Learn
Connecting Small PV Systems with Wisconsin's Utility
Grid
What You Must Do For The Utility
Working With Utility Representatives
Common Interconnection Issues
Information Resources
Photo 5 Inspecting an installed standing seam PV
module.
Liability insurance
- Utilities are not allowed to require liability insurance of more than $300,000 for small distributed generation systems.
- Some insurance companies are hesitant or unwilling to provide liability insurance for a DG system sited on a home. Contact WisconSUN for a list of renewable energy friendly insurance firms.
Photo 6 PV panels on the Mountain Ridge Middle
School in Colorado.
Disconnect switch
Public Utilities require the use of an disconnect switch. For most
systems, an external disconnect switch is a low-cost addition to a PV
system. It may make the insurance company more willing to include the
system in the property insurance. However, for a system located some
distance from the utility service entrance to the building, installation of
the disconnect switch can be costly.
Second meter
A public utility can not require you to install a second meter. The
existing meter must be able to spin backwards. If a rural electric coop or
municipal utility wants you to install a second meter, argue that it will
cost more than to leave the existing meter and allow the system to turn it
backwards.
Dedicated transformers
There is no need for a utility to require a dedicated transformer given
modern non-islanding inverters. A dedicated transformer is often installed
at large generators to address issues such as islanding, harmonics, voltage
fluctuations, triple harmonics, direct current injection, and ferroresonant
overvoltages. For small PV systems, these concerns are overcome by using
a properly-designed non-islanding inverter, or are not a problem for PV
systems (i.e., flicker).
Photo 7 Installing a 16 kW PV array in Nevada.
Photo Credits
Photo 5. Photograph by Warren Gretz
Photo 6. Photograph by Rich Chartier
Photo 7. Photograph by Rex Windom
copyright © 2000 WisconSUN
