Multi-gradient circulating temperature control device for pumped storage main transformer

Abstract

The invention discloses a multi-gradient circulating temperature control device for a pumped storage main transformer, which comprises a cooling oil inlet and a cooling oil outlet which are arranged on the main transformer, the cooling oil inlet and the cooling oil outlet are mutually connected through a circulating pipe (1), and the circulating pipe (1) is sequentially connected with an oil pump (2), an online monitoring device (3) and a cooling mechanism. The on-line monitoring device (3) is used for performing oil chromatographic analysis on the cooling oil; the cooling mechanism comprises a plurality of coolers which are arranged side by side, a water cooling assembly is arranged outside each cooler, a main return pipe (4) is connected to the outside of each cooler, and a first three-way electric control reversing valve (5) is arranged at the joint of each cooler and the main return pipe (4). The energy consumption of the cooling mechanism can be reduced while the cooling effect of the cooling oil of the main transformer is guaranteed.

Description

Technical Field

[0001] The invention relates to a transformer monitoring device, in particular to a multi-gradient circulation temperature control device for a pumped storage main transformer. Background Art

[0002] Since the cooling oil of the main transformer of the pumped storage power station will continue to heat up during operation, the manufacturer needs to circulate and cool the cooling oil to keep the cooling oil of the main transformer within a preset temperature range. In this regard, the current cooling method of the main transformer cooling oil is to install a temperature sensor on the main transformer and use the temperature sensor to monitor the current temperature of the cooling oil. When the temperature of the cooling oil exceeds the threshold, the cooling oil is drawn out by the oil pump and sent to the cooling mechanism, and the cooling mechanism quickly cools the cooling oil and then sends it back to the main transformer, thereby realizing its circulating cooling function.

[0003] However, the drawback of this cooling method is that the cooling oil of the main transformer will cool down quickly after the cooling mechanism is turned on, and the cooling oil will reach the temperature threshold after the cooling mechanism is turned off, so that the working temperature of the cooling oil will fluctuate within the threshold range, thereby affecting the working stability of the main transformer. On the other hand, since the heating rate of the cooling oil is different when the main transformer is in different working conditions, in order to ensure the cooling effect of the cooling oil, the manufacturer needs to select a high-power cooling mechanism to ensure the rapid cooling of the cooling oil under specific working conditions, thereby increasing the power consumption of the cooling mechanism during operation. On this basis, if the cooling mechanism continues to cool the cooling oil during the main transformer process, it will cause excessive cooling of the cooling oil and a significant increase in energy consumption, which cannot meet the economic needs of the manufacturer.

[0004] Therefore, the existing cooling method for the cooling oil of the main transformer has the problems of poor cooling effect and high energy consumption. Summary of the invention

[0005] The object of the present invention is to provide a multi-gradient circulation temperature control device for a pumped storage main transformer, which can reduce the energy consumption of the cooling mechanism while ensuring the cooling effect of the cooling oil of the main transformer.

[0006] The technical solution of the present invention is as follows: a multi-gradient circulation temperature control device for a pumped storage main transformer comprises a cooling oil inlet and a cooling oil outlet arranged on the main transformer, the cooling oil inlet and the cooling oil outlet are interconnected via a circulation pipe, an oil pump, an online monitoring device and a cooling mechanism are sequentially connected to the circulation pipe, and the online monitoring device is used for performing oil chromatography analysis on the cooling oil; the cooling mechanism comprises a plurality of coolers arranged side by side, each cooler is provided with a water cooling assembly on the outside, the plurality of coolers are connected with a main return pipe on the outside, and a first three-way electrically controlled reversing valve is provided at the connection between each cooler and the main return pipe.

[0007] In the aforementioned multi-gradient circulation temperature control device for the pumped-storage main transformer, the cooler includes a main cooler, an auxiliary cooler and a standby cooler. The main cooler is used to cool the cooling oil during the operation of the main transformer, and the auxiliary cooler is used to turn on and cool the cooling oil together with the main cooler after the cooling oil reaches a temperature threshold; the standby cooler is used to turn on and cool the cooling oil when any one of the main cooler and the auxiliary cooler fails.

