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Voltage phase fluctuation characteristic based single-phase permanent fault identification method

A technology with permanent faults and fluctuation characteristics, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve the problems that have not been widely promoted and the accuracy is not high, and achieve a small amount of calculation, accurate judgment, and simple principle Effect

Inactive Publication Date: 2019-03-08
TIANJIN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, the accuracy of adaptive reclosing discrimination at home and abroad is not high, and it has not been widely promoted.

Method used

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  • Voltage phase fluctuation characteristic based single-phase permanent fault identification method
  • Voltage phase fluctuation characteristic based single-phase permanent fault identification method
  • Voltage phase fluctuation characteristic based single-phase permanent fault identification method

Examples

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Comparison scheme
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Embodiment Construction

[0030] Such as figure 1 Shown is a schematic diagram of an EHV / UHV transmission line. The transmission line is connected to two equivalent grid systems m and n, and the line side voltage connected to the m system is U m , the voltage connected to the n side is U n .

[0031] Take the adaptive reclosing device on side m as an example when the line protection judges that a phase A ground fault occurs on the line and operates after the phase A trips:

[0032] (1) Acquire the three-phase voltage u on this side A , u B , u C , three-phase current i A i B i C .

[0033] (2) After the three-phase voltage on the local side to be sampled meets the time window requirements of the Fourier algorithm, the voltage phasor on the line m side can be calculated and voltage phasor

[0034] (3) will improve the phase voltage and Substitute into formula (1) to calculate the polarization voltage

[0035]

[0036] (4) calculation and The amplitude Uma, U mp .

[0037] (5...

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Abstract

The invention relates to a voltage phase fluctuation characteristic based single-phase permanent fault identification method. The method includes the following steps: calculating polarization voltageaccording to sound phase voltage; calculating the phase difference of the sound phase voltage and the polarization voltage; calculating a phase deviation sequence; setting the following criteria: a, avoltage amplitude threshold; b, a proportion threshold; c, a polarization voltage threshold; and d, a phase fluctuation threshold; maintaining the permanent fault flag location in a reclosing devicebeing 0 when the above criteria are put into operation at the same time after single-phase tripping, and judging whether a, b and c are satisfied when fault property identification is performed; not judging the threshold d if any one of the a, b and c is not satisfied, and maintaining the permanent fault flag location in the reclosing device being 0; and judging whether the threshold d is satisfied if the a, b and c are satisfied, and maintaining the permanent fault flag location being 1 if yes.

Description

technical field [0001] The invention relates to the field of power system protection and control, in particular to a permanent fault identification method. Background technique [0002] Among the faults of EHV / UHV transmission lines, more than 70% are single-phase ground faults, most of which are instantaneous. In this case, the single-phase automatic reclosing technology that only trips the faulty phase and delays the reclosing is widely used in the overhead lines of the power system, and effectively guarantees the reliable power supply and safe operation of the power system. However, conventional single-phase automatic reclosing devices generally do not have the ability to identify transient faults and permanent faults. When reclosing is performed on permanent faults, the secondary short-circuit current is more harmful to system stability and equipment insulation performance than single-phase grounding. The failure is even more serious. Therefore, if the locking of the r...

Claims

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Application Information

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IPC IPC(8): G01R31/00
CPCG01R31/00
Inventor 李斌郭子煊姚斌
Owner TIANJIN UNIV
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