JPH0354449B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a cooling system for a transformer for a hydroelectric power plant in which two or more generators are connected to one transformer.

Technical Background of the Invention Generally, in a hydroelectric power plant, two or more generators may be connected to one transformer. Further, a water-cooled type cooler is usually used to cool the transformer. On the other hand, in a hydroelectric power plant, water-cooled coolers are also required for a large number of other devices such as generators. For this reason, if water supply equipment including water supply pumps were installed individually for these coolers, a huge amount of equipment cost and space would be required. Therefore, the applicant first sought to improve the efficiency of equipment in this type of hydroelectric power plant, and at the same time developed a cooling method for the transformer that can cool the transformer without interfering with its operation.

This will be explained in more detail below with reference to FIGS. 1 and 2. In each figure, a transformer body 1 consisting of an iron core and windings, and an insulating oil 2 for cooling and insulating the transformer body are housed in a transformer tank 3. This transformer tank 3 and each cooler 4 are:
The insulating oil 2, which is connected by an oil pipe 6 equipped with an oil pump 5 and has become hot due to the operation of the transformer,
The oil is sent to the cooler 4 by the oil pump 5. The insulating oil 2 cooled by cooling water in the cooler is returned to the transformer main body side, and the contents 1 are cooled. On the other hand, the cooling water is sent to the water supply pipe 8 and the cooler 4 by the water supply pump 7, and after cooling the insulating oil 2, which has reached a high temperature, is discharged from the drain pipe 9 to the drainage equipment.

By the way, when a transformer is connected to two or more generators, there are cases where one generator is operated and the other is stopped. In this case, by controlling the cooler of the transformer in accordance with the operating status of the generator, it is possible to save the auxiliary power source without impairing the life of the transformer.

Therefore, the coolers 4 are grouped, and the coolers in A group No. 3 and 4 are supplied with water from a water supply pump 7A dedicated to the transformer. On the other hand, Group B No.
The coolers 1 and 2 and the coolers of C groups No. 5 and 6 are equipped with coolers 11 for generators 10B and 10C, respectively.
Water is supplied using water supply pumps 7B and 7C of B and 11C. That is, while the transformer is energized, the water supply pump 7A and the No. 3 cooler are operated.
No. 4 is a preliminary cooler, which is activated when a problem occurs with other coolers. On the other hand, No. 1, 2 and No. 5,
The cooler 6 and the water pumps 7B and 7C are controlled in accordance with the operation and stop of the generators 10B and 10C, respectively.

According to the above method, the water supply and drainage equipment for the transformer cooler and the water supply and drainage equipment for other equipment such as generators can be shared, resulting in a more compact equipment and efficient operation of the cooler according to the load condition. Control becomes possible.

Problems with the Background Art However, in the above system, the generator 1
0 and the operation control of the cooler 4 are fixed on a one-to-one basis, for example, when the generator 10B is stopped, only the transformer coolers 4 No. 3 to No. 6 are always operated. , the operation of the oil pump 7 and the cooler 4 will be uneven, which is unfavorable in terms of maintenance. Also, at this time, cooling water is not supplied to No. 1 and 2 coolers,
And the oil pump stops. For this reason, No. 3 to No.
Insulating oil 2, which has been cooled by cooler No. 6 and sent to the transformer body, flows backwards through coolers No. 1 and 2, which have no cooling capacity.
The amount of cooling oil flowing into the transformer tank 3 is reduced, and the cooling effect is reduced. In this case, if the valve 12 attached to the oil pipe 6 is closed, backflow of the insulating oil can be prevented, but manual operation is required, making automatic control of the cooler or unmanned power plant difficult, etc. There was a problem.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a more efficient and rational cooling method for a transformer for a hydroelectric power plant.

SUMMARY OF THE INVENTION In order to achieve this object, the present invention connects the water supply pipes of each generator to a common pipe through respective check valves, and connects the load cooler of the transformer of the common pipe. It is characterized by the following.

Embodiments of the Invention The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 3 shows a water supply and drainage system diagram for explaining a cooling system for a transformer for a hydroelectric power plant according to an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

The configuration in the figure differs from Figure 1 in that the water supply pipe 8
Check valves 13B and 13C are installed at B and 8C, respectively, and connected to the common piping 14, and the water supply pipes of the load coolers No. 1, 2, 5, and 6 are connected to the common piping 14. Also, the drain pipes 9B and 9C of the load cooler are connected by a pipe 16 equipped with a switching valve 15. In addition, 17 in the figure shows a water supply valve, and 18 shows a drain valve.

With the above configuration, the cooler 4 is controlled according to the operating state of the generator 10. That is, during no-load operation, the No. 3 no-load cooler is operated, and water is supplied and drained to the No. 3 cooler via the water supply pump 7A dedicated to the transformer, the water supply pipe 8A, and the drain pipe 9A. On the other hand, during full load operation, the water supply pumps 7B and 7C are also activated, and the cooling water is supplied to Nos. 1, 2, and 3 through the common pipe 14.
Water is supplied to coolers 5 and 6, and the load cooler is operated.

