Covered conductor burn-down prevention for distribution line in Indonesia

摘要

Covered conductor (CC) is used to resolve temporary line to ground fault in the distribution line. However, some cases of CC burn down were found in Indonesia. These phenomena were triggered by lightning strikes that cause transient overvoltage with a magnitude greater than basic insulation level (BIL) of insulator. Consequently, short circuit current will flow through the pinhole on CC. Burn down phenomena will create high impedance fault that is unable to be detected by protection relay, thus the conductor will remain energized and harmful to the surroundings. Therefore, this paper presents study about CC burn down prevention. The study was performed using transient simulation to find the effect of earth wire utilization against the transient overvoltage due to lightning strike. In addition, finite element simulation and laboratory testing were also performed to analyze the effect of power arc device on burn down prevention. The results show that the lightning strike with negative polarity will not cause transient overvoltage with a magnitude greater than the insulator BIL. However, if the lighting strikes have positive polarity then the insulator BIL will be potentially exceeded. Furthermore, the utilization of power arc device will prevent the CC burn down.