Modeling of Current-Limiting Circuit Breakers for the Calculation of Short-Circuit Current

A current-limiting circuit breaker (CLCB) can quickly interrupt circuit faults and limit the short-circuit current. Modeling of a CLCB is important for the calculation of short-circuit current and arc flash energy. Based on the analysis of the arc voltage waveforms of CLCBs, a new arc model is derived. The Schwarz arc model and arc length are used to represent the complicated voltages of CLCBs, and arc length is determined from a differential equation. The test results of a commercial CLCB sequentially deployed in a couple of three-phase power systems are studied, and the parameters of the model are obtained. The three-phase faults in the power systems are simulated. The short-circuit currents and voltages of the CLCB are calculated and compared to the test results. The simulation results are in good agreement with the test data, and the proposed model can predict the high-current arcs in CLCBs. These techniques facilitate the calculation of short-circuit currents.

I. Introduction

Short-Circuit conditions in power systems are serious problems. A current-limiting circuit breaker (CLCB) can rapidly interrupt the faulty circuit and limit the short-circuit current. Short-circuit currents can exhibit dramatically different effects in power systems with and without CLCBs. Therefore, the interaction between a CLCB and the circuit must be studied, and the model of the CLCB should be derived to facilitate calculation of the short-circuit current and arc flash energy.