Method for longitudinal zero-sequence power direction protection of double circuit line on same pole

Abstract

The present invention discloses a method for longitudinal zero-sequence power direction protection of a double circuit line on a same pole, which comprises an own-side zero-sequence power direction criterion and an opposite-side zero-sequence power direction criterion, and the own-side zero-sequence power direction criterion is shown by a formula (I) while the opposite-side zero-sequence power direction criterion is shown by a formula (II), wherein 3I0M and 3I0N are zero-sequence currents of an M side and an N side of one loop, 3I0M' and 3I0N' are the zero-sequence currents of an M side and an N side of the other loop, 3UM0 and 3UN0 are bus zero-sequence voltages of an M side and an N side at a protective mounting part, Arg shows a subsequent phasor phase-taking angle, and K is a zero-sequence mutual inductance influence coefficient. By using the AND gate outputs of the two criterions, when the two formulae are satisfied at the same time, ground faults can be determined to appear in a protected area, and the criterions of the longitudinal zero-sequence power direction protection are acted.

Description

technical field [0001] The invention belongs to the field of electricity, and in particular relates to a longitudinal zero-sequence power directional protection method suitable for paralleling double-circuit lines on the same pole. Background technique [0002] Due to the advantages of narrow outlet corridor, large transmission capacity, low investment, quick effect, improved power supply reliability, simple operation and maintenance, etc., the double-circuit line on the same pole can be well adapted to the modern power system, which is reliable, economical, and large in power transmission capacity. and other requirements, has been widely used. There is not only an electrical connection but also a magnetic connection between the parallel double-circuit lines on the same pole. There is a large zero-sequence mutual inductance effect between the parallel double-circuit lines on the same pole. There is also a fault current flowing in the middle, and the voltage and current of t...

AI Technical Summary

Problems solved by technology

So far, the traditional zero-sequence power directional protection criterion for double-circuit lines paralleled on the same pole is to apply the zero-sequence power directional protection for single-circuit lines directly to double-circuit lines without using double-circuit lines as a Configured as a whole, when a fault occurs, the mutual inductance between the double circuit lines will cause the voltage and current interaction between the double circuit lines, which may lead to misjudgment or refusal of the zero-sequence power direction protection criterion. The zero-sequence power direction protection criterion lose direction

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