Circuit breaking protection circuit

Abstract

The invention discloses a circuit breaker protection circuit. The circuit breaking protection circuit includes a zero-sequence current transformer, a leakage current detection circuit, a peak detection circuit and a microprocessor. The zero-sequence current transformer is used to generate induction current according to the leakage current between the load system and the power system. The leakage current detection circuit is used for receiving the induced current and converting the induced current into a voltage signal. The peak detection circuit is used to detect the peak value of the induced current, and pull up the voltage signal when the peak value is greater than the saturation threshold. The microprocessor is used for receiving the voltage signal, and cutting off the power supply path between the load system and the power system when the voltage signal is greater than the voltage threshold.

Description

technical field [0001] The invention relates to a circuit break protection circuit, in particular to a circuit break protection circuit comprising a peak value detection circuit to compensate a leakage current detection circuit. Background technique [0002] Open circuit protection circuits often use zero-sequence current transformers (ZCT) to detect leakage current between the load system and the power system. However, due to the limitations of the magnetic material, coil characteristics or other parameters of the zero-sequence current transformer, Therefore, when the leakage current is large and the electromagnetic induction of the zero-sequence current transformer reaches saturation, the induced current generated by the zero-sequence current transformer may drop rapidly, and cannot linearly reflect the magnitude of the leakage current; thus , The open circuit protection circuit cannot cut off the line between the load system and the power system in real time, resulting in...

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Problems solved by technology

[0002] Open circuit protection circuits often use zero-sequence current transformers (ZCT) to detect leakage current between the load system and the power system. However, due to the limitations of the magnetic material, coil characteristics or other parameters of the zero-sequence current transformer, Therefore, when the leakage current is large and the electromagnetic induction of the zero-sequence current transformer reaches saturation, the induced current generated by the zero-sequence current transformer may drop rapidly, and cannot linearly reflect the magnitude of the leakage current; thus , the open circuit protection circuit cannot cut off the line between the load system and the power system in real time, resulting in leakage current that continues to affect the efficiency and safety of the system

[0003] The open circuit protection circuit in the prior art often tries to improve the linear operating range of the zero-sequence current transformer by replacing the magnetic material inside the zero-sequence current transformer or modifying the wire turn ratio. However, such modification methods are too time-consuming and may Unable to quickly adapt to the needs of various systems

In addition, the open circuit protection circuit in the prior art may also use the microprocessor to compensate the induced current output by the zero-sequence current transformer. However, this method requires a lot of experiments to develop algorithms suitable for different systems and microprocessors, and due to open circuit The protection circuit requires a highly stable algorithm, so it may also occupy a large amount of computing resources of the microprocessor and increase the complexity of the system

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