Enhancing reliability of energy absorbers in DC circuit breakers

Because of high energy absorption requirements, the energy absorbers in DC circuit breakers will consist of a large number of series- and parallel-connected surge arrester units. This study shows that owing to highly nonlinear I-V characteristic of surge arresters, the failure of a single arrester has a significant impact on the performance of the whole energy absorber. In particular, the arrester column containing the failed unit will draw considerably higher current compared to healthy columns which may lead to cascaded failure of arresters and destruction of the whole column. This paper evaluates and proposes new connection topologies for enhancing the robustness and reliability of energy absorbers in high-voltage DC circuit breakers. A matrix structure is proposed as the topology for the greatest reliability. The impact of the number of breaker modules is also investigated.