United States: NERC Petitions FERC For Approval Of Revised Vegetation Management Standard

On December 21, 2011, the North American Electric Reliability Corporation ("NERC") filed a petition with the Federal Energy Regulatory Commission ("FERC" or "Commission") seeking, among other things, approval of reliability standard FAC-003-2—Transmission Vegetation Management ("FAC-003-2"), which, if approved, would replace the currently-effective Reliability Standard FAC-003-1 ("Petition").¹ NERC initiated the revision of FAC-003-1 in 2007 and went through six drafts and comment periods. NERC asserts that the final version of the proposed FAC-003-2 establishes four critical lines of defense for vegetation management: i) ensuring that Transmission Owners ("TOs") understand the problem they are trying to manage and have fully developed strategies and plans to manage the vegetation problem; ii) requiring that TOs carry out their plans and manage vegetation; iii) ensuring that TOs perform inspections; and iv) addressing cases where the other lines of defenses have failed and the TO has violated the FAC-003-2 reliability standard.²

While FERC approved FAC-003-1 without modification in Order No. 693, FERC identified shortcomings in that reliability standard and directed NERC to address those shortcomings.³ The proposed FAC-003-2 standard attempts to address the Commission's initial concerns. One specific shortcoming noted by the Commission in Order No. 693 was that FAC-003-1 did not include specific clearances between transmission lines and vegetation, or include criteria/procedures to develop such clearances. Instead, that version required TOs to determine and document "Clearance 1," the appropriate clearance, based on - at the time of the vegetation management work - local conditions and when the next expected work would occur, and "Clearance 2," the specific radial clearance, based on IEEE Standard 516-2003, required between vegetation and conductors necessary to prevent flashover between vegetation and conductors.⁴ To that end, FERC directed NERC to develop a reliability standard that defines the minimum clearance needed to avoid sustained vegetation-related outages.⁵

NERC's proposed FAC-003-2 eliminates the concept of "Clearance 1" and "Clearance 2" and, instead, establishes requirements directing TOs to engage in vegetation management to avoid encroachments into the Minimum Vegetation Clearance Distance ("MVCD"). NERC's Petition proposes to include the following definition of MVCD in NERC's Glossary of Terms Used in NERC Reliability Standards ("NERC's Glossary"): "The calculated minimum distance stated in feet (meters) to prevent flash-over between conductors and vegetation, for various altitudes and operating voltages."⁶

Requirement 1 of NERC's proposal requires TOs to manage vegetation to prevent encroachments into the MVDC for lines that are an element of an Interconnection Reliability Operating Limit or an element of a Major WECC Transfer Path, whereas Requirement 2 applies to lines that do not satisfy the criteria for Requirement 1. NERC notes that the currently-effective standard only requires TOs to specify values for "Clearance 1" and "Clearance 2," but that, unlike the current proposal, it does not expressly require TOs to ensure that vegetation does not encroach within that clearance, or take any action related to actually manage vegetation.⁷

NERC proposes to require that TOs use the "Gallet Equation" to calculate the MVCD, replacing the IEEE Standard 516-2003 which is currently used to calculate "Clearance 1" and "Clearance 2" distances. FERC, in Order No. 693, declined to endorse IEEE Standard 516-2003. It deemed the standard to be inappropriate for calculating minimum clearances since it is intended for use by highly-trained maintenance personnel to carry out live-line work in specific conditions (such as clear days without precipitation, high winds or lightning), not for those conditions necessary to safely carry out vegetation management practices.⁸ The "Gallet Equation" is an established method with regard to vegetation management for calculating the flashover distance for various voltages, altitudes, and atmospheric conditions and, according to NERC, better represents the conditions that occur in a transmission corridor.⁹

The proposed FAC-003-2 includes requirements that each TO must: i) ensure that no vegetation encroachments occur within the MVDC by completing 100% of its annual vegetation management plan; and ii) perform a Vegetation Inspection of 100% of its applicable transmission lines at least once per calendar year and with no more than 18 calendar months between inspections on the same Right-of-Way ("ROW").¹⁰ TOs are currently required under FAC-003-1 to develop and implement an annual vegetation management plan, as well as document an inspection schedule that reflects characteristics such as the anticipated growth of vegetation and any other environmental or operational factors potentially impacting vegetation management. NERC asserts that its proposed FAC-003-2 is an improvement over the current version because it expressly requires TOs to ensure no encroachments occur within the MVDC and to perform inspections whereas the current version, in NERC's view, does not expressly require that a TO actually ensure no encroachments occur or implement the documented inspection schedule.¹¹

NERC proposed FAC-003-2, Requirement 4, requires a TO who has confirmed the existence of a vegetation condition that is likely to cause a fault at any moment to notify the control center holding switching authority for the applicable line. Currently, a TO is only required to document a process regarding the immediate communication of vegetation conditions that pose an immediate threat of a transmission line outage.¹²

Additionally, NERC proposes to redefine ROW as: "The corridor of land under a transmission line(s) needed to operate the line(s). The width of the corridor is established by engineering or construction standards as documented in either construction documents, pre-2007 vegetation maintenance records, or by the blowout standard in effect when the line was built. The ROW width in no case exceeds the [TO]'s legal rights but may be less based on the aforementioned criteria." Furthermore, NERC proposes to redefine Vegetation Management as: "The systematic examination of vegetation conditions on a Right-of-Way and those vegetation conditions under the [TO]'s control that are likely to pose a hazard to the line(s) prior to the next planned maintenance or inspection. This may be combined with a general line inspection."¹³

NERC asserts that the proposed FAC-003-2 is an improvement over the current FAC-003-1 because reliability will be improved, enforceability will be clearer and TOs will have greater flexibility to address local vegetation management conditions.¹⁴ FERC is expected to issue a Notice of Proposed Rulemaking on NERC's Petition with a 60-day comment period.

Footnotes

^{1. Petition for Approval of Proposed Reliability Standard FAC-003-2—Transmission Vegetation Management, Docket No. RM12-4-000 (Dec. 21, 2011). NERC's Petition may be viewed here: http://elibrary.ferc.gov/idmws/common/opennat.asp?fileID=12845997.}

^{2. NERC Petition at p 15.}

^{3. Mandatory Reliability Standards for the Bulk-Power System, Order No. 693, FERC Stats. & Regs. ¶ 31,242 (2007), order on reh'g Order No. 693-A, 120 FERC ¶ 61,053 (2007)("Order No. 693") at PP 731-32.}

^{4. FAC-003-1 R1.2.1; FAC-003-1 R1.2.2.}

^{5. Order No. 693 at PP 731-32.}

^{6. NERC's Petition at p 2.}

^{7. Id. at p 22.}

^{8. Order No. 693 at P 731.}

^{9. NERC's Petition at p 22.}

^{10. FAC-003-2 R6; FAC-003-2 R7.}

^{11. NERC's Petition at pp 18, 28.}

^{12. Id. at p 26.}

^{13. Id.}

^{14. Id. at p 3.}

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