System and method for regulating temperature of pure water system in shutdown state of giant water-cooled generator set

Abstract

The present invention belongs to the technical field of pure water temperature regulation for hydro-generators. Specifically, it provides a system and method for regulating the temperature of the pure water system of a giant water-cooled generator set in the shutdown state. The system includes a leak collection mechanism connected to the technical water supply main of the technical water supply system. The connection position of the leak collection mechanism and the technical water supply main is arranged downstream of the technical water supply main valve. The leak collection mechanism is equipped with an electric valve and connected to the secondary water inlet pipe of the pure water cooler of the pure water system to provide secondary cooling for the pure water cooler. The system and method maintain the pure water system temperature at a constant state when the unit is in the shutdown state, eliminating the influence of temperature on the pure water system liquid level, thereby accurately monitoring whether the pure water system has leaks.

Description

Technical Field

[0001] The present invention belongs to the technical field of pure water temperature regulation for hydro-generators, and in particular relates to a temperature regulation system and method for a pure water system of a giant water-cooled generator set in a shutdown state. Background Art

[0002] Large, water-cooled hydro-generator sets are equipped with a generator pure water system. This closed-loop system circulates cooling water to cool the generator stator bars. This pure water system must remain operational regardless of whether the unit is running or shut down. Each unit's pure water system involves thousands of joints and seals. Leaks in these locations can cause internal short circuits or tripping of the generator, making sensitive monitoring of the seals at these joints crucial.

[0003] To prevent condensation during shutdown, a pit heater was installed at the bottom of the generator. However, after the unit shut down, the technical water supply valve used for cooling during operation was too large to fully close, resulting in water leakage.

[0004] Regarding leak monitoring in the pure water system, the system's expansion tank detects leaks by comparing the temperature and liquid level differences. Existing pure water system leak monitoring methods result in excessive false alarms due to the time-consuming pure water temperature fluctuations and the influence of the expansion tank's water pressure on the float. Especially during shutdown, water temperatures in various components are inconsistent due to leaks in the technical water supply to each unit. Because the units are not operating, the heat generated within the generator is limited, limiting the regulating function of the pure water system's three-way valve. The water temperature is low when passing through the pure water cooler due to the secondary cooling effect of the technical water leak on the pure water system. When passing through the generator, the water temperature is elevated due to the pit heater at the bottom of the pit. This prevents the water temperature from being lowered to a stable 38°C during shutdown, resulting in inaccurate measurements.

[0005] Currently, the pit heater activation and deactivation are controlled by measuring the pit temperature. After a unit is shut down, the pit heater is automatically activated if the pit temperature falls below 40°C and automatically deactivated if it exceeds 45°C. Existing pit heater activation and deactivation are completely controlled by air temperature. Furthermore, each unit's technical water supply is leaking. As a result, when the unit is shut down, leaked technical cooling water from the generator stator bars is used to secondary cool the pure water inside the generator, causing the internal temperature to drop. This, in turn, is heated externally by the pit heater. This results in a temperature difference between the inside and outside of the stator bars, causing deformation and inefficient energy conservation. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a temperature regulation system and method for the pure water system of a giant water-cooled generator set in a shutdown state, thereby maintaining the temperature of the unit at a constant temperature when the unit is shut down, eliminating the influence of temperature on the liquid level of the pure water system, and thus accurately monitoring whether there is a leak in the pure water system.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a temperature control system for the pure water system of a giant water-cooled generator set in the shutdown state, including a leakage collection mechanism connected to the technical water supply main pipe of the technical water supply system, the connection position of the leakage collection mechanism and the technical water supply main pipe is set downstream of the technical water supply main valve, an electric valve is provided on the leakage collection mechanism, and the leakage collection mechanism is connected to the secondary water inlet pipe of the pure water cooler of the pure water system to perform secondary cooling on the pure water cooler.

