCC approves / Clarifies “corridor”
2 / December 1, 2011 / Board approves / No substantive change
2 / September 5, 2012 / Board approves / Approved a nomenclature change from “CRT” to “RBP”
2.1 / August 6, 2013 / Errata / WM2 Measure moved to WM3. WM3 Measure moved to WM4. WM4 Measure moved to WM2.
2.1 / December 5, 2013 / Board approves / On October 8, 2013, the Ballot Pool voted to retire WR1, WR2, WR4 and WR5 of TPL-(012 through 014)-WECC-RBP-2 as of the Effective Date of NERC TPL-001-4. On December 5, 2013, the Board ratified that decision.
2.1 / June 24, 2014 / Board changed the RBP designation to that of CRT / No substantive change, only designation.
3 / Pending
Disclaimer
WECC receives data used in its analyses from a wide variety of sources. WECC strives to source its data from reliable entities and undertakes reasonable efforts to validate the accuracy of the data used. WECC believes the data contained herein and used in its analyses is accurate and reliable. However, WECC disclaims any and all representations, guarantees, warranties, and liability for the information contained herein and any use thereof. Persons who use and rely on the information contained herein do so at their own risk.