Interconnection for Wind Energy, 34993-35011 [05-11678]

Agencies

• DEPARTMENT OF ENERGY
• Federal Energy Regulatory Commission

[Federal Register Volume 70, Number 115 (Thursday, June 16, 2005)]
[Rules and Regulations]
[Pages 34993-35011]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-11678]


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DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

18 CFR Part 35

[Docket No. RM05-4-000--Order No. 661]


Interconnection for Wind Energy

June 2, 2005.
AGENCY: Federal Energy Regulatory Commission.

ACTION: Final rule.

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SUMMARY: The Federal Energy Regulatory Commission (Commission) is 
amending its regulations to require public utilities to append to their 
standard large generator interconnection procedures and large generator 
interconnection agreements in their open access transmission tariffs 
(OATTs) standard procedures and technical requirements for the 
interconnection of large wind generation.

EFFECTIVE DATE: This final rule will become effective August 15, 2005.

FOR FURTHER INFORMATION CONTACT:

Bruce A. Poole (Technical Information), Office of Markets, Tariffs and 
Rates, Federal Energy Regulatory Commission, 888 First Street, NE., 
Washington, DC 20426; (202) 502-8468.

G. Patrick Rooney (Technical Information), Office of Markets,

[[Page 34994]]

Tariffs and Rates, Federal Energy Regulatory Commission, 888 First 
Street, NE., Washington, DC 20426; (202) 502-6205.

P. Kumar Agarwal (Technical Information), Office of Markets, Tariffs 
and Rates, Federal Energy Regulatory Commission, 888 First Street, NE., 
Washington, DC 20426; (202) 502-8923.

LaChelle Brooks (Technical Information), Office of Markets, Tariffs and 
Rates, Federal Energy Regulatory Commission, 888 First Street, NE., 
Washington, DC 20426; (202) 502-6522.

Jeffery S. Dennis (Legal Information), Office of the General Counsel, 
Federal Energy Regulatory Commission, 888 First Street, NE., 
Washington, DC 20426; (202) 502-6027.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction
II. Background
III. Discussion
    A. Low Voltage Ride-Through Capability
    1. Comments
    2. Commission Conclusion
    B. Power Factor Design Criteria (Reactive Power)
    1. Comments--Power Factor Range and General Application of 
Requirement
    2. Commission Conclusion--Power Factor Range and General 
Application of Requirement
    3. Comments--Point of Interconnection
    4. Commission Conclusion--Point of Interconnection
    5. Comments--Dynamic Reactive Power Capability
    6. Commission Conclusion--Dynamic Reactive Power Capability
    C. Supervisory Control and Data Acquisition Capability
    1. Comments
    2. Commission Conclusion
    D. Wind Plant Interconnection Modeling
    1. Comments
    2. Commission Conclusion
    E. Self-Study of Interconnection Feasibility
    1. Comments
    2. Commission Conclusion
    F. Applicability to Other Generating Technologies
    1. Comments
    2. Commission Conclusion
    G. Variations From the Final Rule
    1. Comments
    2. Commission Conclusion
    H. Transition Period
    1. Comments
    2. Commission Conclusion
    I. Miscellaneous Comments
    1. Commission Conclusion
    J. Compliance Issues
IV. Information Collection Statement
V. Environmental Analysis
VI. Regulatory Flexibility Act Certification
VII. Document Availability
VIII. Effective Date and Congressional Notification

    Before Commissioners: Pat Wood, III, Chairman; Nora Mead Brownell, 
Joseph T. Kelliher, and Suedeen G. Kelly.
    1. In this Final Rule, to meet our responsibility under sections 
205 and 206 of the Federal Power Act (FPA) \1\ to remedy undue 
discrimination, the Commission adopts standard procedures and technical 
requirements for the interconnection of large wind plants. The 
Commission requires all public utilities that own, control, or operate 
facilities for transmitting electric energy in interstate commerce to 
append to the Large Generator Interconnection Procedures (LGIPs) and 
Large Generator Interconnection Agreements (LGIAs) in their Open Access 
Transmission Tariffs (OATTs) the Final Rule Appendix G adopted here. 
These standard technical requirements provide just and reasonable terms 
for the interconnection of wind plants.\2\ The rule recognizes the 
technical differences of wind generating technology, and benefits 
customers by removing unnecessary obstacles to further development of 
wind generating resources while ensuring that reliability is protected.
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    \1\ 16 U.S.C. 824d-e (2000).
    \2\ As discussed in greater detail below, the Final Rule 
Appendix G applies only to wind plants, due to the unique 
characteristics of wind generating technology.
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I. Introduction

    2. In Order No. 2003,\3\ the Commission adopted standard procedures 
and a standard agreement for the interconnection of large generation 
facilities. The Commission required public utilities that own, control, 
or operate facilities for transmitting electric energy in interstate 
commerce to file revised OATTs containing these standard provisions, 
and use them to provide interconnection service to generating 
facilities having a capacity of more than 20 megawatts.
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    \3\ Standardization of Generator Interconnection Agreements and 
Procedures, Order No. 2003, 68 Fed. Reg. 49,845 (Aug. 19, 2003), 
FERC Stats. & Regs., Regulations Preambles ] 31,146 (2003) (Order 
No. 2003), order on reh'g, 69 Fed. Reg. 15,932 (Mar. 24, 2004), FERC 
Stats & Regs., Regulations Preambles ] 31,160 (2004) (Order No. 
2003-A), order on reh'g, 70 Fed. Reg. 265 (January 4, 2005), FERC 
Stats & Regs., Regulations Preambles ] 31,171 (2004) (Order No. 
2003-B), reh'g pending; see also Notice Clarifying Compliance 
Procedures, 106 FERC ] 61,009 (2004).
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    3. In Order No. 2003-A, on rehearing, the Commission noted that the 
standard interconnection procedures and agreement were based on the 
needs of traditional synchronous generation facilities and that a 
different approach might be more appropriate for generators relying on 
non-synchronous technologies,\4\ such as wind plants.\5\
    Accordingly, the Commission granted certain clarifications, and 
also added a blank Appendix G (Requirements of Generators Relying on 
Non-Synchronous Technologies) to the standard LGIA for future adoption 
of requirements specific to non-synchronous technologies.\6\
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    \4\ A wind generator is considered non-synchronous because it 
does not run at the same speed as a traditional generator. A non-
synchronous generator possesses significantly different 
characteristics and responds differently to network disturbances.
    \5\ Order No. 2003-A at P 407, n. 85.
    \6\ Id.
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    4. Therefore, in a Notice of Proposed Rulemaking (NOPR), the 
Commission proposed technical standards applicable to the 
interconnection of large wind generating plants \7\ to be included in 
Appendix G of the LGIA.\8\ We proposed the standards in light of our 
findings in Order No. 2003-A noted above and in response to a petition 
submitted by the American Wind Energy Association (AWEA) on May 20, 
2004.\9\ The Commission proposed to adopt certain technical 
requirements that Transmission Providers would be required to apply to 
interconnection service for wind generation plants, which are different 
from those required of traditional synchronous generating plants. These 
standard technical requirements are now needed because of the increased 
presence of larger aggregated wind plants on many Transmission 
Providers' systems. The NOPR stated that, except for those articles of 
the LGIA for which wind plants have been exempted,\10\ these 
requirements would supplement the standard interconnection procedures 
and requirements adopted by the Commission in Order No. 2003. 
Additionally, the NOPR sought comments on certain specific issues, 
including whether there are other non-synchronous technologies, or 
other technologies in addition to wind, that should also be covered by 
the proposed Appendix G.
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    \7\ Large wind generating plants are those with an output rated 
over 20 MW at the point of interconnection.
    \8\ See Interconnection for Wind Energy and Other Alternative 
Technologies, Notice of Proposed Rulemaking, 110 FERC ] 61,036 
(2004) (NOPR).
    \9\ See Petition for Rulemaking or, in the Alternative, Request 
for Clarification of Order No. 2003-A, and Request for Technical 
Conference of the American Wind Energy Association (May 20, 2004), 
filed in Docket Nos. RM02-1-005 and PL04-15-000.
    \10\ LGIA article 5.4 (Power System Stabilizers), LGIA article 
5.10.3 (Interconnection Customer's Interconnection Facilities 
Construction), and LGIA article 9.6.1 (Power Factor Design 
Criteria).

