Research On No-Load Switching Overvoltage Of High Voltage Transmission Lines Based On Improved Euler

Switching overvoltage becomes the decisive factor of the insulation level of some electrical equipments in the UHV. With the development of the power grid, longer transmission line, bigger power capability and higher voltage appear, also, with the promotion of the switch’s arc extinguishing capability and the widely used of MO A, no-load switching overvoltage becomes one of the most typical switching overvoltage.This paper advances a numerical methods to transmission no-load overvoltage based on improved Euler, and development it to a program by Visual Basic6.0. Then, verify the accuracy and precision of this program by EMTP.Based on improved Euler, we calculate the no-load switching overvoltage of two transmission lines under the different condition of the power early phase angle, line residual voltage and the operation mode of switch, different factors that influence no-load switching overvoltage and the measures to control overvoltage are expounded.This paper expounds the necessity to cancel the switching resistor and validates its feasibility. We show the measures to control overvoltage while the switching resistor is canceled.