Study of Hybrid Energy Dissipation Method via MOV-Liquid Metal in DC Interruption

With the development of DC power systems, Metal oxide varistor (MOV), as the traditional energy dissipation device, is difficult to meet the requirements of enhancing energy dissipation density. Liquid metal based on magnetic pinch effect can dissipate energy with its arc under fault current, it can be used in hybrid with the MOVs to perform as the energy dissipation device in DC breaker. In this paper, the resistance characteristics of liquid metal arcs is summarized, mathematical models for each stage of liquid metal material arcing are established, and the simulation model of medium-voltage DC breaker with hybrid energy dissipation is established. The influence of the arc channel size of the liquid metal energy-dissipating unit and MOV parameters on the hybrid energy dissipation effect is analyzed and the optimal parameter design of the hybrid energy dissipation method for medium-voltage DC breaking is given. The research result shows that the use of hybrid energy dissipation device can increase the energy consumption power density by 24.9% compared with MOVs of the same level.