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[[Page 34995]]

II. Background

    5. In Order No. 2003, to meet our responsibility under sections 205 
and 206 of the FPA to remedy undue discrimination, the Commission 
required all public utilities that own, control, or operate facilities 
for transmitting electric energy in interstate commerce to append to 
their OATTs the LGIP and LGIA. To achieve greater standardization of 
interconnection terms and conditions, Order No. 2003 required such 
public utilities to file revised OATTs containing the LGIP and LGIA 
included in Order No. 2003.
    6. As explained above, because some of the technical requirements 
in the LGIA were inappropriate for non-synchronous technologies (such 
as wind generators), the Commission clarified in Order No. 2003-A that 
LGIA article 5.4 (Power System Stabilizers), LGIA article 5.10.3 
(Interconnection Customer's Interconnection Facilities Construction) 
and LGIA article 9.6.1 (Power Factor Design Criteria) would not be 
applied to wind generators.\11\ Additionally, the Commission noted that 
``there may be other areas of the LGIP and LGIA that may call for a 
slightly different approach for a generator relying on newer technology 
because it may have unique electrical characteristics.'' \12\
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    \11\ Id. at P 407, n. 85.
    \12\ Id.
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    7. On May 20, 2004, in Docket No. RM02-1-005, AWEA submitted a 
petition for rulemaking or, in the alternative, request for 
clarification of Order No. 2003-A, and a request for a technical 
conference. AWEA asked the Commission to adopt in Appendix G certain 
standards for the interconnection of wind generation plants. 
Specifically, AWEA submitted a proposed Appendix G that it argues 
addresses the concerns of both Transmission Providers and the wind 
generation industry. AWEA's proposed Appendix G included a low voltage 
ride-through capability standard that would allow the Transmission 
Provider to require as a condition of interconnection that wind 
generation facilities have the ability to continue operating or ``ride 
through'' certain low voltage conditions on the transmission systems to 
which they are interconnected. AWEA's proposed Appendix G also included 
that as a condition of interconnection, wind plants would install 
equipment enabling remote supervisory control and data acquisition 
(SCADA) that would limit the maximum plant output during system 
emergency and system contingency events and telemetry communication 
between the system operator and the wind plant for automatic 
forecasting and scheduling. Additionally, AWEA proposed that the power 
factor design criteria of up to 0.95 leading/lagging (required in Order 
No. 2003) be applied to wind generation plants, with flexibility 
regarding whether the reactive support equipment would be located at 
the common point of interconnection of all the generators in the plant 
rather than at the high side of the wind plant substation transformers. 
Further, AWEA proposed that the Commission require Transmission 
Providers and wind generator manufacturers to participate in a formal 
process to develop, update, and improve the engineering models and 
specifications used in modeling wind plant interconnections. Finally, 
AWEA proposed to include language in Appendix G allowing the wind 
Interconnection Customer to ``self-study'' interconnection feasibility 
by entering the interconnection queue without providing certain power 
and load flow data required of other large generators, receiving 
certain information from the Transmission Provider, and conducting its 
own Feasibility Study.
    8. On September 24, 2004, the Commission held a Technical 
Conference to discuss the issues raised by AWEA's petition, including 
the technical requirements for the interconnection of wind plants and 
other such alternative technologies and the need for specific 
requirements for their interconnection. Additionally, the Technical 
Conference considered how wind and other alternative generator 
technologies may respond differently to transmission grid disturbances 
and have different effects on the transmission grid. The Commission 
also solicited and received post-Technical Conference comments from 
interested persons.
    9. As noted above, the Commission's NOPR proposed to adopt in 
Appendix G to the LGIA a somewhat modified version of the low voltage 
ride-through, SCADA and power factor design standards proposed by AWEA 
in its May 20, 2004 petition. Specifically, the NOPR proposed to 
establish uniform standards in Appendix G that would require large wind 
plants seeking to interconnect to the grid to (1) demonstrate low 
voltage ride-through capability; in other words, show that the plant 
can remain on line during voltage disturbances up to specified time 
periods and associated voltage levels; (2) possess SCADA capability to 
transmit data and receive instructions from the Transmission Provider; 
and (3) maintain a power factor within the range of 0.95 leading to 
0.95 lagging, measured at the high voltage side of the substation 
transformers. In the case of the low voltage ride-through requirement, 
the Commission proposed to permit the Transmission Provider to waive 
the requirement on a comparable and not unduly discriminatory basis for 
all wind plants. In the case of the power factor requirement, the 
Commission proposed to permit the Transmission Provider to waive or 
defer compliance with the requirement where it is not necessary. The 
Commission declined, however, to adopt AWEA's proposal to allow a wind 
generator to ``enter the interconnection queue and conduct its own 
Feasibility Study, having obtained the information necessary to do so 
upon paying the initial deposit and submitting its interconnection 
application.'' \13\ We asked for comments on how to balance the need of 
wind generators to obtain certain data from the Transmission Provider 
before completing their Interconnection Requests with the need to 
protect critical energy infrastructure information and commercially 
sensitive data against unwarranted disclosure.
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    \13\ See AWEA Petition at 13.
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III. Discussion

