Current change rate-based coal mine power grid short-circuiting fault quick judging device and method

A technology of current change rate and short-circuit fault, which is applied in the field of rapid judgment device for short-circuit fault of coal mine power grid based on current change rate, can solve the problems of phase angle speed limit and limit, and achieve the effect of fast change speed and significant change

Active Publication Date: 2016-05-11
HENAN POLYTECHNIC UNIV
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Problems solved by technology

However, the speed of phase angle sampling is limited, and there is a certain "dead zone", so the application is limited

Method used

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  • Current change rate-based coal mine power grid short-circuiting fault quick judging device and method
  • Current change rate-based coal mine power grid short-circuiting fault quick judging device and method
  • Current change rate-based coal mine power grid short-circuiting fault quick judging device and method

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Effect test

Embodiment 1

[0033] Coal mine power grid short-circuit fault rapid judgment device based on current change rate, the device includes current signal acquisition part, signal conversion processing part, calculation and judgment part and man-machine interface part, the system structure is as follows figure 1 shown.

[0034] The signal acquisition part consists of a current transformer CT installed on each line, which is responsible for collecting the current on the line, and the CT converts the large current of the line into a small current.

[0035] The signal conversion processing part is composed of a current transmitter, a multiplexer, a sample holder and an analog / digital (A / D) converter. This part collects the current signal on each line in turn and sends it to the CPU for judgment and calculation.

[0036] Among them, the current transmitter further adjusts the current signal, and converts the current signal on the secondary side of the CT into a weak current signal acceptable to the e...

Embodiment 2

[0043] A rapid judgment method for short-circuit faults in coal mine power grids based on the rate of current change, such as figure 2 , 3 , 4, 5, 6, and 7, it is mainly used to judge the short-circuit fault of the coal mine power grid. In the judgment process, the method mainly includes four stages of judgment calculation: the first stage, the calculation of the first-order derivative of the current; the second stage, the first-order current derivative Judgment of the zero-crossing point of the order derivative; the third stage, the judgment of the first order derivative of the current; the fourth stage, the calculation and judgment of the second order derivative of the current; first enter the first stage, continuously calculate the current change rate of the coal mine power grid line; then enter the second stage , to judge whether the first-order derivative crosses zero, if the first-order derivative crosses zero, enter the fourth stage, and start the calculation of the se...

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Abstract

The invention relates to a current change rate-based coal mine power grid short-circuiting fault quick judging device and method. The method includes the following four stages of judgment calculation: stage 1, current first-order derivative calculation; stage 2, current first-order derivative zero point crossing judgment; stage 3, current first-order derivative judgment; and stage 4, current second-order derivative calculation and judgment. The method specifically includes the following steps that: the current change rate of a coal mine power grid line is calculated uninterruptedly; whether a first-order derivative crosses a zero point is judged, if the first-order derivative crosses the zero point, the method enters the stage 4, current second-order calculation is started; if the first-order derivative does not cross the zero point, the method enters the stage 3, the first-order derivative is compared with a previous current change rate calculation result, if the current first-order derivative exceeds a set change range, it is judged that a short-circuiting fault occurs, otherwise, the method enters the stage 1, first-order derivative calculation is further executed; and a current second-order derivative is calculated, and is compared with a previous current change second-order derivative, if the current second-order derivative exceeds a set range, it is judged that a short-circuiting fault occurs, and corresponding operation is carried out, otherwise, the method returns to the stage 1. The current change rate-based coal mine power grid short-circuit fault quick judging device and method provided by the invention can quickly and accurately find faults at the moment when short-circuiting occurs.

Description

technical field [0001] The invention relates to the field of coal mine power grids, in particular to the field of coal mine relay protection devices and coal mine power grid short-circuit fault judgments, and in particular to a coal mine power grid short-circuit fault rapid judging device and method based on current change rate. Background technique [0002] With the continuous increase of the capacity of underground equipment in modern coal mines, the short-circuit current value is also rising when the coal mine power grid fails. The short-circuit current of some branches in the underground power grid has approached or even exceeded the breaking capacity of the underground switch. operation of the grid. The thermal shock and electromotive force generated by the strong short-circuit current are very destructive. Therefore, finding the short-circuit fault as early as possible and cutting off the fault point before the short-circuit current reaches the maximum value can not on...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 赵铁英刘俊领王玉梅杨明杜少通
Owner HENAN POLYTECHNIC UNIV
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