BES Inclusion Guideline 1

Introduction

The Federal Energy Regulatory Commission (FERC) approved the definition of “Bulk Electric System” (BES) in the Glossary of Terms Used in NERC Reliability Standards (NERC Glossary) on March 20, 2014.The BES definition became effective on July 1, 2014 throughout the United States. With its approval of the BES definition, FERC recognized that additional non-BES facilities may be important to the reliability of an interconnection. These facilities are noted in FERC Order 773, related to the definition of BES in the NERC Glossary, and in the joint NERC and FERC staff report Arizona-Southern California Outages on September 8, 2011: Causes and Recommendations (Joint Report), particularly in Recommendation 17. As a result, WECC has determined that it needs a process to identify which non-BES facilities are material to the reliability of the Western Interconnection. To that end, the Reliability Subcommittee has developed this WECC Guideline,[1]to assist each WECC member in determining whether any of its non-BES facilities may warrant further study to determine if the facilities are material to the reliability of the BES.

Application of this Guideline requiresthat each WECC member exercises considerable engineering judgment and operating experience whenapplyingthe screening thresholds. In particular, WECC’s Stipulationand Consent Agreement with FERC states: “The Guideline helps registered entities identify such facilities, and encourages, but does not require, registered entities to consider facilities for inclusion in the BES through the NERC exception procedures. Among other situations that might qualify a non-BES facility for inclusion through the NERC exception procedures are facilities identified as a significant contributing factor in an event analysis report, or where the facility’s single-contingency outage changes the flow on any BES element by more than 10 percent.”[2]

While this Guideline is voluntary, WECCdid indicate that it will monitor the effectiveness of the Guideline.[3] With this, the WECC Reliability Subcommittee encourages all entities responsible for reliabilityto determine which of their non-BES facilities are important to the reliable operation of the Western Interconnection and to follow the process described in this Guideline.

Guideline

Registered entities in the Western Interconnection are required to follow the new definition of BES. However, contingencies may exist where the reliability of the Western Interconnection depends on non-BES elements or facilities. If a WECC member in its capacity as a Transmission Planner, Transmission Operator, Planning Coordinator, Balancing Authority, or Reliability Coordinator identifies non-BES element(s) on which the reliability of the Western Interconnection depends, those elements may be included as part of the BES using the “Procedure for Requesting and Receiving an Exception from the Application of the NERC Definition of Bulk Electric System” (Exception Procedures) located at Appendix 5C of the NERC Rules of Procedure.[4] The analyses to identify situations whereelements should be considered part of the BES include—but are not limited to—actual operation, seasonal studies, near-term operational planning studies, annual planning assessments, or transmission rating studies.

The situations for consideration when conducting the studies above should include, but are not limited to:

  • Non-BES elements identified as a significant contributing causal factor in an event analysis report (e.g., disturbance report).
  • Non-BES elements that are part of a monitored facility of a major transfer path.[5]
  • Non-BES elements identified as part of a blackstart cranking path or a Nuclear Plant Off-site Power Supply.
  • Where a BES element’s single-contingency outage causes on any non-BES element:
  • Anincrease in flow of more than 10 percent of the non-BES element’s applicable Facility Rating,[6] and
  • A subsequent flow above 90 percent of the non-BES element’s applicable Facility Rating.
  • Non-BES elements (e.g., generators, transformers, lines) where a single-contingency outage of that element causes a change in flow on any BES element that is greaterthan10 percent of the BES element’s applicable Facility Rating.

Once a situation is identified, the WECC member’s evaluations should include, but are not limited to:

  • The extent to which the non-BES element is necessary for the reliable operation of the Western Interconnection – such as transfer capability, system stability, or voltage control – based on operating experience.
  • The extent to which the non-BES element affects a System Operating Limit (SOL) or an Interconnection Reliability Operating Limit (IROL).

The time horizon for the WECC member’s evaluations should be the Near-Term Transmission Planning Horizon.

Reliability Subcommittee Process for BES Exception Requests

Background

In FERC Order 773, FERC accepted NERC’s assertion that given the nature of the BES Exception Procedures, it was not feasible to develop a single set of technical criteria that determine whether elements should be included in, or excluded from, the definition of BES for use in the Exception Procedures.[7] FERC indicated that a Regional Entity, Planning Authority, Reliability Coordinator, Transmission Operator, Transmission Planner, or Balancing Authority that has elements covered by an exception request within its scope of responsibility may submit an exception request for the inclusion of an element or elements owned by a registered entity.[8]FERC has also stated that NERC should not necessarily stop at 100 kV and should, through the development of the exception process, ensure that critical facilities operated at less than 100 kV, and that Regional Entities determine are necessary for operating the interconnected network, are included.[9]

FERC found reasonable NERC’s explanation that Regional Entities and owners and operators of system elements will include, through the exception process, facilities identified (1) in the course of performing planning assessments, (2) from day-to-day operating experience, or (3) through assessment of system events, that are not included by application of the definition, but are necessary for reliable operation of the interconnected transmission network.[10] FERC stated that it expects that these entities will submit such elements for inclusion through the exception process.[11]

In addition to the requirements imposed by FERC Order 773, NERC and FERC included Recommendation 17 in their Joint Report, which states:

WECC, as the RE, should lead other entities, including TOPs and BAs, to ensure that all facilities that can adversely impact BPS reliability are either designated as part of the BES or otherwise incorporated into planning and operations studies and actively monitored and alarmed in RTCA systems.

Process

This process applies to the following entities responsible for identifying facilities that affect the reliability of the Western Interconnection: Planning Authorities, Reliability Coordinators, Transmission Operators, Transmission Planners, Balancing Authorities, and owners of system facilities. Consistent with FERC Order 773 and Recommendation 17, each of these responsible entities should review its system planning and operations reliability assessments and should otherwise actively identify which of its non-BES facilities are necessary for the reliable operation of the Western Interconnection.

Once a responsible entity has identified which of its non-BES facilities should be included in the BES, the responsible entity should submit each identified facility for inclusion in the BES through the Exception Process using a BES Inclusion Exception Request in BESnet (the NERC BES exception request Web application).[12]

Western Electricity Coordinating Council

[1] WECC Document Categorization Policy, p. 4.

[2] FERC Order Docket No. IN14-11-000 atP 33.

[3]Id.

[4]Appendix 5C of the NERC Rules of Procedure:

[5]Major WECC Transfer Paths at

[6] Facility Rating is defined in the Glossary of Terms Used in NERC Reliability Standards.

[7] Revisions to Electric Reliability Organization Definition of Bulk Electric System and Rules of Procedure, Order No. 773, 141 FERC ¶ 61,236 (2012) at P 253.

[8] Order No. 773 at P 27.

[9]Order No. 773 atP269.

[10] Id.

[11] Id.

[12] See