A method for checking the fixed value of relay protection distance based on measured impedance

Abstract

The invention discloses a relay protection distance setting value check method based on measured impedance, comprising the following steps: determining a line to be checked and setting fault points; obtaining the measured impedance of protection related to the line after a minimum short-circuit fault occurs to the fault points of the line, and comparing the measured impedance with the setting value of each section of protection to get the action result of each section of protection; testing the selectivity of protection according to the action result of each section of protection and the time setting value thereof; setting fault points at the head and tail ends of the line to be checked, and checking the sensitivity of protection according to the measured impedance of protection after the minimum short-circuit fault occurs to the fault points of the line; calculating the minimum load impedance under the current operation mode, and testing whether the setting value of section-III protection can avoid the minimum load impedance value; and selecting next line to be checked, and repeating the steps. Compared with the common method at present, the proposed scheme has certain advantages in speed of calculation and accuracy of the check result, and can be better used in distance setting value online checking of a large grid.

Description

technical field [0001] The invention belongs to the field of electric power system relay protection, and more specifically relates to a method for checking the fixed value of relay protection distance based on measured impedance. Background technique [0002] The setting value of the relay protection device is obtained by determining the most severe operation mode in the normal operation mode, and ensuring that the setting value meets the requirements of the relay protection action in the most severe operation mode. As the scale of the power grid continues to expand and its structure becomes more and more complex, the operation mode will become more complex and changeable. Once the operation mode of the power grid exceeds the daily arrangement, there will be hidden dangers of misoperation or refusal of protection devices, which will pose a threat to the safety of the power grid. It can be seen that it is of great significance to use the real-time data of the power system to ...

AI Technical Summary

Problems solved by technology

[0004] In view of the above defects, the present invention proposes a method for checking the fixed value of the relay protection distance based on the measured impedance, aiming to solve the problems in the prior art that the existing method cannot Considering the Technical Issues of Checking Speed ​​and Checking Accuracy

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