JPH0134332Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an oil-immersed transformer with improved safety against large and strong vibrations such as earthquakes.

[Technical background of the invention and its problems]

In recent years, transformers have become larger due to the increase in power demand,
Due to the increase in capacity, the bushings used to draw out the conductors are made of long and large-diameter porcelain pipes with excellent insulation and salt damage resistance properties. When these bushings are exposed to large and strong vibrations such as earthquakes, they can not only damage the insulator pipes but also damage the transformer body in which the bushings are used, causing oil inside the transformer to leak out and cause fires, fires, etc. There was a risk of secondary disasters such as environmental pollution.

This point will be explained with reference to FIGS. 1 and 2.
Fig. 1 shows a conventionally commonly used bushing called the center clamp method, in which a center conductor 1 and a capacitor core 1a wound around the center conductor 1 are placed above and below the center conductor 1 through a cylindrical support fitting 2. The bushing is housed in a bushing container consisting of an upper insulator tube 3 supported by a lower insulator tube 4 and an expansion chamber 5 provided at the top of the upper insulator tube 3. A spring 6 compressed between the center conductor 1 and the center conductor 1 is tightened together by a spring force along the axial direction of the center conductor 1. Further, insulating oil 7 is sealed between the capacitor core 1a, the insulator tubes 3 and 4, and the support fitting 2.

As shown in FIG. 2, such a bushing is attached to the upper part of a transformer tank 8b housing a main body 8a consisting of an iron core, a coil, etc., and is electrically connected to the main body 8a. However, when this bushing is exposed to vibrations such as an earthquake, since the upper insulator tube 3 is long and heavy in the upward and downward directions, a large bending moment acts, and excessive stress is generated at the lower end of the insulator tube. If this stress exceeds the allowable stress, the insulator will break. In particular, if the upper insulator tube 3 is damaged, the tightening force by the spring 6 will be lost, and the lower insulator tube 4 and the center conductor 1 will fall downward, as shown in FIG.
This will not only damage the main body 8a of the
Insulating oil 10 in the transformer tank 8b flows into the bushing from the gap 9 created between the lower insulator tube 4 and the lower insulator tube 4. This is because the conservator 12, which is connected to the transformer tank 8b through the communication pipe 11, is installed in the upper part of the transformer 8 at a higher position than the support fitting 2, and due to the pressure difference, a huge amount of oil flows into the bushing. The inflow will be blown out from the broken part of the upper insulator pipe. If the oil spews out, it is not only very dangerous as it may cause fire or human injury, but it is also undesirable as it may lead to environmental pollution.

[Purpose of invention]

The present invention is an oil-immersed transformer that eliminates the above-mentioned drawbacks and improves the safety against vibrations by preventing the oil inside the transformer from flowing into the bushings and leaking out to the outside even if the insulator pipes are damaged. The purpose is to provide

[Summary of the idea]

In order to achieve the above objectives, the present invention provides an oil drain and cutoff device in the communication pipe connecting the transformer tank and the conservator, so that this device can be used to prevent oil leakage when excessive vibrations are applied to the bushings due to earthquakes, etc. This is characterized in that a cutting device is operated to prevent oil from flowing into the bushing.

[Example of idea]

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG. Note that the same parts as in FIGS. 1 and 2 are given the same reference numerals.

In FIG. 3, inside the transformer tank 8b,
A main body 8a consisting of an iron core, a coil, etc. is housed together with oil 10, and a conservator 12 supported by mounting legs 12a is attached to the upper part of the transformer tank 8b. The conservator 12 is connected to the transformer tank 8b through a communication pipe 11 so that oil can flow therethrough, and the oil in the transformer tank 8b passes through the communication pipe 11 and is filled to approximately the middle of the conservator 12. has been done. Furthermore, a bushing 13, which is commonly used in the past and has a structure as shown in FIG.
It is electrically connected to the main body 8a.

In the transformer 8 having such a configuration, in the present invention, a remote-controlled breaker device 15, such as a solenoid valve, for blocking communication between the transformer tank 8b and the conservator 12 is provided in the middle of the communication pipe 11. It is provided.

