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

A zero-sequence power and directional protection technology, applied in the electrical field, can solve the problems of double-circuit configuration, misjudgment or refusal of zero-sequence power directional protection criterion, loss of directionality of zero-sequence power directional protection criterion, etc. The effect of improving accuracy and improving the accuracy of judgment

Inactive Publication Date: 2009-12-02
XJ ELECTRIC +1
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  • Abstract
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  • Application Information

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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

Method used

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

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Example Embodiment

[0023] figure 1 , when a single-phase grounding fault occurs in the I-circuit inside the double-circuit line paralleled on the same pole, the zero-sequence voltage of the busbar on the M side is:

[0024] U · M 0 = U · 0 + α I · 01 Z 0 - - - ( 3 )

[0025] where: is the zero-sequence voltage of the M-side busbar, is the zero-sequence current on the M side of line I, is the zero-sequence voltage at the ground point, Z 0 is the zero-sequence impedance of the line, α is the ratio of the short-circuit point distance to the length of the entire line; the zero-sequence voltage of the N-side bus is

[0026]

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Abstract

The 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

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Claims

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Application Information

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Owner XJ ELECTRIC
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