Daily Rules, Proposed Rules, and Notices of the Federal Government
The Commission also proposes to approve the three definitions, the implementation plan and the Violation Severity Levels associated with the proposed Reliability Standard. Finally, the Commission proposes to direct that NERC revise the Violation Risk Factor for Requirement R2, and approve the remainder of the Violation Risk Factors.
1. Pursuant to section 215 of the Federal Power Act (FPA),
2. Proposed Reliability Standard FAC-003-2 has a number of features that make it an improvement over the Version 1 standard. For example, like Version 1, the proposed Reliability Standard would apply to all overhead transmission lines operated at or above 200 kV, but unlike Version 1, it would explicitly apply to any lower voltage overhead transmission line that is either an element of an Interconnection Reliability Operating Limit (IROL) or an element of a Major WECC Transfer Path.
3. A recurring cause in many blackouts has been vegetation-related outages. In fact one of the initiating causes of the 2003 Northeast blackout was inadequate vegetation management practices that led to tree contact.
4. We also propose to approve the three new or revised definitions associated with the proposed Reliability Standard for inclusion in NERC's Glossary. Specifically, we propose to approve the changes in the definition of “Right-of-Way (ROW)” and “Vegetation Inspection,” as well as the addition of the term “Minimum Vegetation Clearance Distance (MVCD)” as defined in NERC's petition. We also propose to approve NERC's implementation plan for FAC-003-2.
5. While we believe that the proposed Reliability Standard will enhance reliability by requiring sub-200 kV transmission lines that are elements of an IROL or Major WECC Transfer Path to comply with its requirements, we seek comment on how NERC will ensure that IROLs are properly designated, as discussed in detail below. In addition, while we agree that a number of the proposed modifications clarify and make more explicit the transmission owner's obligations, we seek comment with regard to the enforceability of certain provisions.
6. We do not believe, however, that NERC has adequately supported the assignment of a “medium” Violation Risk Factor to Requirement R2, which pertains to preventing vegetation encroachments into the MVCD of transmission lines operated at 200 kV and above, but which are
7. Section 215 of the FPA requires the Commission-certified ERO to develop mandatory and enforceable Reliability Standards, subject to Commission review and approval. Once approved, the Reliability Standards may be enforced by the ERO subject to Commission oversight, or by the Commission independently.
8. Currently-effective Reliability Standard FAC-003-1 is applicable to transmission owners. The requirements of the Version 1 standard apply to (1) all transmission lines operated at 200 kV or above, and (2) lower-voltage lines designated as “critical to the reliability of the electric system” by a Regional Entity.
9. Currently-effective FAC-003-1 contains four requirements. Requirement R1 requires each transmission owner to prepare, and keep current, a transmission vegetation management program (TVMP) that includes,
10. Requirement R2 of the Version 1 standard requires that each transmission owner develop and implement an “annual plan for vegetation management work,” allowing flexibility to adjust to “changing conditions.” Pursuant to Requirement R3, transmission owners must report quarterly to the relevant Regional Entity “sustained transmission line outages * * * caused by vegetation.” Requirement R4 requires the Regional Entity to report the outage information to NERC.
11. On March 16, 2007, in Order No. 693, the Commission approved 83 of 107 proposed Reliability Standards pursuant to FPA section 215(d), including currently-effective FAC-003-1.
12. In the Notice of Proposed Rulemaking (NOPR) that preceded Order No. 693, the Commission proposed two directives requiring modification of NERC's proposed standard pursuant to section 215(d)(5) of the FPA.
13. The Commission instead required NERC to address a modification to the applicability of the standard through its Standards development process, directing NERC to “modify [FAC-003-1] to apply to Bulk-Power System transmission lines that have an impact on reliability as determined by the ERO.”
14. Similarly, while the Commission decided not to require NERC to submit a modification to FAC-003-1 to incorporate a minimum vegetation inspection cycle as part of Order No. 693, the Commission noted that it “continues to be concerned with leaving complete discretion to the transmission owners in determining inspection cycles.
15. With respect to minimum vegetation clearances distances, the Commission approved FAC-003-1's general approach and “reaffirm[ed] its interpretation that FAC-003-1 requires sufficient clearances to prevent outages due to vegetation management practices under all applicable conditions.”
16. Finally, the Commission directed NERC to address certain commenters' suggestion that, for purposes of the FAC-003 Reliability Standard, rights-of-way should be defined to encompass the required clearance area, and not the entire legal right-of-way, particularly where the legal right-of-way may greatly exceed the area needed for effective vegetation management.
