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Method and System for Distinguishing AC Outgoing Line Faults of Converter Stations in Flexible HVDC Transmission System

A technology of flexible direct current and power transmission system, which is applied in the direction of fault location, fault detection according to conductor type, electrical components, etc. It can solve the problems of flexible direct current transmission system setup, failure to consider the control characteristics of flexible direct current transmission system, and difficulty in adapting to application scenarios, etc. To achieve the effect of improving adaptability

Active Publication Date: 2020-04-21
NR ELECTRIC CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Especially for the outgoing line of the converter station, since the current flexible DC transmission system generally has the low voltage ride-through function, when a fault occurs in the outgoing line of the converter station, affected by the control output characteristics of the flexible DC system, the zero negative sequence current voltage felt by the line protection The characteristic component is fundamentally different from conventional transmission lines, and the longitudinal protection using the zero-negative-sequence power direction discrimination in traditional line protection may be difficult to adapt to this application scenario
[0004] In the current conventional line protection logic, the control characteristics of the HVDC system during a line fault are not considered, and the necessary parameters are not set for the HVDC system to recognize this operation scenario

Method used

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  • Method and System for Distinguishing AC Outgoing Line Faults of Converter Stations in Flexible HVDC Transmission System
  • Method and System for Distinguishing AC Outgoing Line Faults of Converter Stations in Flexible HVDC Transmission System
  • Method and System for Distinguishing AC Outgoing Line Faults of Converter Stations in Flexible HVDC Transmission System

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Embodiment 1

[0049] An embodiment of the present invention provides a method for judging faults of AC outgoing lines in converter stations of flexible direct current transmission systems, which may include the following steps:

[0050] First, set the line protection on one side of the converter station to the line protection on the side of the converter station or the line protection on the opposite side of the converter station; correspondingly, the line protection on the other side of the converter station can be set to the line protection on the opposite side of the converter station , or converter station side line protection.

[0051] Then, perform fault judgment on the converter station side and the opposite side of the converter station respectively:

[0052] For the line protection on the converter station side, when the negative sequence current and zero sequence current meet the preset constraint relationship 1, it is determined that the converter station side is a positive direc...

Embodiment 2

[0059] Based on the same inventive idea, the embodiment of the present invention provides a fault identification system for the AC outgoing line of the converter station of the flexible direct current transmission system. No more details are given, and the description will be given below.

[0060] The embodiment of the present invention provides a flexible direct current transmission system converter station AC outlet fault identification system, which may include:

[0061] The line protection setting module is used to set the line protection on the side of the converter station as the line protection on the side of the converter station or the line protection on the opposite side of the converter station;

[0062] The line protection device on the converter station side is used to determine the positive direction fault on the converter station side when the negative sequence current and the zero sequence circuit on the converter station side meet the preset constraint relatio...

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Abstract

The invention discloses a method and a system for judging converter station AC (alternating current) outlet faults of a flexible DC (direct current) transmission system. The method is implemented in line protection and comprises steps as follows: parameters for the line protection are newly added, the protection of the side can be optionally set as protection of a converter side or a side oppositeto a converter; for the line protection of the converter side, when negative-sequence current is lower than a set threshold value, zero-sequence current is higher than the set threshold value and thezero-sequence current and the negative-sequence current meet a mutual proportional relation, the line protection of the side is judged as a forward fault; for the line protection of the side oppositeto the converter, when the negative-sequence current is higher than a set threshold value and the zero-sequence current is lower than the set threshold value, the line protection of the side is judged as the forward fault; the line protection of the two sides is subjected to information interaction, and when the forward faults are determined on both sides, the fault of the line area is determined. The method can be suitable for the converter station AC outlet application scenes of the flexible DC transmission system, and protective action performance of the line is improved.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, and in particular relates to a method and system for judging faults of AC outgoing lines of a converter station of a flexible direct current transmission system. Background technique [0002] The flexible direct current transmission technology utilizes the characteristics that the turn-on and turn-off of fully-controlled devices can be flexibly controlled, and can achieve more excellent power transmission performance control effects. Flexible DC transmission systems have been gradually promoted and applied in the fields of island and weak grid power supply, large city power supply, and renewable energy grid integration. [0003] After the flexible DC transmission system is connected to the conventional AC system, the electrical characteristics of the AC line under fault conditions have changed significantly. Especially for the outgoing line of the converter station, sinc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08H02H7/26
CPCG01R31/085H02H7/268
Inventor 谢华赵青春刘斌季笑庆张婷婷王玉龙戴光武徐晓春
Owner NR ELECTRIC CO LTD