Dc offset
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:
Waveform distortion is defined as a steady state deviation from an ideal sine wave of power frequency, principally characterised by the spectral content of the deviation.
There are five primary types of waveform distortion:
- dc offset
- harmonics
- interharmonics
- notching
- noise
The presence of a dc voltage or current in an ac power system is termed dc offset. This can occur as the result of a geomagnetic disturbance or due to the effect of half-wave rectification. Incandescent light bulb life extenders, for example, may consist of diodes that reduce the rms voltage supplied to the light bulb by half-wave rectification. Direct current in alternating current networks can have a detrimental effect by biasing transformer cores so they saturate in normal operation. This causes additional heating and loss of transformer life. Dc may also cause the electrolytic erosion of earthing electrodes and other connectors.
--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.
Government approach could undermine delivery and regeneration.
World's first mass timber data centre.
The overlooked environmental aspect of data centre development.
Introduction to radon awareness
New technical information sheet published by CIOB.
Updated supplier guide can help electrical contractors engage with NHP.
CIAT confirm the winners of the 2026 architectural technology awards.
Government launches a one stop shop for flood preparedness.
Sir Edwin Lutyens: Britain's greatest architect? Book review.
CIOB publishes free template to help assess and manage risks.
ECA's reflections on Party Conference season
Burnham wants to be confident of winning before asking for a fresh mandate.
New Chief Construction and Scientific Adviser
Sergio Cavalaro, Professor of Infrastructure Systems at Loughborough University.
Building safety levy for England
CIAT publish estimator tool for members.
Water sector faces a growing crisis that could slow the delivery of vital infrastructure.