Conf Call Apr07 John Wiles Utility Interconnection
Photovoltaic Power Systems and
Utility Interconnections SEPA Conference Call April 26, 2007
John C. Wiles Southwest Technology Development Institute New Mexico State University P.O. Box 30001/MSC 3 SOLAR Las Cruces, New Mexico 88003 http://www.nmsu.edu/~tdi e-mail: [email protected] Phone: (505) 646-6105 Fax: (505) 646-3841 Southwest Technology Development Institute 4/20/07
SEPA- 1
Overview • Who is SWTDI/IEE? • Utility Interconnections –Safety for Utility Personnel –Safety for First Responders –Safety for Users
Southwest Technology Development Institute 4/20/07
SEPA- 2
Southwest Technology Development Institute Institute for Energy and the Environment •
Provide National & International Training
•
Research & Implement NEC
•
Review & Assist with UL & IEEE Standards
•
Evaluate Proposals
•
Review System Designs
•
Test & Evaluate PV Systems
•
Design PV Balance of Systems Equipment
•
Develop Prototype PV & Ground-Fault Hardware
•
Develop Data Acquisition Systems
•
Monitor Resources & Assess System Performance Southwest Technology Development Institute 4/20/07
SEPA- 4
Utility Interconnections Safety for Utility Personnel The Utility-Required, Visible-Blade, Lockable-Open Safety Disconnect • Is it needed? – PG&E and SMUD say No. Others require it. • Can UL-Listed Inverters Island? – PNM and SWTDI tests show low, but not zero, probability • Has anyone tested numerous inverters at once? – PG&E (4), SNL (several) • Will the utility linemen: Disconnect feeder, measure voltage, crowbar, ground, measure voltage, and wear PPE? Southwest Technology Development Institute 4/20/07
SEPA- 7
Utility Interconnections Safety for First Responders •
•
• • •
How is the system turned off? – Use the utility disconnect? – Pull the meter? – But…… Hot dc module/array circuits and batteries What are the dangers? – Up to 600 volts dc, 1-1000 amps – Toxic smoke Where do we stand on the roof? How do we ventilate the roof? – Axes and Power Tools Water and electricity don’t mix, PPE may be leather Southwest Technology Development Institute 4/20/07
SEPA- 9
Utility Interconnections Safety for Users •
• • •
Utilities Encourage Renewables – Rebates – Net metering – Renewable Energy Credits (REC) Some provide lists of Recommended Installers Some employ special PV System Inspectors,many don’t Who is liable when the PV system fails/creates problems? – Potential back feed to the grid (dc injection) – Potential damage to service entrance conductors – Potential shock/fire hazards to owner/user Southwest Technology Development Institute 4/20/07
SEPA- 12
Utility Interconnections For further Information •
Codes and Standards –SWTDI/PV/C&S web site –http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/Codes-Stds.html
–National Electrical Code
http://www.nfpa.org
–Underwriters Laboratory Standard 1741 http://www.ul.com –IEEE Standard 1741
•
http://www.ieee.org
Fundamentals of PV for the Fire Service –CALSEIA/SMUD PDF available from SEPA
Southwest Technology Development Institute 4/20/07
SEPA- 13
Utility Interconnections SEPA Conference Call April 26, 2007
John C. Wiles Southwest Technology Development Institute New Mexico State University P.O. Box 30001/MSC 3 SOLAR Las Cruces, New Mexico 88003 http://www.nmsu.edu/~tdi e-mail: [email protected] Phone: (505) 646-6105 Fax: (505) 646-3841 Southwest Technology Development Institute 4/20/07
SEPA- 1
Overview • Who is SWTDI/IEE? • Utility Interconnections –Safety for Utility Personnel –Safety for First Responders –Safety for Users
Southwest Technology Development Institute 4/20/07
SEPA- 2
Southwest Technology Development Institute Institute for Energy and the Environment •
Provide National & International Training
•
Research & Implement NEC
•
Review & Assist with UL & IEEE Standards
•
Evaluate Proposals
•
Review System Designs
•
Test & Evaluate PV Systems
•
Design PV Balance of Systems Equipment
•
Develop Prototype PV & Ground-Fault Hardware
•
Develop Data Acquisition Systems
•
Monitor Resources & Assess System Performance Southwest Technology Development Institute 4/20/07
SEPA- 4
Utility Interconnections Safety for Utility Personnel The Utility-Required, Visible-Blade, Lockable-Open Safety Disconnect • Is it needed? – PG&E and SMUD say No. Others require it. • Can UL-Listed Inverters Island? – PNM and SWTDI tests show low, but not zero, probability • Has anyone tested numerous inverters at once? – PG&E (4), SNL (several) • Will the utility linemen: Disconnect feeder, measure voltage, crowbar, ground, measure voltage, and wear PPE? Southwest Technology Development Institute 4/20/07
SEPA- 7
Utility Interconnections Safety for First Responders •
•
• • •
How is the system turned off? – Use the utility disconnect? – Pull the meter? – But…… Hot dc module/array circuits and batteries What are the dangers? – Up to 600 volts dc, 1-1000 amps – Toxic smoke Where do we stand on the roof? How do we ventilate the roof? – Axes and Power Tools Water and electricity don’t mix, PPE may be leather Southwest Technology Development Institute 4/20/07
SEPA- 9
Utility Interconnections Safety for Users •
• • •
Utilities Encourage Renewables – Rebates – Net metering – Renewable Energy Credits (REC) Some provide lists of Recommended Installers Some employ special PV System Inspectors,many don’t Who is liable when the PV system fails/creates problems? – Potential back feed to the grid (dc injection) – Potential damage to service entrance conductors – Potential shock/fire hazards to owner/user Southwest Technology Development Institute 4/20/07
SEPA- 12
Utility Interconnections For further Information •
Codes and Standards –SWTDI/PV/C&S web site –http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/Codes-Stds.html
–National Electrical Code
http://www.nfpa.org
–Underwriters Laboratory Standard 1741 http://www.ul.com –IEEE Standard 1741
•
http://www.ieee.org
Fundamentals of PV for the Fire Service –CALSEIA/SMUD PDF available from SEPA
Southwest Technology Development Institute 4/20/07
SEPA- 13