[0008] In the aforementioned multi-gradient circulation temperature control device for the pumped-storage main transformer, there are multiple auxiliary coolers, and each auxiliary cooler is turned on and cools the cooling oil after the cooling oil reaches a different temperature threshold.

[0009] In the aforementioned multi-gradient circulation temperature control device for the pumped-storage main transformer, the cooling mechanism includes a box body, which is provided with a plurality of mutually separated cooling chambers, each cooling chamber is provided with a cooler, and the end of the cooler extends to the outside of the box body and is connected to the main return pipe.

[0010] In the aforementioned multi-gradient circulation temperature control device for the pumped storage main transformer, the cooler is a U-shaped tube or an S-shaped tube, and both ends of the cooler are connected to the main return pipe via a first three-way electrically controlled reversing valve. The water cooling component is a spray pipe located in the cooling chamber, and a plurality of nozzles are distributed at intervals on the spray pipe. The outside of the spray pipe extends to the outside of the box and is connected to the spray mechanism. The spray pipe is used to spray cooling water onto the surface of the U-shaped tube to achieve cooling.

[0011] In the aforementioned multi-gradient circulation temperature control device for the pumped-storage main transformer, a cooling water outlet pipe is provided at the bottom of the cooling chamber, and a liquid flow meter is provided on the cooling water outlet pipe. The liquid flow meter is used to detect the water output after any water cooling component is turned on.

[0012] In the aforementioned multi-gradient circulation temperature control device for the pumped-storage main transformer, the oil pump includes a suction pump and a return pump respectively arranged at the front and rear ends of the circulation pipe, the rear end of the main return pipe is connected to the receiving tube via the second three-way electrically controlled reversing valve, the return pump is located at the connection between the receiving tube and the main return pipe, and a liquid level sensor and spare cooling oil are respectively provided in the receiving tube.

[0013] In the aforementioned multi-gradient circulation temperature control device for the pumped storage main transformer, when the amount of cooling oil in the main transformer is less than a threshold value, the second three-way electrically controlled reversing valve adjusts the flow direction and the return pump delivers the spare cooling oil in the receiving cylinder to the main transformer;

[0014] When the cooling oil in the main transformer reaches the maximum temperature threshold, the second three-way electrically controlled reversing valve adjusts the flow direction, and the return pump delivers the spare cooling oil in the receiving cylinder to the main transformer, while the suction pump extracts the cooling oil in the main transformer and delivers it to the receiving cylinder through the cooling mechanism;

[0015] When the cooling oil in the main transformer is lower than the maximum temperature threshold, part of the auxiliary coolers are closed, and at the same time the second three-way electrically controlled reversing valve adjusts the flow direction so that the cooling oil returns directly to the main transformer after being discharged from the cooling mechanism.

[0016] In the aforementioned multi-gradient circulation temperature control device for the pumped storage main transformer, the outside of the cooler is connected to a cleaning pipe, an electric ball valve is provided at the connection between the cleaning pipe and the cooler, and one end of the cleaning pipe is connected to the receiving cylinder via a cleaning pump;

[0017] When any cooler is closed, the first three-way electrically controlled reversing valve corresponding to the cooler adjusts the flow direction to separate it from the main return pipe. At the same time, the electric ball valve corresponding to the cooler opens, and the cleaning pump transports the remaining cooling oil in the cooler to the containing cylinder.

[0018] Compared with the prior art, the present invention has the following characteristics:

[0019] (1) The present invention defines the structure of the cooling mechanism so that the device can control the number of coolers opened according to the temperature of the cooling oil of the main transformer, thereby effectively reducing the overall energy consumption of the cooling mechanism while ensuring the cooling effect of the cooling oil, and is suitable for different main transformer working conditions;

[0020] (2) By dividing the cooler into a main cooler, an auxiliary cooler and a standby cooler, the main cooler can continuously cool the cooling oil when the main transformer is working, thereby alleviating the temperature rise of the cooling oil under normal working conditions, avoiding the up and down fluctuation of the cooling oil within the temperature threshold range, and improving its working stability; by setting up a standby cooler, when any cooler fails, it can replace the cooler to cool the cooling oil, thereby further improving the stability of the present invention;

