May 2003 • NREL/CP-560-34003
IEEE P1547 Series of Standards
for Interconnection
Preprint
T.S. Basso and R. DeBlasio
To be presented at the IEEE/PES Transmission and
Distribution Conference and Exhibition
Dallas, Texas
September 7–12, 2003
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IEEE P1547 Series of Standards
for Interconnection
Thomas S. Basso, Member, IEEE, and Richard DeBlasio, Senior Member, IEEE
Abstract--The IEEE P1547 Standard For Interconnecting Distrib-
uted Resources With Electric Power Systems is the first in the P1547
series of planned interconnection standards, and additional standards
are needed. There are major issues and obstacles to an orderly transi
-
tion to the use and integration of distributed power resources with
electric power systems. The lack of uniform national interconnection
standards and tests for interconnection operation and certification—
as well as the lack of uniform national building, electrical, and safety
codes—is understood, and resolving this requires reasonable lead
time to develop and promulgate consensus. The P1547 standard is a
benchmark milestone for the IEEE standards consensus process and
successfully demonstrates a model for ongoing success in the devel
-
opment of further national standards and for moving forward in mod-
ernizing our nation's electric power system.
Index Terms--certification; communications; dispersed storage and
generation; distributed generation; distributed power; distributed
resources; fuel cells; interconnection; monitoring and control; photo-
voltaic power systems; power distribution; power generation; power
systems; regulation; standards; test.
I. INTRODUCTION
The use of distributed generation and, more generally, dis-
tributed resources (DR)—which includes distributed genera-
tion and energy storage systems—has the potential to provide
more reliable and lower-cost energy for electricity customers
as well as benefits for today’s electric transmission and distri
-
bution (T&D) systems. This may prove to be particularly true
for customer-sited generation. Further, increased interest in
the use of DR is evolving as a result of the advent of competi
-
tion in the electric power industry, the desire for customer
choice, potential opportunities envisioned with the moderniza
-
tion of our T&D systems, and the advanced development of
improved small, modular generation technologies such as fuel
cells, photovoltaics, and microturbines. In addition, the
potential environmental benefits of DR (for example, for re
-
newable resources and combined heat and power systems)
are substantial.
Although the application of distributed generation and stor-
age can have many benefits, the technologies and operational
concepts to properly integrate them into the existing power
system must be developed to realize these benefits and avoid
negative effects on reliability and safety. The electric distribu
-
tion system traditionally was not designed to accommodate
active generation and storage at the distribution level or, gen
-
erally, at the sub-transmission level, and, especially, it was not
designed to allow distributed generators to supply energy to
other distribution customers. The technical issues involved in
R. DeBlasio is with the National Renewable Energy Laboratory, 1617 Cole
Blvd., Golden, Colorado 80401 USA (e-mail: deblasid@tcplink.nrel.gov).
T. Basso is with the National Renewable Energy Laboratory, 1617 Cole
Blvd., Golden, Colorado 80401 USA (e-mail: thomas_basso@nrel.gov).
readily interconnecting and effectively integrating these types
of DR applications with grid operations are significant.
Electricity regulation, zoning and permitting processes, and
business practices developed under the framework of an elec
-
tric industry based on central-station generation and ownership
of generation facilities by a regulated monopoly can be barri
-
ers to the orderly development of market opportunities for DR
in a restructured and modernized electric power industry.
These barriers need to be identified and addressed through
active participation in the development of solutions. Leader-
ship and educational approaches are also needed to reduce
these infrastructure barriers to the grid of the future.
The system integration and application issues related to DR
interconnection are national issues that cut across a number of
industries. There are federal, industry, and professional society
leadership roles for bringing together the various stake
-
holders—manufacturers (e.g., manufacturers of electri-
cal/electronics components and systems, photovoltaics, wind
energy systems, fuel cells, gas turbines, and batteries), utilities,
energy service companies, codes and standards organizations,
state/federal regulators and legislators, and others—to address
the technical, institutional, and regulatory barriers to intercon
-
necting DR to modernized T&D systems. (See
http://www.eere.energy.gov/distributedpower). In a discussion
of national issues, it was suggested that there was a need for
partnerships including industry and government to accomplish
specific goal-oriented objectives such as developing uniform
national technical interconnection consensus standards
[1].
