Low-voltage line electric shock fault judgment method based on triple combination criterion and residual current circuit breaker

Abstract

The invention relates to the field of low-voltage line leakage protection, and discloses a low-voltage line electric shock fault judgment method based on a triple combination criterion and a residual current circuit breaker. According to distribution characteristics of residual current in a transformer area, a current harmonic amplitude change rule during an electric shock fault is studied, two indexes of an even harmonic change rate and a power frequency variation are defined, and a combination criterion combining an even harmonic change rate minimum threshold value, a power frequency change quantity threshold value and a residual current setting value is provided. The triple combination criterion provided by the invention is not only suitable for detecting the occurrence of a fault, but also can detect the situation that the fault disappears, when the third-stage line has a fault, the third-stage residual current circuit breaker acts to break the branch line, at the moment, the second-stage residual current circuit breaker detects that the fault disappears after a certain period of time and does not act, and the fault disappears. An electric shock fault can be better identified, frequent maloperation of the residual current circuit breaker is reduced, and a power grid system can operate more reliably.

Description

technical field [0001] The invention relates to the field of leakage protection of low-voltage lines, in particular to a method for judging electric shock faults of low-voltage lines based on triple combination criteria and a residual current circuit breaker. Background technique [0002] The residual current circuit breaker is one of the main protectors for low-voltage safe electricity use. For the circuit where the electric shock fault occurs, the residual current protector is required to disconnect the circuit in time to protect the safety of the human body. However, in practical applications, the circuit breaker has the problem of malfunction. Because the traditional residual current circuit breaker judges the fault by the method that the operating current exceeds the setting value of the residual current circuit breaker, and in some station areas, the leakage current of the line itself is very large, resulting in the normal line, the operating current is still due to s...

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Problems solved by technology

[0004] Technical purpose: This invention proposes a low-voltage line electric shock fault judgment method and residual current circuit breaker based on the triple combination criterion, aiming at judging electric shock faults of the power grid and improving residual current circuit breaker malfunctions and other issues

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