[0008] In the preferred solution, the leakage collection mechanism includes a leakage collection pipe, a collecting pipe and a water supply pipe. The leakage collection pipe is connected to the technical water supply main pipe, the tail end of the leakage collection pipe is connected to the collecting pipe, and the collecting pipe is connected to the secondary water inlet pipe of the pure water cooler through the water supply pipe. The electric valve is arranged on the leakage collection pipe.

[0009] In a preferred solution, a check valve is provided on the water supply pipe.

[0010] In a preferred solution, when the technical water supply main valve is closed, the water filter water supply electric valve upstream of the connection position between the technical water supply main pipe and the technical water supply water filter is closed, and the electric valve is opened.

[0011] In a preferred solution, the connection position between the leakage water collection mechanism and the secondary water inlet pipe of the pure water cooler is arranged upstream of the secondary water inlet main valve.

[0012] The present invention also provides a method for regulating the pure water temperature of a giant water-cooled generator set in a shutdown state. After the unit is shut down, the technical water supply main valve is closed, the electric valve is opened, and a leakage collection mechanism collects the leakage of the technical water supply main valve of each unit. The leakage water is led to a pure water cooler through the leakage collection mechanism. Part of the delivery water of the pure water pump in the pure water system is introduced into a water inlet of a three-way valve, and the other part is delivered to the pure water cooler for cooling. The opening of the three-way valve is adjusted, and the water cooled by the pure water cooler is mixed with the uncooled water delivered by the pure water pump to regulate the temperature of the pure water in the pure water system.

[0013] In the preferred solution, after the unit is shut down, when the pit temperature is lower than 40°C or the pure water system temperature is lower than 38°C, the pit heater arranged at the bottom of the generator set is put into operation; when the pit temperature is greater than 45°C or the pure water system temperature is greater than 39°C, the pit heater is shut down.

[0014] The present invention provides a system and method for regulating the temperature of a pure water system in a shutdown state of a giant water-cooled generator set, which has the following beneficial effects:

[0015] 1. By collecting the technical water supply leakage when the giant water-cooled generator set is in the shutdown state, using the heat generated during the operation of the pure water pump of the giant water-cooled generator set, and regulating the three-way valve of the pure water system, the temperature of the unit in the shutdown state is maintained at a constant temperature, eliminating the impact of temperature on the liquid level of the pure water system, thereby accurately monitoring whether there is a leak in the pure water system.

[0016] 2. Constant temperature also controls the thermal expansion and contraction of the generator stator bars.

[0017] 3. In addition to the original air temperature control of the pit heater, the logic of controlling the pit heater's activation and deactivation according to the pure water temperature is added to more effectively prevent condensation in the generator set when it is shut down and reduce the deformation of the stator wire rods.

[0018] 4. The present invention does not increase new energy consumption. It only achieves the purpose of accurately monitoring the leakage status of the pure water system and preventing condensation when the unit is shut down, and extending the life of the generator through the comprehensive utilization of the operating logic and water leakage of existing equipment. It is also very energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and examples:

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 It is a structural diagram of the water leakage collection mechanism;

[0022] Figure 3 This is a structural diagram of the technical water supply system;

[0023] Figure 4 It is a structural diagram of the pure water system;

[0024] In the figure: technical water supply main pipe 1; leakage collection mechanism 2, electric valve 201, leakage collection pipe 202, collecting pipe 203, water supply pipe 204, check valve 205; technical water supply main valve 3; pure water cooler 4; secondary water inlet pipe 5; technical water supply filter 6; water filter water supply electric valve 7; secondary water inlet main valve 8; pure water pump 9; three-way valve 10. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] like Figures 1 to 4 As shown, a temperature control system for a pure water system of a giant water-cooled generator set in a shutdown state includes a water leakage collection mechanism 2 connected to a technical water supply main pipe 1 of the technical water supply system. The connection position of the water leakage collection mechanism 2 and the technical water supply main pipe 1 is set downstream of the technical water supply main valve 3. An electric valve 201 is provided on the water leakage collection mechanism 2. The water leakage collection mechanism 2 is connected to a secondary water inlet pipe 5 of a pure water cooler 4 of the pure water system to perform secondary cooling on the pure water cooler 4. The water leakage collection mechanism can be a water pipe.

