JPH02206104A - Transformer - Google Patents

Abstract

PURPOSE:To resume a normal operation immediately even after a power supply has been recovered by a method wherein a water tank is installed at the back- stream side of a cooling tower, a solenoid valve and a waterwheel are installed between a cooler and a lowerpart water tank and a shaft of the waterwheel is connected to a shaft of a circulating pump via a clutch. CONSTITUTION:A water tank 17 of a proper capacity is installed behind a cooling tower 16 at a high place of a building in which a transformer is installed; a waterwheel 24 is installed, via a solenoid valve 23, at a pipe on the cooling-water exit side of a cooler 9 attached to the transformer; cooling water which has flowed out from the waterwheel 24 flows to a lower-part water tank 12. A shaft of the waterwheel 24 is connected to a shaft of a circulating pump 10 for coolant use. When an interruption of electric service or the like is caused, the solenoid valve 23 is released; the cooling water which has flowed out from the cooler drives the waterwheel; the clutch is connected; the circulating pump continues turning until the water in the water tank runs out; a coolant is circulated; a cooling function is maintained. Thereby, the transformer can be started again immediately after power supply has been recovered.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a nonflammable liquid refrigerant. The present invention relates to a liquid-cooled gas insulated transformer, and particularly relates to an indoor-installed liquid-cooled gas insulated transformer that is equipped with a device that maintains cooling performance even during a power outage such as a power outage.

[Conventional technology]

As cities become overcrowded, transformers installed in cities tend to have ultra-high voltage and large capacity, but there is a growing demand for transformers to be nonflammable for disaster prevention purposes. To make large-capacity transformers nonflammable, a nonflammable liquid refrigerant is required to replace transformer oil as an insulating refrigerant.However, considering insulation properties, thermal stability, and cooling performance, perfluorocarbon liquid is the optimal refrigerant.

However, this refrigerant is much more expensive than transformer oil, so in order to make the transformer economical, it is necessary to reduce the amount of this refrigerant used.

In transformers that use only a small amount of refrigerant and use pumps to forcefully circulate the refrigerant to cool structures, when auxiliary equipment such as pumps stops due to a power failure such as a power outage, it is necessary to investigate the cause of the stoppage and implement countermeasures. Therefore, it takes about 10 minutes.

During this time, if current is flowing through the windings of the transformer body, heat generation continues, so the temperature of structures such as the windings rises, and it is necessary to cool them. In particular, when the refrigerant circulation pump stops, the refrigerant flows through natural circulation, which is extremely slow compared to the flow rate of the refrigerant in the case of forced circulation, resulting in a decrease in cooling performance. On the other hand, in transformers installed indoors (including underground), heat is radiated through cooling water through the cooler that cools the refrigerant, but when the power supply for auxiliary equipment is cut off, the cooling water also stops, causing the refrigerant inside the transformer to radiate heat. Temperature rises.

Conventional technology for dealing with this situation is to increase the volume of the cooler in the refrigerant circulation system to hold a large amount of refrigerant, and to supply compressed gas to this cooler from outside the refrigerant circulation system. In preparation, it detects the increase in circulation flow due to the stoppage of the pump, and guides the compressed gas to the cooler.Meanwhile, the valve in front of the cooler is closed, the valve at the refrigerant outlet of the transformer body is opened, and the cooler is opened. A method of circulating refrigerant using the pressure difference between the valves (Japanese Patent Application Laid-open No. 62-2249 (No. 18, No. 62-2)
No. 395 (Publication No. 17) has been proposed.

[Problem to be solved by the invention]

In the conventional technology, when a pump stops due to a power outage or the like, compressed gas is guided from outside the refrigerant system to the cooler, and refrigerant in the refrigerant system is discharged from the refrigerant outlet of the transformer main body. After power is restored, it is necessary to process the introduced gas and refill the discharged refrigerant, so it cannot be restarted immediately. Further, it is necessary to store a large amount of expensive refrigerant in the refrigerant system. Furthermore, while a container is required to collect the discharged liquid, the refrigerant evaporates when the hot liquid is discharged, requiring extra cooling equipment to liquefy the vapor.

