SU851594A1 - Method of detecting short-circuiting in electric power system distributing boards - Google Patents

Description

(54) METHOD FOR DETECTING ARC SHORT CIRCUITS IN THE DISTRIBUTIVE BOARDS OF ELECTRIC POWER SYSTEMS

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This invention relates to relay protection of alternating and direct current electrical power systems.

The known method of detecting arc j short circuits is based on controlling the intensity of the radiation flow of an electric arc {Jl

A disadvantage of this device is its low speed. | Q

The closest to the proposed technical means and the achieved result is a method for detecting arc short circuits in distribution boards (RSC) of power systems, based on controlling the intensity of the arc radiation flux.

The disadvantage of this method is low noise immunity.

The purpose of the invention is to improve the robustness.

This goal is achieved by the fact that in the proposed method, the intensity of the radiation flow of an electric arc of a short circuit is attenuated by an amount determined by the intensity of the flow of radiation of an arc that occurs in electric devices when the currents of metal short circuits are turned off and whether

attenuated flow judged the occurrence of an arc short circuit.

The drawing shows a block diagram of one possible device, explaining the method.

The device consists of a PD photo sensor placed inside the switchboard, the optical system OC of attenuation of the radiation flux installed at the entrance of the FD, the control unit of the control unit controlling the magnitude of the attenuation coefficient of the optical system of the operating system, the reactive organ RO. The electric arc radiation flux, weakened by the OS, enters the PD input, is converted into an electrical signal, and is applied to the RO. For each value of the arc current, the value of the OS attenuation coefficient is set at which the intensity of the short-circuit electric arc (CZ) radiation flux is attenuated by an amount equal to the intensity of the arcing radiation flux.

Claims (2)

As a control parameter, in addition to the arc current, the strength of its magnetic field, as well as the power of the electric arc, can be used. An example of an OS with an adjustable attenuation coefficient is a system consisting of a Farade cell (or a Kerr cell), at the input of which a polarizer is installed, and an analyzer is installed at the output, with their polarization planes parallel. After passing through the polarizer, the radiation is polarized and enters the input of the Farad cell, in which the polarization plane is rotated. Depending on the rotation of the polarization plane in the Farad cell, depending on the strength of the magnetic field in the cell, the radiation is attenuated by the analyzer to a greater or lesser degree. The device works as follows. In the absence of an electric arc in the PR, the OS attenuation coefficient has a value corresponding to the current of the protected network section. As soon as an electric arc arises in the RC, the OS attenuation coefficient under the action of the signal. If a switch-off arc arises in the RCB of a specific current value, then the radiation flux of it, the passage through the OC, the full-cavity weakens, therefore the signal at the PD output is close to zero and does not cause PO to turn on. The device does not work. If an electric short circuit arises in the RC, with the same current value, then at the PD output the signal will exceed the pickup setting PO, since the intensity of the radiation flow of the arc of the arc greatly exceeds the intensity of the radiation flow of the arc of the shutdown. The device is triggered. The proposed method provides improved noise immunity of the protection of working shields from arc short circuits. Claims The method of detecting arc short circuits in distribution boards of electric power systems based on monitoring the intensity of the arc radiation flow, characterized in that, in order to improve noise immunity, the intensity of the short arc radiation flow is reduced by the amount determined by the intensity of the flow the radiation of an arc that occurs in electrical apparatus when the currents of metallic short circuits are disconnected, and according to the intensity of the attenuated flux, Detection of arc short-circuit. Sources of information taken into account in the examination 1.Patent of Germany No. 1126011, cl. 21. from 68/50, 1962. 2. Patent Czechoslovakia No. 140068, cl. 21 p 68/01, 1971. L Pq OS