Liquid metal current limiter (LMCL) is regarded as a viable solution for reducing the fault current in the power grid, but demonstrating the liquid metal arc plasma self-pinching process of the resistive wall and reducing the erosion of LMCL are challenging not only theoretically but also practically. In this work, a novel LMCL is designed with a resistive wall that can be connected to the current-limiting circuit inside the cavity. Specifically, a novel fault current limiter (FCL) topology is put forward that the novel LMCL is combined with fast switch and current-limiting reactor. Further, the liquid metal self-pinch effect is modeled mathematically in three dimensions and the gas-liquid two-phase dynamic diagrams under different short-circuit currents are obtained by simulation. The simulation results indicate that with the increase of current, the time for the liquid metal-free surface begins depressing is dropped, and the position of the depression also changes. Different kinds of bubbles formed by the depressions gradually extend, squeeze, and break. With the increase of current, liquid metal takes less time to break. But the breaks still occur at the edge of the channel, forming arc plasma. Finally, relevant experiments are conducted for the novel FCL topology. The arcing process and current transfer process are particularly analyzed. Comparisons of peak arc voltage, arcing time, current limiting efficiency, and electrodes erosion are presented. The results demonstrate that arc voltage of the novel FCL topology is reduced by more than 4.5 times and the arcing time is reduced by more than 12%. The erosions of liquid metal and electrodes are reduced. Moreover, the current limiting efficiency of the novel FCL topology is improved by 1%‒5%. This work lays a foundation for the topology and optimal design of LMCL.

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Due to its significant attributes, the liquid metal current limiter (LMCL) is considered as a new strategy for limiting short-circuit current in the power grid. A resistive wall liquid metal current limiter (RWLMCL) is designed to advance the starting current-limiting time. Experiments are performed to investigate the dynamic behaviors of liquid metal, and the influence of different currents on the liquid metal self-shrinkage effect is compared and analyzed. Furthermore, the liquid metal self-shrinkage effect is mathematically modeled, and the reason for the formation of arc plasma is obtained by simulation. The laws of arc plasma formation and the current transfer in the cavity are revealed, and the motion mechanisms are explained by physical principles. The simulations are in accordance with the test data. It is demonstrated that the sudden change of the current density at both ends of the wall causes the liquid metal to shrink and depress under the electromagnetic force, and the current starts to transfer from the liquid metal path to the wall resistance path. The RWLMCL can effectively advance the starting current-limiting time.

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