So a Development
Solar
e e op e t in New
e Je
Jersey,
sey, a
and
d
PV Impacts on the Distribution System
Ca eg e Mellon
Carnegie
e o Conference
Co e e ce on
o the
t e
Electricity Industry - March 9, 2011
Jim Calore
Public Service Electric & Gas Co.
Overview
‰ This presentation is intended to be a brief
discussion of PSE&G’s solar development
activities in New Jersey,
y, and specifically
p
y the
impact of the interconnection of large amounts
of solar generation on the distribution system.
‰ The p
presentation will also discuss typical
yp
utility
y
planning concepts, codes and standards, and
federal vs. NJ interconnection procedures.
‰ My thanks to NREL (proceedings from the High
P
Penetration
i
PV W
Workshop
k h
ffrom llast May
M
http://www.nrel.gov/docs/fy10osti/48378.pdf),
DOE, and others for some of the information in
this presentation!
2
Public Service Electric & Gas is the
largest
a ges u
utility
y in New
e Jersey
e sey p
providing
o d g
electric, gas and transmission services
Customers
Electric Sales
Gas Sold
ld and
d Transported
d
Peak Electric Load
Electric
Gas
2.1 Million
1.7 Million
41,961 GWh
11,108 MW
3,500 M
Therms
Sales Mix
Residential
31%
60%
Commercial
58%
36%
Industrial
11%
4%
3
Why
y Grid
G d Connected
Co ec ed U
Utility-Owned
y O
ed
Solar Makes Sense
† Maximizes benefits to ratepayers
¾ Returns value of electric sales, federal ITC and Solar
Renewable
e e ab e Energy
e gy Credits
C ed s (SRECs)
(S Cs) to
o ratepayers
a epaye s
† Engages the solar industry
¾ Uses local contractors and suppliers
† Provides stability in solar market
¾ Financial and operational strength
† Ensures grid reliability
¾ Planned for maximum system benefits
4
PSE&G Solar Programs
‰ More than
h
$750
$ 0
million invested in
solar
¾ Solar Loan
Program
¾ Solar 4 All
Program
5
PSE&G’s Solar 4 All Program
† Two main components:
¾ 40MW Neighborhood Solar
¾ 40MW Centralized Solar
6
PSE&G
S &G Neighborhood
e g o ood So
Solar:
a
Activities and Achievements
† Up to 200,000 smart
solar units on utility
poles (40MW)
† 175 acres of land
would be needed for
40MW
About 76,000 units
installed to date
† Made locally by Petra
Solar of South
Plainfield, NJ
7
PSE&G Centralized Solar:
Activities and Achievements
† 19.5MW
19 5MW installed
¾ PSE&G-owned
PSE&G
d property
t
¾ Third party leased sites
† More than 10 additional
projects in process of
development
8
PSE&G’s Solar Loan Program
† > $247M program
† 195 solar loans closed
since April 2008
† 444 more in
development/review
† $69.9M loaned
† Financed >19MW
of solar capacity
9
Incentives
ce
es for
o Solar
So a Development
e e op e
in
New Jersey
† Federal
ede a So
Solar
a Investment
est e t Tax
a Credit
C ed t (ITC)/Solar
( C)/So a
Grant
¾
30% of the cost of the solar property in cash or take the
ITC as a tax credit (commercial customers and utilities)
† Solar Renewable Energy Certificate (SREC) Program
¾ Earn one (1) SREC for every 1,000 kWh the solar PV
system produces. These can be sold or traded over a
15-year period; approx.
approx $690 per mWh or $0.69
$0 69 per
kWh (2009-2010)
† Power Purchase Agreements (PPA)
† PSE&G Solar Loan Program
¾
¾
Loan provided for 40-60% of system cost
Customers repay using SRECs produced
10
Primer on Distribution Planning
11
Planning Criteria
‰ A utility’s
ili ’ planning
l
i
criteria
i i are iintended
d d to b
be a
guide to provide for the safe, reliable and low
cost development
p
of the utility’s
y electrical
system as loads increase and reinforcements
and/or new facilities are required.
