ABSTRACT
Circuit breakers differ from switches in that they not only manually make and break the circuit while carrying their normal currents, but are also capable of making and breaking the circuit under the severest system conditions. When switching short-circuit currents, small inductive currents, and capacitive currents, high overvoltages appear in the switched circuit. These voltages may reach 5 times, or even greater, the normal circuit voltage and damage of circuit insulation or restrike in the circuit breaker may occur. All arc interruption methods are aimed at disturbing the energy balance of the arc. These methods are to cool the arc, increase its length, and split it into a number of arcs in series, as happens in multi-break circuit breakers and breakers equipped with splitter plates. Circuit breakers with rated capacity based on a symmetrical short circuit are not necessarily capable of interrupting asymmetrical faults. Switching operations produce overvoltages which may damage the circuit breaker and associated equipment insulation.