Here, if the generator 10B stops, the water supply pump 7B also stops, but the other water supply pump 7C
As a result of this operation, cooling water is always supplied to load coolers No. 1, 2, 5, and 6, so there is no problem in the operation of the load coolers. Generally, the cooling capacity of this type of cooler is proportional to the 0.5th power of the change in the amount of cooling water, so even if the amount of cooling water is halved, the reduction in cooling capacity is only about 25%, which is 50% of that of a transformer. There is no problem with load operation. In addition, since a check valve 13 is arranged inside the load water supply pipe, the water supply pipe 8
The check valve 13B is closed by the water supply pressure of C, and the cooling water does not flow backward through the water supply pipe 8B and escape.

Further, at this time, if some of the oil feed pumps 5 of the load cooler are controlled to stop, more efficient operation such as saving of auxiliary power supply and improving the life of the oil feed pump 5 can be performed. In this case, the oil pumps 5 to be stopped are No. 1 and 2.
Since it can be automatically selected arbitrarily without being limited to the cooler, the cooler operation does not become biased as in the conventional case, and rational operation is performed.

Furthermore, in this case, since cooling water is also supplied to the cooler where the oil feed pump 5 has stopped, the insulating oil 2 flowing back is further cooled, compensating for the decrease in the amount of cooling oil in the transformer tank 3, and reducing the overall power consumption of the transformer. There is almost no decrease in the cooling effect.

On the other hand, even if it becomes necessary for the generator 10B to drain the cooling water from the water supply and drainage pipes 8A and 9A due to periodic inspection, etc., by closing the water supply valve 17B and the drain valve 18B and opening the switching valve 15, the other power generation can be performed. machine 10
The No. 1 transformer load cooler with only C water supply and drainage equipment.
1, 2, 5, and 6 operations are possible. In this manner, according to the present embodiment, the transformer contents 1 are efficiently cooled during the single-circuit operation of the generator.

In the above practical example, an example was explained in which two generators were connected to one transformer, but even if three or more generators are connected, the same operation and effect can be obtained by carrying out the same procedure as in the above example. .

Effects of the Invention As described above, according to the present invention, the capacity of the supply and drainage equipment for cooling water dedicated to the transformer can be minimized.
It is possible to reduce equipment costs and occupy space at power plants. In addition, efficient operation is possible by controlling the operation of the cooler in accordance with load fluctuations or single-circuit operation of the generator. Furthermore, there is no need for any switching operation of the cooler oil piping valves, and as a result, unmanned operation of the transformer becomes possible. Further, even when one generator undergoes periodic inspection, excellent effects such as being able to continue operating the transformer using the water supply and drainage equipment of the other generator can be obtained.

[Brief explanation of drawings]

Fig. 1 is a plan view of a cooling water supply and drainage system to explain the cooling system for a transformer for a hydroelectric power plant that the applicant previously developed, Fig. 2 is a partial side view thereof, and Fig. 3 is an embodiment of the present invention. FIG. 2 is a plan view of a cooling water supply and drainage system for explaining a cooling method for a transformer for a hydroelectric power plant according to an example. 1...Contents of transformer, 2...Insulating oil, 3...Transformer tank, 4...Cooler, 5...Oil pump, 6
... Oil piping, 7 (A, B, C) ... Water pump,
8 (A, B, C)... Water supply pipe, 9 (A, B, C)
...Drain pipe, 10 (B, C) ... Generator, 11
(B, C)... Generator cooler, 12... Valve, 1
3 (B, C)...Check valve, 14...Common piping, 1
5...Switching valve, 16...Piping, 17 (A, B,
C)... Water supply valve, 18 (A, B, C)... Drain valve.

Claims (1)

[Claims] 1. In a cooling method for a transformer for a hydroelectric power plant in which two or more generators are connected to one transformer body having a plurality of coolers, each cooler is used for no-load cooling. In addition, the no-load cooler group is provided with a dedicated water supply pipe system, while the load cooler group is provided with a water supply pipe system opposite to each of the generator side cooling water pipes. A cooling method for a transformer for a hydroelectric power plant, characterized in that a stop valve is arranged and connected to a common pipe, and a water supply pipe system shared with each of the generators is connected from the common pipe to the load cooler group. . 2. In claim 1, the no-load cooler group is provided with a dedicated drain pipe system, while the load cooler group is provided with a switching valve for each of the generator-side cooling drain pipes. 1. A cooling system for a transformer for a hydroelectric power plant, characterized in that a drainage pipe system is provided which is connected to the provided piping and is shared by each of the generators and which is connected from the piping to the load cooler group. 3. In claim 1 or 2, when the transformer is not loaded, a cooler connected to the water supply and drainage system dedicated to the transformer is operated, while when the transformer is loaded, the generator is operated according to the number of operating generators. A cooling method for transformers for hydroelectric power plants that is characterized by shutting down the cooler connected to the cooling water supply and drainage system.