[0021] (3) On the basis of the above, the present invention further specifically defines the structure of the cooling mechanism and the water cooling assembly so that the above cooling effect can be achieved; through the structural definition of the spray mechanism, the cooling water outlet pipe and the circulating water pool, the static cooling and circulating spraying of the cooling water can be achieved, thereby ensuring the water cooling effect of the present invention on the cooling oil;

[0022] (4) By setting up the accommodating cylinder, on the one hand, the cooling oil in the main transformer can be replenished when the amount of cooling oil is insufficient, so as to prevent the auxiliary coolers from increasing the amount of cooling oil occupied after being opened one after another, thereby ensuring the stability of the use of the cooling oil; on the other hand, when the cooling oil in the main transformer reaches the maximum temperature threshold, the spare cooling oil in the accommodating cylinder can be used to replace the cooling oil in the circulation pipe for refilling, thereby quickly reducing the temperature of the cooling oil returned to the main transformer, that is, realizing rapid cooling of the main transformer;

[0023] (5) On the basis of the above, by setting up the purge pipe, the purge pump can be turned on after the cooler is closed to send the cooling oil in the cooler to the receiving tube, thereby realizing the centralized placement and management of the cooling oil and facilitating the manufacturer's regular replacement;

[0024] Therefore, the present invention can reduce the energy consumption of the cooling mechanism while ensuring the cooling effect on the cooling oil of the main transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of Example 1;

[0026] Figure 2 is a schematic structural diagram of Example 2;

[0027] Figure 3 is a schematic diagram of the connection between the cooling mechanism, the spraying mechanism and the circulating water pool in Example 2;

[0028] Figure 4 It is a schematic diagram of the connection between the cooling mechanism, the spraying mechanism, the circulating water pool and the containing cylinder in Example 3.

[0029] The markings in the accompanying drawings are: 1-circulation pipe, 2-oil pump, 3-online monitoring device, 4-main return pipe, 5-first three-way electrically controlled reversing valve, 6-main cooler, 7-auxiliary cooler, 8-standby cooler, 9-box, 10-cooling chamber, 11-spray pipe, 12-spray mechanism, 13-cooling water outlet pipe, 14-circulating water pool, 15-second three-way electrically controlled reversing valve, 16-receiving cylinder, 17-clearing pipe. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0031] Embodiment 1. A multi-gradient circulation temperature control device for a pumped storage main transformer is constructed as follows Figure 1 As shown, it includes a cooling oil inlet and a cooling oil outlet arranged on the main transformer, the cooling oil inlet and the cooling oil outlet are connected to each other through a circulation pipe 1, the circulation pipe 1 is sequentially connected with an oil pump 2, an online monitoring device 3 and a cooling mechanism, the online monitoring device 3 is used to perform oil chromatography analysis on the cooling oil; the cooling mechanism includes a plurality of coolers arranged side by side, each cooler is a conventional cooler for cooling oil of the main transformer, and the cooling efficiency and energy consumption of different coolers are different from each other; the outsides of the plurality of coolers are connected with a main return pipe 4, and a first three-way electrically controlled reversing valve 5 is provided at the connection between each cooler and the main return pipe 4.

[0032] The cooler includes a main cooler 6, an auxiliary cooler 7 and a standby cooler 8. The main cooler 6 is used to cool the cooling oil during the operation of the main transformer. The auxiliary cooler 7 is used to turn on and cool the cooling oil together with the main cooler 6 after the cooling oil reaches a temperature threshold. The standby cooler 8 is used to turn on and cool the cooling oil when any one of the main cooler 6 and the auxiliary cooler 7 fails.

[0033] An oil temperature sensor is provided in the main transformer, and the cooler is turned on or off according to monitoring data of the oil temperature sensor.

