Research On No-Load Opening Operating Overvoltage Of High Voltage Transmission Lines

Electric power industry plays a very important role in the development of national construction and national economy. In the power system, the no-load opening operation overvoltage is a kind of the switching overvoltage. The amplitude of no-load line opening operation overvoltage is high, and it last for a long time. It can causes insulator flashover and breakdown. So it is necessary to study, calculate and analyze the no-load opening operation overvoltage.The paper established the no-load line equivalent model in consideration of the capacitive coupling, this can simulate the high voltage transmission line more accurate and real. First, choose Gauss elimination method to calculate the sinusoidal steady state; then, choose improved Euler method to calculate the no-load opening operation overvoltage and introduces the transient process of the circuit in details; Finally, use Visual Basic6.0as the programming tool to calculate the opening operation overvoltage.In the end, apply the program to a500kV power system under different conditions like different length of transmission line, different time of circuit breaker, whether using the shunt reactor at the end of the line or not, whether transpose the line or not. Then analysis the results and draw conclusions which have some reference for practical engineering.