NIST reviews impact of conservation voltage reduction for electric power industry. (News Brief).

The old debate about the possibility of reducing the peak power demand that electric utilities have to meet by lowering the system voltage level by a few percent (known as a "brownout") has been rekindled by the incidence of rolling blackouts in response to overloaded transmission and distribution systems. The state of California is considering this approach, now called conservation voltage reduction (CVR), which rests on the undisputed fact that constant-resistance loads--such as incandescent lighting--draw power proportional to the square of the supply voltage. It would appear that a systematic reduction of a few percent could significantly reduce the peak demand, reducing the possibility of overloads. Such overloads might otherwise make it necessary to arbitrarily cut-off the supply to some sections of the distribution system to avoid a collapse of the complete system.

Prompted by these CVR proposals, a NIST researcher has completed an objective review of their implications for publication by Electric Power Research Institute, the major electric power industry R&D organization, as a PQ Commentary.

The conclusion of this review, entitled The Power Quality Implications of Conservation Voltage Reduction (see www.epri.peac.com), is that while some peak demand shaving might be beneficial, sophisticated loads that are already sensitive to brief voltage reductions, known as sags, caused by incidents on the power grid would be even more vulnerable if these sags would occur during a CVR period. The report urges cooperation among equipment manufacturers and users, together with electric utilities and regulatory agencies, supported by an objective test program on the possible side effects of CVR. This report will serve to illuminate the old debate and help to raise awareness of the possible negative consequences to power quality before CVR is implemented.

CONTACT: Gerald FitzPatrick, [phone]; [e-mail].