Measurement and analysis of transient overvoltages in full-size 11.4 kV distribution line

To increase the transmission capacity of 6.6 kV distribution lines economically, 11.4 kV distribution system that is constructed of existing 6.6 kV equipment in use is being examined. For the application of the 11.4 kV distribution system to the real field, we are trying to calculate transient overvoltage by EMTP to decide the rational test voltage of 11.4 kV equipment. So, to confirm the calculation precision of EMTP concerned with transient overvoltage in 11.4 kV distribution line, we had made an experiment measuring the characteristics of overvoltages, which occur in 11.4 kV distribution lines. We compared the calculated waveform with the measured waveform, and investigated the difference of the two. We compared the calculated waveform by EMTP with the measured waveform for some test data, and we found that the range of computing errors were from 1.8% to 10.8%.