SU1476547A1 - High-voltage gas circuit-breaker - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to expand the field of application at low ambient temperatures and increase reliability. A high-voltage gas switch using sulfur hexafluoride as an arc extinguishing and insulating medium contains an arc extinguishing chamber 1 at a high potential constantly filled with the specified gas, elements of the drive and support insulating structures isolating the said chamber from the ground and driving it into action, drive and control cabinet on the ground potential. The switch is equipped with a capacitor 5 located outside the arc-suppressing chamber 1, a gas pipeline 6 connected to it and having a thermal resistance of the wall substantially less than that of the arc-suppressing chamber 1. In addition, the switch is provided with an additional reservoir 7 with a heater 8 located on the ground potential associated with arc chute chamber gas 10. The capacitor 5 is also located on the ground potential and is connected in the lower part with the lower part of the specified reservoir additional pipeline 9, providing a sink end ensata addition tank 7. Moreover, the capacitor 5 is at the bottom provided with a condensate trap 12, the thermal resistance of the wall which is not less than the thermal resistance of the wall of the arc chamber. The condenser is provided with a tube with a cross section much smaller than the cross section of the condenser, the upper part of which is connected to the gas pipeline and the lower part is lowered into the condenser. The additional tank is equipped with a level 11 relay that monitors the presence of condensate and controls the preheater 8. 4 ° C f-ly, 4 ill.

Description

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cops of drive and supporting insulating structures that isolate the said chamber from the earth and drive it into action, drive and control cabinet on the ground potential. The switch is equipped with a capacitor 5 located outside the arcing chamber 1, a gas pipeline connected to it and having a thermal resistance of the wall substantially less than that of the arc-treating chamber 1. In addition, the switch is equipped with an additional reservoir 7 with a heater 8 located on the ground potential connected with an arc-extinguishing chamber by a gas line 10. The capacitor 5 is also located on the ground potential and is connected in the lower part with the lower part of the indicated reservoir by an additional pipeline 9, providing drainage condenser 5 in the lower part is equipped with a condensate collector 12, the thermal resistance of the wall of which is not less than the thermal resistance of the wall of the arcing chamber .. The condenser is equipped with a tube with a cross section much smaller than the cross section of the condenser, the upper part of which is connected to the gas pipeline, and bottom is lowered into the condenser. The additional tank is equipped with a level 11 relay that monitors the presence of condensate and controls the heater 8. 4Cp f-ly, 4 silt,

 .

The invention relates to electrical engineering, namely to high-voltage gas switches using sulfur hexafluoride (SF6) as an arc extinguishing medium.

The aim of the invention is to expand the field of application of switches at low ambient temperatures and increase the reliability of the switch,

FIG. 1 shows a high-voltage gas switch equipped with a capacitor and an additional reservoir with a heater in FIG. 2 — an additional tank with a spill level switch in FIG. 3 - condenser with condensate collector; in fig. 4 - the same, with an additional tube of small diameter.

The arcing chamber 1, made of insulating material, is continuously filled with gaseous sulfur hexafluoride to a filling density p 5ap exceeding by another a density sufficient to provide switching capacity Rxm installed on the supporting insulator 2, in this example also filled with sulfur hexafluoride and connected on gas with a camera. The support insulator is located on the control cabinet 3, inside of which there is an actuator connected to the arcing chamber by a pull 4. The switch is equipped with a remote condenser 5, the thermal resistance of the wall of which is substantially less than the resistance of the wall of the arcing chamber made, for example, copper or aluminum and connected in the upper part of the pipeline 6 with the internal cavity of the reference insulator or chamber. The switch can also be equipped with an additional tank 7 with a heater 8 located in the control cabinet 3 and connected to the condenser 5 by a pipe 5 connecting 9 the lower parts of the additional tank 7 and the condenser 5, providing condensate drain from the condenser 5 to the specified tank 7. In the upper parts

0 an additional tank is connected to the internal cavity of the support insulator or chamber by a gas pipeline 10.

The additional tank 7 (Fig. 2) is equipped with a relay 11 of a liquid SF6 gas level, which controls the presence of condensate and controls the operation of the preheater 8.

FIG. 3 shows a capacitor, in the lower part, equipped with a condensate collector 12, the thermal resistance of the wall of which is not less than the thermal resistance of the wall of the arcing chamber 1.

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FIG. 4 shows a capacitor equipped with a tube 13 with a cross section much smaller than the cross section of the capacitor, the upper part of the tube is connected to the gas pipeline 6, and the lower part is lowered into the condenser.

The switch works as follows.

With a decrease in the ambient temperature due to a substantially lower thermal resistance of the wall of the capacitor, the gas in its internal cavity cools much faster than in the arc chamber and the supporting insulator.

