SF6断路器空载介质恢复特性数值模拟中的耦合计算方法

SF6高压断路器空载下介质恢复特性的数值模拟取决于液压操动机构的输出动力特性、开断过程中灭弧室内气流场的分布以及电场总分布.传统方法对介质恢复特性的数值模拟是先分别对上述三部分进行数值计算,然后根据三部分的数值计算结果计算介质恢复特性.本文以介质强度的计算为纽带,将三者联系起来,首先建立了对介质恢复特性进行数值模拟的耦合方程,然后在液压机构操动力的驱动下,对每一行程步距通过耦合方程,计算每一步距下的液压操动机构的输出特性、灭弧室内气流场与电场的分布及介质恢复强度,最后求得全行程下的介质强度恢复特性.通过空载开断过电压的校核,证明所求得的介质恢复特性满足对该断路器空载开断能力的要求.

Coupling Calculation Method for Numerical Simulation of Dielectric Recovery Property of SF6 Circuit Breaker Under No-Load Breaking

The numerical simulation of the dielectric recovery property (DRP) for SF6 high voltage circuit breaker under no-load breaking depends on the output dynamic characteristics of hydraulic actuator,the distribution of electric field and the distribution of flow field in the arc quenching chamber. The conventional way for numerical simulation of DRP is to calculate those three parts separately. Then using the numerical results to calculate DRP. In this paper,the output dynamic characteristics of hydraulic actuator,the distribution of the electric field and the distribution of flow field in the arc quenching chamber are linked through calculating the dielectric recovery strength. First,the coupled equations for numerical simulation of the DRP are set up,and then under the output of hydraulic actuator,the distributions of gas flow field and electric field and the dielectric recovery strength are calculated at each calculation step according to the coupled equations. The coupled numerical simulation is carried out step by step until the dielectric recovery property obtained. The simulated dielectric recovery property is detected by no-load over voltage value,which shows that the no-load interrupting requirement for this SF6 high voltage circuit breaker is well satisfied.