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In an electric power system, a fault or fault current is any abnormal electric current. For example, a short circuit is a fault in which a live wire touches a neutral or ground wire. An open-circuit fault occurs if a circuit is interrupted by a failure of a current-carrying wire (phase or neutral) or a blown fuse or circuit breaker.
A sudden fail-open fault can cause multiple secondary failures if it is fast and the circuit contains an inductance; this causes large voltage spikes, which may exceed 500 volts. A broken metallisation on a chip may thus cause secondary overvoltage damage. [1]
The open-circuit test, or no-load test, is one of the methods used in electrical engineering to determine the no-load impedance in the excitation branch of a transformer. The no load is represented by the open circuit, which is represented on the right side of the figure as the "hole" or incomplete part of the circuit.
fault A short circuit, open circuit, or other disruption of a power system. fax Facsimile, the transmission of paper images by radio or by wire. feed forward A control system that adjusts the controlled variable based on a model of the process and measurements of disturbances, instead of feedback from measurement of the process. feedback amplifier
Additionally, zones possess the following features: zones overlap, overlap regions denote circuit breakers, and all circuit breakers in a given zone with a fault will open in order to isolate the fault. Overlapped regions are created by two sets of instrument transformers and relays for each circuit breaker.
During those 1.5 cycles, other separate circuits can see voltage dips or blinks until the affected circuit opens to stop the fault current. Automatically closing the breaker after it has tripped and stayed open for a brief amount of time, usually after 1 to 5 seconds, is a standard procedure. [5]
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All circuit breaker systems have common features in their operation, but details vary substantially depending on the voltage class, current rating and type of the circuit breaker. The circuit breaker must first detect a fault condition. In small mains and low-voltage circuit breakers, this is usually done within the device itself. Typically ...