How Does a Transformer Affect Power Quality?
Quick answer — A transformer affects power quality through its impedance (which causes a voltage drop and regulation, and limits fault current), its magnetising inrush on energisation, its no-load/load losses, its harmonics interaction (eddy losses, K-factor), and its nonlinear magnetising current. Harmonics from nonlinear loads increase the eddy/stray loss, and a transformer can also be derated or need a K-rating for a high-harmonic load.
How does a transformer affect power quality?
Voltage regulation
The impedance causes a voltage drop under load, so the transformer regulates the secondary voltage (and tap-changing compensates it).
Harmonics
Nonlinear loads produce harmonics that increase the eddy and stray loss and heat the windings, so a K-rated or derated transformer may be needed.
Inrush and magnetising current
The magnetising current (and inrush on energisation) contains harmonics, which can distort the voltage and trip sensitive protection; the transformer contributes its own nonlinear characteristic.
References & standards
- IEC 60076-1
- IEEE C57.12.00
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
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Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
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