Direction longitudinal temporary state quantity protection method applicable for electric transmission line containing UPFC

Abstract

The invention belongs to the technical field of electric power system fault recognition, and particularly relates to a direction longitudinal temporary state quantity protection method applicable foran electric transmission line containing a UPFC. The method comprises the following steps: step one, extracting a current line mode component in each outgoing line of a busbar in a fault transient state, and carrying out wavelet decomposition on the current line mode component to obtain the wavelet energy entropy of each outgoing line; step 2, calculating the specific value of relative reference value of wavelet energy entropy of each outgoing line, comparing with protection setting criteria, opening or closing protection on the side, and sending a shutting or trip permitting signal to the opposite side of the circuit; and step 3, judging faults inside and outside a region by comprehensively judging information on the side and opposite side of the circuit, and recognizing whether a busbarfault occurs or not. The method solves the problem that single-ended transient state quantity protection of a circuit containing elements such as UPFC and SSSC is easily refused to move, and the method is high in quickness and high in transition resistance and is applicable for common electric transmission lines as well.

Description

technical field [0001] The invention belongs to the technical field of power system fault identification, and in particular relates to a directional longitudinal transient quantity protection method suitable for lines containing unified power flow controller (UPFC) components. Background technique [0002] In order to improve the transmission capacity and system stability of transmission lines, static synchronous series compensator (SSSC) and unified power flow controller (UPFC) are currently the most advanced flexible AC transmission system (FACTS) devices. has been put into actual operation. When the line fails, the rapid regulation of FACTS components changes the short-circuit path that reflects the power frequency; the inverter-type power supplies such as DC and new energy also change the power characteristics that reflect the power frequency. It has brought a severe test to the power frequency relay protection relying on the invariant characteristics of "source" and "p...

AI Technical Summary

Problems solved by technology

The traveling wave method is not affected by the distributed capacitance current of the line, but it needs to introduce additional voltage for calculation, and has higher requirements for time synchronization on both sides, and there are few studies on the applicability of lines containing UPFC and SSSC.

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