Naslov
New method for determination of steady-state temperature rises of transformers

Autori
Godec, Zdenko

Izvornik
IEE proceedings. Part A, Physical science, Measurements and instrumentation, Management and education, Reviews (0143-702X) 131 (1984), 5; 307-311

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Transformers, Measurement and measuring, Matematical tecniques, Temeperature rise

Sažetak
For transformers whose thermal time constant exceeds two hours, unacceptably large systematic errors occur if recommended methods for determination of steady-state temperature rise are used. Therefore a new criterion for heat run duration and a new method for determination of steady-state temperature rise are proposed, which ensure reliable determination of steady-state temperature rise independent of transformer thermal time constant. According to this proposal, the heat run should be continued until the temperature rise exceeds 95% of the steady-state temperature rise, which is estimated by a three- points method. Then, by the method of least squares, a more accurate value of steady-state temperature rise is obtained by extrapolating only those measured points that are higher than 60% of the previously estimated steady-state temperature rise. For those instrument transformers whose largest thermal time constant of the system (transformer) is governed by the time constant of the winding, a universal intermittent heat run independent of the transformer time constant is proposed: ton/toff = 120 min/2 min. Estimation errors of the steady-state temperature rise and thermal time constant when applying the three- points method and the intermittent heat run are analysed.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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