Delayed Closing Suppression Strategy of the Transformer Inrush Current Based on the Offset Principle Between Remanence and Magnetic Bias

Traditional inrush current suppression strategy delayed closing strategy, due to the measurement error of remanence will cause the problem of poor suppression effect. Therefore, this paper proposes a delayed closing strategy that does not require the measurement of remanence and is based on the offset principle between remanence and magnetic bias. Firstly, this paper analyzed the transient processes in the transformer core after the breaker has been closed. And studied the offset principle between remanence and magnetic bias. Secondly, the limitation of the traditional delayed closing strategy is analyzed. A delayed closing inrush current suppression strategy based on the offset principle between remanence and magnetic bias is proposed, and its closing steps are studied. Finally, taking the auxiliary transformer of a nuclear power plant as the prototype, a simulation platform is constructed to simulate, and the delayed closing inrush current suppression strategy based on the offset principle between remanence and magnetic bias is simulated and analyzed. The results show that, under ideal conditions, the proposed delayed closing strategy based on the offset principle between remanence and magnetic bias, the inrush current suppression effect reaches 85% and above, almost completely suppressing the excitation inrush current.