[0034] There are two auxiliary coolers 7, one of which is turned on when the cooling oil reaches 55°C, and cools the cooling oil together with the main cooler 6; the other auxiliary cooler 7 is turned on when the cooling oil reaches 65°C, and cools the cooling oil together with the main cooler 6 and the previous auxiliary cooler 7.

[0035] Working principle of the present invention: When the present invention is in use, the cooling oil in the main transformer is extracted through the cooperation of the oil pump 2 and the circulation pipe 1 and sent to the online monitoring device 3 and the main return pipe 4 in sequence, and then the online monitoring device 3 performs oil chromatography analysis on the cooling oil, and judges whether the main transformer has a fault according to the dissolved gas components and content in the cooling oil. After the cooling oil flows out of the online monitoring device 3, it enters the main cooler 6, and the main cooler 6 cools the cooling oil. After the cooling oil flows out of the main cooler 6, it directly returns to the circulation pipe 1 through the main return pipe 4 and flows back to the main transformer, thereby realizing continuous circulation and cooling of the cooling oil.

[0036] When the cooling oil is still in a temperature rise state under the cooling effect of the main cooler 6 and reaches 55°C, one of the auxiliary coolers 7 is turned on and the cooling oil passes through the main cooler 6 and the auxiliary cooler 7 in turn during the circulation cooling process, thereby improving the cooling effect on the cooling oil and avoiding the continued temperature rise of the cooling oil. Similarly, when the cooling oil is still in a temperature rise state and reaches 65°C in this state, another auxiliary cooler 7 is turned on, so that the three groups of coolers are used to cool the cooling oil in turn, that is, the cooling effect on the cooling oil is further improved to ensure the working stability of the main transformer. When the main cooler 6 or any auxiliary cooler 7 fails, the cooler is closed by the first three-way electrically controlled reversing valve 5 and the standby cooler 8 is opened, so that the standby cooler 8 is used to replace the cooler to cool the cooling oil, that is, the cooling stability of the cooling oil is ensured, and sufficient maintenance time is left for the manufacturer.

[0037] Embodiment 2. A multi-gradient circulation temperature control device for a pumped storage main transformer is constructed as follows Figure 2-3As shown, it includes a cooling oil inlet and a cooling oil outlet arranged on the main transformer, the cooling oil inlet and the cooling oil outlet are connected to each other through a circulation pipe 1, the circulation pipe 1 is sequentially connected with an oil pump 2, an online monitoring device 3 and a cooling mechanism, the online monitoring device 3 is used to perform oil chromatography analysis on the cooling oil; the cooling mechanism includes a plurality of coolers arranged side by side, each cooler is provided with a water cooling assembly on the outside, the plurality of coolers are connected with a main return pipe 4 on the outside, and a first three-way electrically controlled reversing valve 5 is provided at the connection between each cooler and the main return pipe 4.

[0038] The cooler includes a main cooler 6, an auxiliary cooler 7 and a standby cooler 8. The main cooler 6 is used to cool the cooling oil during the operation of the main transformer. The auxiliary cooler 7 is used to turn on and cool the cooling oil together with the main cooler 6 after the cooling oil reaches a temperature threshold. The standby cooler 8 is used to turn on and cool the cooling oil when any one of the main cooler 6 and the auxiliary cooler 7 fails.

[0039] An oil temperature sensor is provided in the main transformer, and the cooler is turned on or off according to monitoring data of the oil temperature sensor.

[0040] There are multiple auxiliary coolers 7 , and each auxiliary cooler 7 is turned on and cools down the cooling oil after the cooling oil reaches a different temperature threshold.

[0041] The cooling mechanism comprises a box body 9 , in which a plurality of mutually separated cooling chambers 10 are arranged. Each cooling chamber 10 is provided with a cooler, and the end of the cooler extends to the outside of the box body 9 and is connected to the main return pipe 4 .

[0042] The cooler is a U-shaped tube or an S-shaped tube, and both ends of the cooler are connected to the main return pipe 4 through the first three-way electrically controlled reversing valve 5. The water cooling component is a spray pipe 11 located in the cooling chamber 10, and a plurality of nozzles are distributed at intervals on the spray pipe 11. The outside of the spray pipe 11 extends to the outside of the box body 9 and is connected to the spray mechanism 12. The spray pipe 11 is used to spray cooling water onto the surface of the U-shaped tube to achieve cooling.

