A method and apparatus for monitoring the synchronous state of a line protection pilot channel

Abstract

The invention discloses a method for monitoring the synchronous state of a line protection pilot channel. The method comprises the steps of: step 100: collecting transmission line parameters and electric quantities on the two sides and then performing the step 200; step 200, calculating a relationship curve between the theoretical value of the included angle of the two sides and the theoretical value of the current of the own side according to the line equivalent model by using the collected line parameters and the electric quantities of the two sides, and then executing step 300; step 300, obtaining the theoretical value of the included angle of the two sides current and the theoretical value of the included angle of the two sides voltage according to the calculation result in the step 200 and the electric quantity of the two sides collected in the step 100, and then executing the step 400; step 400, according to the calculation result of step 300 and the electric quantities on both sides collected in step 100, determining the synchronization state of the line protection pilot channel by error analysis. At the same time, the invention discloses a corresponding apparatus for monitoring the synchronous state of a line protection pilot channel. This method does not depend on GPS pairs and is not affected by load current.

Description

technical field The invention belongs to the technical field of power grid relay protection, and in particular relates to a method and a device for monitoring the synchronous state of a transmission line protection longitudinal channel. Background technique Transmission line current differential protection is a kind of transmission line main protection, and its theoretical basis is Kirchhoff's current theorem. When the transmission line is working normally or there is a fault outside the area, ignoring the influence of the distributed capacitance of the line, the current flowing into the line is equal to the current flowing out, the differential current is zero, and the differential relay does not operate. When the transmission line internal fault, ignoring the influence of line distributed capacitance, the differential current is equal to the fault current flowing into the line, and the differential relay operates. The principle of current differential protection is simple...

AI Technical Summary

Problems solved by technology

This monitoring method is greatly affected by capacitive current and sampling accuracy, and there is no clear differential current threshold to distinguish normal and abnormal states; and the load current of transmission lines is small, so it cannot be monitored

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