A single-phase AC line protection method and system for an AC-DC system

An AC-DC system, single-phase AC technology, applied in power transmission AC network, emergency protection circuit device, fault detection according to conductor type, etc., can solve AC-DC system with low judgment accuracy and rich harmonic and non-periodic components Protects against malfunction or refusal to achieve the effects of improving accuracy, easy implementation, and improving stability

Active Publication Date: 2021-09-28
国网山西省电力公司经济技术研究院 +1
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Problems solved by technology

[0005] In view of the above analysis, the embodiment of the present invention aims to provide a single-phase AC line protection method and system for AC and DC systems, so as to solve the problem of misoperation of the existing protection methods for the protection of AC and DC systems with rich harmonic and aperiodic components. Or refusal to move may cause low judgment accuracy

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  • A single-phase AC line protection method and system for an AC-DC system
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  • A single-phase AC line protection method and system for an AC-DC system

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[0068] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the application and together with the embodiments of the present invention are used to explain the principle of the present invention and are not intended to limit the scope of the present invention.

[0069] Most of the traditional protection methods are power frequency protection. With the increasing proportion of AC lines in the system, the traditional protection methods may malfunction or refuse to operate for the protection of AC and DC systems with rich harmonic and non-periodic components, resulting in The problem of low accuracy in judging the fault distance is solved. To this end, this application proposes a single-phase AC line protection method and system for an AC-DC system. Through the KCL theorem and the KVL theorem, the voltage and current equation of a fault on the inverter s...

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Abstract

The invention relates to a single-phase AC line protection method and system for an AC-DC system, which belongs to the technical field of relay protection, and solves the problems of malfunction or refusal in existing protection methods for the protection of AC-DC systems with rich harmonic and aperiodic components It may cause the problem of low judgment accuracy. Including: collecting the three-phase voltage and three-phase current of the AC bus on the inverter side and the three-phase current flowing from the inverter to the AC bus; based on the zero-mode equivalent circuit of the AC-DC interconnected grid, using the KCL theorem and the KVL theorem to obtain a certain The fault is related to the voltage and current equation of the AC bus; based on the three-phase voltage and three-phase current of the AC bus, the three-phase current flowing from the inverter to the AC bus and the voltage and current equation, the fault distance is obtained; the fault type is judged and the circuit breaker is controlled according to the generated The signal controls the circuit breaker on the inverter side to perform corresponding actions to realize the protection of the single-phase AC line, which improves the applicability and accuracy.

Description

technical field [0001] The invention relates to the technical field of relay protection, in particular to a single-phase AC line protection method and system for an AC-DC system. Background technique [0002] When the AC line on the inverter side fails, the inverter station is easily affected and commutation failure occurs. Coupled with the flexible and fast control of the DC system, the DC system presents strong nonlinear characteristics. In addition, when a commutation failure occurs, it is equivalent to a superimposed fault in the AC and DC system, and the DC system as an additional fault source brings a huge challenge to the reliability of the AC protection action. [0003] When the AC line fault causes commutation failure on the inverter side, the DC side can be equivalent to a controlled current source, and the inverter injects a large number of high-order harmonics and aperiodic components into the AC system, and the aperiodic components exhibit exponential decay char...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26H02J3/36G01R31/08
CPCG01R31/086G01R31/088H02H7/262H02J3/36Y02E60/60
Inventor 马静刘晨周晓东周易
Owner 国网山西省电力公司经济技术研究院
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