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 and news
International Electrician Day, 10 June 2025
Celebrating the role of electrical engineers from André-Marie Amperè, today and for the future.
New guide for clients launched at Houses of Parliament
'There has never been a more important time for clients to step up and ...ask the right questions'
The impact of recycled slate tiles
Innovation across the decades.
EPC changes for existing buildings
Changes and their context as the new RdSAP methodology comes into use from 15 June.
Skills England publishes Sector skills needs assessments
Priority areas relating to the built environment highlighted and described in brief.
BSRIA HVAC Market Watch - May 2025 Edition
Heat Pump Market Outlook: Policy, Performance & Refrigerant Trends for 2025–2028.
Committing to EDI in construction with CIOB
Built Environment professional bodies deepen commitment to EDI with two new signatories: CIAT and CICES.
Government Grenfell progress report at a glance
Line by line recomendation overview, with links to more details.
An engaging and lively review of his professional life.
Sustainable heating for listed buildings
A problem that needs to be approached intelligently.
50th Golden anniversary ECA Edmundson apprentice award
Deadline for entries has been extended to Friday 27 June, so don't miss out!
CIAT at the London Festival of Architecture
Designing for Everyone: Breaking Barriers in Inclusive Architecture.
Mixed reactions to apprenticeship and skills reform 2025
A 'welcome shift' for some and a 'backwards step' for others.
Licensing construction in the UK
As the latest report and proposal to licence builders reaches Parliament.
Building Safety Alliance golden thread guidance
Extensive excel checklist of information with guidance document freely accessible.
Fair Payment Code and other payment initiatives
For fair and late payments, need to work together to add value.
Pre-planning delivery programmes and delay penalties
Proposed for housebuilders in government reform: Speeding Up Build Out.
High street health: converting a building for healthcare uses
The benefits of health centres acting as new anchor sites in the high street.