Pilot protection method for direct-current transmission line and application of pilot protection method

Abstract

The invention belongs to the field of power system relay protection, and particularly relates to a direct-current transmission line pilot protection method and application thereof, and the method comprises the steps: collecting and filtering voltage and current, and calculating the comprehensive admittance of a single-pole line if the single-pole line is the single-pole line; if the line is a bipolar line, calculating differential current of a positive line and a negative line and an integral value of the differential current in a current time window for fault pole selection, and calculating voltage common modulus and voltage differential modulus of a rectification side and an inversion side to calculate common-mode comprehensive admittance and differential-mode comprehensive admittance; fault area judgment is carried out by using a criterion based on unipolar line comprehensive admittance; or, if the pole selection result is single-pole grounding, the criterion based on common-mode comprehensive admittance is adopted for fault area judgment, and if the pole selection result is inter-pole short circuit, the criterion based on differential-mode comprehensive admittance is adopted for fault area judgment. According to the method, the criterion is simple, the transition resistance resistance is high, no line parameter is needed, and compared with a traditional current differential protection non-locking process, the action speed of line backup protection can be effectively improved.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, and more specifically relates to a method for longitudinal protection of direct current transmission lines and its application. Background technique [0002] The DC transmission system has the advantages of long transmission distance, large transmission capacity, flexible control, and asynchronous networking between AC systems, and has been widely used in the world. The transmission distance of HVDC transmission lines is long, and the probability of failure is high. As an indispensable part of the protection system of HVDC transmission projects, DC line protection undertakes the major task of quickly detecting and clearing line faults, and its performance directly affects the entire DC Operational performance of transmission projects. [0003] The current DC transmission line protection usually adopts the protection schemes of ABB and SIEMENS. Among them, the traveling ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the defects and improvement needs of the prior art, the present invention provides a DC transmission line longitudinal protection method and its application, the purpose of which is to solve the technical problem in the prior art that the backup protection action delay of the DC line is too long

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