Original scientific paper
TEMPERATURE RISE OF POWER TRANSFORMERS: COMMENTS AND PROPOSALS TO IEC 60076-2:2011
Zdenko Godec
; Končar - Electrical Engineering Institute Inc.
Vjenceslav Kuprešanin
; Končar - Electrical Engineering Institute Inc.
Abstract
Two years ago, a new, third edition of IEC 60076-2 standard was published [1]. Over a period of
two years, we have had the opportunity to evaluate this new standard in practice. In the paper, it is shown
that the criterion for stagnation 1K/ h + 3h is not entirely satisfying. Better criterion is 1K/3h, or
extrapolation to stagnation - as given in second edition of the standard. A formula for hot-spot
determination is not complete and it is suggested how to improve it. In the new standard, three formulas
for winding average temperature determination are given. Based on experiments, we conclude that the
best formula is the simplest one, and two additional formulas are without any benefit. According to [1],
paragraph 7.11, measurement uncertainty estimates of results should be given in test reports - but only
as information. No procedure for measurement uncertainty estimation is given, and measurement
uncertainty is not used in decision-making. Therefore, the third edition of the standard is uncompleted and
not motivating in terms of efforts to increase the quality of the measurement results. In the paper, the
procedure for measurement uncertainty estimation is proposed and suggestion is given for appropriate
decision making.
Keywords
Power transformers; temperature rise test; measurement uncertainty; decision-making
Hrčak ID:
199074
URI
Publication date:
15.8.2017.
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