17. In its petition, NERC maintains that proposed Reliability Standard FAC-003-2 is just and reasonable, as the proposal meets or exceeds each of the criteria the Commission has identified for evaluating a proposed Reliability Standard.
18. Further, NERC maintains that proposed Reliability Standard FAC-003-2 represents an improvement over the currently-effective standard, as FAC-003-2 enhances reliability, facilitates enforceability, and preserves necessary flexibility for transmission owners to address local vegetation conditions.
The probability of a flashover, given a drop in voltage to 85% of the `Critical Flashover Voltage (CFO),' is roughly .135% (or approximately 10
However, this is not the only event being considered when attempting to model the probability of a vegetation flashover. The probability of achieving a maximum switching overvoltage (“Peak Voltage”) in excess of the CFO must also be considered. This is shown on page 40 in equation 6 of the Technical Reference Document, and is specified there as roughly 0.135% (also approximately 10
In other words, the conditional probability of flashover given that the 85% CFO has been exceeded is approximately 10
19. NERC states that proposed FAC-003-2 continues to give transmission owners the necessary discretion to determine how to achieve the required clearances,
20. NERC states that proposed FAC-003-2 was designed to address directives from Order No. 693, including the directives requiring that NERC address proposed modifications to expand the applicability of FAC-003-1, evaluate and consider specific proposals made by parties commenting on FAC-003-1, develop compliance audit procedures to identify appropriate inspection cycles, define the minimum clearances needed to avoid sustained vegetation-related outages applicable to transmission lines crossing both federal and non-federal land, and address suggestions that rights-of-way should be defined to encompass required clearance areas only. NERC also explains that proposed FAC-003-2 is one of the first Reliability Standards developed using NERC's “results-based” approach and, therefore, includes some restructuring of the standard to focus on completing objectives and achieving goals, as well as to ensure that enforcement is undertaken in a consistent and non-preferential manner.
21. NERC proposes an implementation plan for FAC-003-2.
22. Accordingly, NERC requests that the Commission approve proposed FAC-003-2 and the associated Violation Risk Factors and Violation Severity Levels. NERC requests as an effective date for the Reliability Standard, “the first day of the first calendar quarter that is twelve months following the effective date of a Final Rule in this docket.”
23. The proposed Reliability Standard includes seven requirements.
25. NERC has bifurcated the basic requirement to prevent encroachment into the MVCDs. Requirement R1 applies to IROL elements and Major WECC Transfer Path elements and is assigned a high Violation Risk Factor. Requirement R2 sets forth the same substantive requirements but pertains to non-IROL and non-Major WECC Transfer Path elements and is assigned a medium Violation Risk Factor. NERC explains that it bifurcated the requirement to “eliminate commingling of higher risk reliability objectives and lesser risk reliability objectives.”
26. In addition, NERC has included a footnote describing certain conditions or scenarios, outside the transmission owner's control, where an encroachment would be exempt from Requirements R1 and R2, including natural disasters and certain human or animal activity.
32. NERC explains in its petition that certain requirements in the currently-effective Reliability Standard have not been translated into a requirement in the proposed standard. In particular, NERC notes that the Version 1 standard's reporting requirements, R3 and R4, have been moved into the compliance section of proposed standard FAC-003-2.
33. In addition, NERC acknowledges that the proposed standard no longer contains a requirement that personnel involved in the design and implementation of a vegetation management program have appropriate qualifications and training (currently set out in sub-requirement R1.3).
34. NERC is also seeking to revise the definitions of Right-of-Way (ROW) and Vegetation Inspection, and to add a new definition for MVCD.
35. NERC explains in its petition how it will approach enforcement of each Requirement under FAC-003-2, noting that each Requirement has an associated compliance measure that identifies what is required and how the Requirement will be enforced. NERC explains,
36. NERC asserts that it has addressed seven directives in Order No. 693 regarding NERC's vegetation management standard.
37. As NERC explains in its petition, the Standard Drafting Team applied the “Gallet equation” to derive the MVCDs set forth in FAC-003-2. NERC describes the Gallet equation as a “well-known method of computing the required strike distance for proper insulation coordination.”
38. The Commission's Office of Electric Reliability retained the Pacific Northwest National Laboratory (PNNL) to undertake an “analysis of the mathematics and documentation of the technical justification behind the application of the Gallet equation and the assumptions used in the technical reference paper [Exh. A of NERC's petition].”
