This paper begins with a focused study of Maxwell's first equation, and concludes that the magnetic field is generated by electric current, and there will be no magnetic field without electric current. Subsequently, the characteristics of the magnetic field energy of the reactor are analyzed. Given that its magnetic field energy has the properties of continuity and inability to be stored statically, it is deduced that, in the scenario of disconnecting the high-voltage shunt capacitor device, if the current in the reactor is not zero, the circuit breaker will definitely generate an arc. Subsequently, this research starts to construct an equivalent simplified circuit model corresponding to the disconnection of the high-voltage capacitor device, striving to accurately replicate the actual working conditions. Finally, based on this simplified circuit, three typical cases are carefully selected for simulation calculations and in-depth analysis. Furthermore, a series of summary results with engineering reference value are condensed, aiming to provide reliable theoretical basis and practical guidelines for relevant engineering practices.