    10. Based on AWEA's petition, the comments received during and 
after the Technical Conference, and the comments filed in response to 
the NOPR, the Commission is adopting certain standard procedures and 
technical requirements for the interconnection of wind generating 
plants, as discussed in greater detail below. These procedures and 
technical requirements will be appended, as Appendix G, to both the 
LGIP and the LGIA.\14\
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    \14\ In the NOPR, the Commission proposed to include Appendix G 
as an attachment to the LGIA only. Upon further consideration, the 
Commission directs that the Final Rule Appendix G provisions related 
to completion of the Interconnection Request by a wind plant 
interconnection customer be appended to the LGIP, since they are 
procedural in nature, and that the remaining technical requirements 
be appended to the LGIA, to ensure that the provisions adopted here 
are applied throughout the interconnection process.
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    11. These technical requirements for the interconnection of wind 
plants recognize the unique design and operating characteristics of 
wind plants,\15\ their increasing size and

[[Page 34996]]

increasing level of penetration on some transmission systems (in terms 
of the wind generating capacity's percentage contribution to total 
system generating capacity), and the effects they have on the 
transmission system. In Order No. 2003, the Commission noted that in 
the past, requests for interconnection frequently resulted in complex 
and time-consuming disputes over technical matters such as feasibility, 
cost, and cost responsibility.\16\ That is true for wind 
interconnection as well as interconnection of more conventional 
generation. The special standard procedures we are adopting for the 
interconnection of large wind plants will minimize opportunities for 
undue discrimination by Transmission Providers and remove unnecessary 
obstacles to the development of wind generation, while protecting 
system reliability.\17\ Like the LGIP and LGIA in Order No. 2003, the 
Final Rule Appendix G is to be added to the OATT of each public utility 
that owns, controls, or operates facilities for transmitting electric 
energy in interstate commerce.
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    \15\ As noted above, wind plants over 20 MW in total size are 
subject to the standard technical requirements in the Final Rule 
Appendix G. These wind plants are generally made up of several small 
induction wind generating turbines, laid out over a large area, and 
connected through a medium-voltage collector system. This collector 
system is connected to the low voltage side of the step-up 
transformer, which is then connected to the transmission system at a 
single Point of Interconnection.
    \16\ Order No. 2003 at P 11.
    \17\ See id. at P 11-12.
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    12. The Final Rule Appendix G we adopt here applies only to the 
interconnection of wind plants. As discussed further below, the 
Commission does not believe at this time that the standard procedures 
and technical requirements in this Final Rule are appropriate for other 
alternative generating technologies that may supply over 20 MW at one 
Point of Interconnection. The standard procedures and technical 
requirements adopted here recognize the unique characteristics of wind 
plants, including the fact that they use induction generators, consist 
of several or numerous small generators connected to a collector 
system, and do not respond to grid disturbances in the same manner as 
large conventional generators.
    13. The Appendix G procedures and technical requirements for the 
interconnection of wind generation plants are not the sole 
interconnection requirements for wind plants; large wind plants are 
subject to the other standard interconnection procedures and 
requirements adopted by the Commission in Order No. 2003, unless wind 
plants are exempted from such procedures and requirements by Order No. 
2003 and its rehearing orders, and this order.
    14. Additionally, as discussed further below, the Commission adopts 
a reasonable transition period for the technical requirements adopted 
in the Final Rule. Specifically, the standard technical requirements, 
if applicable, for low voltage ride-through capability, SCADA 
capability, and power factor design criteria apply only to LGIAs 
signed, filed with the Commission in unexecuted form, or filed as a 
non-conforming agreement, on or after January 1, 2006, or the date six 
months after publication of the Final Rule in the Federal Register, 
whichever is later. The procedural requirements related to the 
completion of the Interconnection Request by a wind plant 
Interconnection Customer, however, apply when the Final Rule takes 
effect, which is 60 days after the date of publication in the Federal 
Register.\18\
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    \18\ As discussed in greater detail below, in this Final Rule 
the Commission is adopting procedures that permit a wind plant 
Interconnection Customer to provide in the Interconnection Request a 
set of electrical design specifications that depict the wind plant 
as a single generator. These procedures recognize that the unique 
characteristics of wind plants do not permit them to submit a 
detailed electrical design in the initial Interconnection Request 
stage, and allow wind plants to enter the queue and receive the base 
case data necessary to provide a detailed design to the Transmission 
Provider.
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A. Low Voltage Ride-Through Capability

    15. As the Commission stated in the NOPR, early wind generator 
technology would shut down the wind generating unit if there was a 
sudden change in voltage on the transmission system. With the 
increasing number and size of wind plants in the United States, there 
is a concern that wind plants tripping off-line during a low voltage 
situation could raise significant reliability concerns. As a result, 
Transmission Providers state that they need large wind plants to remain 
on-line during low voltage occurrences to maintain reliability. 
Further, in the past, Transmission Providers would often shut down wind 
units during a system disturbance. Wind generators would prefer to stay 
on-line, but they are concerned that having each Transmission Provider 
design its own low voltage ride-through requirement would greatly 
affect wind turbine manufacturing costs. As a result, both wind 
generators and most Transmission Providers support having a low voltage 
ride-through standard for large wind plants.
    16. The NOPR proposed to require that large wind plants seeking to 
interconnect to the transmission system demonstrate low voltage ride-
through capability, unless waived by the Transmission Provider on a 
comparable and not unduly discriminatory basis for all wind plants. 
Specifically, the NOPR Appendix G would require that wind generating 
plants demonstrate the ability to remain on-line during voltage 
disturbances up to the time periods and associated voltage levels set 
forth in Figure 1 of the NOPR. We proposed to measure voltage levels at 
the high voltage side of the wind plant substation transformer. The 
NOPR noted that while low voltage ride-through capability is needed for 
wind plants, it is less of a concern for large synchronous generating 
facilities because most of these facilities are equipped with automatic 
voltage control devices to increase output during low voltage events.
    17. The NOPR sought comments on the proposed low voltage ride-
through standard. In particular, the Commission was interested in 
comments addressing whether it should adopt a low voltage ride-through 
standard at all, whether the proposed standard or another standard is 
appropriate, and whether the proposed standard is specific enough. 
Specifically, the Commission sought comments on whether the required 
time periods and associated voltage levels proposed in Figure 1 of the 
NOPR Appendix G were appropriate or should be modified.
1. Comments
    18. Several commenters, including AWEA,\19\ Western, FirstEnergy, 
and the Midwest ISO, state that they support the low voltage ride-
through standard in Figure 1 of the NOPR. Midwest Reliability 
Organization suggests, however, that the standard could be in article 
9.6 of the LGIA. CenterPoint contends that the reliability concerns 
presented by the failure of a large wind plant to ride through a low 
voltage event also exist if other generators also fail to ride through 
such events, and thus would apply a low voltage ride-through 
requirement to all generators. Western supports the standard as 
proposed, with the understanding that it may need to be modified later 
if it causes unforeseen problems on the transmission system.
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    \19\ See AWEA Reply Comments (April 1, 2005) at 10. 
Specifically, AWEA asks that the proposed low voltage ride-through 
standard be adopted, specifically the proposed standard of Figure 1.
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    19. Numerous other entities support the proposed low voltage ride-
through requirement with modifications. For instance, numerous 
commenters, including AWEA, PacifiCorp-PPM Energy, FPL Energy, Southern 
California Edison, AEP, Xcel, PJM, National Grid and Southern, believe 
that the required voltage should be measured at the point of 
interconnection, as opposed to the

