Low-voltage power distribution network multi-point differential earth leakage protection method based on power distribution internet of things

Abstract

The invention discloses a low-voltage power distribution network multi-point differential earth leakage protection method based on a power distribution internet of things, and belongs to the field of power distribution network relay protection. Traditional residual current protection only utilizes in-situ residual current information, needs multi-stage cooperation, and is easy to cause maloperation and low in sensitivity. The low-voltage power distribution network multi-point differential earth leakage protection method based on the power distribution internet of things can be realized based on a power distribution internet of things platform, and comprises the following steps: arranging a protection device at the upstream of a protected section, subtracting the sum of the measured residual current amplitude and the measured residual current amplitude of each detection point of a downstream section, and taking the difference as an action criterion, so as to realize electric leakage protection. On one hand, the method can be fully combined with the power distribution internet of things technology to realize intelligent and informationized leakage protection; on the other hand, the influence of factors such as downstream unbalanced leakage current can be effectively overcome, and protection maloperation is reduced; in addition, the method does not need delayed cooperation, and the action speed is high; and a relatively low action threshold can be set, and the sensitivity is high.

Description

technical field [0001] The invention proposes a low-voltage distribution network multi-point differential leakage protection method based on the distribution Internet of Things, which is suitable for the low-voltage distribution network and belongs to the field of distribution network relay protection. Background technique [0002] As the "last mile" of the power system, the low-voltage distribution network has the characteristics of a wide variety of equipment, wide coverage areas, and uneven users. At the same time, it is limited by construction level and technical cost, and there are many risks of leakage failures. Leakage fault refers to the current leakage caused by insulation damage and other reasons, including personal electric shock and shell collision fault. According to the statistics of the National Bureau of Statistics, the national average annual electrocution death is about 8,000 people, of which more than 85% occur in the low-voltage distribution network, whil...

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Problems solved by technology

The document "Adaptive Leakage Protection Technology and Its Application" proposes an adaptive leakage protection technology. By analyzing the change of leakage current, the floating threshold is used to realize adaptive leakage overcurrent protection, but the effect is limited; the document "New Phase Discrimination "Research on Amplitude Discrimination Leakage Relay" puts forward the amplitude discrimination and phase leakage protection method, which comprehensively utilizes the change of residual current amplitude and phase to judge the leakage fault, which can reduce the action dead zone of residual current overcurrent protection, but its setting method is relatively complicated , and it is easy to misoperate when the load or line is switched; the literature "Research on Leakage Protection Method Based on Residual Current and Leakage Impedance" distinguishes the switching of leakage loads by observing the positive and negative characteristics of the real part of leakage impedance, and theoretically eliminates It is difficult to measure the leakage impedance directly

In general, the leakage faults and protection problems of low-voltage distribution network are becoming more and more prominent, and the existing leakage protection methods need to be further improved

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