Interconnecting to the grid

1
Interconnecting to the grid

• A birds eye view

2
Here kitty kitty
3
Can I please connect to your grid?
Cost recovery
Safety
Unfair to rate payers
Power Quality
Fault Detection
Liability
Blah Blah Blah
4
But its good for you!!!

• TD deferral
• Reduce peak
• Improved reliability
• Voltage support
• Yada, Yada, Yada

5
History

• First power plants were CHP
• Grids were served by local plant
• Regulated Utilities consolidated
• PURPA 1978
• EPACT 2005

Source IEEE
Source IEEE
6
Bigger is Better?
Source ACEEE
7
Hey, what happened to my energy?
Source ACEEE
8
Why do I have to study history?
Source Casten, T. Casten, S. Transforming
Electricity
9
Jargon

• Cogen
• CHP
• BCHP
• CCHP
• RE
• TE

• DG
• DE
• DR
• DER
• DP
• DRP

10
Types of Operation

• Grid Isolated
• Export
• Import
• Buy All/Sell All

• Synchronous
• Inductive
• Inverter

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Grid Isolated
PCC
Switch Open No Power Flow
Loads
Loads
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Import
Switch Closed Power Flow
PCC
Loads
Loads
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Export
Switch Closed Power Flow
PCC
Loads
Loads
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Buy All/Sell All
Switch Closed Power Flow
PCC
Switch Closed Power Flow
Loads
Loads
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Technical Issues(lots of math but solutions are
possible)

• Anti-Islanding
• Grid Protection
• Generator Protection

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Anti-islanding
Substation
X
Feeder Breaker
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Anti-islanding

• Over/Under Frequency 81o/u
• Overvoltage 59
• Undervoltage 27
• Good for DG lt 15 of feeder load
• 15,000 small DG with no reported injuries1

1IREC
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Anti-islanding

• Reverse Power - 32
• Directional Over-Current - 67
• Instantaneous Over-voltage - 59I
• Trip Transfer

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Grid Protection

• Fault Current Contribution
• Power Flow
• Ground Fault (Transformer Selection)
• Over voltage damage to Grid Equipment
• Ferroresonance
• Power Quality Issues

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Generator Protection

• Synch Check - 25
• Negative Phase sequence - 46 / 47
• Loss of Excitation - 40
• Circulating Currents

21
Technologies
22
Regulatory / Business Issues(hardly any math but
solution almost impossible)

• Standards
• Rates
• Permitting
• Obligation to serve
• Liability
• Incentives

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Standards We dont need no stinking standards

• IREC Model Interconnection Standards
• IEEE 1547
• PJM
• FERC
• Texas
• California Rule 21

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Interconnect Standards for DG
in effect
under development
(May 2007)
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Consideration of EPACT 2005 Interconnect Standard
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
rejected
X
under consideration
X
adopted
(May 2007)
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Rates

• Avoided Cost
• Back Stand Charge
• Exit Fee
• Additional Facilities Charge
• Curtailable
• Net Metering
• RTP

27
Net metering
www.dsireusa.org


May 2007
NH 25 MA 60 RI 25 CT 100
100
VT 15/150
100


100
50

40

25
10/400
30
20

25/100

25


no limit
500
PA 50/1,000/2,000 NJ 2,000 DE 25 MD
2,000 DC 100 VA 10/500

40


150



25
2,000
10

25

1,000
15

20/100

100
25/300

10
10/100
80,000

50
25/100
50
varies
Net metering is available in 41 states D.C.
State-wide net metering for all utility types
State-wide net metering for certain utility
types (e.g., IOUs only)

Net metering offered by one or more individual
utilities
(Numbers indicate system size limit in kW in
some cases limits are different for residential
and commercial systems, as shown)
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Consideration of EPACT 2005 Net Metering
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
rejected
X
under consideration
X
adopted
(May 2007)
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So what am I supposed to do?

• Define your project
• Generation information
• Transformer type
• Protection scheme
• Operational characteristics
• Understand your benefits (think out of the box)
• Rates impacts
• Incentives
• Reliability / Productivity

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So what am I supposed to do?

• Understand the rules
• PURPA
• Utility interconnection rule set
• PUC
• Permitting Air, Siting, NEC, Water, etc.
• Understand the process
• Talk to your Utility (a lot be a nice pest)
• Talk to others who have done a project
• Talk to experts

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Where to get help
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Where else to get help

• www.eere.energy.gov/de/chp/chp_applications/inform
  ation_resources.html
• www.epa.gov/chp/
• www.dsireusa.org
• www.irecusa.org
• www.uschpa.org
• www.districtenergy.org

33
Questions
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Contact Info

• Keith McAllister, PE
• Co-Director
• CHPCenterSE
• NC Solar Center
• NC State University
• 919-515-3933
• keith_mcallister_at_ncsu.edu