Electricity leakage protection plug

Abstract

The invention discloses an electricity leakage protection plug. The plug can not only prevent electric shock accidents caused by electrical appliance faults, but also prevent electric shock accidents caused by accidental electrification of ground wires. The plug is also provided with a weak current detection sensor, wherein a primary winding and a secondary winding of the weak current detection sensor are insulated from each other and are wound on an iron core of the weak current detection sensor; a detection loop formed by series connection of the primary winding and a current-limiting and capacitance-resisting element is connected between a ground wire and a null wire; a drive circuit of an electromagnetic coil is also provided with a second SCR; one output end of the secondary winding of the weak current detection sensor is connected with the trigger electrode of the second SCR and the other output end of the secondary winding is connected with the anode of a first clamp diode; theanode and cathode of the second SCR are respectively connected with the anode and cathode at the output end of a rectifying circuit; and the output ends of a secondary winding of a zero-sequence current transformer are respectively connected with the input end of the drive circuit of the electromagnetic coil in parallel.

Description

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

AI Technical Summary

Problems solved by technology

[0003] It can be seen from the above that the prerequisite for the existing leakage protection plug 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. Therefore, the existing leakage protection plug has the following defects: when in use, whether the ground wire in the grounding system is missing (for example: the socket ground wire is falsely connected to cause no grounding) and the insulation failure of the electrical appliances at the load end of the leakage protection plug Leakage, or when the grounding system is abnormal (for example: short circuit of phase wire and ground wire) causes the ground wire to be electrified accidentally, 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 Therefore, although the exposed metal parts of electrical appliances have been charged with dangerous voltage, the existing leakage protection plugs will not automatically trip in this case, only when the human body or livestock touch these already brought When the exposed metal parts are powered on, a loop is formed through the human body or livestock, resulting in residual current or accidental current in the ground wire, which makes the leakage protection plug trip within 0.1S and disconnects the phase wire, neutral wire, and ground wire. It can be tripped in time to protect the life safety of people or livestock, but in this case, the existing leakage protection plug 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 Tripping disconnects the phase wire, neutral wire, and ground wire, so the existing leakage protection plug will still cause electric shock accidents to humans or livestock

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