[[Page 34997]]

high side of the wind plant substation transformer.
    20. Additionally, several entities dispute the specific time 
periods and associated voltage levels set forth in Figure 1 of the 
proposed Appendix G. American Superconductor states generally that the 
proposed low voltage ride-through curve in Figure 1 of the NOPR is 
unrealistic and does not resemble voltage situations that wind plants 
are likely to encounter. It also argues that the low voltage 
requirement proposed in the NOPR is not comparable to what is required 
of conventional generators. Midwest ISO TOs, CenterPoint and Xcel 
assert that requiring the low voltage ride-through capability to go 
only to 15 percent of the rated line voltage (as set out in Figure 1 of 
the NOPR) may be too high and may present reliability problems. They 
recommend that the Figure 1 low voltage ride-through profile require 
the wind turbine to ride through low voltage at zero percent of the 
rated line voltage for 150 milliseconds. NUSCo recommends that the 
Commission require wind generators to ride through a fault with zero 
percent of the rated line voltage at the point of interconnection for 
250 milliseconds (15 cycles). American Transmission argues that the low 
voltage ride-through curve of Figure 1 should show the voltage to be at 
0.90 per unit prior to time zero. ISO New England states that to the 
extent the Commission adopts a low voltage ride-through requirement, it 
should require wind plants to remain connected to the transmission 
system for a zero voltage level for the time period associated the 
typical time it takes to clear a normal design contingency fault.\20\
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    \20\ NERC similarly states that to meet its general reliability 
standards for system performance, wind plants should remain online 
``through a normally cleared fault.'' NERC Comments at 3. Also, PJM 
states that wind plants should be required to operate during a zero 
voltage level at the Point of Interconnecton until the fault is 
cleared by primary protective devices on the Transmission System.
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    21. Several of the commenters, including AWEA, Gamesa, and GE 
suggest that the low voltage ride-through standard should be clarified 
to apply only to three-phase faults. AWEA also asks that the 
requirement be clarified to state that a wind plant would not be 
expected to continue to operate in low voltage situations where the 
wind farm is tripped off-line following a fault if (a) this action is 
performed intentionally under a special protection scheme, or (b) if 
the fault is on the Transmission Provider's side of the Point of 
Interconnection and clearing the fault would effectively disconnect the 
wind plant from the system. Midwest ISO TOs and Montana-Dakota 
Utilities also seek clarification regarding application of the proposed 
standard to unbalanced phase voltages.
    22. Many commenters, while supportive of requiring wind plants to 
possess low voltage ride-through capability, argue that the specific 
standard should be permitted to vary based on reliability needs. For 
example, the New York PSC, while agreeing that large wind plants should 
possess low voltage ride-through capability, argues that the specific 
voltage-time standard should be developed on a case-by-case basis to 
reflect system needs. Midwest ISO TOs similarly contend that 
Transmission Providers should be able to establish different low 
voltage ride-through standards on a case-by-case basis. NYISO asserts 
that the low voltage ride-through standard proposed by the Commission 
should be a minimum performance requirement, and that Transmission 
Providers should have the flexibility to require a higher low voltage 
ride-through standard if the particular site location or wind plant 
design requires a higher standard to protect system reliability. 
Similarly, LIPA suggests that the Commission adopt a two-part low 
voltage ride-through standard; the first part would be the standard 
proposed in the NOPR, while the second part would apply a more 
stringent low voltage ride-through standard where the studies indicate 
that the NOPR requirements are inadequate, such as in locations with 
special reliability concerns. ISO New England recommends that the 
Commission not adopt a specific standard for low voltage ride-through 
capability, or alternatively, that the standard serve only as a 
guideline for wind turbine manufacturers. BPA and NERC contend that the 
development of low voltage ride-through standards should be left to the 
Western Electricity Coordinating Council, NERC, regional reliability 
councils, the Institute of Electrical and Electronics Engineers (IEEE), 
and the American National Standards Institute.\21\ American 
Superconductor, Nevada Power, and NUSCo, among others, assert that the 
low voltage ride-through standard should be based on established 
regional reliability standards. Likewise, NorthWestern Energy asks that 
the standard be modified to allow the Transmission Provider to use the 
reliability council standard in effect when the LGIA is signed.
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    \21\ Similarly, EEI suggests that the Commission adopt standards 
on an interim basis, until NERC, the regional reliability councils, 
or IEEE establish formal standards.
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    23. FPL Energy asks that the proposed low voltage ride-through 
requirement be modified so that the determination of whether a wind 
plant must have low voltage ride-through capability is made on a case-
by case basis. According to FPL Energy, the NOPR would have the 
``unintended consequence'' of mandating costly low voltage ride-through 
technology for all wind plants because Transmission Providers will not 
be able to determine that the capability will never be needed.\22\ FPL 
Energy argues that the Commission's Final Rule should require the 
Transmission Provider to determine through the System Impact Study, on 
a case-by-case basis, whether the wind plant is required to possess low 
voltage ride-through capability. It notes that currently, Transmission 
Providers may not require an Interconnection Customer to be responsible 
for Network Upgrades that are not identified in the studies as 
necessary, and that a similar process should apply to the low voltage 
ride-through requirement. Finally, FPL Energy expresses concern that 
the use of the term ``demonstrate'' in the proposed requirement could 
be interpreted to require the wind plant to physically demonstrate the 
capability, risking harm to its electrical equipment.
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    \22\ FPL Energy estimates that for a 100 MW wind farm, the cost 
of low voltage ride-through exceeds $1.5 million.
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    24. With regard to the Commission's proposal to permit the 
Transmission Provider to waive the low voltage ride-through 
requirement, NUSCo and Tucson Electric both argue that no waiver of the 
low voltage ride-through requirement should be permitted. NUSCo asserts 
that the reliability of one Transmission Provider's system may be 
affected by the grant of a waiver by a neighboring Transmission 
Provider.
    25. Xcel and LIPA believe there should also be a high voltage ride-
through standard for wind plants, comparable to the high voltage ride-
through standards for conventional generators.
2. Commission Conclusion
    26. As discussed further below, we adopt the low voltage ride-
through standard proposed in the NOPR, but will not require that it be 
met unless the System Impact Study shows that it is needed. 
Specifically, under the requirement we adopt in this Final Rule, a wind 
plant is required to satisfy the low voltage ride-through standard if 
the Transmission Provider shows, through the System Impact Study, that 
such