Standardized technical requirements tend to provide the
framework for greater product and service quality, more inter-
operability, lower engineering and design costs, and stream-
lined installation, operation, and maintenance. They also help
safeguard against hazards. In addition, uniform technical in
-
terconnection standards facilitate simplified contractual and
other institutional interconnection agreements at the interna
-
tional, national, state, and local levels while facilitating indus-
trial efficiency and robust commerce for DR in the increas-
ingly competitive worldwide electric industry marketplace.
II. B
ACKGROUND
IEEE—being a transnational technical professional society
with a membership of more than 380,000 individual electrical,
electronics, and computer engineers in 150 countries—
oversees IEEE standards activities through its IEEE Standards
Board Standards Association (IEEE SA). The IEEE SA pur
-
sues programs on an IEEE-wide basis that enhance globaliza-
tion of IEEE standards to promote the development of electro-
technology and allied sciences and the application of those
technologies. IEEE is a world leader in the development and
1
dissemination of voluntary, consensus-based standards involv-
ing today's leading-edge electro-technologies. IEEE has
nearly 900 active standards, with 700 under development.
On June 25, 1998, the IEEE Standards Board, encouraged
by IEEE members, decided that a serious standards effort
needed to be launched to address the needs of members re
-
garding distributed power systems on a national level. With
that came an expansion of the responsibilities of IEEE Stan
-
dards Coordinating Committee 21 (SCC21), which reports
directly to the IEEE Standards Board and oversees all stan
-
dards development activities for DR. The scope of SCC21
includes all distributed generation and energy storage, and its
official title is IEEE SCC21 on Fuel Cells, Photovoltaics, Dis
-
persed Generation, and Energy Storage. Its responsibilities
include overseeing the development of standards in the areas
of fuel cells, photovoltaics, dispersed generation, and energy
storage and coordinating in those fields among the various
IEEE societies and other affected organizations to ensure that
all such IEEE standards are consistent and properly reflect the
views of all applicable disciplines. In addition, SCC21 reviews
all proposed IEEE standards in those fields before their sub-
mission to the IEEE SA for approval and coordinates submis
-
sion to other organizations.
III. P1547 S
ERIES OF STANDARDS
The first organizational meeting of the expanded SCC21
was held in December 1998 and was hosted by the United
States Department of Energy (US DOE) in Washington, DC.
At that meeting, participants proposed an interconnection
standards project. The interest to proceed was overwhelming,
and it was determined that the document should indeed be an
IEEE "standard" as opposed to a "guideline" or a "recom
-
mended practice." In March 1999, the IEEE Standards Board
approved the project authorization request as submitted by
SCC21 Chair and P1547 Sponsor Mr. R. DeBlasio. Addi
-
tional IEEE interconnection standards project activities were
first discussed at the January 2001 P1547 development meet
-
ing, and complementary projects were approved by IEEE and
are now designated under the P1547 series of interconnection
standards (Fig. 1).
Support for P1547 activities, from both the work group
members and the electric power community at large, has been
overwhelming. Members’ organizations have sponsored a
number of the P1547 meetings, and many meetings were spon
-
sored by the US DOE/National Renewable Energy Laboratory
(NREL) (e.g., see P1547 Minutes at
http://grouper.ieee.org/
groups/scc21/1547/1547_archives.html)
. It is estimated that the
P1547 standard amounted to an approximately $4.5-million
investment by the organizations and individuals supporting the
P1547 meetings. These ongoing public/private partnerships,
in conjunction with the IEEE consensus approach, are a large
contributing factor to the success of P1547 development.
IV. S
TATUS OF P1547 SERIES OF STANDARDS
IEEE SCC21 P1547 Series of Interconnection Standards
P1547
Draft Standard for Interconnecting Distributed
Resources with Electric Power Systems.
P1547.1
Draft Standard for
Conformance Test
Procedures for
Equipment
Interconnecting
Distributed
Resources with
Electric Power
Systems.
P1547.2
Draft Application
Guide for IEEE
P1547 Draft
Standard for
Interconnecting
Distributed
Resources with
Electric Power
Systems.
