Transmission line fault direction element

Abstract

The present invention provides a transmission line fault directional element, including: a wave head polarity acquisition unit 100, which respectively obtains the wave head polarities MMIα, MMIβ, and MMIγ of the three current modulus fault transient traveling waves of the transmission line; the initial polarity The characteristic acquisition unit 200 respectively acquires the initial polarities Sα, Sβ, and Sγ of the power frequency components in the three voltage modulus fault transient traveling waves of the transmission line; the comparison unit 300 compares the three current modulus fault transient The wave head polarities MMIα, MMIβ, MMIγ of the state traveling wave are compared with the initial polarity of the power frequency component in the voltage fault transient traveling wave corresponding to the modulus, and the fault direction of the transmission line is determined according to the judgment result . Therefore, the long-standing problem that the capacitive voltage transformer cannot transmit the wave head of the transient traveling wave of the voltage fault and cannot form a traveling wave fault directional element and traveling wave directional protection that can be applied to the actual power system is solved.

Description

technical field [0001] The invention relates to the technical field of relay protection and fault detection of power systems, in particular to the field of fault direction detection of power transmission lines. Background technique [0002] The parameters of high-voltage transmission lines, especially EHV and UHV long-distance transmission lines, have obvious distribution parameter characteristics. The traditional relay protection based on power frequency electrical quantities is affected by factors such as the distributed capacitance of the transmission line and the saturation of the current transformer, and cannot accurately detect faults on the line. But in fact, the fault transient traveling wave after the fault contains a wealth of fault information. The voltage fault transient traveling wave head and current fault transient traveling wave head signal after a fault is a signal with a wide spectrum range, and it is a signal of the whole frequency domain in theory. As e...

AI Technical Summary

Problems solved by technology

However, the existing research shows that the current transformer used in the power system can effectively transmit the transient traveling wave of the fault current, and the voltage transformer widely used in the power system 220kV and above voltage level - capacitive voltage transformer, It can only transmit and transform the voltage signal of a very narrow frequency band around the operating frequency of the power system (50Hz or 60Hz), and cannot effectively transform the transient traveling wave head of the fault voltage fault on the primary side of the power system to the secondary side of the transformer

Therefore, fault direction detection and directional protection based on voltage fault transient traveling waves and current fault transient traveling waves cannot be realized, which is also an unresolved technical problem in the field of power system traveling wave protection research for many years

Images