Page 228 - Sustainable On-Site CHP Systems Design, Construction, and Operations

Electrical Design Characteristics and Issues 201

reciprocating engines, and about 2 percent reverse power for combustion turbines.
As the trip points are a point in time and a point in power setting using an inverse
time characteristic for this relay is neither appropriate nor desirable.
40-Field relay. When this relay senses loss of field excitation, it will disconnect the gen-

erator set from the bus and shut it down. This device should look into the generator,
using the AC current and voltage relationships to determine a loss of excitation.

Summary
The electrical systems design for a CHP facility should be one that is configured to
allow for maximum flexibility and optimization of energy supply to the facility. In
doing so, the electrical design must take into account the complex requirements and
regulations that govern the interconnection of the CHP facility and serving utility, and
must provide the necessary protection, controls, and switchgear to protect the utility,
switchgear, equipment, and personnel. Most importantly, the electrical system designer
must work closely with the rest of the CHP design team and the facility owner to ensure
this complex system is well coordinated and provides value to the owner.

References

Cooley, C., Whitaker, C., and Prabhu, E., California Interconnection Guidebook, California
Energy Commission, November 13, 2003, available at http://www.energy.ca.gov/
reports.
Davis, M. (chair), “Edison Electric Institute Distributed Resources Task Force
Interconnection Study,” Institute Electrical Electronic Engineers, June 2000, available
at http://grouper.ieee.org/groups/scc21/1547/docs.
Toomer, R. J. (chair), et al. National Electrical Code 2008. Quincy, MA: NFPA, 2007.