Guide for Networks
Guide for Impacts
Guide for Islanding
DP Specifications
and Performance
Guide
For
Interconnection
System
Certification
P1547.3
Draft Guide for Monitoring,
Information Exchange and
Control of DR
Interconnected with EPS.
The above identifies existing IEEE SCC21 standards development projects (P1547 series)
and potential activities under discussion by SCC21 Work Group members.
P1547 Scope. This standard establishes criteria and requirements for
interconnection of distributed resources (DR) with electric power sys-
tems (EPS). Purpose. his document provides a uniform standard
for interconnection of DR with EPS. It provides requirements relevant
to the performance, operation, testing, safety, and maintenance of
the interconnection.
P1547.1 Scope. his standard specifies the type, production, and com-
missioning tests that shall be performed to demonstrate that interconnec-
tion functions and equipment of a DR conform to IEEE (Draft) Standard
P1547. Purpose. nterconnection equipment that connects DR to an
EPS must meet the requirements specified in IEEE Standard 1547.
Standardized test procedures are necessary to establish and verify com-
pliance with those requirements. These test procedures must provide
both repeatable results, independent of test location, and flexibility to
accommodate a variety of DR technologies.
P1547.2 Scope. his guide provides technical background and applica-
tion details to support the understanding of IEEE Standard 1547 Stan-
dard for Interconnecting Distributed Resources with Electric Power
Systems. Purpose. his document facilitates the use of IEEE P1547 by
characterizing the various forms of DR technologies and the associated
interconnection issues. dditionally, the background and rationale of
the technical requirements are discussed in terms of the operation of the
DR interconnection with the EPS. Presented in the document are tech-
nical descriptions and schematics, applications guidance, and intercon-
nection examples to enhance the use of IEEE Standard 1547.
P1547.3 Scope. his document provides guidelines for monitoring,
information exchange, and control for DR interconnected with EPS.
Purpose. his document facilitates the interoperability of one or more
DR interconnected with EPS. scribes functionality, parameters, and
methodologies for monitoring, information exchange, and control for
the interconnected DR with, or associated with, EPS. DR include sys-
tems in the areas of fuel cells, photovoltaics, wind turbines, microtur-
bines, and other distributed generators as well as distributed energy
storage systems.
T
T
I
T
T
A
T
T
It de
The P1547 standard is targeted for IEEE publication in
Fig. 1. IEEE SCC21 P1547 Series of Interconnection Standards
2003. Since initiation of the P1547 project, the working group
has grown to more than 350 members, with 100 attendees par-
and then meeting three or four times per year for the next two
ticipating in meetings every other month for the first two years
years. Now, individual co-located meetings for the P1547.1,
2
P1547.2, and P1547.3 work groups (WG) are proceeding on a
regular basis. These complementary standards are in their
formative stages of development, and those members wish to
maintain accelerated schedules for development. They are
targeting two to three years to have voting drafts completed.
V. H
ISTORY OF P1547 STANDARD DEVELOPMENT
Since the founding meeting in December 1998, P1547 par-
ticipants have been very active and have provided numerous
background documents, papers, draft materials, and presenta
-
tions. An IEEE Web site and a list server for member e-mail
exchanges were also developed.
The P1547 minutes include voluminous amounts of infor-
mation. For the first six months of deliberations, P1547 mem-
bers developed two complete versions of a work group re-
source document (see WGRD II dated June 6, 1999). After
that, they provided addenda to the WGRD. In accordance
with the P1547 WGRD draft outline/major topical headings,
task forces were established to lead the drafting of topical in-
formation, which later evolved into draft clauses within the
respective P1547 outline areas. Participants volunteered and
contributed according to their choice and expertise. The
WGRD was used as the basis for “P1547 Draft 1 – 9/21/99,”
which was somewhat skeletal in parts but was purposely writ-
ten along the lines of providing mandatory requirements while
minimizing guidance and alternative recommended practices.
A P1547 writing group was established, and it drafted ongo-
ing revisions to the outline and specific clauses based on open
and full work group review and feedback. A number of P1547
drafts evolved. These solidified and captured the overall
P1547 work group’s “consensus” deliberations and fleshed out
the original, skeletal Draft 1 outline and clauses.
