RU2501112C1 - Column gas-filled circuit breaker - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: column gas-filled circuit-breaker contains hollow base insulator, the second insulator, arc suppressor placed inside the second insulator, drive connected to arc suppressor by insulating pull-rod passing inside hollow base insulator, exhaust pipe placed in the same insulator and electric heater under its base. The second insulator is fixed at hollow base insulator by means of flanges with current lead located in-between them to arc suppressor. The other current lead to arc suppressor is fixed at the upper flange of the second insulator. Inside the second insulator there is the second exhaust pipe located in-between current leads around arc suppressor. Parts of current leads inside insulators are made with slots and/or channels.

EFFECT: preventing of unacceptable decrease in SF6 density at low temperatures without necessity to fill the circuit breaker with excessive quantity of gas, improving switching capacity and operational reliability.

3 dwg

Description

The invention relates to electrical engineering, namely to gas-insulated high-voltage electric apparatus operating in cold climates.

Known gas-insulated core switch (patent RU No. 2087976, class H01H 33/53, publication 08/20/2008), containing an arcing device located inside a porcelain insulator mounted on a supporting insulator floor using connecting fittings with ribs on its outer surface. The internal cavities of the supporting hollow insulator and the porcelain insulator communicate with each other and are filled with SF6 gas. To prevent a decrease in the density of SF6 gas due to its condensation at low temperatures, the circuit breaker has an electric heater located under the lower base of the support hollow insulator.

The switch operates as follows. When the ambient temperature drops below the condensation temperature of SF6 gas, the latter precipitates in the form of a liquid phase on the internal surfaces of the circuit breaker. LPG flows down to the base of the hollow support insulator. When the pressure of gaseous SF6 gas is reduced to a predetermined level at which the circuit breaker is still operational, the electric heater is turned on. The electric heater evaporates the liquefied gas, its vapor rises, condensing on the internal surfaces of the circuit breaker. The condensation energy released in this case maintains the temperature of the internal surfaces at a level at which the pressure of the SF6 gas does not drop below the permissible limit. Condensed SF6 flows back down to the lower base of the hollow support insulator and the cycle repeats.

The disadvantage of such a switch is the need to fill it with an excess amount of SF6 gas, exceeding its amount, which is necessary when the switch operates in the summer. An excess of SF6 goes to its condensation and maintenance of the heat transfer process at low temperatures. An excess of SF6 gas not only increases the cost of the circuit breaker, including due to the need to create more durable structures operating at higher pressures, but also complicates the process of monitoring its leaks due to density changes during condensation.

Another disadvantage is the presence of fins on the outer surface of the connecting fittings, since they increase the heat transfer from the switch to the outside air. This requires an additional increase in the power of the electric heater, leads to an increase in the amount of liquefied SF6 flowing down the walls and, therefore, leads to the need to increase the excess filling of the switch with it. On the contrary, the use of fins on the inner surfaces of the circuit breaker could enhance the processes of convective heat transfer, in which gas condensation is not used, and, in the limit, would allow heat exchange to be carried out without phase transitions at all.

Closest to the proposed solution is a gas-filled column switch (patent RU No. 2443036, class H01H 33/53, published 02.20.2012), containing a hollow support insulator, a second insulator, an arcing device located inside the second insulator, a drive connected to an arcing a device with an insulating rod passing inside the hollow support insulator, an exhaust pipe located in the same insulator, and an electric heater under its base, while the second insulator is mounted on the hollow support insulator using flanges with a lower current supply between the arc suppressor located between them, another current supply to the arcing device is mounted on the upper flange of the second insulator.

The internal cavities of both insulators communicate with each other. To prevent an unacceptable decrease in the density of SF6 gas at low temperatures, the circuit breaker has a tank-evaporator of liquefied SF6 gas, located above the electric heater in the control cabinet of the circuit breaker. The evaporator tank communicates with the cavity of the hollow support insulator using a chimney. In addition, the circuit breaker has an SF6 gas condenser tank located in the open air, connected by one tube to the lower part of the hollow support insulator, and the other by the indicated vaporizer tank.

When the ambient temperature drops below the gas condensation temperature, liquefied gas is deposited on the switch walls, which flows down and enters the condenser tank together with gaseous SF6 gas. There is an additional liquefaction of SF6 gas, after which the liquid enters the evaporator tank, heated by an electric heater, from where it evaporates. The generated vapor enters the upper part of the hollow support insulator through the exhaust pipe and rushes to its walls, surfaces of the contact systems, the internal cavity of the second insulator due to its communication with the cavity of the first insulator, and other internal surfaces of the circuit breaker elements. The gas condenses on them with such intensity that their temperature becomes the same and corresponds to the gas pressure in the switch according to the saturation curve of SF6. The temperature and pressure of the gas in it will vary depending on air temperature and wind speed. However, the solution does not describe how the communication of the internal cavities of the circuit breaker insulators occurs.