[0043] A cooling water outlet pipe 13 is provided at the bottom of the cooling chamber 10, and a liquid flow meter is provided on the cooling water outlet pipe 13. The liquid flow meter is used to detect the water output after any water cooling component is turned on. When the water output of the water cooling component is lower than the threshold, it indicates that the cooler has a fault, and then the cooler is turned off and the standby cooler 8 is turned on.

[0044] The outside of the cooling water outlet pipe 13 is connected to a circulating water pool 14 . The cooling water enters the circulating water pool 14 after being discharged through the cooling water outlet pipe 13 . The spray mechanism 12 extracts the cooling water at the bottom of the circulating water pool 14 .

[0045] Compared with Example 1, this embodiment further defines the structure of the cooling mechanism and the water cooling assembly, so that after the cooling oil flows into the cooler, the cooling water can be sprayed onto the cooler surface by the external spray mechanism 12, thereby exchanging heat with the cooling oil inside to achieve a cooling effect. After spraying, the cooling water flows to the bottom of the cooling chamber 10, and is collected by the cooling water outlet pipe 13 and uniformly flows into the circulating water pool 14. The spraying amount of the spray mechanism 12 can be monitored through the cooling water outlet pipe 13 on the cooling water outlet pipe 13, and when the spray mechanism 12 fails, the cooler is closed and the standby cooler 8 is opened, thereby achieving a switching function.

[0046] Embodiment 3. A multi-gradient circulation temperature control device for a pumped storage main transformer is constructed as follows Figure 4 As shown, it includes a cooling oil inlet and a cooling oil outlet arranged on the main transformer, the cooling oil inlet and the cooling oil outlet are connected to each other through a circulation pipe 1, the circulation pipe 1 is sequentially connected with an oil pump 2, an online monitoring device 3 and a cooling mechanism, the online monitoring device 3 is used to perform oil chromatography analysis on the cooling oil; the cooling mechanism includes a plurality of coolers arranged side by side, each cooler is provided with a water cooling assembly on the outside, the plurality of coolers are connected with a main return pipe 4 on the outside, and a first three-way electrically controlled reversing valve 5 is provided at the connection between each cooler and the main return pipe 4.

[0047] The cooler includes a main cooler 6, an auxiliary cooler 7 and a standby cooler 8. The main cooler 6 is used to cool the cooling oil during the operation of the main transformer. The auxiliary cooler 7 is used to turn on and cool the cooling oil together with the main cooler 6 after the cooling oil reaches a temperature threshold. The standby cooler 8 is used to turn on and cool the cooling oil when any one of the main cooler 6 and the auxiliary cooler 7 fails.

[0048] An oil temperature sensor is provided in the main transformer, and the cooler is turned on or off according to monitoring data of the oil temperature sensor.

[0049] There are two auxiliary coolers 7 , and each auxiliary cooler 7 is turned on and cools down the cooling oil after the cooling oil in the main transformer reaches 55° C. and 65° C. respectively.

[0050] The cooling mechanism comprises a box body 9 , in which a plurality of mutually separated cooling chambers 10 are arranged. Each cooling chamber 10 is provided with a cooler, and the end of the cooler extends to the outside of the box body 9 and is connected to the main return pipe 4 .

[0051] The cooler is a U-shaped tube or an S-shaped tube, and both ends of the cooler are connected to the main return pipe 4 through the first three-way electrically controlled reversing valve 5. The water cooling component is a spray pipe 11 located in the cooling chamber 10, and a plurality of nozzles are distributed at intervals on the spray pipe 11. The outside of the spray pipe 11 extends to the outside of the box body 9 and is connected to the spray mechanism 12. The spray pipe 11 is used to spray cooling water onto the surface of the U-shaped tube to achieve cooling.

