Insulation Thermal Coefficient Measurement in ...

Transformers play a key role in power distribution networks. A reliable and endless supply of electricity is highly dependent on good operation of these elements. A huge number of customers are directly supplied via any of the transformers. Loading of the transformers under unbalanced conditions is an important factor that influences the life of their insulation. In this paper we will consider two typical 315 KVA, 20 kV distribution transformers with the same characteristics but under different operating conditions. One transformer supplies a three phase industrial load while another transformer supplies an urban area consisting variety of three and single phase loads and experiences unbalanced conditions that highly influence its insulation system. Thermal coefficients and remnant life of two distribution transformers are measured and show a remarkable difference between thermal coefficients of two transformers.