A large zero sequence voltage was found to have been induced ontoa 138 kV line from adjacent 500 kV lines where these share the sametransmission right-of-way. This zero sequence voltage distorted the2.5-element revenue metering schemes used for two large industrialcustomers supplied directly from the affected 138 kV line. As a result,these two customers were overcharged, on average, approximately 3.5% for15 years. The work done to trace the origins of the zero sequencevoltage and quantify the metering error is described. Customer refundswhich, in the end, totalled $4 million are calculated
展开▼
