Case Study on Double-Circuit Lightning Fault of UHV Transmission Line

Abstract

The Tokyo Electric Power Company, Inc (TEPCO) plans UHV power network system in Japan in order to meet the steadily increasing demand for electricity. Four-hundred kilometer UHV-designed double-circuit transmission lines have already been constructed and are now operated at 500kV. Double-circuit flashovers on the UHV minami-iwaki transmission line occurred the first time with successful re-closing of the circuit in 2006.
In this paper, we report on the melted OPGW500mm², lightning location system (JDLN), oscillograph, and the phenomenon analyzed by using EMTP. The results are as follows: (1) Double-circuit flashovers on the UHV minami-iwaki transmission line occurred for the first time. The overhead ground wire (OPGW500mm²) was melted by lightning. (2) According to the oscillograph, the fault was occurred at the phase of 270 degrees. (3) Lightning peak current was about +265kA by using JLDN. The melted component wires of OPGW500mm² were caused by the lightning, and the amount of melted wires was estimated at 3 wires in 1L, 4 wires in 2L. (4) From the result of EMTP analysis, the lightning peak current was +265kA, and the rise time was 2.5µs∼3.5µs. It shows that EMTP result doesn't contradict the lightning current estimated by JLDN.