Derating of transformers for operation under extreme weather conditions in networks having other voltage and/or frequency ratings

Abstract

This paper suggests a procedure for determining the available apparent power of transformers when used in networks of voltage and/or frequency different from the transformer’s rated design values. Also, the effect of extreme values of the ambient temperature will be taken into account. The model allows the consideration of the above three issues simultaneously. A daily ambient temperature profile is applied in order to compute the daily variation of the transformer’s tolerable rating, and to assess the resulting reduction in the available energy delivered. The procedure is derived in a normalized way, so that it can be easily applied to practically any power transformer.

• Power transformers
• derating
• losses
• voltage
• frequency
• temperature

Additional information

Notes on contributors

Mohamed Saied

Mohamed Mostafa Saied

Dr M Saied was born in Egypt in 1945. He received the B.Sc. degree (Honors) in Electrical Engineering from Cairo University in 1965. From 1965 to 1967 he was a research and teaching assistant at Cairo University. He received the DiplomIngenieur and Doktor-Innigeeur degrees from the Rheinisch - Westfaelische Technische Hochschule (RWTH) Aachen, Germany, in 1970 and 1974. From 1974 to 1983, he was a faculty member at Assiut University, Egypt. In 1983, Dr. Saied joined Kuwait University where he is now a full professor of Electrical Power Engineering. He spent one-year sabbatical leave (1998) as a Visiting Professor at Cairo University. Prof. Saied is a senior member of the IEEE, the Forschungs-gesellschaft Energie (FGE) in Germany and the CIGRE’ in Paris.