A method for evaluating the abnormal action probability of differential protection devices caused by communication delay errors

Abstract

The invention discloses a method for evaluating the abnormal action probability of a longitudinal difference protection device caused by a communication delay error code, and belongs to the technical field of electric power system control. The present invention measures the transmission delay and bit error information of the longitudinal difference protection signal in real time of the longitudinal difference protection device, and calculates the abnormal action probability of the current longitudinal difference protection device according to the measured delay and bit error information, including the lateral asymmetric delay Probability of misoperation of protection device caused by longitudinal symmetric delay, probability of refusal of protection device caused by longitudinal symmetric delay, probability of refusal of protection device caused by bit error, probability of refusal of protection caused by delay error code. The invention analyzes the impact of the current communication system on the relay protection device by measuring the delay and error code of the protection signal transmission in real time, makes up for the deficiency in the reliability evaluation of the current relay protection device, and has strong practicability.

Description

technical field [0001] The invention belongs to the technical field of power system control, and in particular relates to a reliability evaluation and analysis method for a longitudinal difference protection device of a power system. Background technique [0002] With the rapid development of the smart grid, the power system is increasingly dependent on the communication system. Problems in the communication system will inevitably endanger the safety, stability and economic operation of the power system. Relay protection signals have the characteristics of strong real-time, low transmission probability, and uncertain transmission time, which put forward strict requirements on the transmission performance of protection channels, and also pose new challenges to the research of protection reliability. For example, when a 500kV line of China Southern Power Grid failed in June 2003, its differential protection refused to operate due to the long time delay of the fiber optic chan...

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Problems solved by technology

[0003] At present, there are very few studies considering the impact of communication delay and error codes on relay protection devices, and they are not deep enough

Most of them only explored the impact of communication delay and bit error on protection devices from a qualitative or experimental point of view and gave relevant conclusions. From the perspective of probability, there were fewer achievements in analyzing the impact of delay and bit errors on relay protection devices.

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