Research on early warning method for pollution flashover based on phase angle of insulator leakage current

Pollution flashover is a systematic disaster of power system. It is significant to early warning insulator pollution flashover in real time and accurately. The phase angle of the insulator leakage current is a critical parameter for insulator pollution flashover early warning. However, in field applications, the operating voltage waveform cannot be obtained so that this characteristic parameter cannot be applied to the insulator pollution flashover early warning system. This paper proposes a method to obtain the phase angle of the leakage current of the online insulator. This method avoids the direct measurement of the operating voltage waveform, but uses the stray capacitance between the signal plate of the early warning device metal shell and the transmission line to obtain the operating voltage signal indirectly. In this paper, the method and the early warning mechanism of pollution flashover are analyzed theoretically, and then the early warning device for pollution flashover is designed. Finally, the effectiveness of the early warning device is verified by experiments.