Thermal Field Simulation of High Voltage Shunt Capacitor Based on Electrothermal Coupling in Harmonic Environment

The high voltage shunt capacitor is rated to work at power frequency voltage and current. Due to the existence of harmonic current in power system, the temperature rise of the high voltage shunt capacitor is different from the power frequency condition during stable operation. In order to study the heating characteristics of high voltage shunt capacitors under harmonic conditions, this paper constructs a series equivalent model of high voltage shunt capacitors considering the influence of frequency, and proposes the construction method of solving the electric and thermal field models of capacitors under harmonic conditions. According to the series model, the internal heat source distribution of capacitors is refined, and a full equivalent simulation model of the capacitor thermal field based on electrothermal coupling is built. The simulation model can calculate the capacitor temperature distribution under various current excitation conditions. The heating characteristics of capacitor under power frequency current, single harmonic current and power frequency superimposed single harmonic excitation are simulated and analyzed, and the influence of harmonic on the heating characteristics of capacitor is summarized.