Leakage protecting device

Abstract

The invention discloses a leakage protecting device, which not only can prevent electric-shock accidents caused by malfunctions of electric appliances, but also can prevent the electric-shock accidents caused by the accidental electrification of a ground wire and the abnormality of a power supply. The leakage protecting device is provided with a weak-current detection inductor, wherein a detection circuit which is formed by serially joining a primary winding of the weak-current detection inductor and a current-limiting resistance-capacitance element is arranged between the ground wire and a zero wire, the output ends of secondary windings of a zero-sequence current mutual inductor and the weak-current detection inductor are respectively connected with input ends of a first amplification circuit and a second amplification circuit, output ends of the first and the second amplification circuits are respectively connected with anodes of a first diode and a second diode, cathodes of the first and the second diodes are respectively connected with a trigger electrode of a controllable silicon, the anode and the cathode of the controllable silicon are respectively connected with the anodeand a common electrode on an output end of a rectifier circuit, and an electromagnetic coil is arranged between the anode and the common electrode on the output end of the rectifier circuit.

Description

technical field [0001] The invention relates to the technical field of electricity safety protection, in particular to an electric leakage protection device. Background technique [0002] The Chinese patent literature publication number is CN1142618C discloses a kind of earth leakage protection device which can be opened and closed. The earth leakage protection device is not only equipped with a zero-sequence current transformer through which both the phase line and the neutral line pass, but also has a ground wire through It is an electrified detection sensor for the over ground wire, so it can not only detect whether there is any residual current between the phase wire and the neutral wire at the load end, when the residual current between the phase and neutral wires reaches the preset threshold (for example: 10mA ), it will trip immediately and cut off the phase wire, neutral wire and ground wire; and when the ground wire is accidentally electrified due to an abnormal gro...

AI Technical Summary

Problems solved by technology

[0003] It can be seen from the above that the prerequisite for the existing leakage protection device to trip when the load end is faulty or the ground wire is accidentally electrified is that there must be a residual current between the load end phase and the neutral wire or there must be an accidental current flow on the load end ground wire. and the working power supply must be normal to trip, otherwise the protection cannot be realized

Therefore, the existing leakage protection device has the following defects: when in use, no matter when the ground wire of the grounding protection system is missing (for example: no grounding is caused by a virtual connection of the ground wire of the socket) and the insulation fault of the electrical appliance at the load end of the leakage protection device leaks, or When the grounding protection system is abnormal (for example: phase wire, grounding wire short circuit) and the grounding wire is accidentally electrified, it will cause the exposed metal parts of the electrical appliances to carry dangerous voltage, but they have not formed a loop, so there is no residual current or grounding. Therefore, although the exposed metal parts of electrical appliances have been charged with dangerous voltage, the existing leakage protection devices will not trip automatically in this case, only when the human body or livestock touch these charged parts When the exposed metal parts are exposed, the human body or livestock will form a circuit, resulting in residual current or ground wire accidental current, which will cause the leakage protection device to trip within 0.1S and disconnect the phase wire, neutral wire, and ground wire, although it can be released in time. The buckle protects the life safety of people or livestock, but in this case, the existing leakage protection device must first pass through the human body or livestock to generate residual current or ground wire accidental current and flow through the human body or livestock before it can trip. The phase wire, neutral wire, and ground wire are disconnected; at the same time, when the power end is abnormal (for example: when the power end phase wire or neutral wire is accidentally disconnected, or the power end phase wire and the ground wire are reversed), then the existing The electromagnetic tripping in the advanced leakage protection device and the electromagnetic coil of the locking device cannot generate electromagnetic force because there is no electricity, so the leakage protection device cannot trip, and the phase line contact, neutral line contact and ground wire will still be maintained. The contact is in the connected state. At this time, once the ground wire is accidentally electrified (for example: the phase wire and the ground wire are reversed) or the phase wire leaks, the leakage protection device cannot be tripped, so the phase wire contact and the neutral wire contact cannot be disconnected. Disconnected from the ground contact

[0004] In summary, the existing leakage protection devices may still cause electric shock casualties

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