FERC-725M, (DLO in RD22-2) Mandatory Reliability Standard: FAC-003-5, Transmission Vegetation Management

FERC-725M, Mandatory Reliability Standard: FAC-003-4, Vegetation Management (OMB Control No. 1902-0263) for a three-year period. FERC-725M is an existing data collection with reporting requirements in 18 Code of Federal Regulations (CFR), Part 40. FAC-003-4 extends NERC’s vegetation management requirements to Generator Owners with qualifying interconnection facilities, including requirements to create and maintain records related to the Generator Owner’s vegetation management work plan and performance of inspections As stated by NERC in its Petition (dated 3/14/2016 [footnotes omitted]) in Docket No. RD16-4, “[t]he purpose of proposed Reliability Standard FAC-003-4 is to require entities to manage vegetation located on transmission rights of way (ROW) and minimize encroachments from vegetation located adjacent to the ROW to reduce the risk of vegetation-related outages that could lead to Cascading. Proposed Reliability Standard FAC-003-4 reflects revisions developed under Project 2010-07.1 Vegetation Management to provide a revised gap factor applied in the Gallet equation supporting the appropriate Alternating Current Minimum Vegetation Clearance Distances (referred to herein as “MVCD values”) stated under the Reliability Standard. The MVCD value reflects the minimum distance between vegetation and conductors to prevent a flash-over. This revised gap factor was developed as a result of the 2015 Technical Report prepared by EPRI entitled Supplemental Testing to Confirm or Refine Gap Factor Utilized in Calculation of Minimum Vegetation Clearance Distances (“MVCD”): Tests: Results and Analysis (“EPRI Report”) filed at the Commission in Docket No. RM12-4-000 in compliance with the Commission’s directive in Order No. 777. The EPRI Report, the preliminary report preceding it, and EPRI’s recent update to the EPRI Report filed in Docket No. RM12-4-000 are attached at Exhibit E. As reflected in this Petition and the attached exhibits, the EPRI test results indicated that MVCD values under currently effective Reliability Standard FAC-003-3 might not be suitable or sufficiently conservative in all situations. The EPRI testing revealed that the gap factor used to determine those MVCD values under the Gallet equation was too high for all situations with varying tree and conductor configurations. The gap factor is a multiplier that adjusts MVCD values for different configurations of vegetation and conductors to avoid flashover (a lower gap factor correlates to higher MVCD values). The EPRI tests thus led to the conclusion that MVCD values under existing Reliability Standard FAC-003-4 appeared low. The EPRI test results demonstrated the Gallet equation should apply a more conservative, lower, gap factor of 1.0 to calculate MVCD values for Reliability Standard FAC-003-4. Proposed Reliability Standard FAC-003-4, therefore proposes higher and more conservative MVCD values. These higher MVCD values will enhance reliability and provide additional confidence by applying a more conservative approach to determining the vegetation clearing distances.” In the Delegated Order (dated 4/26/2016) in Docket No. RD16-4, FERC approved the revised Reliability Standard proposed by NERC.

The latest form for FERC-725M, (DLO in RD22-2) Mandatory Reliability Standard: FAC-003-5, Transmission Vegetation Management expires 2023-04-30 and can be found here.

FERC-725M, Final Rule in RM12-16 (one-time and ongoing)

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