[0052] A cooling water outlet pipe 13 is provided at the bottom of the cooling chamber 10, and a liquid flow meter is provided on the cooling water outlet pipe 13. The liquid flow meter is used to detect the water output after any water cooling component is turned on. When the water output of the water cooling component is lower than the threshold, it indicates that the cooler has a fault, and then the cooler is turned off and the standby cooler 8 is turned on.

[0053] The outside of the cooling water outlet pipe 13 is connected to a circulating water pool 14 . The cooling water enters the circulating water pool 14 after being discharged through the cooling water outlet pipe 13 . The spray mechanism 12 extracts the cooling water at the bottom of the circulating water pool 14 .

[0054] The oil pump 2 includes a suction pump and a return pump respectively arranged at the front and rear ends of the circulation pipe 1. The rear end of the main return pipe 4 is connected to the receiving tube 16 via the second three-way electrically controlled reversing valve 15. The return pump is located at the connection between the receiving tube 16 and the main return pipe 4. A balancing air valve is provided on the top of the receiving tube 16. A liquid level sensor and spare cooling oil are respectively provided in the receiving tube 16.

[0055] When the amount of cooling oil in the main transformer is less than the threshold value, the second three-way electrically controlled reversing valve 15 adjusts the flow direction and the return pump delivers the spare cooling oil in the receiving cylinder 16 to the main transformer;

[0056] When the cooling oil in the main transformer reaches 65°C, the second three-way electrically controlled reversing valve 15 adjusts the flow direction, and the return pump delivers the spare cooling oil in the receiving tube 16 to the main transformer for emergency cooling. At the same time, the suction pump extracts the cooling oil in the main transformer and passes through the cooling mechanism to the receiving tube 16.

[0057] When any cooler is closed, the second three-way electrically controlled reversing valve 15 adjusts the flow direction so that the cooling oil is discharged from the cooling mechanism and directly returns to the main transformer.

[0058] The outside of the cooler is connected to a cleaning pipe 17, and an electric ball valve is provided at the connection between the cleaning pipe 17 and the cooler. One end of the cleaning pipe 17 is connected to a one-way valve, and the other end of the cleaning pipe 17 is connected to the receiving cylinder 16 via a cleaning pump.

[0059] When any cooler is closed, the first three-way electrically controlled reversing valve 5 corresponding to the cooler adjusts the flow direction to separate it from the main return pipe 4. At the same time, the electric ball valve corresponding to the cooler opens, and the cleaning pump transports the cooling oil remaining in the cooler to the containing tube 16.

[0060] Compared with the second embodiment, the embodiment of the present invention is provided with the cooperation of the receiving tube 16 and the second three-way electrically controlled reversing valve 15, so that the receiving tube 16 can be in a closed state when the main transformer is in normal use, or a fixed amount of cooling oil is filled into the main transformer after the auxiliary cooler 7 is opened, thereby ensuring sufficient cooling oil in the main transformer. When the cooling oil in the main transformer reaches the maximum temperature threshold, the receiving tube 16 is opened and the second three-way electrically controlled reversing valve 15 adjusts the flow direction, so that the cooling oil in the circulation pipe 1 is discharged from the cooling mechanism and then enters the receiving tube 16, and the cooling oil in the receiving tube 16 is filled into the main transformer, that is, the receiving tube 16 replaces the cooling mechanism to supply oil. In this state, the low-temperature cooling oil in the receiving tube 16 can quickly cool the main transformer after being filled in the first time, that is, the stability of the main transformer is ensured; at the same time, the receiving tube 16 can also serve as a transfer area, so that it can accommodate the excess cooling oil discharged from the main transformer after being filled with cooling oil, thereby preventing the overflow of cooling oil while achieving rapid cooling, and ensuring its stability in use.

[0061] On this basis, through the structural coordination of the cleaning pump and the cleaning pipe 17, after any cooler is closed, the cooling oil in the cooler can be discharged into the containing tube 16 through the cleaning pump, thereby realizing the reflux and centralized management of the cooling oil and ensuring the stability of the overall operation of the temperature control device.

