Fast Judgment Method of Fault Current Based on Multiple Data Windows

Abstract

The invention relates to a fault current rapid judgment method based on multiple data windows. Its characteristic is that it includes the following steps: (1) Firstly, carry out proportional reduction of the current, and reduce the three-phase alternating current to a detectable standard, that is, 0-300mA; (2) carry out AD sampling of the alternating current, that is, the discretization of the analog signal , calculate and process the discrete signal; (3) perform sampling calculation on the processed signal; (4) perform fault detection in the form of multiple data windows on the obtained sampling value; (5) perform short-gate action or send out an alarm signal. The beneficial effects of the method of the present invention also include: 1. The time for redundant judgment can be greatly reduced. 2. Compared with the traditional method, the specific time point of the circuit failure can be obtained more accurately (the error is within 5ms). 3. The complexity of the algorithm is low, and the calculation pressure of the controller is small.

Description

technical field [0001] The invention relates to a fault current rapid judgment method based on multiple data windows. Background technique [0002] The most common and dangerous fault in electrical equipment is the occurrence of various forms of short circuit. The following consequences may occur when a short circuit occurs: 1. A large short-circuit current through the fault point and the ignited arc damage the faulty component. 2. Due to the action of heat and electromotive force, when the short-circuit current passes through non-faulty components, it will cause damage or shorten its service life. 3. The voltage in some areas of the power system is greatly reduced, which will damage the stability of users' electricity consumption or affect the quality of factory products. 4. Destroying the stability of parallel operation of the power system, causing system oscillation, and even disintegrating the entire system. Faults and abnormal operating conditions may cause accidents ...

AI Technical Summary

Problems solved by technology

[0002] The most common and dangerous fault in electrical equipment is the occurrence of various forms of short circuit. The following consequences may occur when a short circuit occurs: 1. A large short-circuit current through the fault point and the ignited arc damage the faulty component

2. Due to the action of heat and electromotive force, when the short-circuit current passes through non-faulty components, it will cause damage or shorten its service life

3. The voltage in some areas of the power system is greatly reduced, destroying the stability of users' electricity consumption or affecting the quality of factory products

4. Destroying the stability of the parallel operation of the power system, causing system oscillation, and even disintegrating the entire system

[0004] At present, many electrical equipment use full-wave Fourier transform and zero-sequence signal detection to make corresponding fault judgments. The two-stage full-wave Fourier method will make the entire judgment process greater than 40ms, that is, at least two Fu Lie’s frequency domain conversion, this method is first of all difficult to accurately locate the time when the fault occurs, its positioning accuracy is 20ms, and the judgment time from the occurrence of the fault to the detection of the fault is too long

The zero-sequence signal detection method refers to the detection of the zero-sequence signal in the three-phase circuit as the basis for fault judgment. After detecting the fault, it is still necessary to carry out the full-wave Fourier transform to determine and judge the fault, otherwise it is impossible to know the type of fault and which phase circuit the fault occurred in

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