A Residual Current Circuit Breaker with Self-tuning Function

Abstract

The invention relates to a residual current breaker with a self-tuning function. The residual current breaker comprises a power module, as well as a leakage mutual inductor, a signal amplifying module, a control module, a controllable silicon and a tripping device which are connected in series, wherein the leakage mutual inductor is connected with a three-phase circuit; the control module comprises a microprocessor with an EEPROM therein in which a set action value and a minimum value of a leakage induction signal in the last time period are saved; the leakage induction signals of the leakage mutual inductor are amplified by the signal amplifying module, and then sent to the control module; the microprocessor calculates the sum of the set action value and the minimum value of the leakage induction signal in the last time period to serve as a new set action value for comparing with an input leakage induction signal, if the leakage induction signal is larger than the new set action value, the microprocessor outputs a control signal to trigger the controllable silicon, and accordingly the tripping device acts to drive the breaker to trip. Compared with the prior art, the breaker has the self-tuning function, and can avoid false tripping caused by inherent leakage current.

Description

technical field

[0001] The invention relates to a circuit breaker, in particular to a residual current circuit breaker with self-adjusting function. Background technique

[0002] Residual current circuit breakers (leakage current circuit breakers) are widely used in power supply systems to protect people, equipment and lines. However, there are always inherent leakage currents in the user's electrical equipment and lines themselves, which are related to factors such as the length of the power supply line, cable structure, environment, and climate. The existence of inherent leakage current will not cause accidents to equipment lines and personal injury. However, the existence of inherent leakage current makes the protection of leakage circuit breakers inaccurate and even wrong. For example, the leakage operating current of a leakage circuit breaker is 30mA. If the inherent leakage current is 14mA, then the leakage current of 16mA occurs in the equipment line, and the leakag...

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