Lightning current and flashover path measurement on high voltage transmission lines

A method of measurement the current and the path of a lighting flashover is put forward. When a lighting break an insulator string on high voltage power transmission lines, an impulse current will flow through the string, and an impulse voltage will appear at the tower end of the string. A voltage sensor can measure the voltage pulse. An inductance coil current sensor can measure the current pulse. Contrasting the polar of the sensor signals, we can distinguish the shielding failure and back flashover, and obtain the polarity of the lighting. To establish this method, the authors designed a voltage sensor, a current sensor and an optical fiber transmission system. An impulse current generator was used to generate lighting current about 10 kA, which flow through a 2.5Omega resistance to simulate the lighting flashover. The voltage sensor and the current sensor were place above the resistance to measure the signals. The outputs of the sensors were converted to light signal and transmitted by optical fiber to measurement system. The experiment result shown this method has excellent feasibility.