CHARACTERISTICS

Electric energy is supplied to customers at a utilization voltage that is maintained within prescribed limits to insure proper operation of customer equipment. Maintaining the voltage as close to the standard as is practical controls electrical losses and contributes to improved system efficiency. Careful engineering of distribution system components and the use of voltage-regulating equipment are required. Connecting single-phase load in a careful way eliminates losses associated with residual current flow. These reductions in distribution system losses in turn reduce generation demand and GHG emissions.

SIZE:
Applicable to all voltages.

FEATURES:
Voltage regulation is accomplished by adjusting the turns ratio of transformers and by the control of reactive power. Automatic control of transformer taps and shunt capacitors and shunt reactors can be accomplished with Supervisory Control and Data Acquisition (SCADA) and automation systems.

COST:
The cost of the voltage control function is bundled into the overall cost of SCADA and automation systems.

CURRENT USAGE:
Power factor control capacitors are installed on primary distribution feeder circuits.

POTENTIAL USAGE:
Advances in distribution automation will allow improved control over voltages on distribution feeders.

ISSUES ASSOCIATED WITH IMPLEMENTING ACTION

• Voltage regulating equipment has high capital costs, and increases the equipment operating & maintenance costs. Savings due to energy loss reductions may not offset the costs of new equipment or replacement of existing line and terminal components; voltage upgrades are generally only cost-effective when done to increase capacity.

CLIMATE CHANGE IMPACT

EMISSION EFFECT:
    

CONDITIONS FOR EMISSIONS MITIGATION:

• Reducing distribution system losses reduces generation demand and GHG emissions.

EMISSION ESTIMATE:
Varies according to the source of electricity generation.

COST-EFFECTIVENESS:
Improved reliability means that consumers will not use GHG producing alternative energy sources.

SECONDARY EFFECTS:
Improved reliability through reduction in forced outages will have a secondary benefit in the form of fewer hours of lost production and a higher quality of life for customers.

RESOURCES

• The National Rural Electric Cooperative Association Closed-Loop Voltage Control Project (RER #91-8) led to the development of a new system to control voltage regulators remotely, achieving a better voltage profile on distribution feeders.
• National Rural Electric Cooperative Association, 1991, The Distribution System Loss Manual.

CONTACTS

General Reliability Consultants
Sudhir K. Agarwal
San Diego, CA
Fax: (760) 737-0941
Agarwal@gri-us.com

Harza Engineering
Peter Donalek
Electric Power Systems Department
Chicago, IL
Tel: (312) 831-3170
Fax: (312) 831-3999
pdonalek@harza.com
http://www.harza.com

National Rural Electric Cooperative
Association (NRECA)
James Willis
International Programs Division
Arlington, VA
Tel: (703) 907-5669
Fax: (703) 907-5532
jim.willis@nreca.org
http://www.nreca.org