39. PNNL's final
40. While the PNNL Report points out benefits of the use of the Gallet equation, it raises questions about potential inconsistencies in NERC's filing.
41. The PNNL Report further asserts that without NERC's assumption “that the gap between a power line and growing vegetation is stronger (by 30%) than the reference gap used in developing the Gallet equation,” the minimum distances calculated would be about 50% larger.
42. The PNNL Report also asserts that “[t]hough there is no obvious way to relate tower clearance to vegetation clearance,” the proposed MVCDs in FAC-003-2 are small when compared to transmission tower design clearances:
The values for tower clearance for a line at 500 kV in the Transmission Line Reference Book range from 8.3 ft. to over 17 ft. The NERC filing requires a gap less than 6 ft for the same voltage, even at high altitude. There is no reason to suppose that a tree could safely be allowed so much closer to a line (less than 6 ft) than a tower.
43. Nine sets of comments were filed in response to the PNNL Report, with timely submissions made by NERC, the Canadian Electricity Association, American Electric Power (AEP), Duke Energy Corporation (Duke), Oncor Electric Delivery Company LLC (Oncor), Kansas City Power & Light and KCP&L Greater Missouri Operations Company (KCP&L), Arizona Public Service Company (APS), and Salt River Project Agricultural Improvement and Power District (Salt River), as well as a joint submission by the Edison Electric Institute, the American Public Power Association, the National Rural Electric Cooperative Association and the Electric Power Supply Association (collectively, the Trade Associations).
44. In its comments, NERC asserts that the PNNL Report “(a) improperly juxtaposes data included in the FAC-003-2 Reliability Standard; (b) disregards NERC's justification regarding the selection of transient overvoltage calculations; (c) fails to consider joint probability of independent events when analyzing flashover probability; and (d) disagrees with the choice of gap factor for vegetation without providing any empirical evidence, scientific reasoning or expert consensus on what an appropriate gap factor should be.”
45. With regard to the assertion in the PNNL Report that there is no evidence that statistics relating to tower design are usable with vegetation, NERC explains the rationale for its use of the Gallet equation in some detail (discussed further in PP 47-48 below), and notes that the PNNL Report “disagrees with [NERC's] choice of gap factor for vegetation without providing any empirical evidence, scientific reasoning, or expert consensus on what an appropriate gap factor should be.”
46. With regard to PNNL's assertion that “inconsistencies are found in NERC's filing”, NERC states that the “inconsistencies” identified by the PNNL Report in NERC's Technical Reference Document result from PNNL erroneously comparing two separate sets
47. With respect to the gap factor, NERC maintains that it relied on a widely known and regarded source for determining the appropriate gap factor, which indicates that an appropriate gap factor for a conductor-to-lateral structure configuration is in the range of 1.25 to 1.40.
48. NERC then states that use of a gap factor of 1.3 is conservative:
It is worth noting that the gap factors for many shapes that could approximate vegetation are even higher than the 1.3 used in FAC-003-2, with ranges that include values as high as 1.6. Hileman notes that in regards to the substation environment (which includes many objects, conducting and non-conducting, with varying shapes and configurations): “Practically, the lowest gap factor in the substations is 1.3, which normally is conservative.”
[T]he [SDT] did not rely on any specific properties inherent in trees, rather, the [SDT] conservatively assumed that vegetation had the same properties as metal. The [SDT] elected to use the “typical” value for “conductor to lateral structure.” Unlike the other examples given, which specify a “typical” value that is equivalent to the midpoint of the range, this value (1.3) is within the conservative third of the range (1.25-1.4).
49. In response to the assertion in the PNNL Report that “[t]here is no reason to suppose that a tree could safely be allowed so much closer to a line * * * than a tower” (see P 42,
[C]are must be taken when making an interpretation of the tabular data, as the original survey participants may have answered the questions in a general context involving multiple structure designs. The final structure design parameters provided in the Red Book include the CFO gap plus other factors (such as insulator geometry, personnel safety and extreme lightning events). Accordingly, they should not be considered the final word with regard to Vegetation Management, as those distances were established to address a number of other issues. FAC-003-2 is not intended to mandate the parameters for all future line designs; it is focused solely on the distances necessary to mitigate the risk of vegetation related outages.
