Rapid voltage changes
BSRIA Power quality guide (AG 2/2000) was written by C C Pearson and V Uthayanan and published by BSRIA in July 2000. It states:
There are several terms for rapid voltage variations, depending on the length of time and the direction of change. Each type of variation can be designated as instantaneous, momentary, or temporary, depending on its duration as classified in Table 15.
Table 15 Classification of voltage changes by size and duration
Short-duration voltage variations are caused by fault conditions, the energization of large loads which require high starting currents, or intermittent loose connections in power wiring. Depending on the fault location and the system conditions, the fault can cause sags, swells and interruptions.
The fault condition can be close to or remote from the point of interest. In either case, the impact on the voltage during the actual fault condition is of short duration variation until protective devices operate to clear the fault.
--BSRIA
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
The heritage of nuclear and conventional power stations.
New measures to stop people being ripped off
Government to protect families from cowboy builders and aggressive bailiffs.
New Futurebuild showcase brings an innovation-first approach.
National Planning Policy Framework
Understanding the 2026 changes.
ECA's public affairs priorities
Member consultation opens to shape priorities for 2027 to 2030.
Dutyholder responsibilities from 1 July 2026.
Where performance meets practice
The Building Envelope Stage at UKCW Birmingham.
CIAT publishes briefing on planning reforms.
Leaders in Learning for Practice Network
Call for conservation leaders in learning to register interest in new network.
The importance of early engagement
Construction lessons from the Trillium HealthWorks Experience Centre.
Mayors are to be given planning call in powers
Mayors across England will be able to make the most important planning decisions.
The Master Builder: William Butterfield and his times. Book review.