Transcript Interconnecting DER with Electric Power Systems

POWER SYSTEM
2002 CONFERENCE
-- IMPACT OF
DISTRIBUTED
GENERATION
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Interconnecting DER
With Electric Power
Systems
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Interconnecting DER with Electric Power Systems
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Existing IEEE Standards
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Current IEEE Standards Work
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Standards Coordinating Committee 21:
 IEEE Standard 929-2000
Recommended Practice for Utility Interface of
Photovoltaic (PV) Systems
Standards Coordinating Committee 23
 IEEE Standard 1001-1988
Guide for Interfacing Dispersed Storage and
Generation Facilities with Electric Utility Systems
IEEE P-1547 Standard for Interconnecting Distributed Resources with
Electric Power Systems
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Interconnecting DER with Electric Power Systems
Definitions:
Area EPS Facility
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PHASE TO
GROUND
PHASE TO
PHASE
THREE PHASE
A
B
C
G
POINT OF
COMMON
COUPLING
(PCC)
PCC
DISTRIBUTED
RESOURCE
PCC
L
L
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POINT OF
INTERCONNECTION
(PI)
DISTRIBUTED
RESOURCE
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Interconnecting DER with Electric Power Systems
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P-1547 Project Approved in March 1999
4 - 6 meetings of Working Group per year since then
Working Group Members
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More than 200 names on Working Group Roster
 100+ members attend each Working Group Meeting
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Interconnecting DER with Electric Power Systems
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Three Official IEEE Balloting Member Categories
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User
 The user is the person who will apply the standard when interconnecting
DER to the electric power system. For example, the utility, the DER
owner, etc.
Producer
 The producer is the person who will apply the standard when producing
equipment that will be interconnected to the electric power system. For
example, equipment manufacturers, installers, etc.
General Interest
 The general interest person is one who is interested, but not directly
involved in interconnecting DER to the electric power system. For
example, regulatory agencies, financial institutions, advocacy groups, etc.
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Interconnecting DER with Electric Power Systems
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Draft 7 circulated for ballot --- closing date of April 1, 2001
Vote Results:
VOTE COUNT --- DRAFT 7
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Voter
Category Affirmative Negative Totals
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User
31
23
54
Producer
General
Interest
37
12
49
30
15
45
Totals
98
50
148
66% Affirmative, not enough for approval (75% required)
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Draft 8 circulated for ballot -- closing date of October 2, 2001
Vote Results
VOTE COUNT --- DRAFT8
Voter
Category Affirmative Negative Totals
User
25
33
58
Producer
General
Interest
43
6
49
35
14
49
103
53
156
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Totals
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66% Affirmative, not enough for approval (75% required)
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IEEE Standard 929
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Aimed at Photovoltaic Generator Systems, using solid-state inverters for
interconnection
 Usually low kilowatt capacity
 Inverter inherently limits fault current
 Inverter tends to shut down automatically upon overload or reverse power
IEEE Proposed Standard P-1547
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Intended to address DER without regard to prime mover (wind, fuel cell, etc)
 Attempts to address systems up to 10 Mw in size
 Seeks to provide ‘universal’ solution
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“User” Concerns
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Safety of Personnel
 Personnel must be able to work on the EPS and DER facility without
undue risk of injury or death
 General public should not be exposed to hazardous conditions
 Fault duty, including DER, should not exceed ratings of distribution system
equipment, including customer-owned equipment connected to the system
 Equipment damage, downed conductors, vault fires, etc.
 Normal load-carrying and interrupting capabilities, including DER, should not
be exceeded
 Reduction of system reliability, premature failure of equipment
 Protective relaying and control equipment, should not be subject to misoperation as a result of DER additions
 More and longer interruptions, high/low voltage problems
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Producer and General Interest Concerns
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Interconnection costs must be minimal
 Interconnection equipment should be some fraction of the cost of the DER
being connected.
 Utility involvement should be minimized
 Impact studies cost too much
 Some utilities use interconnection standards as a means of ‘killing’
DER
Interconnection must be ‘simple’ so that it won’t discourage DER applications
Interconnection apparatus should be ‘maintenance free’ as much as possible
Interconnection operation should be ‘automatic’
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Basic Problem:
Most Utility Electric Power Systems (EPS) were/are not
designed to accommodate active generation and energy
storage at the distribution level.
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Basic Need:
Develop technology and operational concepts that will enable
realization of DR benefits while avoiding negative impacts on
system reliability and safety
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Significant Problem Areas
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Scaling
“My typical distribution feeder has a peak load of 4 Mw. Adding a few kW of
PV is a whole different problem than adding 400 kW.”
Islanding
Utility is still responsible for voltage and frequency of all its customer
connections. Creating an island where some utility customers are supplied
with un-controlled voltage or frequency is unacceptable
Safety
Personnel working on the distribution system MUST be protected from
backfeed or accidental energization
Protection System Design
Radial distribution line protection is designed and coordinated for ‘one way’
power flow. Bi-directional flow in some part or all of a feeder is a whole
new world of problems
Networked Distribution System
Consideration postponed to future updates
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What’s Next?
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Working Group meeting to discuss ballot results, possible resolution was held
January 30-February 1
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Writing Group to meet and attempt to resolve negative ballots received on
Draft 8
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New Draft of P-1547 to be circulated for ballot before mid-year
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Still optimistic on submitting proposed standard to IEEE Standards Board
before the end of 2002
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