Hybrid excitation multifunctional saturated iron core alternating current fault current limiter and current limiting method

Abstract

The invention relates to a saturated iron core type alternating current fault current limiter technology, in particular to a mixed excitation multifunctional saturated iron core alternating current fault current limiter and a current limiting method, the current limiter comprises an iron core, a first direct current winding, a second direct current winding, a first alternating current winding, a second alternating current winding and a direct current peripheral circuit; the iron core is of a five-column type structure and comprises a left outer side air gap supporting column, a right outer side air gap supporting column, a middle supporting column, a left working iron core, a right working iron core, an upper transverse yoke and a lower transverse yoke, the left working iron core is located between the left outer side air gap supporting column and the middle supporting column, and the right working iron core is located between the right outer side air gap supporting column and the middle supporting column. The upper transverse yoke and the lower transverse yoke are located above and below all the supporting columns respectively, and a permanent magnet is embedded in the middle supporting column. The current limiter can effectively adjust the power flow of a power system when the power system operates normally; when a short-circuit fault occurs in a power system, the fault current of the system is effectively limited, the eddy-current loss of the permanent magnet is reduced, and the utilization rate of the current limiter is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of a saturated iron core AC fault current limiter, in particular to a hybrid excitation multifunctional saturated iron core AC fault current limiter and a current limiting method. Background technique [0002] With the improvement of the system voltage level and the continuous increase of the load scale, the short-circuit current level of the system has risen sharply, and some places even exceed the breaking capacity of the circuit breaker. The problem of excessive short-circuit current is becoming more and more serious, which brings hidden dangers to the safe and stable operation of the system, and it is imminent to take current limiting measures for the system. Fault current limiter is a very promising current limiting device. It has low steady-state impedance and high transient impedance. It can automatically switch impedance and effectively limit short-circuit current. Among them, the saturated iron cor...

AI Technical Summary

Problems solved by technology

An existing closed-loop iron-core hybrid excitation SCFCL topology is as follows: image 3 As shown, it further reduces the DC excitation loss of the current limiter, but the eddy current effect will be generated when the alternating magnetic flux passes through the permanent magnet, which will cause the heating problem of the permanent magnet, which will make the permanent magnet face the risk of demagnetization, and then affect the permanent magnet and Current limiter stability

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