No abstract

No abstract

In this paper, a coupling model of the AC filter branch circuit with the arc plasma in the circuit breaker was built to investigate the arcing process considering the harmonic current. The comparisons among the current at power frequency (50 Hz), power frequency combining the 11th harmonic and power frequency combining the 24th harmonic show that the high-order harmonic current would lead to higher decreasing rate of current before current-zero period. In addition, the influence of arc on the amplitude of high-order harmonic current is not negligible. Thus, the coupling of arc with AC filter branch circuit is quite necessary in the numerical modeling of the circuit breaker in the AC filter branch at the high voltage direct current converter station.

The calculation of critical electrical field, based on the balancing between the ionization and attachment of the electrons, has been widely used to obtain the dielectric breakdown strength of hot gas after arc burning. However, due to the negligence of electron drift, diffusion and photon ionization process and geometry of electrodes, this method should be further improved. In this work, a new approach for the dielectric breakdown calculation of residual hot gas has been established by combining particle transport calculation and Boltzmann analysis, which considers both the influence of dissociations and strong electrical field. The method has been applied in the evaluation of SF 6 dielectric breakdown, which is a commonly used gas media in the field of switch gears. The influences of temperature, pressure and electrode distance have also been investigated. The results in this calculation agree well with the previous test, indicating its potential to predict the dielectric breakdown more accurately.

No abstract