The disadvantage of this solution is the need to fill the circuit breaker with an excessive amount of gas (the reasons for this were discussed above), which increases the cost of the circuit breaker design. The second disadvantage is that the condensation method of heat transfer does not ensure the maintenance of the required switching ability of the switch. This is due to the fact that upon condensation heating of the apparatus, the SF6 gas in it becomes saturated with steam. But when the current is turned off, the pressure in the arcing device increases briefly. As a result, part of the vapor condenses on its walls. This leads to a decrease in pressure growth in it and breaking capacity (V. G. Egorov, S. A. Rodina, K. I. Seryakov, Modeling of SF6 puffer interrupters, CIGRE 1994 session, rep.13-105, Paris, 1994) .

Thirdly, the condensation of SF6 gas complicates the tightness control of the circuit breaker and reduces the reliability of this control, since in the conditions of partial gas condensation it is practically impossible to isolate what contribution the gas leaks contributed to the decrease in density, and what its condensation did. Fourthly, the introduction of a tank-condenser into the design of the circuit breaker only complicates its design and worsens the work, since the surfaces from which the heat transfer from the switch increases are increased. This should be offset by an increase in heating power, that is, an increase in the cost of maintaining the circuit breaker. To the condensate present in the evaporator tank, condensate is added, which accumulates in the condenser tank. Therefore, due to the introduction of the condenser tank, the amount of condensed SF6 gas increases and to prevent an unacceptable decrease in its pressure, the circuit breaker will have to be filled with even more SF6 gas to compensate for the amount that turns into liquid at low temperatures. The fifth drawback is the excessive complexity of the design by the introduction of an exhaust pipe into it, because the use of such pipes is advisable for convective heat transfer of gas. Condensing heat transfer is also used here.

The technical result of the proposed solution is to simplify the design of the switch, increase the switching ability and reliability, reduce its cost.

This technical result is achieved due to the fact that in the core gas-filled switch containing a hollow support insulator, a second insulator, an arcing device located inside the second insulator, a drive connected to the arcing device with an insulating rod passing inside the hollow support insulator, an exhaust pipe located in the same insulator, and the electric heater - under its base, while the second insulator is mounted on the hollow support insulator using flanges with the bottom located between them okopodok to the arcing device, and another current supply to the arcing device is mounted on the upper flange of the second insulator, the new is that inside the second insulator is additionally placed a second exhaust pipe located between the current leads around the arcing device, and parts of the current leads inside the insulators are made with slots and / or channels.

The use of an electric heater, a first exhaust pipe passing through the hollow support insulator, a second exhaust pipe located inside the second insulator located between the current leads and covering the arcing device, as well as current leads made with slots and / or channels in the part located inside the insulators , allows you to heat all the internal surfaces of the switch in both insulators with a stream of heated gas to temperatures that reduce or exclude the possibility of condensation, including le in the arcing device in the process of disconnecting the current. This allows you to reduce the filling pressure of the circuit breaker with SF6 gas, reduce its material consumption and cost, increase the breaking capacity, increase the reliability of the tightness control.

The proposed design is simplified by eliminating from it such elements as a tank-evaporator and a tank-condenser with an external pipe, which increases the reliability of the circuit breaker, leads to a decrease in mass and size indicators and its cost. In addition, the surfaces from which heat transfer occurs are reduced, and this reduces the required heating power and the cost of maintenance of the circuit breaker.

Figure 1 shows a section of one pole of the inventive core gas-filled circuit breaker with one arcing device and an electric heater.

Figure 2 shows a section along aa of the current supply located on the upper flange of the second insulator of the pole of the gas-filled core switch.

Figure 3 shows a section along BB of the lower current supply.

The pole of the gas-filled column switch (FIG. 1) comprises a hollow support insulator 1, a second insulator 2, an arcing device 3. The arcing device is located inside the second insulator. The actuator 4 is connected to the arcing device by an insulating rod 5, which extends inside the hollow support insulator. In the same insulator there is a chimney 6, and under its base 7 there is an electric heater 8. The passage of the insulating rod through the base is sealed with a sliding seal (not shown in Fig.). The second insulator is fixed to the hollow support insulator using flanges 9, between which the lower current supply 10 to the arcing device is fixed. The second current lead 11 to the arcing device, which is also the pole cover, is mounted on the upper flange 12 of the second insulator.

