Method for distinguishing fault types of non-transposition same-tower double-circuit line

Abstract

The invention discloses a method for distinguishing fault types of a non-transposition same-tower double-circuit line. The method comprises the steps that firstly, when the non-transposition same-tower double-circuit line fails, voltage information and current information at the protection installation position of the non-transposition same-tower double-circuit line are collected in real time through a current transformer and a voltage transformer; secondarily, positive-phase-sequence identical-phase-sequence current components, positive-phase-sequence differential-phase-sequence current components, negative-phase-sequence identical-phase-sequence current components, negative-phase-sequence differential-phase-sequence current components, the zero-phase-sequence identical-phase-sequence current components and zero-phase-sequence differential-phase-sequence current components of the double-circuit line are extracted by using the six-sequence component conversion method, and the relative phase angle between the differential-phase-sequence components and the identical-phase-sequence components of positive-phase-sequence currents and the relative phase angle between the differential-phase-sequence components of negative-phase-sequence currents and the differential-phase-sequence components of the positive-phase-sequence currents are calculated; then whether the non-transposition same-tower double-circuit line has a same-name-phase crossing-line fault or a single-circuit-line fault or a non-same-name-phase crossing-line fault is judged. By means of the method, the single-circuit-line fault, the same-name-phase crossing-line fault and the non-same-name-phase crossing-line fault of the non-transposition same-tower double-circuit line can be distinguished correctly. Excellent fault distinguishing capacity can be still kept when non-transposition parameters and line parameters of the same-tower double-circuit line are seriously unsymmetrical.

Description

technical field [0001] The invention belongs to the technical field of electric power systems, relates to the technical field of phase selection for faults of double-circuit lines on the same tower without transposition, and specifically relates to a method for distinguishing fault types of double-circuit lines without transposition on the same tower. Background technique [0002] Due to the large transmission power of lines paralleled on the same tower, how to avoid the simultaneous removal of double-circuit lines when cross-line faults occur is an important issue that has been widely concerned in engineering applications. The solution to the above problems depends on fault selection with good performance. phase element. At the same time, the performance of the fault phase selection element has a direct impact on the correct operation of the automatic reclosing device. Therefore, it is of great theoretical and practical significance to study the fault phase selection elemen...

AI Technical Summary

Problems solved by technology

[0003] At present, for the research on phase selection of double-circuit faults on the same tower, except for the phase selection principle of six-sequence components, the rest of the phase selection schemes are improved on the basis of common phase selection principles. Complex fault phase selection requirements for tower double circuit lines

The phase selection principle of the six-sequence component can well identify various single-circuit faults and cross-line faults that occur on the double-circuit line on the same tower, and has a good phase selection effect, but it must use the electrical quantity of the two circuits, so Has not been field applied

However, in production practice, short-distance double-circuit lines on the same tower are often erected without transposition, which makes the phase-to-phase and line-to-line mutual inductance parameters asymmetrical, and also changes the fault characteristics of the six-sequence component in the ideal transposition

At this time, simply using the magnitude of the six-sequence component to distinguish the fault type becomes very unreliable, and it is difficult to meet the requirements of the fault phase selection element for the double-circuit line on the same tower without transposition in the high-voltage large power grid

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