Claims

1. A multi-gradient circulation temperature control device for a pumped storage main transformer, characterized in that: The invention comprises a cooling oil inlet and a cooling oil outlet arranged on a main transformer, the cooling oil inlet and the cooling oil outlet are connected to each other via a circulation pipe (1), the circulation pipe (1) is sequentially connected to an oil pump (2), an online monitoring device (3) and a cooling mechanism, the online monitoring device (3) being used to perform oil chromatography analysis on the cooling oil; the cooling mechanism comprises a plurality of coolers arranged side by side, each cooler being provided with a water cooling assembly on the outside, the plurality of coolers being connected with a main return pipe (4) on the outside, and a first three-way electrically controlled reversing valve (5) being provided at the connection between each cooler and the main return pipe (4).

2. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 1 is characterized in that: The cooler comprises a main cooler (6), an auxiliary cooler (7) and a standby cooler (8); the main cooler (6) is used to cool the cooling oil during the operation of the main transformer; the auxiliary cooler (7) is used to start after the cooling oil reaches a temperature threshold and cool the cooling oil together with the main cooler (6); the standby cooler (8) is used to start and cool the cooling oil when any one of the main cooler (6) and the auxiliary cooler (7) fails.

3. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 2 is characterized in that: There are a plurality of auxiliary coolers (7), and each auxiliary cooler (7) is turned on and cools the cooling oil after the cooling oil reaches a different temperature threshold.

4. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 1 is characterized in that: The cooling mechanism comprises a box body (9), wherein a plurality of mutually separated cooling chambers (10) are arranged in the box body (9), each cooling chamber (10) is provided with a cooler, and an end of the cooler extends to the outside of the box body (9) and is connected to a main return pipe (4).

5. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 4 is characterized in that: The cooler is a U-shaped tube or an S-shaped tube, and both ends of the cooler are connected to the main return pipe (4) via a first three-way electrically controlled reversing valve (5). The water cooling component is a spray pipe (11) located in the cooling chamber (10), and a plurality of nozzles are arranged at intervals on the spray pipe (11). The outside of the spray pipe (11) extends to the outside of the box (9) and is connected to a spray mechanism (12). The spray pipe (11) is used to spray cooling water onto the surface of the U-shaped tube to achieve cooling.

6. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 5 is characterized in that: A cooling water outlet pipe (13) is provided at the bottom of the cooling chamber (10), and a liquid flow meter is provided on the cooling water outlet pipe (13). The liquid flow meter is used to detect the water output of any water cooling component after it is turned on.

7. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 3 is characterized in that: The oil pump (2) comprises a suction pump and a return pump respectively arranged at the front and rear ends of the circulation pipe (1); the rear end of the main return pipe (4) is connected to a receiving tube (16) via a second three-way electrically controlled reversing valve (15); the return pump is located at the connection between the receiving tube (16) and the main return pipe (4); and a liquid level sensor and spare cooling oil are respectively arranged in the receiving tube (16).

8. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 7 is characterized in that: When the amount of cooling oil in the main transformer is less than a threshold value, the second three-way electrically controlled reversing valve (15) adjusts the flow direction and the return pump delivers the spare cooling oil to the main transformer; When the cooling oil in the main transformer reaches the maximum temperature threshold, the second three-way electrically controlled reversing valve (15) adjusts the flow direction, and the return pump delivers the spare cooling oil in the receiving tube (16) to the main transformer, while the suction pump draws out the cooling oil in the main transformer and passes through the cooling mechanism to the receiving tube (16); When any cooler is closed, the second three-way electrically controlled reversing valve (15) adjusts the flow direction so that the cooling oil is discharged from the cooling mechanism and directly returns to the main transformer.

9. The multi-gradient circulation temperature control device for a pumped storage main transformer according to claim 8, characterized in that: The outside of the cooler is connected to a cleaning pipe (17), and one end of the cleaning pipe (17) is connected to the receiving cylinder (16) via a cleaning pump; When any cooler is closed, the first three-way electrically controlled reversing valve (5) corresponding to the cooler adjusts the flow direction so that it is separated from the main return pipe (4), and the cleaning pump transports the cooling oil remaining in the cooler to the receiving cylinder (16).

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