A method and system for identifying grounding and phase-to-phase faults in a microgrid

A technology of interphase fault and identification method, applied in short-circuit test, continuity test and other directions, can solve the problems of slow operation speed, low reliability and insufficient sensitivity of microgrid, so as to improve the operation speed, solve the lack of sensitivity, and improve the operation speed The effect of reliability

Active Publication Date: 2021-12-28
NARI TECH CO LTD +4
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Problems solved by technology

[0005] The purpose of the present invention is to provide a method and system for identifying micro-grid grounding and phase-to-phase faults, so as to solve the problems of insufficient sensitivity, low reliability, and slow action speed in micro-grid protection caused by the prior art

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  • A method and system for identifying grounding and phase-to-phase faults in a microgrid
  • A method and system for identifying grounding and phase-to-phase faults in a microgrid
  • A method and system for identifying grounding and phase-to-phase faults in a microgrid

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Embodiment Construction

[0050] In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0051] The first aspect: if figure 1 , discloses a method for identifying microgrid grounding and phase-to-phase faults, the method comprising the following steps:

[0052] Step 1: Based on the negative-sequence electrical quantity being the fault characteristic quantity, collect the sampled current value and sampled voltage value of the measured point, and calculate the negative-sequence power frequency mutation value, negative-sequence voltage power-frequency mutation value, and negative-sequence current power frequency mutation value. Mutation value; the specific calculation method is as follows:

[0053]

[0054]

[0055]

[0056] In the above formula is the phase a voltage at the current sampling time, is the b-phase voltage at ...

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Abstract

The invention discloses a method and system for identifying faults between grounding and phase-to-phase of a microgrid, which collects the sampling current value and sampling voltage value of the measured point, and calculates the power frequency mutation value of negative sequence power, the power frequency mutation value of negative sequence voltage, and the power frequency mutation value of negative sequence voltage. Negative sequence current power frequency mutation value; collect the real-time load current and real-time load voltage value of the measured point, and calculate the negative sequence power floating threshold, negative sequence voltage floating threshold, and negative sequence current floating threshold; according to the negative sequence power working The frequency mutation value, negative sequence voltage power frequency mutation value, negative sequence current power frequency mutation value and negative sequence power floating threshold value, negative sequence voltage floating threshold value, and negative sequence current floating threshold value are compared one by one to determine the fault point ; This method improves the reliability of the protection action and the speed of the protection action of the microgrid.

Description

technical field [0001] The invention relates to a method and system for identifying grounding and phase-to-phase faults in a microgrid, and belongs to the technical field of electric power system relay protection. Background technique [0002] Due to the short circuit of the microgrid and the characteristics of multiple power sources, variable operation modes, and three-phase asymmetry, it is difficult to set the protection value caused by the protection range of the line and the coordination between adjacent lines with the overcurrent protection of the single-ended criterion. . The micro-power sources in the micro-grid are mostly connected by inverters, and their fault current is limited by semiconductor devices to within 2 times the rated current. Therefore, the fault current at the outlet of the micro-power source will not be as large as that of the traditional grid. When the micro-grid is running off-grid When there is only one micro-power supply, the maximum short-circ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/52G01R31/54
Inventor 李志坚张海滨郑玉平王伟梅德冬潘书燕刘辉宋鹏侯宇许广婷董璇孙蓉
Owner NARI TECH CO LTD
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