[[Page 34998]]

capability is required to ensure safety or reliability. This differs 
from the NOPR, which proposed to require low voltage ride-through 
capability in all cases, except when the Transmission Provider waived 
the requirement on a comparable and not unduly discriminatory basis for 
all wind plants. Additionally, the Final Rule adopts the Point of 
Interconnection as the point of measurement for the low voltage ride-
through standard, instead of the proposed high side of the wind plant 
substation transformers, and replaces the term ``demonstrate'' with 
``possess.'' We also grant certain clarifications, as discussed further 
below.
    27. The Commission believes that establishing the achievable low 
voltage ride-through standard in this Final Rule if the Transmission 
Provider shows that it is necessary to maintain safety or reliability 
provides certainty to wind plant developers that their interconnection 
to the grid will not be frustrated, and limits opportunities for undue 
discrimination. A requirement based on a uniform standard ensures that 
wind developers are not faced with widely varying interconnection 
standards in different areas of the country, which would increase 
manufacturing costs needlessly. We believe that in the long run this is 
in the best interests of the wind industry and customers, as it helps 
provide a secure and reliable power supply, and will facilitate 
increased use of wind as a generation resource while ensuring that 
reliability is protected.
    28. As noted above, the Commission requires low voltage ride-though 
capability only if the Transmission Provider shows that it is needed on 
a case-by-case basis, as FPL Energy requests. Specifically, low voltage 
ride-through capability is required only if the Transmission Provider 
shows, through the System Impact Study, that it is required to ensure 
the safety or reliability of the Transmission Provider's transmission 
system. Given that Transmission Providers have responsibility for 
ensuring the reliable operation of their systems (pursuant to NERC and 
regional reliability council standards), the Commission believes that 
they are in the best position to establish whether low voltage ride-
through capability is needed in individual circumstances. The System 
Impact Study is the best vehicle for assessing the need for such 
capability, and this study should determine if there is a need for a 
wind plant to remain on-line during low voltage events to ensure the 
safety or reliability of the system. Requiring low voltage ride-through 
capability only if the System Impact Study shows it to be necessary 
ensures that the increased reliance on wind plants does not degrade 
system safety or reliability. It also ensures that the Transmission 
Provider does not require a wind plant to install costly equipment that 
is not needed for grid safety or reliability. This limits the 
opportunities for undue discrimination; a wind plant Interconnection 
Customer will not have its interconnection frustrated by unnecessary 
requirements to install costly equipment that is not needed for safety 
or reliability. Should the wind plant Interconnection Customer disagree 
with the Transmission Provider that the System Impact Study shows that 
low voltage ride-through capability is needed, it may challenge the 
Transmission Provider's conclusion through dispute resolution or appeal 
to the Commission.
    29. Given our decision to apply the low voltage ride-through 
capability standard only on a case-by-case basis if the Transmission 
Provider shows, through the System Impact Study, that it is needed to 
ensure safety or reliability, there is no need for the waiver provision 
in the NOPR. As a result, issues raised by commenters regarding the 
waiver provision are moot.
    30. As noted above, many entities representing a broad mix of 
market participants request that the low voltage ride-through 
requirement be modified to require that the voltage be measured at the 
Point of Interconnection, as opposed to the high voltage side of the 
wind plant substation transformer. Given the need to protect grid 
safety and reliability by having wind plants ride through low voltage 
events where necessary, and continue to provide output at the point 
where the plant and its associated interconnection facilities join the 
grid, we will do so. Use of this measurement point recognizes that the 
Point of Interconnection is the point at which the Interconnection 
Customer's responsibility ends and the Transmission Provider's 
responsibility begins. Additionally, this change to the NOPR is broadly 
supported, and simplifies the interconnection process by maintaining 
the same Point of Interconnection definition adopted in Order No. 2003.
    31. We also find convincing FPL Energy's argument that using the 
term ``demonstrate the ability'' could be interpreted to require the 
wind plant to physically demonstrate that it has low voltage ride-
through capability and thus could lead to unnecessary tests that could 
harm the wind plant electrical equipment. Accordingly, we replace the 
term ``demonstrate the ability'' with ``be able.''
    32. We also clarify certain portions of the low voltage ride-
through standard. First, we clarify that the low voltage ride-through 
requirement, and the time periods and associated voltage levels set 
forth in Appendix G, Figure 1, apply to three-phase faults.\23\ This is 
because three-phase faults are the most severe, whereas two-phase or 
single-phase faults drop the voltage to a level not as low as that 
specified in Figure 1. Further, in response to AWEA, we clarify that a 
wind plant is not required to satisfy the standard in Appendix G, 
Figure 1 if the wind plant is intentionally tripped off line following 
a fault under a ``special protection scheme'' \24\ agreed to by the 
Transmission Provider. These situations may include a fault on the 
Transmission Provider's side of the Point of Interconnection, as well 
as a fault other than a three-phase fault covered by the low voltage 
ride-through standard.
---------------------------------------------------------------------------

    \23\ A three-phase fault is an unintentional short circuit 
condition involving all three phases in an electric system. It is 
the most severe in its impact, but occurs least frequently. For 
complete reliability, it is virtually universal to design an 
electric system for three-phase faults. Other types of faults are: 
single line-to-ground fault, line-to-line fault, and double line-to-
ground fault.
    \24\ A special protection scheme is an automatic protection 
scheme designed to detect abnormal or predetermined system 
conditions and take corrective actions to maintain system 
reliability. Such actions may include changes in demand, generation, 
or system configuration to maintain acceptable voltage or power 
flows.
---------------------------------------------------------------------------