[0027] The connection position between the leakage water collection mechanism 2 and the secondary water inlet pipe 5 of the pure water cooler 4 is set upstream of the secondary water inlet main valve 8.

[0028] In this embodiment, if Figure 2 As shown, the leakage collection mechanism 2 includes a leakage collection pipe 202, a collecting pipe 203 and a water supply pipe 204. The leakage collection pipe 202 is connected to the technical water supply main 1, and the tail end of the leakage collection pipe 202 is connected to the collecting pipe 203. The collecting pipe 203 is connected to the secondary water inlet pipe 5 of the pure water cooler 4 through the water supply pipe 204. The electric valve 201 is set on the leakage collection pipe 202.

[0029] First, the amount of water leakage after the technical water supply main valve 3 of each unit is collected and then uniformly distributed through the collection pipe 203. This prevents the inability to accurately adjust the pure water temperature due to inconsistent water leakage from each unit. It also prevents the water pressure from not meeting the requirements due to the technical water supply main pipe 1 being too thick.

[0030] Preferably, when the technical water supply main valve 3 is closed, the water filter water supply electric valve 7 upstream of the connection position between the technical water supply main pipe 1 and the technical water supply filter 6 is closed, and the electric valve 201 is opened.

[0031] A leak collection pipe 202, installed behind the technical water supply main valve 3, directs leaking water to a collection pipe 203. This pipe is equipped with an electric valve 201, which closes when the technical water supply main valve 3 opens and exits the system when closed. During unit shutdown, in addition to the technical water supply main valve 3, the filter water supply electric valve 7 at the inlet of the technical water filter 6 automatically closes to prevent leakage pressure from reaching the pure water system cooler due to the excessive diameter of the main pipe. Water from the collection pipe 203 flows through the water supply pipe 204 to the pure water coolers 4 of each unit, enabling temperature regulation of the pure water during unit shutdown.

[0032] The water supply pipe 204 is provided with a check valve 205 to prevent the secondary cooling water from flowing back when the unit is running.

[0033] During the operation of the unit, the water in the pure water system is pressurized by the pure water pump, and part of the water goes directly to the three-way valve interface, and the other part of the pure water passes through the pure water cooler and enters the other interface of the three-way valve. The three-way valve controls the amount of cold and hot water entering the three-way valve by adjusting its opening. After the pure water temperature is controlled at 38°C, it flows out through the third outlet of the three-way valve and enters the generator stator rod. After cooling the stator rod, the pure water temperature rises and becomes hot water. It enters the pure water pump and re-enters the next cycle.

[0034] An expansion water tank is located at the top of the pure water system, connected to the pure water cooling loop for the generator stator windings via piping. The expansion water tank accommodates changes in the pure water's volume due to temperature fluctuations, which are reflected in changes in the tank's liquid level. When the generator is powered on, the stator generates heat as the unit load fluctuates. Since heat is generated in various parts of the generator, the temperature of the pure water flowing through it gradually increases until it completely flows out of the generator stator windings, where it no longer rises. However, the outlet water temperature maintains a fixed relationship with the expansion water tank's liquid level. By observing whether the temperature changes at the pure water pump inlet are consistent with the changes in the expansion water tank's liquid level, it is possible to determine whether the pure water system is leaking.

[0035] In the shutdown state, the stator itself does not generate heat, and the pure water pump remains running regardless of whether the unit is powered on or off. As long as the temperature of the water circulating within the pure water system remains stable at around 38°C, the expansion tank liquid level remains at a fixed value. Therefore, when the unit is shut down, any drop below this fixed value indicates a leak in the pure water system.

