Many blackouts are caused by flashovers or contact between transmission lines and trees. In fact, the serious blackout affecting the Northeast in August 2003 was the result of contact between transmission lines and trees. When approving NERC’s initial reliability standards in Order No. 693, FERC expressed concerns about the scope of the reliability standard related to vegetation management (FAC-003-1) and required NERC to use its standards development process to “modify [the standard] to apply to Bulk-Power System transmission lines that have an impact on reliability as determined by” NERC. Mandatory Reliability Standards for the Bulk-Power System, 118 FERC ¶ 61,218 at P 706 (2007).
NERC has complied with the requirement set forth in Order No. 693 by filing proposed reliability standard FAC-003-2 to supersede FAC-003-1. On October 18, 2012, FERC issued a NOPR (Docket No. RM12-4) proposing to approve NERC’s proposed vegetation management standard, with one revision. Revisions to Reliability Standard for Transmission Vegetation Management, 141 FERC ¶ 61,046 (Oct. 18, 2012).
The proposed vegetation management reliability standard has seven requirements. The first two requirements (R1 and R2) obligate transmission owners to “manage vegetation to prevent encroachments into the MCVD [Minimum Vegetation Clearance Distance] of its applicable line(s).” R1 applies to facilities that are elements of Interconnection Reliability Operating Limits (“IROLs”) or Major WECC Transfer Paths. R2 applies to other overhead transmission lines operated at 200 kV or above. Any encroachment into the MCVD is a violation of FAC-003-2. For this reason, NERC describes the new standard as a “zero tolerance” approach to vegetation management. NOPR at P 24.
The third requirement (R3) requires transmission owners to document maintenance strategies to prevent vegetation encroachment into the MCVD. R4 requires transmission owners observing a vegetation condition that is likely to produce a fault to notify the appropriate control center “without any intentional time delay.” R5 requires transmission owners that are constrained from performing vegetation management work needed to prevent encroachments into MCVD to address the problem prior to implementing its next annual work plan. R6 obligates transmission owners to inspect 100% of applicable lines on an annual basis and with no more than 18 months between inspections on the same rights of way. Finally, pursuant to R7, transmission owners must complete 100% of their annual vegetation work plans (as those plans may be modified in a manner that does not permit encroachment into MCVD).
Proposed reliability standard FAC-003-2 expands and clarifies the facilities subject to the vegetation management requirements. Like the currently-effective standard, the proposed standard will apply to all overhead transmission lines operated at or above 200 kV. As described above, the proposed standard will also apply to lower voltage overhead transmission lines that are elements of IROLs or Major WECC Transfer Paths. Noting that IROL status can change at any time that operating conditions so require, FERC seeks comment from the industry regarding how transmission owners will become aware that their overhead transmission lines operated at less than 200 kV have been designated as IROLs. FERC also seeks comment from the industry regarding whether the facilities to which proposed standard FAC-003-2 will apply comports with Order No. 693’s mandate that vegetation management requirements apply to “Bulk-Power System Transmission lines that have an impact on reliability.”
FERC proposes to revise the Violation Risk Factor (“VRF”) NERC proposed to assign to violations of R2 – vegetation encroachments into the MVCD of transmission lines operated at 200 kV and above but which are not part of an IROL or Major WECC Transfer Path. NERC had proposed to assign a “medium” VRF to such encroachments, but in the NOPR, FERC proposes to direct NERC to change the VRF to “high.”
Comments on the NOPR will be due 60 days after it is published in the Federal Register.