    33. We reject the requests that the standards be only guidelines. 
The Commission sets forth in this Final Rule a low voltage ride-through 
standard that it believes, after consideration of the comments from all 
interested entities, including the wind industry, is achievable and 
will maintain grid safety and reliability while facilitating the 
increased use of wind resources. As noted above, the Commission is 
setting a standard for low voltage ride-through to provide certainty 
and diminish the opportunities for undue discrimination. Permitting 
Transmission Providers to set their own specific low voltage ride-
through standards would create too great a risk that this opportunity 
would be used to frustrate wind plant interconnections or to favor a 
Transmission Provider's wind generating affiliate.
    34. In response to comments suggesting that we should allow NERC 
and the regional reliability councils to establish low voltage ride-
through standards, we are aware of the work being done by these 
organizations to address wind plant interconnection standards. However, 
no such standards are available today, and Transmission

[[Page 34999]]

Providers and wind Interconnection Customers are looking for 
interconnection standards to apply now. If other entities develop an 
alternate standard, a Transmission Provider may seek to justify 
adopting them as variations from Appendix G, as discussed below. 
Additionally, the Commission would consider a future industry petition 
to revise Appendix G to conform to NERC developed standards.
    35. With respect to Midwest ISO TOs' concern that Appendix G, 
Figure 1 does not contain information on how the standard would apply 
to unbalanced voltages in close proximity to the point of 
interconnection,\25\ we note that it is impossible to identify all 
possible conditions and circumstances that may arise on the 
transmission system. The low voltage ride-through standard is a general 
one that will be adequate under most circumstances. We recognize that 
special circumstances may occur. These may be identified by the System 
Impact Study, which should identify any additional protection 
requirements in addition to this standard. We also note that, as 
discussed below, the Commission permits variations from the Final Rule 
Appendix G that are ``consistent with or superior to'' the standard 
provisions, that are based on regional reliability council 
requirements, or that are offered by independent entities such as 
Regional Transmission Organizations (RTOs) or Independent System 
Operators (ISOs).
---------------------------------------------------------------------------

    \25\ Additionally, a number of commenters suggest low voltage 
ride-through levels and timing or cycling standards different from 
those reflected in the NOPR Appendix G, Figure 1.
---------------------------------------------------------------------------

    36. Similarly, we are not persuaded to alter the specific time 
periods and associated voltage levels in Figure 1 of the NOPR Appendix 
G. The low voltage ride-through standard proposed in that figure and 
adopted here is close to the standard used in other countries and was 
presented to the Commission by representatives of the wind industry as 
an achievable requirement. Several commenters, including Transmission 
Providers, support the standard as one that would safeguard 
reliability. The Western Electricity Coordinating Council (WECC), a 
regional reliability council, has approved a similar low voltage ride-
through standard. The standard we adopt in this Final Rule is an 
international standard that has been accepted for use by the Alberta 
Electric System Operator and Germany, and was developed following 
detailed study. We do not believe it would be appropriate to deviate 
from such a widely-accepted and achievable standard in this rulemaking.
    37. We are not convinced of a need for a separate high voltage 
ride-through standard for wind generators. The record developed here 
does not indicate that this is a general concern across the country. 
Parties that believe a high voltage ride-through standard is required 
should ask NERC or the regional reliability councils to address this 
need. A Transmission Provider may seek to justify variations from 
Appendix G to establish these requirements under the variation 
provisions of Order No. 2003 and its rehearing order, as briefly 
summarized below in section III.G, ``Variations from the Final Rule.''

B. Power Factor Design Criteria (Reactive Power)

    38. The Commission stated in the NOPR that until recently, 
Transmission Providers did not require wind generators to have the 
capability to provide reactive power because the generators were 
generally small and had little effect on the transmission grid. 
However, because of the larger size of many of the wind plants being 
built and the increased presence of wind energy on various transmission 
systems, the Commission proposed to require wind plants to operate 
within a specified power factor range to help balance the reactive 
power needs of the transmission system.
    39. Specifically, the NOPR proposed to require that large wind 
plants maintain a power factor within the range of 0.95 leading to 0.95 
lagging (as required by Order No. 2003), to be measured at the high 
voltage side of the wind plant substation transformer.\26\ In Appendix 
G of the NOPR, we further proposed to allow wind plants flexibility in 
how they meet the power factor requirement; for example, using either 
power electronics designed to supply this level of reactive capability, 
fixed and switched capacitors if agreed to by the Transmission 
Provider, or a combination of the two.\27\ Additionally, the NOPR 
proposed to allow the Transmission Provider to waive the power factor 
requirement for wind plants where it is not needed at that location or 
for a generating facility of that size, provided that such waiver is 
not unduly discriminatory ( that is, is offered on a comparable basis 
to similarly situated wind plants). The NOPR stated, however, that if 
the Transmission Provider waived the power factor requirement, the 
interconnection agreement would be considered a non-conforming 
agreement under section 11.3 of the LGIP and thus would have to be 
filed with the Commission. The NOPR also proposed to require that wind 
plants have the capability to provide sufficient dynamic (as opposed to 
static) voltage support to interconnect to the transmission system, if 
the System Impact Study shows that dynamic capability is necessary for 
system reliability.\28\
---------------------------------------------------------------------------

    \26\ This proposed measurement point is different from Order No. 
2003, which measures the power factor at the Point of 
Interconnection.
    \27\ Conventional generators inherently provide reactive power, 
whereas most induction-type generators used by wind plants currently 
can only provide reactive power through the addition of external 
devices.
    \28\ NOPR at P 18.
---------------------------------------------------------------------------

    40. The NOPR sought comments about whether the proposed power 
factor range should be increased or decreased for wind generating 
plants. It also sought comments as to whether any dynamic (i.e., 
controllable) reactive capability should be required of wind plants, 
and if so, how much. Finally, the NOPR sought comments on the proposed 
waiver provision.
    41. The comments received fall into several categories, including 
the general application of a power factor requirement to wind plants 
and the waiver provisions, the power factor range and operation within 
that range, measurement of the power factor requirement at the point of 
interconnection, and whether dynamic reactive power capability should 
be a requirement. These subcategories are separately addressed below.
1. Comments--Power Factor Range and General Application of the 
Requirement
    42. Western, NERC, BPA and Great River support the proposed power 
factor range of 0.95 leading to 0.95 lagging (hereinafter stated as +/-
0.95). Southern California Edison agrees that the proposed power factor 
range is appropriate unless it is waived by the Transmission Provider.
    43. Numerous other commenters state that they support the standard, 
but that the Transmission Provider should be allowed to impose a wider 
power factor range on a wind generating plant to maintain the 
reliability of the transmission system. American Superconductor, for 
instance, believes that the +/-0.95 power factor range should be 
adopted as a standard except in cases where the Transmission Provider's 
System Impact Study indicates that additional reactive support is 
needed. Similarly, EEI asserts that the wind plant should operate 
within the +/-0.95 power factor range unless the Transmission Provider 
has established a different standard that

