Method of real discharge magnitude estimation

Partial discharge in electrical equipment can give rise to deterioration in insulating material. Therefore, partial discharge detection and assessment play an important part in detecting insulating states of electrical equipment. However, a device for measuring partial discharge is only able of obtaining apparent discharge magnitude, not that of real discharge. This paper puts forward a method to fulfill the task of real discharge magnitude estimation. Using a three-capacitance model, the real discharge magnitude can be estimated by apparent discharge magnitude, equivalent discharging capacitance and voltage difference between two discharging instants. A nanosecond-level equivalent circuit for partial discharge measurement is built according to real cases. For the convenience of calculating and analyzing, linear lumped parameters are utilized in the circuit, and the validity of the model is proven by relevant experiments. So, the equations for the equivalent capacitance estimation are achieved in laboratory. Furthermore, the equations for real discharge magnitude estimation are obtained. Three-capacitance discharge experiments validate the method of estimation.