Phase selection method for double circuit lines on the same pole

Abstract

The invention discloses a phase selection method for double-circuit lines on the same pole, and the technical problem to be solved is to improve the phase selection accuracy of double-circuit lines on the same pole. The present invention adopts the following technical solutions: a phase selection method for a double-circuit line on the same pole, including the following steps: 1. Judgment on input of cross-line phase selection, and the protection device enters cross-line phase selection judgment; ; 3. Satisfy the negative-sequence voltage judgment criterion; 4. Detect cross-line two-phase faults, and the phase selection ends. Compared with the existing technology, the present invention can greatly improve the accuracy of phase selection when a cross-line fault occurs based on various impedance characteristics, and is not affected by the channel, and can be applied to longitudinal protection and distance protection. It is easy to implement in electrical protection, ensuring the reliability and sensitivity of the action.

Description

technical field [0001] The invention relates to a method for protecting a power transmission line in a power system, in particular to a phase selection method for a cross-line fault of a double-circuit line on the same pole. Background technique [0002] As the power grid structure becomes tighter and the outlet corridors become less and less, erecting double-circuit lines or even four-circuit lines on the same pole has been widely used. Due to the short distance between the transmission lines of the double-circuit line on the same pole, there may be a fault across the outgoing line. The operating experience of power systems at home and abroad shows that the probability of cross-line faults accounts for 10% to 20% of the total number of faults. Phase selection for cross-line faults of double-circuit lines on the same pole has always been a major problem in line protection. The existing technology uses differential current elements for phase selection. In longitudinal and di...

AI Technical Summary

Problems solved by technology

Phase selection for cross-line faults of double-circuit lines on the same pole has always been a major problem in line protection. The existing technology uses differential current elements for phase selection. In longitudinal and distance protection, differential current elements cannot be used for phase selection, and the channel It cannot be applied when there is a problem

The phase selection method of the prior art can still accurately select the phase when the near-end fault is selected across the line, but it is really helpless for the remote fault. It is extremely detrimental to the safe and stable operation of transmission lines

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