[[Page 35000]]

applies to all generators in its control area. New York PSC agrees with 
the NOPR power factor range, but argues that the Transmission Provider 
should be able to require a power factor of 0.90 lagging if the System 
Impact Study indicates it is needed for system reliability. FirstEnergy 
and American Transmission believe that to ensure a greater level of 
reliability, the Commission should adopt a power factor range of 0.90 
lagging to 0.95 leading. NRECA-APPA maintains that while most 
Transmission Providers impose the +/-0.95 power factor requirement on 
conventional generators, some impose a larger range, such as 0.90 
lagging to 0.95 leading, to meet reliability criteria. In that 
situation, they contend that the Transmission Provider should be 
allowed to impose that same wider power factor range on wind generating 
plants. In similar comments, NYISO urges the Commission to (1) consider 
the power factor standard a minimum requirement, as opposed to a 
maximum, and (2) find that the large wind farms should not be able to 
depend on the transmission system interconnection for the plants' 
excitation power.
    44. NRECA-APPA and Xcel also state that the standard is unclear 
about whether the wind generator can operate anywhere in the +/-0.95 
range. Xcel asks that the Commission clarify whether the wind generator 
is expected to operate over the entire +/-0.95 power factor range or at 
a specified point within that range.
    45. Several commenters assert that the adherence to the 
Transmission Provider's voltage schedule is more important than merely 
maintaining a power factor within the specified range. NRECA-APPA asks 
that the wind plant be required to comply with the Transmission 
Provider's voltage schedule directives. PacifiCorp/PPM Energy asks the 
Commission to revise the proposed power factor standard to require the 
Transmission provider to specify a power factor or voltage control set 
point within the 0.95 leading to 0.95 lagging range. PacifCorp/PPM 
Energy also contends that the parenthetical in the proposed Appendix G 
(stating ``taking into account any limitations due to voltage level, 
real power output, etc.'') is ambiguous and should be eliminated.
    46. AWEA argues that we should specify the minimum real power 
output of the wind facility at which the +/-0.95 power factor range 
would apply. It states that to be clear about the limits of this 
standard, the reactive power output criteria should use a minimum real 
power output set at greater than 10 percent of the rated output of the 
generator. FPL Energy states that General Electric wind turbines cannot 
meet the proposed power factor standard over the full range of real 
power output, and that dynamic VAR control (DVAR) banks or static 
capacitors would have to be installed at an additional expense to meet 
the proposed power factor over the entire range. FPL Energy asserts 
that such costs would provide limited reliability benefits.
    47. Zilkha, FirstEnergy, NorthWestern Energy, and BPA indicate that 
the Transmission Provider should be allowed to waive the power factor 
requirement where it is not required. NUSCo, ISO New England and 
Midwest ISO TOs oppose allowing such a waiver. Midwest ISO TOs argue 
that if the Commission allows waiver, it should require that, where the 
Transmission Provider granting the waiver is not also the owner, the 
Transmission Owner approve the waiver. AWEA asserts that the proposed 
requirement that an interconnection agreement be filed with the 
Commission as a non-conforming agreement if the Transmission Provider 
has waived the reactive power requirement is inappropriate and 
inconsistent with Order No. 2003-A.
    48. AWEA and FPL Energy ask that the +/-0.95 power factor standard 
not be required of a wind plant unless the Transmission Provider shows 
that it is needed for system safety or reliability. FPL Energy states 
that the Transmission Provider should have the burden of demonstrating 
that the reactive power standard is needed. It suggests that the 
Commission use the same test it used in the NOPR for dynamic voltage 
support, which requires that the Transmission Provider, before 
requiring such capability, must show that it is necessary for system 
reliability. The CPUC recommends a ``least cost, best fit'' approach to 
dealing with the reactive power requirement needs of wind farms.
    49. Southern California Edison states that because reactive power 
at wind generating plants may be produced from devices external to the 
generator, a time delay may be necessary to allow for switching of 
reactive resources to enable the wind generator to operate at the 
appropriate power factor within the +/-0.95 power factor range. It 
states, however, that exempting the wind generating plant altogether 
from the power factor requirement is inappropriate.
2. Commission Conclusion--Power Factor Range and General Application of 
the Requirement
    50. We adopt the power factor range of +/-0.95 for large wind 
generating plants. We modify other parts of the proposed requirements. 
First, this Final Rule requires the wind plant to maintain the required 
power factor range only if the Transmission Provider shows, through the 
System Impact Study, that such capability is required of that plant to 
ensure safety or reliability. This differs from the NOPR, which 
required the wind plant to maintain the required power factor in all 
cases, except if the Transmission Provider waived or deferred 
compliance with the reactive power standard. Establishing an achievable 
reactive power standard if it is needed for safety or reliability 
provides assurance to wind plant developers that their interconnection 
to the grid will not be frustrated or face uncertainty due to a lack of 
standards, and thus will limit opportunities for undue discrimination. 
This uniform standard ensures that wind developers, when they seek to 
interconnect, are not faced with widely varying standards in different 
areas, or for different wind technologies, manufacturers, or plant 
owners. This should remove unnecessary obstacles to the increased 
growth of wind generation. Furthermore, ensuring that a large wind 
plant provides reactive support to the transmission grid if needed will 
ensure that safety and reliability is protected.
    51. Specifically, the Commission revises the proposed power factor 
standard to require that the wind plant maintain the required power 
factor only on a case-by-case basis if the Transmission Provider, in 
the System Impact Study, shows that it is necessary to ensure safety or 
reliability. The reactive power standard adopted here properly requires 
the Transmission Provider to show that reactive power capability is 
needed for each wind plant Interconnection Customer. As we noted with 
regard to low voltage ride-through capability, because the Transmission 
Provider is responsible for the safe and reliable operation of its 
transmission system (pursuant to NERC and regional reliability council 
standards), it is in the best position to establish if reactive power 
is needed in individual circumstances. The System Impact Study is the 
appropriate study for assessing the need for reactive power capability, 
and this study should determine if there is a need for a wind plant to 
have reactive power capability to ensure that the safety or reliability 
of

