SU650143A2 - Unized distributing device cabinet - Google Patents

Description

one

The invention relates to electrical engineering.

Known cabinet on DOS. auth. St. No. 414669 of a complete switchgear, containing a switch with a drive and a drive activation control element in the event of an arc short circuit, in which a photothyristor installed in the cabinet is used in the distribution zone of the light in order to speed up arc localization within the cabinet. flow from the arising arc and connected to the drive disconnect coil.

A disadvantage of the known device 1 is the possibility of a false triggering of the photothyristor and the switching off of a switch due to light interference.

The aim of the invention is to improve the reliability of the device.

The goal is achieved by the fact that, in the switchgear cabinet, in series with the photo thyristors, a magnetically controlled contact is inserted into the circuit of the drive-off coil, placed next to the wire driver, with its busbar, which controls the magnitude of the magnetic field around the conductor w, and the bus and closes the coil turning off the switch only in case of an emergency increase in the bus current.

FIG. 1 shows the proposed switchgear cabinet with an indication of the installation sites of photo thyristors, a section; in fig. 2, 3, and 4 are variants of the connection circuits of the photo thyristors and the magnetically controlled contact with the drive disconnect coil; in fig. 5 shows time diagrams for the operation of the drive activation control element during electric arc closures.

The switchgear cabinet is divided into four compartments by partitions: compartment 1 for the withdrawable carriage 2; compartment 3, in which the lower disconnecting contacts 4, current transformers 5 and cable assembly 6 are located; compartment 7, in which the upper disconnecting contacts 8 are located, and compartment 9 of busbars 10.

The compartment 1, with the cart 2 removed, is separated from the compartments 3 and 7 by means of the shutters 11.

The compartment 9 is separated from the compartment 7 by a solid metal partition, and the current leads 12 from the busbars 10 to the upper disconnecting contacts 8 pass through the bushing insulators 13.

The partition between the compartments 3 and 7 is made translucent, for example, mesh. In the compartment 7, a photothyristor 14 is installed, which is oriented in space

so that its window is illuminated by the radiation flow of an electric arc, burning both in compartment 7 and in compartment 3.

To record the occurrence of an electric arc in the compartment 9 of busbars 10, photo thyristors 15 are also installed, the number of which is chosen so that the ignition of the electric arc anywhere in compartment 9 leads to the activation of one of these photo thyristors.

The magnetically operated contact 16 is installed in the busbar compartment adjacent to the busbar 12 of the middle phase. The distance / between the magnetic contact and the bus is chosen according to the detuning conditions of the maximum operating current of the bus / slave. max, ensuring the dielectric strength of the insulation between the bus and the contact and ensuring reliable operation at damage currents:

yy yy

- - Chrab.max

2cc

wed

.

one

2t1I ;.

wed

I is the distance between the magnetically operated contacts and the busbar;

/ {2)

/ slave Max Az is the peak value of the maximum operating current of the cabinet and the short circuit current, respectively; NSR - magnetic field strength, at which the Magnetically operated contact is activated (shorted);

/ Ci is the safety factor (detuning), / (, 2-1.3;

K.W. - reliability coefficient, / (2 - 0.5.

The bus current at which the magnetically controlled contact operates, i.e., the response current can be changed by moving the contact relative to the bus, since

/ er 27yasr /.

The photo thyristors controlling the illumination in the compartments of the cabinet are connected in parallel to each other and are connected in series with the magnetically controlled contact 16 into the circuit of the switch-off coil.

To protect the switchgear section, all the photo thyristors installed in the cabinets are connected in parallel and are connected in series with the magnetically controlled contact located in the busbar compartment of the input cell in the circuit of the input switch opening coil.

FIG. 2 is a diagram of the connection of photothyristors and a magnetically controlled contact when powering the switch actuator by direct current. When powering the switch drive from the AC network, the photo thyristors are included in the diagonal of the diode bridge 17.

In those cases when a magnetically controlled contact for switching capacity does not allow its inclusion directly into the disconnecting coil circuit 18, a circuit can be used (Fig. 4) in which the inclusion of one of the photothyristors when the magnetically controlled contact 16 is closed causes the intermediate a disconnect relay 19, through the closure contacts 20 of which a voltage is applied to the disconnecting coil 18. To improve the operation of the intermediate relay from a pulse voltage and to protect the magnetically controlled contact CTA 16 from reheat coil parallel to its recommended include semiconductor diode nonconductive nairavlenii.

FIG. 5 - time diagrams of the protection device. Before the occurrence of a short circuit, the magnetically controlled contact is open, since the magnitude of the current / 21 in the current-carrying current is less than the current of operation of the magnetically controlled contact (Fig. 5a) and the false activation of the photo thyristors does not cause the switch to open. At the time of occurrence of electric arc overlap, the current in controlled phase 22 increases by a factor of 10–15 times (Fig. 5a).

The magnetically controlled contact starts to close and open the power supply circuit of the disconnecting coil 18 when the emergency current 22 arrives at each half-wave, triggered when the current exceeds the response level / cf and returns when the current drops below the return level / c. The closure of the magnetically controlled contact 16 each time leads to the instantaneous turning on of one of the photo thyristors, which is illuminated at this moment by the radiation of the arc. As a result, the disconnecting coil 18 is surrounded by a current 23 (Fig. 56) and the drive shuts off the switch, relieving the voltage from the emergency section.

The time from the moment of arcing of the arc to the breaking of the switch does not exceed 0.2 s.

Average current value / average disconnect coil 18 for the period is determined by the expression

f - 9i

Wednesdays - -

amplitude value

current 23 in

Claims (1)

disconnect coil; the duration of the closed state of the magnetically controlled contact for half the period; period of industrial frequency. Claims of the Cabinet of switchgear on the author. St. No. 414669, which is based on the fact that, in order to increase the reliability of operation, a magnetically controlled contact is placed in series with the drive disconnect coil, placed near the busbar. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 414669, cl. H 02B 13/00, 1972. it., 0 g- and H t