12
Basic Planning Principles
‰ With all facilities in service:
¾ Loads on the system must be within normal
equipment ratings
¾ Must provide acceptable voltages to
connected customers
‰ With the outage of any single piece of
equipment (N-1 Criteria Violation):
¾ Affected load must be within the emergency
rating of the remaining facilities
¾ System must provide minimum emergency
voltages
13
Basic Planning Principles
‰ N-1 criteria are applied in a similar fashion to:
¾ Substations
¾ Distribution
Di t ib ti
Facilities
F iliti
¾ Subtransmission Facilities
¾ Transmission Facilities
14
Basic Planning Principles
‰ Load Forecasting
¾ Substation
¾ Feeder
‰ Distribution Circuit Reinforcement
¾ Ratings
g
¾ N-1 Criteria
‰ New Business
¾ Connected vs. Estimated Loads
¾ Load Build-up Schedules and Load Shifting
¾ Distributed
Di t ib t d G
Generation
ti
15
Su s a o Forecast/Planning
Substation
o ecas / a
g Process
ocess
Substation & Area Planning
‰ Substation & Area
‰ System Reinforcement
Capacity
Modeling
¾ Firm N-1 Criteria
¾ Interstation
¾ Includes Automatic 13Capacity Ties
kV ICT Transfers
¾ Station
‰ Capacity Processing
Reinforcement
¾ Load vs
vs. Capacity
¾ New Station
Analysis
‰ Load Relief Modeling
¾ Generation
¾ Power Factor
Correction
¾ Load Transfers
¾ Distributed Generation
16
Interconnection Standards
17
18
Federal
ede a (
(PJM)
) Jurisdictional
u sd c o a
Interconnection Standards
† Applies to generators participating in PJM
PJM’s
s
wholesale market, regardless of size and
interconnection voltage level
† Follows standard FERC-approved procedures
d
developed
l
d under
d the
h authority
h
off the
h PJM OATT
† Procedures and requirements are based on size
¾ Large Generating Facilities (>20 MW)
¾ Small
S
ll Generating
G
i
Facilities
F ili i (<20
( 20 MW)
† PJM’s Small Generator Interconnection Standards
use a streamlined process for smaller generators
¾ Fast Track Study Process for small generators
¾ 10 kW Inverter Process for certified inverter based
generators no larger than 10 kW
generators must meet IEEE 1547 ((Manual 14a))
¾ Small g
19
S a e Jurisdictional
State
u sd c o a
Interconnection Standards
† In NJ,
NJ applies to generators up to a certain size (2
MW), connected to the distribution system
¾ Net Metering, PURPA or similar arrangement for
“retail
retail sales
sales” of electricity to the host utility only
¾ Distribution interconnections of “wholesale sales
to PJM” projects on non-PJM jurisdictional
distribution facilities are State regulated
¾ Typically covers renewables and other small DR,
all customer classes
† NJ
NJ’s
s regulations generally conform with the FERC
SGIP, but have some significant differences
† Technical standards focused on IEEE 1547, and for
inverters UL 1741 for connection to the grid
inverters,
20
IEEE 1547 Interconnection Standards
NREL High Penetration PV Workshop
21
P1547.7 - Draft Guide to Conducting
Distribution Impact Studies for DR
Interconnection
† Describes criteria, scope, and extent for engineering
studies of the impact of DR on distribution system.
† Provides methodology for performing engineering
studies.
† Study
St d scope and
d extent
t t described
d
ib d as functions
f
ti
off
identifiable characteristics of:
¾
¾
¾
The distributed resource
The area electric p
power system
y
The interconnection
¾
¾
¾
¾
When impact studies are appropriate
What data is required
performed
How studies are p
How the study results are to be evaluated
† Criteria described for determining the necessity of DR
impact mitigation.
† Guide provides a methodology for determining:
22
P1547.8 - Recommended Practice for Establishing
Methods and Procedures that Provide Supplemental
Support for Implementation Strategies for
Expanded Use of IEEE Standard 1547
† Needed to address industry driven
recommendations, and NIST smart grid
standards framework recommendations (e.g.,
NIST SGIP Priority Action Plan - “PAP
PAP 7
7”)).
† Example considerations include: low voltage
ride through (LVRT) of PV; VAR (reactive)
support;
t grid
id support;
t two-way
t
communications and control; advanced
interactive grid to DR operations; high
penetration
t ti
off DR
DR; area EPS with
ith multiple
lti l DR
interconnections; interactive inverters; energy
storage; electric vehicles; etc.