If the capacitor is made, for example, of thin copper, then its thermal resistance is three orders of magnitude less than the thermal resistance of the chamber and support insulators. When the temperature in the condenser is below the liquefaction point when the density of the RZS | P in it begins to liquefy the gas, which will be accompanied by a drop in pressure and the gas from the inside of the switch will be drawn into the condenser, while the gas will be still at higher temperatures and pressures. Thus, when the temperature drops to a predetermined temperature, based on liquefaction at a switching density pKOA, all the excess SF6 gas stored for leaks will be in the liquid phase in the condenser and then in the additional tank, and the gas in the switch will have a density, and condensation inside an arcing chamber and a support insulator will not take place.

When the ambient temperature rises, the condenser heats up faster than the arc-suppressing chamber, so the SF6 gas in the liquid phase begins to evaporate, its pressure in the condenser rises, and through pipe 6 the SF6 vapor flows back into the internal cavity of the insulator 2 or chamber 1.

At a high rate of evaporation of condensate, the gas from the extinguishing chamber 1 does not have time to warm up, and the pressure of the SF6 gas increases, in which case condensation begins in the arc extinguishing chamber, which is unacceptable.

To prevent this, it is necessary to slow down the evaporation of liquid oleg-ja in the condenser, which can be achieved in various ways.

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0

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sobami. For example, a condenser may be provided with a condensate collector 12. In this case, the condensation of the SF6 gas occurs in the upper part of the condenser with low wall resistance. The stack, condensate is collected in the condensate collector, the thermal resistance of the wall of which is large, and evaporation occurs slowly. The rate of evaporation can be adjusted so that the gas in the arc chamber has warmed up so that with new values of temperature and pressure condensation in the chamber will not occur.

The process of evaporation of condensate in a condenser can also be slowed down using tube 13. In this case, condensation occurs throughout the entire volume of the condenser, and evaporation with increasing ambient temperature is slowed down due to the small cross-section of the tube. The evaporation in the closed volume of the condenser 5 is difficult due to the increase in pressure in it, and the exit of gas from this volume will be impeded by a liquid gate.

Thus, when the ambient temperature drops to Trty, at which the gas phase density provides full switching capacity, the excess SF6 stored in the switch for leakage compensation is in a condenser or in an additional tank in an amount equal to

(Рз «п Я

k OM

) V

ъ t

0

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Where

P Jan P com

- filling density,

density at which full switching capacity is provided j

V in - the volume of the internal cavities of the switch.

If there are leaks in the switch during this period, the pressure in it and in the condenser starts to decrease, the corresponding part of the liquid gas passes into a gaseous state and replenishes the loss of the gas.

In the presence of an additional tank 7 with a heater 8 in the switch, the process at the beginning of the liquefaction of SF6 gas in the condenser 5 has a circular character. Liquid SF6 gas from the condenser 5 flows through the pipeline 9 into the tank 7, when the heater is turned on, it starts to discharge 51

from and through the gas pipeline 10 to the insulator, heat the gas there.

Relay 11 turns on the heating when condensation occurs and turns it off if it is not.

The advantage of this solution compared with the analogs is as follows.

The zone of negative temperatures is expanded, at which the full breaking capacity of the switch is ensured without altering the design of the arc chamber and increasing the gas pressure, which is inevitable when using a mixture of SF6 gas and nitrogen.

Compared with the prototype, this circular system is more stable and reliable, prevents condensation of the SF6 gas in the arcing chamber and insulating tubes. Thus, a higher level of insulation of the switch is provided, as well as corrosion resistance of the system.

The useful national effect from the implementation of this proposal is provided by the expansion of the switch's use area; the reliability of its operation while maintaining the disconnect capacity; in addition, gas technology is simplified and cheap compared to the use of gas mixtures with other gases, and consequently, operation is simplified.

Claims (5)

1. High-voltage gas circuit breaker with use of hexafluoric sulfur as the arc-extinguishing and insulating medium, containing a high-potential arc-suppressing chamber, constantly filled with the indicated gas, elements of the drive and supporting insulating structures, isolating the said chamber from the ground and leading its operation, drive and control cabinet on the ground potential, which is characterized by the fact that it is equipped with a capacitor located outside the arc chute chamber, connected to it by a gas pipeline having a thermal resistance in order to expand the scope of applications at low ambient temperatures and increase reliability walls, significantly smaller arc chamber. 2. The switch according to claim 1, characterized in that, for the purpose of five 0 5 d five 0 five further expanding the field of application at subzero ambient temperatures, the switch is equipped with an additional tank with a heater located on the ground potential, connected to the arc chute, a gas pipeline, the condenser is also located on the ground potential and connected in the lower part with the lower part of the tank indicated by an additional pipeline, providing condensate drain from the condenser to the additional tank. 3. A switch according to claim 1, characterized in that the condenser in the lower part is equipped with a condensate trap, the thermal resistance of the wall of which is not less than the thermal resistance of the wall of the arcing chamber. 4. The switch according to claim 1, characterized in that the capacitor is provided with a tube with a cross section much smaller than the cross section of the capacitor, the upper part of which is connected  with a gas pipeline, and the bottom is lowered into the condenser. 5. The switch according to claim 2, characterized in that the additional tank is equipped with a level switch that monitors the presence of condensate and controls the preheater. 2 fig.Z