A Model Considering Deep Saturation of the Iron Core for 10 kV Potential Transformers

An accurate model of the potential transformer (PT) is essential for studies such as overvoltage monitoring, simulation analysis and protections. Aiming at the disadvantage of conventional PT models, an improved π model considering deep saturation of the iron core for 10 kV PT is proposed in this paper. A hybrid ac-dc power source is connected to the secondary winding of the PT, and then saturation inductances of two magnetizing branches in different saturation levels can be measured and calculated by a novel method. Over voltage tests are conducted to validate this improved model. Results by simulations on the ATP-EMTP platform and experiments in the laboratory match well.