In the oil-immersed transformer of the present invention configured as described above, in the event that the bushing 13 is destroyed due to excessive vibrations caused by an earthquake or the like,
The shredder 15 is operated by remote control to disconnect the insulating oil in the conservator 12 from the transformer tank 8b, and seal the inside of the conservator 12. Therefore, the insulating oil in the conservator 12 will not flow into the transformer tank 8b due to the pressure difference, and the insulating oil in the transformer tank 8b will also be prevented from flowing into the transformer tank 8b.
Since the communication pipe 11 with the conservator 12 is sealed tightly, there is no possibility that it will flow out from the damaged opening of the bushing 13. On the other hand, due to the breakage of the bushing 13, a small amount of insulating oil in the bushing 13 falls below the transformer 8 along the transformer tank 8b, but is generally stored in a pit 16 provided around the transformer 8. Therefore, it will not spread to the substation premises where the transformer 8 is installed. Therefore, not only is safety improved in terms of disaster prevention, but also environmental pollution is prevented.

Although the above explanation deals with the case where the bushing 13 is damaged, the present invention is also effective in cases where a crack occurs in a part of the welded part of the transformer tank 8b, which is generally manufactured with a welded structure. In addition, there is no need to modify the bushing 13 so that the insulating oil in the transformer tank 8b will not flow out even if the insulator pipe is damaged, and the conventional bushing with a simple structure can be used as is. Another advantage is that the present invention can be applied to transformers as well.

FIG. 4 shows another embodiment of the present invention, in which a device 17 for detecting seismic motion, such as an accelerometer, is installed in the transformer tank 8b near the attachment part of the bushing 13. The signal from the device 17 is used as a control signal for the shear cutting device 15. That is, as shown in the block diagram of FIG. 5, the signal generated by the detection device 17 is converted into a digital signal by the A/D converter 18 and input to the computer 19. In the computer 19, comparison calculations are performed, and when the bushing 13 reaches a dangerous level or is destroyed, a signal is output to the relay 20 and the cutoff device 15 is operated. After the shrinking operation, it is also possible to automatically recover by determining the damage caused by bushing. In this embodiment, seismic motion can be monitored in real time and the shrunken breaker can be operated before the bushing is destroyed, further increasing the reliability of accident prevention.Also, since everything can be controlled by computer, unmanned substations can be installed. It has great merits, such as being effective even with

[Effect of idea]

As described above, according to the oil-immersed transformer of the present invention, an oil draining device such as a solenoid valve is provided in the communication section connecting the transformer tank and the conservator, so that excessive vibration caused by seismic motion can be prevented. When the bushing is damaged, this shredder disconnection device is activated to separate the insulating oil in the conservator from the oil in the transformer tank and seal it, so in the event that the bushing breaks, the oil in the conservator will be removed. This prevents leakage, and even if the bushing does not break and a small crack occurs in the transformer tank, the leakage of insulating oil inside the transformer tank to the outside can be minimized, preventing disasters and environmental pollution. It is possible to improve safety. In addition, by installing equipment to detect seismic motion on the transformer, the transformer can be monitored in real time by computer control, and it can also be controlled unattended, improving reliability and saving labor.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of a general bushing, Fig. 2 is a sectional view of a conventional oil-immersed transformer at the time of an accident, and Fig. 3 is a sectional view showing an embodiment of the oil-immersed transformer of the present invention. 4 and 5 are sectional views and block diagrams of main parts showing other embodiments of the present invention. 1... Center conductor, 2... Metal fitting, 3... Upper insulator tube, 4... Lower insulator tube, 8... Transformer, 8a... Main body, 8b... Transformer tank, 10... Insulating oil, 1
1...Communication pipe, 12...Conservator, 13...
Bushing, 15... shearing device, 17... seismic motion detection device, 19... computer.

Claims (1)

[Claims for Utility Model Registration] (1) A transformer tank that houses a main body consisting of an iron core and windings together with oil, a bushing attached to the transformer tank, and an attachment part for the bushing on the top of the transformer tank. In an oil-immersed transformer consisting of a conservator installed at a higher position and a communication pipe that communicates this conservator with a transformer tank, there is an oil-filled transformer in the middle of the communication pipe that cuts off in response to vibrations. An oil-immersed transformer characterized by being equipped with a cut-off device. (2) The oil-immersed transformer according to claim 1, wherein the shearing device operates in response to a signal from a detection device that detects vibrations in the transformer tank.