50. In addition to providing a response to the technical issues raised by the PNNL Report, NERC argues that the Commission is obligated under FPA section 215(d)(2) to give due weight to NERC's technical expertise with respect to the content of proposed standards.
51. Trade Associations, Duke, Oncor and other commenters support NERC's technical analysis. AEP and Oncor agree with NERC that the PNNL report contains inappropriate comparisons of data NERC presented in its petition and supporting materials, and that if NERC's Gallet-generated numbers are compared to the distances calculated under IEEE-516, the “clearances determined by the two calculations are in fact closely aligned.”
52. KCP&L comments that the PNNL Report should have “included discussion regarding a correction factor
53. APS questions whether either the Gallet equation or the IEEE standard incorporated in currently-effective FAC-003-1 “provides a demonstrable indicator of the flash-over distance between conductors and ground vegetation * * *, ”
54. Salt River supports the PNNL Report's analysis, noting that it has questioned the applicability of the Gallet equation for vegetation clearances throughout the development of FAC-003-2. Salt River further agrees that there is insufficient evidence to suggest that a tree could safely be allowed much closer to a line than a tower. Finally, Salt River supports the experimental verification of any proposed guidelines regarding required vegetation clearances.
55. On May 4, 2012, Commission staff issued data requests to NERC. NERC submitted a timely response to the data requests on May 25, 2012, addressing matters such as the correct understanding and enforceability of certain provisions of the proposed Reliability Standard. Relevant elements of NERC's response to the data requests are discussed further below.
56. Pursuant to section 215(d) of the FPA, we propose to approve Reliability Standard FAC-003-2, including the associated new and revised definitions and implementation plan, as just, reasonable, not unduly discriminatory or preferential, and in the public interest. As discussed in Section A below, we believe the proposed Reliability Standard will enhance reliability and satisfies a number of the outstanding directives from Order No. 693. In addition, we seek further comment on certain aspects of the proposed Reliability Standard. Accordingly, we discuss the following matters below: (A) proposal to approve FAC-003-2; (B) applicability of the standard to sub-200 kV transmission lines; (C) clearance distances; (D) appropriate Violation Risk Factor for Requirement R2; (E) enforcement issues; (F) inclusion of reporting obligations as a compliance measure; and (G) proposed definitions.
57. We believe that proposed standard FAC-003-2 is an improvement over the currently-effective Version 1 standard, will support vegetation management practices that can effectively protect against vegetation-related transmission outages, and satisfies a number of the outstanding directives from Order No. 693. As discussed earlier, NERC has explained how many of the Requirements improve upon the currently-effective Version 1 standard. In support of our proposal to approve FAC-003-2, we highlight several of these improvements. For example, in accordance with our directives in Order No. 693, as discussed further below, NERC has expanded the applicability of the Reliability Standard so that it now applies not only to all transmission lines above 200 kV, but also to transmission lines operated
58. In addition, NERC has incorporated minimum clearance distances into the text of the Reliability Standard, and no longer includes a required clearance distance based on distances set by IEEE-516 which, as indicated in Order No. 693, served a different purpose than vegetation management. Proposed FAC-003-2 requires a transmission owner to prevent an encroachment into the MVCD, even if the encroachment does not result in a flashover or fault. As NERC explains, “FAC-003-2 presents a `zero-tolerance' approach to vegetation management, explicitly treating any encroachment into the MVCD * * * as a violation * * *.”
59. While the Commission did not require NERC to adopt a minimum inspection cycle as part of Order No. 693, the Commission did express concern both prior to and as part of Order No. 693 that inspection cycles should not be left entirely to the discretion of the transmission owner. Accordingly, in Order No. 693, the Commission stated that:
The Commission continues to be concerned with leaving complete discretion to the transmission owners in determining inspection cycles, which limits the effectiveness of the Reliability Standard. Accordingly, the Commission directs the ERO to develop compliance audit procedures * * * which would identify appropriate inspection cycles based on local factors. These inspections cycles are to be used in compliance auditing of FAC-003-1 by the ERO or Regional Entity to ensure such inspection cycles and vegetation management requirements are properly met by the responsible entities.
60. Thus, based on the overall benefits of proposed FAC-003-2, we propose to approve Reliability Standard FAC-003-2 and propose to direct a change in the VRF level assigned to Requirement R2, as discussed further below.
61. In considering whether to approve Reliability Standard FAC-003-2, we give due weight to NERC's technical expertise. In light of our proposal to approve the proposed Reliability Standard, commenters' suggestions th