Research on Influence Factors and Acceleration Methods of Current Commutation

Abstract

The vacuum interrupter is widely used due to the advantages of no arc-extinguishing medium and high insulation strength. However, the arc voltage generated by the commonly used CuCr contacts is low. In hybrid DC circuit breakers (DCCB), hybrid automatic transfer switches (ATS), medium voltage compound switches and other fields, it is difficult to rely on vacuum arc to complete natural commutation, which restricts the development of hybrid switches. In order to understand the current commutation process deeply, the influence of internal and external factors on the current commutation is analyzed by experiments. The coupling mathematical model of arc-commutated branch is established. The criterion for the success of current commutation is summarized. The parameters of the arc model are reconstructed through repeated breaking experiments to explore the influence of internal factors on the arc characteristics. Based on this, the influence law of arc current, contacts gap and transverse magnetic field (TMF) is analyzed. An acceleration method of current commutation is proposed. A prototype for accelerating experiments with an electromagnetic repulsion mechanism and TMF is developed. The commutated branch equivalent to practical applications is built. The experimental results show that the commutation time is effectively shortened and meets the requirements of practical applications through the acceleration method, which provides new thought for the development of hybrid switches.