23
IEEE 1547 Interconnection Standards
Use: Federal,
Use
ede a , Regional,
eg o a , S
State
a ea
and
d Local
oca
Authorities/Jurisdictions
NREL High Penetration PV Workshop
24
PV Impact
pac S
Studies,
ud es, Analysis,
a ys s,
Challenges and Goals
25
Key
ey Areas
eas of
o Focus
ocus for
o PV
Interconnection Impact Studies
‰ Voltage
g Regulation
g
¾ Steady state conditions, fluctuating conditions
(flicker), cap bank and tap changer cycling issues,
reverse power flow issues, voltage unbalance
‰ Fault Currents and Protection Coordination
¾ Impact on fault levels, device coordination,
interrupting ratings, ground fault current detection
desensitization
‰ Ground Fault Overvoltages
¾ Important especially for non-effectively grounded DG,
which is how PV devices are often configured
‰ Islanding
I l di
¾ Important especially in complex situations with
multiple DG present, or with fast reclosing and no
g
live-line reclose blocking
NREL High Penetration PV Workshop : Defining High Penetration PV –Multiple Definitions and Where to Apply Them - Phil Barker, Nova Energy Specialists
26
So e Use
Some
Useful
u Penetration
e e a o Ratios
a os for
o
Engineering Analysis
† Minimum Load to Generation Ratio -
¾ Is the annual minimum load on the relevant area
electric power system (EPS) section divided by the
aggregate DG capacity on the area EPS
† Stiffness
S iff
Factor
F
-
¾ Is the available utility fault current divided by DG
rated output current in the area EPS
† Fault Ratio Factor -
¾ Is the available utility fault current divided by DG
fault contribution in the area EPS
† Ground Source Impedance Ratio -
¾ Is the ratio of zero sequence impedance of DG
ground source relative to utility ground source
impedance in the area EPS
NREL High Penetration PV Workshop : Defining High Penetration PV –Multiple Definitions and Where to Apply Them - Phil Barker, Nova Energy Specialists
27
PV Penetration
e e a o Ratios
a os and
a d Their
e
Suggested Uses
NREL High Penetration PV Workshop : Defining High Penetration PV –Multiple Definitions and Where to Apply Them - Phil Barker, Nova Energy Specialists
28
PV Penetration
e e a o Ratios
a os and
a d Their
e
Suggested Uses
† Notes:
1. Ratios are meant as guides for radial 4-wire, multigrounded neutral distribution system DG applications,
and calculated based on aggregate DG on the area EPS.
2 “Minimum
2.
“Mi i
lload”
d” iis th
the llowestt annuall lload
d on th
the line
li
section of interest (up to the nearest applicable
protective device). Power factor of load is assumed to be
0.9 inductive.
3. Useful when DG or its interface transformer provides a
ground source contribution. Must include the effect of
the step-up transformer if present.
4 Inverters are weaker ground fault sources than rotating
4.
machines, therefore a smaller ratio is allowable.
5. If DG application falls in this “higher penetration”
category it means some system upgrades/adjustments
are likely needed to avoid power system issues.
issues
NREL High Penetration PV Workshop : Defining High Penetration PV –Multiple Definitions and Where to Apply Them - Phil Barker, Nova Energy Specialists
29
PV Interconnection
e co ec o Issues
ssues a
and
d
Barriers
‰
Descriptions
p
of key
y issues/barriers
/
for interconnecting
g PV
¾
¾
¾
¾
¾
Lack of data, and system analysis techniques and tools to
sufficiently model and simulate specific impacts of solar on
the grid (Voltage effects, GFP, Islanding, PQ, etc.)
Need for intelligent bundling of PV with demand side
management, communications and controls, and storage
technologies
Need to enhance system protection and coordination
capability
bilit th
through
h th
the use off advanced
d
d instrumentation,
i t
t ti
measurement and controls devices
Must develop methods, equipment and technologies to
effectively
y mitigate
g
the intermittency
y of solar
Development and investigation of codes and standards to
determine limitations on grid integration equipment
capabilities and to establish stakeholder consensus
DOE – EE&RE, HPPV Systems into the Distribution Grid Workshop – Feb 2009
30
PV Inverter Technical Challenges
† Implementing
p
g VAR Control,
o o , LVRT,, and
a d Dynamic
y a
Control – is technically achievable
† Most inverter modification can be done through
g
software upgrades
† Minor hardware changes at minimal additional cost
would include:
¾ Additional sensors
¾ UPS for LVRT capability
† In VAR Control mode inverter will operate at higher
current levels when not at unity power factor – will
also have impacts on efficiency and reliability,
especially if running at night for regulation purposes.
NREL High Penetration PV Workshop: PV Inverters with VAR Control, LVRT, and Dynamic Control - Ray Hudson –BEW Engineering
31
PV Interconnection Goals
† Ensure safe and reliable two-way
two way electricity flow
† Develop smart grid interoperability
† Develop advanced communication and control
functionalities of inverters
† Integrate renewable systems models into power
system planning and operation tools
† Integrate with energy storage, load management,
and demand response to enhance system flexibility
† Understand
U d
d high-penetration
hi h
i
li
limiting
ii
conditions
di i
† Understand how various climates and cloud
transients affect system
y
reliability
y
U.S. Department of Energy Solar Energy Technologies Program Goals
32
Any Questions?
33