Three-phase variable leakage current protective device

Abstract

The invention discloses a three-phase variable leakage current protective device, belonging to the field of protective devices used for protecting safeties of persons and electrical apparatuses. The device comprises a slowly-changing signal forming circuit, a signal amplifier circuit, a memory circuit, a clock circuit, a phase variable decomposer circuit, a positive / negative leakage current identifier circuit, a 150Hz square wave, an action current presetting device circuit, a break-time presetting device circuit, a time delay monostable circuit, a switch on / off mechanism and a self-restoring time presetting device circuit. Compared with the prior art, the three-phase variable leakage current protective device has the advantages that: the break time can reach the standard and no override trip occurs, no negative leakage trip occurs, the self-restoring mode is randomly selected by users according to local situations, special testers are configured, the power-on test is realized, and the like.

Description

technical field [0001] The utility model relates to a three-phase phase variable leakage current action protector, which belongs to the field of protective equipment for protecting personal and electrical safety. Background technique [0002] In the three-phase or three-phase four-wire low-voltage power grid, in order to ensure the safety of people and equipment, leakage protection measures are adopted. The leakage protector must be able to operate quickly and accurately when the personal electric shock or the line leakage exceeds the allowable value. When the power is turned on, the current leakage protector usually has the function of electric shock leakage protection, but the main problem still exists in the protection dead zone (blind zone), such as when there is leakage in one of the three phases A, B, and C, the other two phases The protection will fail, lose the protection function or have a large error in the protection function, and there is also the defect of tripp...

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Problems solved by technology

[0003] After retrieval, the current similar products have the following problems: 1. None of them can realize no dead zone leakage protection; 2. The breaking time is not up to standard; 3. There is a defect of negative leakage signal tripping; 4. The number of self-recovery times cannot realize humanized management ;5. There will be several times of tripping and power failure during the regular inspection of the leakage protector in online operation

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