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Directional longitudinal transient protection method suitable for transmission lines with upfc

A technology of transient quantities and lines, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of less applicability research, higher requirements for time synchronization on both sides, etc., achieve good speed and sensitivity, and be easy to use The effect of setting

Active Publication Date: 2020-08-04
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Abstract
  • Description
  • Claims
  • Application Information

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.

Method used

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  • Directional longitudinal transient protection method suitable for transmission lines with upfc
  • Directional longitudinal transient protection method suitable for transmission lines with upfc
  • Directional longitudinal transient protection method suitable for transmission lines with upfc

Examples

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Embodiment 1

[0030] The invention proposes a directional longitudinal transient quantity protection scheme suitable for lines containing UPFC components.

[0031] In order to reduce the three-phase coupling effect in the power system, the Karenbauer transformation is used to decouple the currents of each phase. Since the line mode component can theoretically reduce the dispersion effect in the process of traveling wave propagation, the line mode component is used for analysis, that is, Im=Ia+Ic-2Ib. Since the busbar capacitance has a significant attenuation effect on the transient energy in the 50-100kHz frequency band, the sampling frequency is set to 200kHz. In order to accurately extract the energy change at the sudden change of the signal, the Db4 wavelet with better frequency division ability is selected to decompose the transient signal into three layers of discrete wavelets, and the low frequency components are counted as the fourth layer, which are respectively denoted as D1, D2, D...

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PUM

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26
CPCH02H7/261
Inventor 王增平吕哲
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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