DC leakage current detection and protection circuit and detection and protection method

Abstract

The invention discloses a DC leakage current detection and protection circuit and a detection and protection method. A detection circuit used for detecting a difference value between an output current and an input current of a DC power supply, a difference value signal amplification and comparison circuit, a relay interlocking and thyristor (SCR) control protection circuit and a DC leakage protection testing circuit are adopted. According to the DC leakage current detection and protection circuit and the detection and protection method, the leakage current is detected by adopting the method of measuring the sampling resistance drop difference value, so the anti-interference capability of the circuit is guaranteed; the voltage drop difference value is amplified through a differencing circuit formed by an operational amplifier, and a leakage protection control signal is outputted through a comparison circuit formed by a precise stabilized power supply TL431. When the leakage current exceeds the maximum allowable value, power supply of a load is cut off through a relay and a thyristor. The DC leakage current detection and protection circuit and the detection and protection method integrate the functions of DC leakage current detection and open circuit protection, and have the advantages of being high in precision and reliability, strong in anti-interference capability, easy to install, convenient to debug, and the like.

Description

technical field

[0001] The invention relates to a DC leakage current detection and protection circuit and a detection and protection method. Background technique

[0002] Currently, DC power supplies are widely used. The DC leakage detection and protection circuit can ensure the safety of equipment and personnel when leakage occurs in the DC circuit. DC screen is the abbreviation of DC operating power system. Simply put, a DC screen is a device that provides a stable DC power supply. The power operating power supplies in power plants and substations are all DC power supplies today, which provide power for control loads, power loads, and DC accident lighting loads, and are the basis for control and protection of contemporary power systems. DC leakage is one of the common faults of DC operating power supplies in power systems, which may cause malfunctions of signaling devices, control circuits, and relay protection devices, or trip circuit breakers. Therefore, it is necess...

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