Distribution characteristics of the dielectric loss and capacity incremental values for transformer oil bushings

Summary

It is of great importance to study the overall distribution characteristics of the dielectric loss and capacity incremental values based on large amount of data to determine the health level of running bushings. In this paper, based on more than 23,390 dielectric loss values, 8875 capacitance variation values (110kV ~ 500kV rated voltage level, 6652 bushings), a new distribution function of the dielectric loss and capacitance variation values is developed combining histograms and nonparametric tests. Meanwhile, the evaluation index of fitting effect is defined to obtain the optimal distribution function of dielectric loss and capacitance variation values. And, the distribution curves are carried out under rated voltage levels, different manufacturers, running years, circumstance temperature and relative humidity dimension. Then, the factors such as bushing structure, technology levels, and running years, which might affect the distribution curves of dielectric loss and capacitance variation values, are discussed. And the conclusions are very useful to formulate more rational evaluation index and effective maintenance strategy of bushings.

Additional informations

Authors

J. XIONG, G. WU, Y. LIU, L. GAN

Keywords

transformer oil bushing, dielectric loss, capacity incremental values