Method and system for detecting ground fault of converter valve arm

A technology for ground faults and converter valves, applied in the field of converter valves, can solve the problems of inability to distinguish between internal and external ground faults, chain breakdown, overvoltage of power electronic devices, etc., to achieve protection from breakdown, improve reliability, The effect of improving stability

Inactive Publication Date: 2018-11-06
NORTH CHINA ELECTRICAL POWER RES INST +3
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The present invention is used to solve the problem that the existing converter valve arm overcurrent protection strategy cannot distinguish the internal and external grounding faults of the valve, which will also cause overvoltage of the power electronic devices in the valve arm sub-module, and there is a risk of chain breakdown

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  • Method and system for detecting ground fault of converter valve arm
  • Method and system for detecting ground fault of converter valve arm
  • Method and system for detecting ground fault of converter valve arm

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Embodiment Construction

[0036] In order to make the technical features and effects of the present invention more obvious, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings. The present invention can also be described or implemented in other different specific examples. The equivalent transformations done within all belong to the protection category of the present invention.

[0037] In the description of this specification, descriptions referring to the terms "an embodiment", "a specific embodiment", "some implementations", "for example" and the like mean specific features, structures, materials described in conjunction with the embodiment or example. Or features are included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or charact...

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Abstract

The invention provides a method and a system for detecting a ground fault of a converter valve arm, wherein the method comprises the steps as follows: collecting a three-phase valve arm current and adirect current of a converter valve; calculating a zero-sequence current of the valve arm according to the three-phase valve arm current; calculating a differential current according to the zero-sequence current and the direct current of the valve arm; monitoring an amplitude value of the differential current, determining the theoretical occurrence of an intra-valve ground fault when monitoring that the amplitude value of the differential current is greater than a first predetermined threshold value, and disconnecting an AC (alternating current) circuit breaker connected with the converter valve. According to the invention, whether the ground fault occurs inside the converter valve can be accurately determined through the differential current calculated according to the zero-sequence current and the direct current of the valve arm; and through the disconnection of the AC circuit breaker connected with the converter valve, a valve arm sub-module can be protected from being broken down,and the stability and the reliability of the system operation can be improved.

Description

technical field [0001] The invention belongs to the technical field of converter valves, and in particular relates to a method and system for detecting a ground fault of a converter valve arm. Background technique [0002] With the gradual expansion of the global large power grid system, the requirements for grid interconnection technology are getting higher and higher. The traditional AC transmission method has more and more disadvantages, and it is not suitable for the high-voltage and high-power transmission method required now. Therefore, the demand for converters is gradually increasing. Compared with the line commutated converter (LCC) based on thyristors, power electronic converters do not have the problem of commutation failure and have small switching losses. , high output waveform quality and other advantages, it is widely used in power generation, power transmission, power transformation, power distribution and power consumption. Therefore, in industrial, power t...

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Application Information

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IPC IPC(8): G01R31/02H02H7/12
CPCG01R31/50H02H7/1203
Inventor 曹天植葛俊邓占锋刘蓁王晓斐徐彭亮陈瑞王丰郑立宋洁莹刘海军黄天啸谢欢刘苗李烜王长瑞刘军娜
Owner NORTH CHINA ELECTRICAL POWER RES INST
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