SU1709411A1 - Load high-voltage gas-blast circuit breaker - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to increase the breaking capacity and increase reliability in operation. Through holes are made in the walls of the arc-suppressing chamber, the outlets of which into the cavity of the arc-suppressing chamber are located near the base of the fixed arc-contact. 2 Il.

Description

The invention relates to the design of high voltage circuit breakers and can be used in high voltage AC switching devices.

The aim of the invention is to improve the breaking capacity of the load switch and increase the reliability of this switch.

FIG. 1 shows an autogas high-voltage switch-disconnector: in FIG. 2, node I in FIG. the lower part of the arc chute chamber t in gas flow directions.

The switch contains a steel welded frame 1. insulators 2, main movable 3 and main fixed 4 contacts, arcing chamber 5. having insulating walls 6. movable arcing contact 7. fixed arcing contact 8. having a base 9. mounted on a fixed main contact 4 through holes (in Fig. 1 and 2 one hole is shown) for outputting gases 10 with an axis 11. In FIG. 1 shows the trajectory 12 of the movement of the moving arcing contact 7. And FIG. 2 shows portions 13 and 14 of the flow of the resulting gases and the contact end 15 of a fixed arcing contact 8. There is an annular gap 16 between the movable main contact 3 and the walls of the chamber 6.

Autogas high-voltage switch operates as follows.

When disconnected, the fixed 4 and the movable 3 main contacts are opened first. Then the movable 7 and the fixed 8. arcing contacts are opened. An electric arc arises between them, under the action of which gases are emitted from the insulating walls 6 of the arcing chamber 5. The resulting gas stream is divided into two almost equal parts. One part of the flow 13 passes along the movable arcing contact 7. and the other 14 passes along a fixed arcing contact 8. In this case, a two-sided blast is formed. Under the action of these gas flows, the arc at the passage of current through zero is quenched, and the contacts, continuing to move, diverge by the distance required by the insulation conditions.

Uniform separation of the flow of exhaust gases is ensured by observing the following ratio of dimensions; The total cross-sectional area of the through holes 10 for gas discharge should be 0.7-1-1 of the cross-sectional area 16 of the gap between the movable main contact 3 and the walls of the chamber 6, and the outlets of the holes 10 in the cavity of the chamber 5 should be located relative to the contact end 16 of the fixed arcing contact 8 with a shift towards the base of the contact 8, equal to not less than 1/3 of the height h of the contact 8.

The improvement in the breaking capacity of an autogas high-voltage switch-disconnector and the increase in reliability in operation are due to two-sided blowing. If the aspect ratio is not satisfied, the positive effect is reduced. When the cross-section of the through holes 10, which is less than 0.7 cross section 16 of the gap between the movable main contact 3 and the walls of the chamber 6, the discharge of gases is insufficient, and the increased pressure causes damage to the arc-suppressing chamber. To avoid this, it is necessary to reduce switchable current.

If this ratio is greater than one, the effect decreases as the total pressure in the chamber decreases. The hole pattern also influences the positive effect. If they are located below the contact end 15 by less than 1/3 of the height h of the stationary arcing contact 8, then there will be a bad contact blow. The plasma jet emanating from the base of the arc at a fixed arcing contact 8, falling into the intercontact gap, reduces its dielectric strength, which leads to a decrease in the disconnected current. If the outputs of the holes 10 will be located below the contact end 16 more than 1/3

heights h, airflow will be better, since the gas flow will be directed away from the contact gap.

The indicated size ratios were selected and tested in practice when this high voltage breaker was operated in direct circuits for testing high voltage equipment.

A two-sided blast provides a better and faster deionization of the contact gap, and as a result, a large tripping current, a lower cosine of the circuit to be switched off, which makes it possible to improve the breaking capacity of the switch and increase the reliability of its operation.

Claims (1)

Claims of the invention: An autogas high-voltage switch-disconnector containing a steel welded frame with insulators mounted on it with fixed and fixed main contacts, an arcing chamber, between the walls of which there is an arcing contact and a fixed arcing contact, the base of which is fixed to the indicated fixed main contact, characterized in that, in order to increase the breaking capacity and reliability in operation, the walls of the arcing chamber are with openings for the output of gases whose outlets into the cavity of the arcing chamber are located near the base of the stationary arcing contact with a shift relative to the contact end of the stationary arc extinguishing equal to at least one third of the height of the stationary arc extinguishing the contact, the axes of the holes are directed tangentially to the path of movement of the movable arcing contact, and the total cross-sectional area of the through holes is chosen to be 0.7-1 the cross-sectional area of the annular gap between the movable arcing contact and the walls of the arcing chamber.