Phase selection method for faults of double-circuit lines on same tower

Abstract

The invention discloses a phase selection method for faults of double-circuit lines on the same tower. The method includes the steps that the fault types and the fault phases are judged according to sequence voltage and voltage between phases, and different criteria are adopted for judging the physical fault phase of the local lines according to the fault type; the interphase impedance criterion and the ground impedance criterion are adopted for the two-phase grounding faults; the interphase impedance criterion and the impedance direction criterion are adopted for the two-phase non-grounding faults; the three-phase impedance direction is adopted for the three-phase faults. The phase selection method is simple and reliable in principle, the phase can be selected correctly under the single-return-wire faults and the overline faults, and the practical and feasible phase selection method is provided for protecting the lines on the same tower.

Description

technical field [0001] The invention relates to a phase selection method for faults of double-circuit lines on the same tower, and can also be used for other types of lines on the same tower. Background technique [0002] With the development of my country's power grid construction, the same-tower transmission technology has been widely used due to its advantages of small footprint, narrow transmission corridor, low investment cost, and large transmission capacity. Compared with traditional transmission lines, the same-tower line has the characteristics of large number of conductors, short distance between loops, and various operation modes, which makes its fault types and fault transient characteristics far more complex than single-circuit lines. Taking double-circuit lines on the same tower as an example, there are 98 types of cross-line faults, accounting for about 82% of all fault types. According to domestic and foreign operating experience, the probability of cross-lin...

AI Technical Summary

Problems solved by technology

The cross-line fault of the same-tower line brings new challenges to the protection phase selection. The existing phase-selection scheme of the same-tower line has the problems of incomplete identification criteria for cross-line, complex logical judgment, and wrong selection. In severe cases, it will lead to protection rejection movement, malfunction, endangering the safe and stable operation of the power grid

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