[[Page 35001]]

the system is maintained. Also, as we reasoned above with regard to low 
voltage ride-through, requiring wind plants to maintain the required 
power factor only if the System Impact Study shows it to be necessary 
ensures that the increased reliance on wind plants does not degrade 
system safety or reliability. It also ensures that the Transmission 
Provider does not require a wind plant to install costly equipment that 
is not needed for grid safety or reliability. Furthermore, requiring 
that the System Impact Study find a need for reactive power will limit 
the opportunities for undue discrimination; a wind plant 
Interconnection Customer will not have its interconnection frustrated 
by unnecessary requirements that are not necessary to maintain safety 
or reliability. Should a wind plant Interconnection Customer disagree 
with the Transmission Provider that the System Impact Study shows that 
the power factor requirement is needed, it may challenge the 
Transmission Provider's conclusion through dispute resolution or appeal 
to the Commission.
    52. Given our decision to require that a wind plant maintain the 
power factor standard only on a case-by-case basis where the 
Transmission Provider shows, through the System Impact Study, that 
reactive power is needed to ensure reliability, there is no need to 
retain the waiver provisions proposed in the NOPR. As a result, issues 
raised by commenters regarding the waiver provisions are moot.
    53. We clarify that the wind generating plant, if required to 
provide reactive power capability as described above, should be able to 
operate anywhere in the +/-0.95 power factor range.
    54. We reject proposals to change the power factor range standard 
in Appendix G to 0.90 lagging to 0.95 leading. Adopting such a standard 
would make the power factor requirement more onerous for wind plants 
than for conventional generators. Concerning NYISO's request that the 
Commission consider the standard as a minimum requirement as opposed to 
a maximum, as we declined to do so in Order No. 2003, we decline to do 
so here for the same reasons.
    55. In response to those who assert that adherence to the voltage 
schedule is more important than merely maintaining a power factor 
within the specified range, we note that article 9.6.2 of the LGIA 
already requires that the ``Interconnection Customer * * * operate the 
Large Generating Facility to maintain the specified output voltage or 
power factor at the Point of Interconnection.'' This language applies 
to wind plants and addresses this concern.
    56. We disagree with PacifiCorp/PPM Energy that the parenthetical 
statement in the NOPR, ``taking into account any limitations due to 
voltage level, real power output * * *,'' is ambiguous and unnecessary. 
AWEA explains that the stated power factor range cannot be accomplished 
by all equipment vendors at all levels of output, and asks that the 
wind plant be held to the +/-0.95 power factor range only when it is 
generating above 10 percent of its rated output. The parenthetical 
statement is necessary due to the technical differences of wind plants, 
which cannot meet the power factor standard below certain levels of 
output, and addresses the concern raised by the wind industry.
    57. We disagree with the CPUC's recommendation of a ``least cost, 
best fit'' approach. Such a ``standard'' is not a standard at all. 
Adopting such a least cost approach would result in widely varying 
``standards'' for wind turbines and related equipment. This would not 
only open the door further for the undue discrimination that this rule 
is designed to eliminate, but also would lead to high cost 
individualized generator designs by equipment manufacturers that would 
not serve the long-term needs of the wind industry.
3. Comments--Point of Interconnection
    58. In the NOPR, the Commission proposed to measure the required 
power factor at the high side of the wind plant substation 
transformers, as opposed to the Point of Interconnection measurement 
point used in Order No. 2003. Numerous commenters, including NUSCo, 
Southern, National Grid, PacifiCorp/PPM Energy, and Southern California 
Edison request that the power factor be measured at the Point of 
Interconnection, as opposed to at the high voltage side of the wind 
plant substation transformer. FPL Energy notes that while meeting the 
power factor requirement at the Point of Interconnection may be more 
costly for wind plants that have long generation tie lines, reliability 
requirements will not be met by measuring the power factor at a 
different point. AWEA states that the appropriate point of measurement 
is either at the Point of Interconnection or at the high side of the 
wind plant's transformer, depending upon the particular electrical 
circumstances. It adds that the point of measurement should be 
determined based on the Transmission Provider's System Impact Study.
4. Commission Conclusion--Point of Interconnection
    59. We adopt the Point of Interconnection as the appropriate 
measurement point for the power factor standard. We agree that adopting 
the Point of Interconnection as the measurement point will better 
protect system reliability because it is closer to the bulk electrical 
power system, and will be consistent with Order No. 2003. In addition, 
numerous Transmission Providers and wind energy developers including 
PPM Energy and FPL Energy endorse establishing the point of measurement 
at the Point of Interconnection, instead of the high side of the 
substation transformers, as proposed in the NOPR. Moreover, FPL Energy 
supports this measurement point, even though it may be more costly for 
plants with long generation tie lines, because it is necessary for 
system safety and reliability.
5. Comments--Dynamic Reactive Power Capability
    60. The Commission proposed in the NOPR to require wind plants to 
be able to provide sufficient dynamic voltage support if the System 
Impact Study shows that it is needed to maintain system reliability. 
Several commenters assert that wind generators should have dynamic 
reactive capability for the entire power factor range, and that dynamic 
reactive capability must be required in every instance. Midwest ISO TOs 
assert that the System Impact Study may show that no such capability is 
needed at the time of the study, but the need may arise later. They 
contend that at a minimum, a wind plant should not degrade the 
transient under-voltage performance of the transmission system at the 
Point of Interconnection.
    61. Midwest ISO points to language from NERC standards \29\ and 
argues that the need for dynamic reactive power capability cannot be 
determined by the System Impact Study because it is almost impossible 
to conceive of every possible disturbance scenario ahead of time. AEP 
argues that dynamic reactive capability must be required and that the 
specific level of dynamic capability should be determined on a need 
basis. ISO New England states that the wind

[[Page 35002]]

plant's rate of response for dynamic voltage control should be 
comparable to that provided by a conventional synchronous generator 
using an automatic voltage regulator.
---------------------------------------------------------------------------

    \29\ Specifically, Midwest ISO cites the following language: 
``Dynamic reactive power support and voltage control are essential 
during power system disturbances. Synchronous generators, 
synchronous condensers, and static var compensators (SVCs and 
STATCOMs) can provide dynamic support.'' See Comments of Midwest ISO 
at 5-6, citing NERC Planning Standard I. D., System Adequacy and 
Security--Voltage Support and Reactive Power, approved by the NERC 
Board of Trustees on September 16, 1997.
---------------------------------------------------------------------------

    62. FirstEnergy and FPL Energy ask the Commission to clarify what 
it meant by the term ``sufficient dynamic voltage support.'' It claims 
that the term ``sufficient'' is vague and requires clarification. 
Si