An object of the present invention is to provide a liquid-cooled gas insulated transformer that is equipped with a power outage countermeasure that allows for immediate return to normal operation even after power is restored without releasing liquid or increasing the amount of liquid. shall be. Another object is to provide a method that can suppress the temperature rise of the refrigerant during power outages.

[Means to solve the problem]

The present invention uses stored potential energy to drive a refrigerant circulation pump. In other words, in the cooling water system that cools the refrigerant of the transformer, a water storage tank with an appropriate capacity is installed after the cooling tower located high in the building where the transformer is installed, and the cooling water outlet of the cooler attached to the transformer is installed. A water wheel is installed in the side piping via a solenoid valve, and the cooling water that exits the water wheel flows to the lower water tank. Note that the shaft of the water turbine is connected via a clutch to the shaft of a refrigerant circulation pump or the shaft of a motor that drives the circulation pump. In addition, a pipe is installed in which the cooling water exiting the cooler flows to the lower water tank without passing through the water wheel, and a solenoid valve is installed in the middle.

Another method uses compressed air to drive an air turbine, which in turn drives a circulation pump.

[Operation] During normal operation, the water tank holds an appropriate amount of cooling water, and this cooling water flows down to the lower water tank through the cooler. When a power failure such as a power outage occurs, the solenoid valve installed on the upstream side of the water turbine is opened, and the solenoid valve in the piping that flows directly from the cooler to the lower water tank is closed, and the cooling water leaving the cooler is closed. drives a water wheel. Furthermore, the clutch between the circulation pump shaft and the water wheel shaft is connected, and the rotational power of the water wheel is transmitted to the circulation pump, which rotates without stopping until the water in the water tank runs out. Subsequently, the refrigerant is circulated to cool the transformer structure, so that the cooling function can be maintained. Note that in the event of a power failure due to a power outage or the like, it only takes about 10 minutes for a supervisor or the like to judge the situation and take countermeasures, so the amount of water held in the water tank does not need to be large.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Iron core 2. Low voltage winding 3. The high voltage winding 4 is immersed in a nonflammable liquid refrigerant 6, and the liquid refrigerant 6 is contained in a space surrounded by a container 5 and a separator 8. These structures are housed in a tank 1, and the space between the container 5 and the tank 1 is filled with an insulating gas 7 for insulation. The liquid refrigerant 6 is sent into the tank 1 via the plumber 1 by a circulation pump 10 placed outside the tank 1, cools the pipe lines, etc.
It is taken out from the upper part of the tank and cooled by cooling water 13 in a cooler 9. On the other hand, the cooling water 13 is pumped up from the lower water tank 12 by a pump 14 and sent via piping 15 to a cooling tower 16 installed above a building or the like. The cooling water 13 is cooled by a cooling tower 16 and temporarily stored in a water storage tank 17. The cooling water 13 enters the cooler 9 from the water storage tank 17 via pipes 18 and 19, and returns to the lower water tank 12 via the pipes 19, 20 and the solenoid valve 21 during normal operation. Further, a pipe 22 is provided branching off from the pipe 19', and a water turbine 24 is provided via a solenoid valve 23. The shaft of the water wheel 24 and the shaft of the circulation pump 10 are connected to a clutch 25.
connected by. This clutch is disengaged during normal operation, and rotational power is transmitted during a power outage. Note that a system may be provided in which the cooling water 13 flows directly from the water storage tank 17 to the water turbine 24 through the pipes 18 and 26 and the valve 27.

If a problem occurs with the auxiliary power supply during a power outage with a transformer configured like this, the circulation pump 10 or pumping pump 1
Since the motor driving 4 is stopped, cooling water cannot be pumped up. However, the cooling water in the water tank 17 tends to fall. Because the solenoid valve 21 closes and the solenoid valve 23 opens due to a power outage, the cooling water in the water storage tank 17 that has potential energy with respect to the lower water tank 12 passes through the pipes 18, 19 and the cooler 9, and then passes through the pipes 19', 22, the water passes through the solenoid valve 23, turns the water wheel 24, and falls into the lower water tank 12. In addition, when the clutch 25 loses power, the rotational power of the water turbine 24 is transmitted to the circulation pump 10, so the circulation pump 10 rotates, and the liquid refrigerant 6 is forcibly circulated within the transformer in a state similar to that of normal operation, and the winding 3,
4 etc. can be cooled with better performance than when the circulation pump 10 has no power. Note that the refrigerant 6 is also a cooler 9,
Because it is cooled by cooling water in almost the same way as during normal operation.

