Analysis and Modeling of Electromagnetic Radiation Characteristics During Switch Operation of Electrical Isolation

Abstract

The electromagnetic radiation generated by the operation of the electrical isolation switch will cause electromagnetic interference problems such as the insulation risk of the primary side of the system and the malfunction of the secondary equipment. Electromagnetic interference will directly cause the power grid protection to malfunction or damage, and affect the reliability of the secondary circuit. With the ultra-fast transient overvoltage waveform and frequency components, the process of conduction coupling and radiation coupling is analyzed. According to the process of ultra-fast transient overvoltage passing through CT, CVT and space electromagnetic field, the mechanism of secondary cable interference is discussed. The following models are established, a line model with distributed parameters, a model of an isolating switch with repeatable breakdown, a model of an isolating switch with opening and closing resistors, and a phase-controlled circuit breaker. Numerically calculate the overvoltage generated by the internal disconnector and circuit breaker operating the no-load circuit. Numerical calculations are made for the overvoltage generated by the disconnector and circuit breaker operating the no-load circuit. Combined with the analysis method of the typical circuit of the power system, the overvoltage analysis model of the electrical isolation switch is established, and the electromagnetic radiation characteristic simulation is realized. Experiments show that during the whole process of the isolation switch closing operation, the isolation switch will break down hundreds of times. The short-line disturbance voltage follows the change of the power frequency power supply voltage in a jump mode, presents a step voltage wave, and the overvoltage disturbance lasts for several hundred milliseconds.