Residual current protection device

Abstract

A residual current protection device, comprising: a first detection magnetic core (107) and a second detection magnetic core (108) which are borne around a conducting wire of a main loop; a first fault current detection circuit (102) coupled with the first detection magnetic core (107), wherein the first fault current detection circuit (102) is dependent on a grid voltage and conducts full current sampling on the main loop, so as to detect a high-frequency alternating current fault residual current, a pulse direct current residual current and a smooth direct current residual current; a second fault current detection circuit (103) coupled with the second detection magnetic core (108), wherein the second fault current detection circuit (103) conducts electromagnetic current sampling on the main loop independent of the grid voltage, so as to detect a power-frequency alternating current residual current and a pulse direct current residual current; a drive circuit (104), wherein the input thereof is connected to the first fault current detection circuit (102) and the second fault current detection circuit (103), and the output thereof is connected to an executing mechanism (106) to trigger the executing mechanism (106) to act; and a bipolar power source module (105) connected to the main loop and the first fault current detection circuit (102).

Description

technical field [0001] The present invention relates to a current protection device, more specifically, to a residual current protection device sensitive to full current. Background technique [0002] Realizing current protection by monitoring the residual current is an important protection measure in electrical circuits. The existing technology mainly uses the excitation circuit to generate high-frequency current in the magnetic core, thereby generating a high-frequency magnetic field. When the primary coil has low-frequency or DC current When, it can cause the change of the saturation degree of the magnetic circuit and the deviation of the high-frequency magnetic field to measure the DC current. [0003] For example, the Chinese patent application with publication number CN1387213A titled "Detection Transformer for Earth Leakage Protection Device and Earth Leakage Protection Device" discloses an earth leakage fault current detection transformer in the form of an annular ir...

AI Technical Summary

Problems solved by technology

The defect of CN1387213A is that complex circuits such as integral circuit and saturation detection module are used, which increases the cost and complexity of the circuit

US4,276,510 requires a third coil and a complex analog circuit, which greatly increases the difficulty and cost of implementation and affects the detection accuracy

[0006] To sum up, the excitation circuits used in the prior art usually require high electric power and have complex structures, which greatly increase the cost of the circuit, and are accompanied by large losses and severe heat generation. In addition, more complex excitation circuits are not applicable Small size design and electromagnetic compatibility for miniature circuit breakers

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