With the rapid development of DC power systems and the increasing demand for DC circuit breakers, electromagnetic repulsive drives-based Thomson coil actuators (TCA) are widely investigated to provide the high-speed actuating required for ultra-fast mechanical switches, especially those used in hybrid DC circuit breakers. The actuating mechanism is required to be fast, reliable, and economic. This article summarizes the development of Thomson coil actuators in circuit breakers in recent years, further illustrating the basic principles and the actuator topology. In addition, it discusses the various structural components of TCA and describes the utilized modeling and simulation methods. The main objective was to provide a comprehensive overview of the TCA field.

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In most industrial applications, plasma has an important feature that the erosion products produced by plasma will undergo a phase transition and affect the properties of plasma mixtures. Calculating the transport coefficients of the plasma mixtures, usually, gas–metal mixtures, is an important approach to study this feature. However, most transport coefficient calculation methods have some difficulties in dealing with the solid and liquid components of gas–metal plasma mixtures. In this study, a modified method for calculating transport coefficients of gas–metal plasma mixtures containing solid and liquid status is proposed, considering that the liquid and solid components are usually in the form of clusters. Based on this modified method, the influence of the metal phase transition on the transport coefficients of gas–metal plasma mixture is explored with the example of H2–Cu plasma mixture. The findings revealed in this study are as follows: (1) The modified calculation method is applicable for not only gas–metal plasma mixtures but also other plasma mixtures containing solid and liquid status. (2) Ignoring the metal phase transition in the calculation of transport coefficients of gas–metal plasma mixtures will inevitably produce considerable variances. (3) The variances, caused by ignoring the metal phase transition, are tightly associated with the pressure, the proportion of metal, and the unbalanced degree of gas–metal plasma mixtures. In summary, the variances caused by ignoring the metal phase transition might be ignorable only when the pressure, proportion of metal, and unbalanced degree of gas–metal plasma mixture are all in extremely small values.

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