Influences of DC component of short-circuit current on TP KMEA arc model parameters of 126 kV SF6 circuit breaker

With the development of the power system, the problem that the decay time constant of the DC component in the short-circuit current of the system exceeds the standard time constant of the existing circuit breaker is becoming more and more prominent, which is easy to cause significant losses due to breaking failure. However, the research on the influence of short-circuit current DC component on the breaking performance of high-voltage circuit breakers is lacking. And at present, the research of black box arc model is relatively mature. Based on this, this paper studies the variation law of black-box model parameters under different DC component time constants τ (45, 75 and 120 ms). The T100a type test of 126 kV SF
6
high voltage circuit breaker was carried out, and the TP KEMA model parameters were extracted from the test data by using the algorithm. The accuracy of the model was verified by simulation, and the influence of time constant and arcing time on black-box arc model parameters was discussed. The research results show that the prediction accuracy of this model for the breaking of circuit breakers studied in this paper reaches 100 %. Under the same arcing time, with the increase of the DC component time constant, the arc cooling power decreases and the arc time constant increases, and the interruption is more difficult. Under the same DC component time constant, with the increase of arcing time, the arc cooling power increases and the arc time constant decreases, and the breaking is easier.