Isolated alternating current fault current limiting circuit

Abstract

The invention relates to an isolated alternating current fault current limiting circuit comprising a transformer and a conducting loop. The transformer has a primary side winding that is arranged in series between a power supply input system and a load output system; And a secondary side winding and the primary side winding share an iron core and are electrically isolated windings. Being connected with the secondary side winding, the conducting loop is formed by a switch and a power-off element in a series connection mode. When a power source system is short-circuited, the power-off element of the conducting loop induces large short-circuit currents of the primary side winding and thus is fused and conduction is cut off; therefore, the transformer is converted into an open circuit state to provide high impedance exciting reactance and the equivalent internal impedance in the power supply input system is increased; and thus an objective of limitation of the fault current is achieved. As a result, a circuit interrupting device of the power source system enables the short circuit fault to be isolated successfully, so that it can be avoided that the influence area of the short-circuit accident is enlarged and there is a power failure for a long time.

Description

technical field [0001] The invention relates to an isolated AC fault current limiting circuit, in particular to a short-circuit fault current limiting circuit electrically isolated from an AC power supply system. Background technique [0002] Now the industrial power distribution system has been quite advanced, but due to poor insulation of machines or lines, lightning strikes or switching surges, human negligence, etc., even if technology advances in the future, short-circuit faults cannot be completely avoided. When a fault occurs, a large short-circuit current will be generated. The protection equipment must quickly isolate the faulty machine or line to prevent the short-circuit current from continuing to flow, and reduce equipment damage and blackout areas caused by the short-circuit current in the power system. [0003] It is known that a circuit breaker (such as a circuit breaker or a fuse) is used to isolate the short-circuit current. If the short-circuit current is t...

AI Technical Summary

Problems solved by technology

[0005] The invention provides an isolated AC fault current limiting circuit, which is used to overcome the shortcomings of traditional power supply systems that only use inductors to limit the fault current, resulting in unstable voltage and no electrical isolation during normal operation.

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