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We develop a consistent model for a line lightning protection device (LLPD) and demonstrate that it can explain the two modes of current quenching-impulse quenching and current zero quenching-observed in such devices. A dimensional analysis shows that impulse quenching can always be obtained if the power loss from the electric arcs is large enough as compared to U I f 0 , where U 0 is the grid voltage and I f is the maximum follow current after a lightning strike. We further show that the two modes of quenching can be reproduced in a full 3D arc simulation coupled to the appropriate circuit model, which allows us to analyze the power loss from the arc in greater detail. Because of the high temperature, the main mechanism of power loss is radiation which has to be correctly modeled in order to obtain physically meaningful results. The results will allow us to use numerical simulations to optimize the quenching ability to LLPDs in the future.

Abstract. Two distinct modes of follow current suppression were observed in multi-chamber systems (MCS) under lightning overvoltage: Zero Quenching (ZQ) and Impulse Quenching (IQ). Sufficiently lower erosion of electrodes and evaporation of discharge chamber walls makes the IQ more preferable as a mechanism of arc quenching. Since experimental search for best MCS design is both difficult and expensive numerical modeling is considered as a prospective method for geometry optimization. Several steps were made towards development of efficient arc model. This article highlights most important results of arc quenching simulation and current status of arc model development.

Abstract. Arc simulations require a coupled solution of the flow and electromagnetic equations. Despite of industrial interest, there is no established simulation framework available yet. We assess the usability of STAR-CCM+ for low voltage circuit breaker simulations using a test case of a model arc chamber, since this toolkit allows to define and control the simulation in a single environment. In spite of a partially implemented arc root model, the results agree well with reference data of previous publications.