Study on Lightning Overvoltage in Long Span Section After AC to DC Operation of Transmission Lines
摘要
Transmission lines to DC operation, due to the polarity effect of the wire and the space electric field is different, the lightning pilot development process has changed, and large span section of the line gear distance is long, tower height is more vulnerable to lightning strikes. Therefore, it is necessary to compare and analyze the similarities and differences of lightning overvoltage under different operation modes of AC and DC. In this paper, through the establishment of large span section transmission line electromagnetic transient simulation model, calculate the transmission line in the original AC insulation configuration, AC and DC operation mode of the difference between the large span section lightning overvoltage. The results show that the same insulation configuration of DC operation when the line is subject to lightning overvoltage value is greater than the overall AC mode of operation. When the lightning current is above 100 KA, the lightning current bypasses the transmission line, the DC line overvoltage is about 18.3% larger than the AC line overvoltage, bringing a hidden danger to the insulation configuration of the original AC line.