Black-Box Modeling of Back-Up Short-Circuit Tests

Black-box models are employed to simulate the coupled clearing of a short-circuit fault by two breakers in back-up configuration. The novel feature of electromagnetic contact repulsion is introduced in the proposed black-box model of miniature circuit breakers to account for the anticipated contact opening before the mechanical actuation. Simulations agree with available experimental tests, predicting reliable current-peaks and let-through energy. A significant reduction of necessary and expensive lab tests is expected.