Inside the second insulator is additionally placed a second exhaust pipe 13 located between the current leads 10, 11 around the arcing device. Both exhaust pipes are made of insulating material.

Parts of the current leads that are inside both insulators are made with slots 14 and 15 (FIGS. 1, 2) and channels 16 (FIGS. 1, 3).

In the part of the lower current supply 10, which is located inside the insulators 1 and 2, radial slots 14 are made on both sides of it. Channels 16 are made between these slots in the form of two ring groups (figure 3). The slots 14 form the ribs 17 (Fig. 3), in which two annular recesses 18 (on each side) are also made, extending to the channels 16 and located on the same diameter as the annular partition between the two annular groups of channels 16.

At the current lead 11, the radial slots 15 (FIG. 2) are made on that part of it that goes inside the second insulator. In the formed radial ribs 17a, an annular undercut 18a is made, but not to their entire height.

The second exhaust pipe is inserted at its ends into the recesses 18 and 18a of the current leads. The first exhaust pipe with its upper end is inserted into the lower recess 18 in the lower current lead 10 and fixed therein (mounting device not shown).

The internal cavities of both insulators are in communication with each other due to through radial slots 14 and channels 16 in the lower current lead 10 and are filled with SF6 gas.

The heating system of the switch operates as follows. With a decrease in air temperature and its approximation to a temperature at which condensation of SF6 gas is possible at its lower maximum permissible density, an electric heater 8 is turned on. Heated SF6 gas first enters the exhaust pipe 6, then through slots 14 and channels 16 made in the lower current lead 10 and located inside exhaust pipes 6 and 13, it enters the second exhaust pipe 13 and rises up. Having passed through the slots 15 in the current lead 11, the SF6 gas drops down between the pipe 13 and the inner surface of the second insulator 2. Then through the slots 14 and the channels 16 of the lower current lead 10 located between the insulators and exhaust pipes, and then through the gap between the hollow support insulator 1 and the first with the exhaust pipe 6 it again approaches the heated lower base of the switch 7. Passing through the slots and channels in the metal-supplied current leads, the SF6 gas cools along the walls of the insulators, its density on the outside of the exhaust pipes novitsya more than inside. This maintains continuous circulation of the SF6 gas in the circuit breaker when the heater is on. As it cools, it loses its heat to the circuit-breaker elements outside, thereby preventing an excessive decrease in their temperature and gas condensation on them.

At the same time, there is no need to fill the circuit breaker with an excess amount of SF6 gas and additional hardening of its design. Since in such an apparatus a change in the density of the filling gas is possible only due to its leakage, the tightness control can be carried out in the simplest and most reliable way - control of the gas density. This increases the reliability of the circuit breaker, since the control of SF6 leakage is not interrupted during the winter period.

Switches with condensation heat transfer have the advantage that all elements of the apparatus are heated to the same temperature. As a result, heat transfer to the air and the required heating power become the minimum possible. The proposed solution achieves almost the same result by adjusting the size of the side surfaces of the slots and channels in the current leads. Moreover, all air-cooled circuit breaker elements inside are heated to the same minimum acceptable temperature, and thereby minimize heat loss, heating power and maintenance costs.

The placement of the arcing device inside the second exhaust pipe ensures its additional heating due to blowing by the flow of the most heated SF6 gas. As a result, it has overheating with respect to current leads and insulators, which eliminates the possibility or reduces the rate of condensation of SF6 gas in the arcing device in the process of increasing pressure in it when the current is turned off. This eliminates the negative effect of such condensation on the breaking capacity of the circuit breaker and, therefore, increases the reliability of its operation in winter conditions.

Considering that the breaking capacity of the circuit breaker depends on the filling pressure of it with SF6 gas, this solution can be used in gas-filled core circuit breakers designed both for operation in cold climates and in temperate climates, with a tripping current of 50 kA or higher or at a voltage of gap of 220 kV and higher.

Claims (1)

A gas-filled column switch containing a hollow support insulator, a second insulator, an arcing device located inside the second insulator, a drive connected to the arcing device by an insulating rod passing inside the hollow support insulator, an exhaust pipe located in the same insulator, and an electric heater under its base while the second insulator is mounted on the hollow support insulator using flanges with a lower current supply between them to the arcing device, another current water to the interrupter device is fixed on the upper flange of the second insulator, characterized in that the inside of the second insulator further arranged a second exhaust pipe located between the current supplies around the arc device, wherein part electrical connections inside the insulators, formed with cuts and / or channels.

Images