The temperature rise of the structures inside the transformer can be suppressed to a small level.

In addition, if a power outage occurs at a substation, it takes about 10 degrees to determine the cause and situation and take countermeasures, so the flow rate of cooling water to rotate the water turbine 24 is reduced to normal operation. It doesn't have to be the same amount as time.

On the other hand, even if the power is restored, the amount of water in the water tank will only change compared to normal operation, and normal operation can be resumed easily and immediately.

The effects of this embodiment are that during a power outage, cooling performance can be maintained for a short time, the temperature rise of structures such as windings can be suppressed, and excessive failures and accidents are less likely to occur.

In addition, in order to circulate the refrigerant, there is a proposal in which the cooling water from the cooling tower turns a water wheel, and this water wheel drives a circulation pump, but this is not suitable for normal operation. Considering the efficiency of a pumping pump or a water wheel, it is less efficient and uneconomical than a circulation pump driven by a motor.

Another embodiment of the present invention will be explained with reference to FIG.

9 is a cooler, 10 is a circulation pump, and a pipe 29 supplies compressed air 35 from a compressor (not shown) to the accumulator 3.
1, and 30 is a valve.

The compressed air 35 passes through a valve 32, is guided to the air turbine 28 via a pipe 33, and is discharged to the atmosphere via a pipe 34. 25 is a clutch. In the event of a power failure such as a power outage,
Valve 32 is opened and compressed air 35 drives air turbine 28 . The circulation pump 10 is rotated by receiving rotational power from the air turbine 28 through the clutch 25 . Note that the cooler 9 may be cooled by cooling water or may be cooled by a fan or the like in the atmosphere.

When a power outage occurs, the motor that drives the circulation pump stops generating power, but the compressed air 35 stored in the accumulator 31 is supplied to the air turbine 28 by opening the valve 32 and generates rotational power. Then, the clutch 25 drives the circulation pump 10. According to this embodiment, even after a power outage, the liquid refrigerant 6 is forced to circulate, making it possible to suppress the temperature rise of the transformer structure to a small level. Furthermore, even after power is restored, normal operation can be started immediately.

〔Effect of the invention〕

According to the present invention, even in the event of a power failure due to a power outage, it is possible to judge the situation and investigate the cause without releasing liquid refrigerant.

The circulation pump can be driven for the time required to implement countermeasures, and the cooling performance of the transformer structure can be maintained. Furthermore, even after power is restored, the transformer can be restarted immediately.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a transformer according to one embodiment of the invention, and FIG. 2 is a system diagram of another embodiment of the invention. 1...tank, 6...liquid refrigerant, 9...cooler,
10...Circulation pump, 12...Lower water tank, 13...
・Cooling water, 14... Pump, 16... Cooling tower 17... Water tank, 18, 19. 19',
20.22...Piping, 21.23...Solenoid valve, 24.
...Water wheel, 25...Clutch, 28...Air turbine, 31...Accumulator, 35...Compressed air.

Claims (4)

[Claims] 1. In a transformer that forcibly circulates a liquid refrigerant by a circulation pump and cools the liquid refrigerant with cooling water in a cooler, a certain capacity of the cooling water is held on the downstream side of a cooling tower that cools the cooling water. 1. A transformer comprising: a water storage tank for obtaining water; an electromagnetic valve and a water wheel are provided between the cooler and the lower water tank; and a rotation shaft of the water turbine and a rotation shaft of the circulation pump are connected via a clutch. 2. In the transformer according to claim 1, during a power outage,
A transformer characterized in that the potential energy of the accumulated substance is used to drive the circulation pump of the liquid refrigerant. 3. A transformer that cools a liquid refrigerant by forcibly circulating it with a circulation pump, characterized in that during a power outage, the circulation pump is driven using accumulated compressed air pressure energy. 4. A transformer that forcibly circulates liquid refrigerant with a circulation pump and cools it with a cooler includes an accumulator that accumulates compressed air, an air turbine operated by the compressed air, a rotating shaft of the air turbine, and a rotation shaft of the circulation pump. A transformer comprising means for connecting a rotating shaft via a clutch.