SU1372418A1 - Device for monitoring fuses in parallel circuits of electric installation - Google Patents

Abstract

The invention relates to electrical engineering and is intended for use in the protection systems of electrical switching devices of high-power electrical conversion plants from emergency currents. The purpose of the invention is to increase the reliability of control and ease of operation setting with a variable number of reserved fuses. When the fuses (П) 1 are in good condition in parallel circuits x 2, the block contacts (БК) 3 are closed. The potential of the control input (HC) of the sensitive element (SE) 5 is almost equal to the potential of the negative output of source 7. The SE 5 is de-energized, its output contact 11.2 in the circuit 14 of the electrical installation outage is closed. The protected electrical installation is in operation. When a given number P 1 is triggered, the corresponding BC 3 opens, the potential of the UV FE 5 becomes greater than the potential of the negative terminal of the source 7. The FE 5 trips, opening the output contact 11.2 in the circuit 14 of the electrical installation disconnection, as a result of which the latter is turned off. 1 il. g (L

Description

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The invention relates to electrical engineering and is intended for use in the protection systems of electrically switching devices of high-power electrical converters from emergency currents.

The purpose of the invention is to increase the reliability of control and ease of operation setting with a variable number of reserved fuses.

The drawing shows a diagram of the proposed device.

A device for monitoring the state of fuses 1 installed in parallel circuits of 2 electrical installations, for example, in series with semiconductor valves - diodes or thyristors, contains on each fuse 1 auxiliary contact 3, which is closed in the normal state and opens during combustion fuse For each fuse 1, a current limiting element-Zener diode 4 is provided. In addition, there are a sensitive element 5, a resistor 6 and a power supply 7 with a voltage of 12-110 V.

Zener diodes 4 are connected each in parallel to the corresponding block-contact 3 of the fuse 1. All Zener diodes 4 are connected in series and this chain is connected through a resistor 6 between the terminals of the source 1 and 7, and the zener diodes 4 are connected oppositely to the polarity of this source. The sensing element 5 is made in the form of a voltage relay, which contains a transistor 8 with an input Zener diode 9 and a bias resistor 10.

The collector circuit of the transistor 8 includes a winding of the electromagnetic relay 11 with contacts 11.1 and 11.2. Contact 11.1 by means of diodes 12 and 13 shunts the input and output circuits of the transistor 8. The output contacts 11.2 of the relay 11 are connected to the emergency disconnect circuit 14 of the protected electrical installation.

The device works as follows.

When the fuses 1 are in good condition, the auxiliary contacts 3 are closed. In the circuit containing source 7, resistor 6 and zener diodes 4, shunted by pin 3, a current i LU / R flows, and the potential of point a (control input of element 5) is almost equal to the potential of the negative terminal of source 7. Transistor 8 element 5 is closed, the relay 11 is de-energized. The contact 11.2 of the circuit 14 of the electrical emergency disconnection is closed. The protected electrical installation is in operation.

When any fuse 1 is triggered, due to the breakdown of the circuit 2 protected by it, the corresponding block contact 3 is opened and a zener diode 4 is additionally introduced into the source circuit 7, creating a potential difference between point a and the negative terminal of source 7. The potential cfg of point a is equal to the number K of fuses 1 multiplied by i; a voltage (stabilization of the stabilization of the ptrona, i.e. Lf. Potential if Bosz; acts on the input of the element 5. If tpg is less than the voltage Uq of the stabilization of the zener diode 9, then element 5 remains in an unexcited state SRI, contact 11.2 is closed. If RAN and the current through the zener diode 9 increases dramatically, the transistor 8 is opened, including a Contact 11. turnips 11.1 samoblokiruets relay 11 and the contact 14 opens the circuit 11.2 emergency deflection providing electrical shutoff.

Device tuning is reduced to the choice of stabilization voltage of Zener diode 9, which provides ease of setup and high reliability of the device.

Claims (1)

Invention Formula A device for monitoring fuses in parallel circuits of an electrical installation, comprising an auxiliary contact and a current-limiting element for each fuse, a sensing element, a resistor and a power source, characterized in that, in order to increase the reliability of control and ease of setting of the operation with a variable number of redundant fuses, elements are made in the form of zener diodes, and the sensitive element is in the form of a voltage relay, the output contact of which is intended to emergency shutdown electrical circuit, the chain sopgasno serially connected current-limiting elements - Zener diodes through a resistor connected between the source terminals elektropi313724184 tani, the zener diodes of the included element are connected to the extreme outward polarity of the source and shun-water of the current-limiting chain each block-contact of the corresponding zener diodes from the side of the controlled controlled positive pole of the electrical anthranitel source, with a positive lead and a negative terminal - with the druvod of the control input, the sensitivity of the extreme output of this chain.