Differential protection discrimination method based on integrated sequence component

Abstract

The invention discloses a differential protection discrimination method based on an integrated sequence component. The integrated sequence component differential protection is composed of three parts including a positive sequence current differential element, a negative sequence current differential element, and a phase current differential element. The positive sequence current differential element is used to identify three-phase faults. The negative sequence current differential element is used to identify asymmetrical faults. The phase current differential element is used to identify fault phases. If both the positive sequence current differential element and three-phase current differential element operate, a three-phase fault is determined. If the negative sequence current differential element operates and a single-phase or two-phase current differential element operates, an in-region asymmetric fault, including single-phase or two-phase faults, is determined. The differential protection discrimination method can quickly and accurately identify a fault section after the fault is generated in a regional power grid, can greatly reduce the number of used optical transformers, saves the project cost, is not affected by the load-side zero sequence component, reliably unoperate in case of out-region faults and reliably operates in case of in-region faults.

Description

technical field [0001] The invention relates to a method for distinguishing and identifying a fault area when a fault occurs in a multi-stage series power supply cable line, in particular to a differential protection discrimination method based on a comprehensive sequence component. Background technique [0002] The application of multi-level series power cable lines in large and medium-sized cities is becoming more and more extensive. The protection of series power cables is generally based on distance or overcurrent protection. The series power cables are generally connected to multiple loads. The level difference cannot meet the reliability requirements of power supply, and it is difficult to confirm the location of cable faults. In order to improve the reliability of power supply and improve the ability to quickly restore power supply, without affecting the operation of the equipment, a group of light The flexible transformer transmits the measured phase-separated curren...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a differential protection discrimination method based on the comprehensive sequence component, which is used to solve the problem that the fault area cannot be distinguished and identified when a fault occurs in a multi-stage series power supply cable line , and is not affected by the branch load of the multi-stage series supply line

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