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Method of using negative sequence voltage to lock broken line power transmission line

A negative-sequence voltage and transmission line technology, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve the problems that affect the discrimination results and the mutual inductance between the zero-sequence component lines.

Inactive Publication Date: 2017-11-24
NR ELECTRIC CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its disadvantage is that in multi-circuit transmission lines, the zero-sequence component is greatly affected by the mutual inductance between lines, which easily affects the discrimination results

Method used

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  • Method of using negative sequence voltage to lock broken line power transmission line
  • Method of using negative sequence voltage to lock broken line power transmission line
  • Method of using negative sequence voltage to lock broken line power transmission line

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Embodiment Construction

[0026] The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0027] Such as figure 1 As shown, the present invention provides a method for locking a broken transmission line using negative sequence voltage. On the premise that the transmission line has judged that there is a broken line fault in the nearby power grid, the following steps are performed:

[0028] Step 1, collect the three-phase current on the local side of the transmission line three-phase voltage and the opposite three-phase current three-phase voltage

[0029] Step 2, convert the three-phase current and three-phase voltage on both sides of the line into negative-sequence current and negative-sequence voltage respectively:

[0030] Negative sequence current on this side

[0031] Negative sequence voltage on this side

[0032] opposite side negative sequence current

[0033] opposite side negative sequence voltage ...

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Abstract

The invention discloses a method of using a negative sequence voltage to lock a broken line power transmission line. The method comprises the following steps of step1, collecting a three-phase current and a three-phase voltage of a local side of a power transmission line and converting into a negative sequence current and a negative sequence voltage; step2, calculating a negative sequence voltage reckoning value of an opposite side when the power transmission line is hypothesized not to be broken, and sending the negative sequence voltage reckoning value to the opposite side; step3, receiving a local-side negative sequence voltage reckoning value sent by the opposite side; and step4, calculating a difference of a local-side actual negative sequence voltage and the negative sequence voltage reckoning value sent by the opposite side and determining whether the power transmission line is a broken line. The method is not influenced by a mutual inductance among multiple loop lines, and accuracy of a determination result is increased, which is good for relay protection to selectively cut a broken line fault.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, in particular to a method for locking broken transmission lines by using negative sequence voltage. Background technique [0002] In the large current grounding system, the single-phase or two-phase disconnection of the transmission line belongs to the phase failure state, which is different from the transverse fault formed by the short circuit, and belongs to the longitudinal fault. Although the disconnection fault is not as serious as the short-circuit fault, it also has a certain impact on the operation of the rotating electrical machine and the system and the relay protection. If the disconnection fault cannot be effectively removed, the line will be in a non-full-phase operation state, and the negative-sequence and zero-sequence currents that appear may cause the relay protection of the power system to leapfrog action, resulting in the expansion of the blackout range...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/02
CPCG01R31/50G01R31/58
Inventor 赵青春谢华陆金凤沈军徐晓春
Owner NR ELECTRIC CO LTD