Method and apparatus for suppressing impact of compensator on line distance protection

Patent metadata

Field	Value
Publication number	US-10965114-B2
Application number	US-201816617124-A
Country	US
Kind code	B2
Filing date	May 22, 2018
Priority date	May 26, 2017
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

A method and apparatus for suppressing the impact of a compensator on line distance protection is provided, wherein the method comprises: obtaining a first current of a line connected to a compensator or series converters in the compensator, and a first voltage of a bus connected to the compensator or the line connected to the compensator; exiting the series converters and series transformers if the first current is greater than a preset current threshold and a duration is greater than a first preset time threshold; exiting the series converters and the series transformers if the first voltage is less than or equal to a preset voltage threshold and duration is greater than a second preset time threshold set the output voltage of the series converters to zero, and if a second current of an element corresponding to the first current meets conditions which the first current needs to meet; and otherwise, canceling the setting of the output voltage of the series converters to zero and obtaining a first current if a second voltage of the line corresponding to the first voltage is greater than the preset voltage threshold and the duration is greater than a third preset time threshold.

First claim

What is claimed is:

1. A method for suppressing an impact of a compensator on a line distance protection, characterized in that, the method comprising:
acquiring a current of a line connected to a compensator or a series converter in the compensator to obtain a first current; wherein the compensator is configured to control the current of the line connected to the compensator, the compensator comprising a static synchronous series compensator, a unified power flow controller, an interline power flow controller, and a convertible static compensator;
acquiring a voltage of a bus connected to the compensator or a voltage of the line connected to the compensator to obtain a first voltage;
comparing a relationship between the first current and a preset current threshold;
comparing a relationship between the first voltage and a preset voltage threshold;
exiting the series converter and a series transformer, if the first current is greater than the preset current threshold, and a first duration is greater than a first preset time threshold; wherein the series transformer is a device in the compensator, the first duration is a duration in which the first current is greater than the preset current threshold;
setting the output voltage of the series converter to zero, and acquiring the current of a component corresponding to the first current to obtain a second current, if the first voltage is less than or equal to the preset voltage threshold and a second duration is greater than the second preset time threshold; wherein the second duration is a duration in which the first voltage is less than or equal to the preset voltage threshold;
exiting the series converter and the series transformer if the second current is greater than the preset current threshold, and a third duration is greater than the first preset time threshold; wherein the third duration is a duration in which the second current is greater than the preset current threshold;
acquiring a voltage of a line corresponding to the first voltage to obtain a second voltage, if the second current is less than or equal to the preset current threshold, or if the second current is greater than the preset current threshold and the third duration is less than or equal to the first preset time threshold; and
canceling the setting of the output voltage of the series converter to zero, and performing the acquiring of the current of the line connected to the compensator or the series converter in the compensator to obtain the first current, if the second voltage is greater than the preset voltage threshold, and a fourth duration is greater than the third preset time threshold; wherein the fourth duration is a duration in which the second voltage is greater than the duration of the preset voltage threshold.

2. The method according to claim 1 , characterized in that, said exiting the series converter and the series transformer comprising:
locking the series converter and triggering a fast bypass to be turned on which in parallel with said series transformer ; and
closing a mechanical bypass switch in parallel with the series transformer.

3. The method according to claim 1 , characterized in that, further comprising the following steps after said exiting the series converter and the series transformer:
acquiring the current and voltage of the line connected to the compensator when a preset time comes; and
enabling the series converter and the series transformer, if the current of the line connected to the compensator is within a preset current range, and the voltage of the line connected to the compensator is within a preset voltage range.

4. The method according to claim 1 , characterized in that, further comprising the following steps after said acquiring the current of a component corresponding to the first current to obtain a second current:
sending a first execution instruction to a line protection apparatus if the second current is less than or equal to the preset current threshold, or if the second current is greater than the preset current threshold and the third duration is less than or equal to the first preset time threshold; wherein the line protection apparatus is configured to protect the line connected to the compensator, and the first execution instruction is used to instruct the line protection apparatus to update a set value of the distance protection impedance of the line connected to the compensator according to a first preset rule;
acquiring the second voltage after a preset time period from sending the first execution instruction; and
sending a second execution instruction to the line protection apparatus if the second voltage is greater than the preset voltage threshold, and the fourth duration is greater than the third preset time threshold; wherein the second execution instruction is used to instruct the line protection apparatus to reset the set value of the distance protection impedance of the line connected to the compensator to a value before updating the set value of the distance protection impedance of the line connected to the compensator.

5. The method according to claim 1 , characterized in that, further comprising the following steps after said exiting the series converter and the series transformer:
sending a third execution instruction to the line protection apparatus when the mechanical bypass switch is turned off; wherein the third execution instruction is used to instruct the line protection apparatus to update the set value of the distance protection impedance of the line connected to the compensator according to a second preset rule;
starting timing after sending the third execution instruction, after a preset duration, acquiring the current and voltage of the line connected to the compensator;
enabling the series converter and the series transformer if the current of the line connected to the compensator is within a preset current range, and the voltage of the line connected to the compensator is within a preset voltage range; and
sending a notification signal to the line protection apparatus when the mechanical bypass switch is closed; wherein the notification signal is used to inform the line protection apparatus to reset the set value of the distance protection impedance of the line connected to the compensator to a value before updating the set value of the distance protection impedance of the line connected to the compensator.

6. The method according to claim 1 , characterized in that, the first preset time threshold is less than a first time; wherein the first time is the sum of the time required for the line protection apparatus to analyze and calculate a distance protection (I) segment of the line connected to the compensator and a protection action delay time of the distance protection (I) segment; or the first preset time threshold is smaller than the difference between the first time and the response time for triggering the fast bypass switch.

7. A method for suppressing the impact of a compensator on line distance protection, characterized in that, the method comprising:
receiving a first execution instruction sent by a compensator; and
acquiring a set value of distance protection impedance of a line connected to the compensator in response to the first execution instruction and setting the set value to a first impedance;
updating the set value of the distance protection impedance of the line connected to the compensator based on the first impedance and a first preset rule, comprising:
performing an equivalent processing on the impedance of the series converter based on the impedance of the line side connected to the compensator to obtain a second impedance;
adding the first impedance, the second impedance, and a leakage reactance of the series transformer to obtain a thi

Assignees

• Nr Electric Co Ltd
• Nr Engineering Co Ltd

Inventors

• Pan Lei
• Tian Jie
• Dong Yunlong
• Lu Yu
• Huang Ruhai
• Jiang Chongxue
• Lu Jiang
• Zhang Baoshun
• Qiu Defeng
• Xie Hua

Classifications

• H02H7/26 Primary

  Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured (locating faults in cables G01R31/08) · CPC title

• H02J3/18

  Arrangements for adjusting, eliminating or compensating reactive power in networks · CPC title

• H02H1/0007 Primary

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• H02H3/40 Primary

  responsive to ratio of voltage and current · CPC title

• H02H7/261

  involving signal transmission between at least two stations (transmission of signals in general H02H1/0061) · CPC title