A comprehensive phase selection method for double-circuit lines paralleled on the same tower

Abstract

The invention relates to the technical field of relay protection, and relates to a comprehensive phase selection method for double-circuit lines paralleled on the same tower: using the six-sequence component method to eliminate the mutual inductance current between the phases; according to the transformed six-sequence component, First distinguish the ground fault and non-ground fault, and then select the fault phase according to the following steps: According to the current amplitude characteristics of the single circuit fault, the non-identical phase cross-line fault and the same name phase cross-line fault, distinguish the non-identical phase span line fault, single circuit fault and phase line fault with the same name; for a single circuit fault, the phase angle of the positive and negative zero-sequence components in the same direction is 0° or 180° from the two The fault line is selected from three lines, and then the phase selection is carried out according to the negative sequence and zero sequence current phase selection principles; for the cross-line faults of the same name phase and non-same name phase, the fault type is judged respectively. The invention can make up for the disadvantages of incomplete phase selection function and even wrong phase selection of other phase selection methods currently used on double-circuit lines.

Description

technical field [0001] The invention relates to the field of relay protection of power systems, in particular to a fault phase selection method for double-circuit power transmission lines paralleled on the same tower in a power transmission network. Background technique [0002] The double-circuit line on the same tower has the advantages of less investment, saving land and unit corridors, and large transmission capacity. It is currently widely used in the transmission network of 220kV and above voltage levels in my country. The faults of double-circuit lines on the same tower are very complicated. There are 120 types of faults, including 22 types of single-circuit faults and 98 types of cross-line faults. According to the requirement of dual main protection, in addition to installing two sets of split-phase longitudinal differential protection parallel outlets using single-circuit electric power for double-circuit lines on the same tower, it is also necessary to install sec...

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Problems solved by technology

Zero-sequence negative-sequence current phase selection [6～7] It adopts the principle of phase selection based on the relative phase relationship of fault current sequence components, and has the advantages of being less affected by fault transition resistance and not affected by load current, but it will cause wrong phase selection when used in double-circuit lines on the same tower.

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