Research On The Inverse Calculation Modeling Methods Of Potential Transformer Under Lightning Over-voltage

This paper was accomplished by developing the project"The development of one 10-35kV new over-voltage on-line monitoring system"of ChinaSouthern Power Grid Corporation Ltd. The paper presents a new method for over-voltage online monitoring based on chain parameters (ABCD parameters) of the equipments in the substation. The method models the PT, secondary cables and voltage divider as several two-port networks in cascade by means of their ABCD parameters. Adoption of this model can derive the over-voltage waveform of the high-voltage port of the PT from the voltage signal of the secondary device by means of time domain recursive convolution. The two-port ABCD parameters model of a 10kV PT is built by using this method. The comparison between the calculated results and measured data verify the feasibility of this method.