Low-voltage power distribution system leakage current fault monitoring method based on Hausdorff distance

Abstract

The invention discloses a low-voltage power distribution system leakage current fault monitoring method based on a Hausdorff distance, and belongs to the technical field of power distribution automation. The method is characterized by comprising the following steps: a, collecting and uploading residual current; b, numbering and storing the residual current in sequence; c, obtaining a mismatching matrix of the residual current sequence; d, judging whether a fault judgement condition is met or not, if so, executing the step e, and if not, executing step f; e, uploading the position of the faultsection; and f, enabling the section to run normally. According to the Hausdorff distance-based leakage current fault monitoring method for the low-voltage power distribution system, leakage current monitoring is realized by adopting an edge terminal, a Hausdorff distance algorithm is introduced by utilizing waveform difference degree characteristics of residual currents on two sides of a fault point, a distance value represents the difference degree of the residual currents between adjacent terminals, and a section where a fault is located is determined by utilizing a fault unified criterion.The recognition capability of the method is not affected by downstream normal residual current caused by various reasons, and the monitoring sensitivity is improved.

Description

technical field [0001] The invention discloses a low-voltage power distribution system leakage current fault monitoring method based on Hausdorff distance, which belongs to the technical field of power distribution automation. Background technique [0002] At present, the 0.4kV low-voltage distribution network at home and abroad mainly adopts residual current protection device (Residual Current Protective Device, RCD), also known as leakage protector, to realize electric shock protection. The leakage current protection of my country's low-voltage distribution network generally consists of two or three levels of protection, including general protection, intermediate protection, and terminal protection, to realize the selectivity of leakage current protection actions. However, the traditional residual current protection mostly adopts single-ended electrical value coordination. Under the TN-C-S grounding mode, external environmental factors and the three-phase unbalanced curren...

AI Technical Summary

Problems solved by technology

The disadvantage of the amplitude comparison method is that when the three-phase residual current is unbalanced, there are insensitive action areas and over-sensitive action areas, and it does not have the function of distinguishing the electric shock current of the human body from the residual current of the line, etc., which affects the reliability and safety of the electric shock protection device. correct delivery rate

The disadvantage of the current pulse method is that when the sudden unbalanced current (not the residual fault current) reaches a certain value, it may cause the residual current protection device to malfunction, and the protection device has many measurement and control circuit links and high cost

The disadvantages of the amplitude and phase detection method are: the phase modulation signal and the reference signal will still be affected by the amplitude; there is still a protection dead zone; the protection device is large in size, and it is difficult to make a small household circuit breaker type, which is generally used as a leakage relay; The structural form is relatively monotonous, the electronic circuit is more complex, and the cost is the highest

The disadvantage of the phasor mutation method is that when the residual current amplitude of the line is relatively large (such as reaching hundreds of mA) during normal operation, the error of the calculated residual current phasor mutation is still large due to the influence of measurement and calculation errors

Its algorithm is complicated, the circuit is complicated, and the cost is high. It is still in the stage of research and development and function improvement, and there is still a long way to go before it is officially put into production and operation.

[0007]In addition to the above-mentioned various methods and defects, the current traditional residual current monitoring method mostly adopts single-ended electric quantity and numerical value coordination during the implementation process, and cannot ignore the downstream The influence of normal residual current leads to frequent misoperation of residual current protection devices, so the sensitivity is low

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