Modular Conventional Protection and its Enhancement through Electronic Circuit Breaker Systems

Abstract

Conventional mechanical CBs protect AC and DC circuits from overload and short circuit conditions. Electronic circuit breakers offer more features compared to mechanical ones. Features like nearly unlimited short circuit capability by current limitation, programmable rated current, programmable trip time curve, wire break indication, remote controllability and monitoring functions for current and voltage. In addition it offers millions of operations without any abrasion, (it should be mentioned, that the life of an electronic circuit breaker and the one of a mechanical circuit breaker are differently defined and therefore not comparable) but they do not provide physical isolation due to the leakage current at OFF-state and they are especially susceptible to line induced voltage spikes, which have to be suppressed by additional components like suppressor diodes. To protect against field induced electromagnetic pulses additional shielding is required. Therefore electronic circuit breakers often use an electrical contact in series with the power semiconductor, which will stay open in the OFF- state thus withstanding the required isolation voltages