Around August 2000, drafts 4B to 5 evolved to a point at
which the outline and its topical clauses were stabilizing. The
group then instituted an approach for a standardized feedback
and review format similar to the IEEE ballot comment format.
This approach was designed to collect comments on individual
clauses/sections and required recommended rewording and the
rationale. At P1547 WG meetings, individuals had time to
further express their feedback/rationale and answer questions
from fellow participants. The overall P1547 draft document
remained open for discussion and review, but it appeared the
work group thought the standardized feedback and review
format was appropriate and beneficial. However, that ap
-
proach took some getting used to, and some individuals still
don’t understand it. Around January 2001 (and feedback on
Draft 6) the P1547 WG decided that with the agreed-upon
changes, P1547 Draft 7 should go to IEEE for formal ballot.
In March 2001, P1547 Draft 7 was voted on by the P1547
ballot group, which had 167 members. Following the 30-day
voting period, there was a 91% return of ballots, which
achieved the IEEE 75% return requirement. This was encour
-
aging and showed the voters’ determination and support for
completing the standard. However, the IEEE requirement of
75% affirmation was not met; the draft received only 66%
affirmative votes.
A combined P1547 WG and ballot group meeting was held
in April 2001 to address the ballot results. Based on discus
-
sion and the ballot comments, it was decided to proceed with a
recirculation ballot of a reworded P1547 Draft 7. The P1547
writing group then developed a reworded P1547 Draft 7. That
was reviewed at another combined P1547 WG and ballot
group meeting in June 2001. Based on feedback, P1547 Draft
8 was established.
P1547 Draft 8 underwent a recirculation ballot September–
October 2001. The Draft 8 ballot resulted in an increase of
ballots returns, reaching 96%, and an increase in affirmatives.
But again, it had only 66% affirmatives, short of the 75% re
-
quired to move forward.
Again, a P1547 combined WG and ballot group meeting
was held in October 2001. The participants developed rec
-
ommended wording changes and encouraged Chair DeBlasio
to intensify efforts for balloting another reworded draft. How-
ever, it appeared that rewording might not be adequate to get
beyond the 66% affirmation level.
During the next meeting, held in January 2002, P1547 Draft
8 and its ballot comments underwent a more pointed and fo
-
cused review on a clause-by-clause basis. The first part of the
P1547 Draft 8 review approach was to remove the information
that was more appropriate for other standards or documents.
That information included procedure requirements, application
guidance, safety practices, and supporting information such as
that needed for protocols, specific DR-electric power system
applications, equipment-specific criteria (e.g., distributed gen
-
erators or distribution transformers), type-specific utility grid
configurations, operational aspects, and regulatory aspects.
The material removed is being considered for recommendation
under the P1547.1 testing project, the P1547.2 application
guide to P1547 project, or the P1547.3 guide for monitor
-
ing/control project or for additional future standards projects
or technical or regulatory review and study.
After the P1547 WG completed the clause-by-clause review
of P1547 Draft 8, the resulting refined P1547 outline was
again reviewed, this time for recommendations toward align
-
ment with the idea that P1547 shall state the mandatory, mini-
mum functional technical requirements that are universally
needed to help ensure a technically sound interconnection,
such as is stated in the P1547 introduction.
Also at the January 2002 meeting, it was announced that the
P1547 writing group was being expanded to 25 individuals,
maintaining the consensus balance that IEEE requires only for
the ballot group. The P1547 expanded writing group held
three meetings from February to May 2002 to write P1547
Draft 9. The establishment of P1547 Draft 9 involved signifi
-
cant changes from the previous draft. That meant the P1547
ballot pool would be newly formed, such that previous ballot
members had to renew their commitment to ballot.
P1547 Draft 9 was sent by e-mail for comment by the P1547
WG and the past P1547 ballot group. The comments and rec
-
ommended rewording that were received were compiled and
distributed and discussed at the June 2002 P1547 WG meet
-
ing. The attendees at the June meeting provided and discussed
additional comments and recommended rewording. At the
June meeting, the expanded P1547 writing group participated
in the open discussions and also directly interacted with indi
-
vidual attendees, discussing concerns and recommended re-
3