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A line protection method and system adaptable to flexible direct access

A line protection, direct technology, applied in the field of power system, can solve the problems of differential current drop, braking current rise, insufficient protection sensitivity, etc., to achieve the effect of solving the current draw, high reliability, and improving sensitivity

Active Publication Date: 2022-04-08
STATE GRID CORP OF CHINA +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The short-circuit current provided by the flexible DC is greatly affected by the control strategy, which may cause the current angle on both sides of the line to be an obtuse angle, resulting in the situation of draining the current, causing the differential current to drop and the braking current to rise. Under the weak AC system, there is protection sensitivity insufficient risk

Method used

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  • A line protection method and system adaptable to flexible direct access
  • A line protection method and system adaptable to flexible direct access
  • A line protection method and system adaptable to flexible direct access

Examples

Experimental program
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Effect test

Embodiment 1

[0053] Such as figure 1 , figure 2 As shown, the main idea of ​​the line protection method for adapting to flexible direct access provided by this embodiment is: the operating characteristics of the operating element are the OR logic of the existing differential protection operating area and the extended operating area, and the "adaptive flexible" is set in the distance protection. The extended action area of ​​direct entry" control word, the extended action area adopts different action characteristic equations and protection criteria to realize adaptive protection according to the throwing and withdrawing conditions of the control word of "extended action area adapted to flexible direct entry". The specific process is as follows:

[0054] S1. Collect the secondary current of the current transformer (CT) where the line protection device is installed, including the A-phase current, B-phase current and C-phase current;

[0055] S2. According to the secondary current, calculate...

Embodiment 2

[0092] This embodiment provides a line protection system adaptable to flexible direct access, which includes:

[0093] The current calculation module is used to collect the secondary current of the current transformer where the line protection device is installed, and calculate the differential current and braking current of the line according to the secondary current of the current transformer;

[0094] The control word judging module is used to judge whether the control word of "expanded action area adapting to soft direct entry" is the set cut-in value, if the control word is the set cut-in value, the function of the extended action area is put into operation, otherwise the function of the extended action area is exited;

[0095] Extended action area line protection module, used to judge whether the function input of the extended action area is sufficient, and perform line protection for the extended action area with sufficient conditions;

[0096] The line protection modul...

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Abstract

The present invention relates to a line protection method and system adaptable to flexible direct access, including content: S1, collecting the secondary current of the current transformer where the line protection device is installed, and calculating the differential current of the line according to the secondary current of the current transformer and braking current; S2, judging whether the control word of "expanded action area adapted to soft direct entry" is the set cut-in value, if the control word is the set cut-in value, then the function of the extended action area is put into operation and enters S3; otherwise, the extended action area Exit the function and enter S4; S3, judge whether the function input conditions of the extended action area are sufficient according to the set conditions, if so, determine that it is a fault in the area, the protection action trips, and remove the fault; if the function input conditions of the extended action area are not sufficient, enter S4 ; S4. If the function of the extended action area is withdrawn or the input conditions of the extended action area are not sufficient, judge whether the differential current and braking current on both sides of the line meet the current differential action condition, if so, determine it as an internal fault, and the protection action Trip, remove the fault, otherwise the protection returns.

Description

technical field [0001] The invention relates to a line protection method and system adapted to flexible direct access, and relates to the technical field of power systems. Background technique [0002] In order to solve the increasingly severe fossil energy crisis and environmental problems, wind power, photovoltaic and other new energy power generation technologies have developed rapidly. As of the end of 2017, the cumulative installed capacity of wind power and photovoltaics in my country reached 164 million kW and 130 million kW, respectively, most of which were collected through stations and then connected to the grid through high-voltage transmission lines. The correct action of the relay protection of the sending line is very important for the safety and efficient utilization of large-scale new energy power. [0003] The short-circuit current provided by the flexible DC is greatly affected by the control strategy, which may cause the current angle on both sides of the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26H02H3/28H02J3/36
CPCH02H7/268H02H3/28H02J3/36Y02E60/60
Inventor 刘颖肖智宏宋璇坤高旭申洪明李铁臣苏毅王紫琪张祥龙陈炜杜娜杜兆强范登博
Owner STATE GRID CORP OF CHINA