[0036] However, in the shutdown state, due to water leakage in the technical water supply of each unit, the water temperature of each part is actually inconsistent; because the unit is not running, the heat generated inside the generator is limited, resulting in limited regulating effect of the three-way valve of the pure water system; when passing through the pure water cooler, the water temperature is low due to the secondary cooling effect of the technical water supply leakage on the pure water system. When passing through the generator, the water temperature is high due to the action of the pit heater at the bottom of the pit. The water temperature cannot be lowered and stably controlled at 38°C in the shutdown state, resulting in inaccurate judgment on whether there is a leak in the pure water system.

[0037] The present invention provides a method for regulating the temperature of pure water in a shutdown state of a giant water-cooled generator set. After the unit is shut down, the technical water supply main valve 3 is closed, the electric valve 201 is opened, and the leakage water collection mechanism 2 collects the leakage of the technical water supply main valve 3 of each unit. The leakage water is led to the pure water cooler 4 through the leakage water collection mechanism 2. Part of the delivery water of the pure water pump 9 in the pure water system is passed into a water inlet of the three-way valve 10, and the other part is delivered to the pure water cooler 4 for cooling. The opening of the three-way valve 10 is adjusted, and the water cooled by the pure water cooler 4 is mixed with the uncooled water delivered by the pure water pump 9 to regulate the temperature of the pure water in the pure water system.

[0038] By collecting technical water supply leakage when the giant water-cooled generator set is shut down, utilizing the heat generated during the operation of the pure water pump of the giant water-cooled generator set, and regulating the pure water system's three-way valve, the temperature of the unit when shut down is maintained at a constant state, eliminating the impact of temperature on the pure water system's liquid level, thereby accurately monitoring whether there is a leak in the pure water system; at the same time, the constant temperature also controls the thermal expansion and contraction of the generator stator wire rods.

[0039] After the unit is shut down, the pit heater located at the bottom of the generator set activates when the pit temperature falls below 40°C or the pure water system temperature falls below 38°C. It deactivates when the pit temperature exceeds 45°C or the pure water system temperature exceeds 39°C. In actual production, when there are no leaks in the technical water supply, the pure water temperature is typically 10°C higher than the pit temperature. The heating control logic has two activation conditions: if either condition is met, the system activates; if either condition is met, the system deactivates.

[0040] In addition to the original air temperature control of the pit heater, the logic of controlling the pit heater's activation and deactivation according to the pure water temperature is added to more effectively prevent condensation in the generator set when it is shut down and reduce the deformation of the stator wire bars.

[0041] The present invention does not increase new energy consumption, but only achieves the purpose of accurately monitoring the leakage status of the pure water system and preventing condensation when the unit is shut down, and extending the life of the generator through the comprehensive utilization of the operating logic and water leakage of existing equipment, and is very energy-saving.

[0042] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A temperature control system for a pure water system of a giant water-cooled generator set in shutdown state, characterized in that: The invention comprises a leakage collecting mechanism (2) connected to a technical water supply main pipe (1) of a technical water supply system, wherein the connection position between the leakage collecting mechanism (2) and the technical water supply main pipe (1) is arranged downstream of a technical water supply main valve (3), an electric valve (201) is provided on the leakage collecting mechanism (2), and the leakage collecting mechanism (2) is connected to a secondary water inlet pipe (5) of a pure water cooler (4) of a pure water system to perform secondary cooling on the pure water cooler (4); the pure water system comprises a pure water cooler (4), a pure water pump (9) and a three-way valve (10), leaked water is led to the pure water cooler (4) through the leakage collecting mechanism (2), a part of the conveyed water of the pure water pump (9) in the pure water system is passed into a water inlet of the three-way valve (10), and the other part is conveyed to the pure water cooler (4) for cooling, and the opening of the three-way valve (10) is adjusted, and the cooled water of the pure water cooler (4) is mixed with the uncooled water conveyed by the pure water pump (9), thereby regulating the temperature of the pure water of the pure water system.

2. A temperature control system for a pure water system of a giant water-cooled generator set in shutdown state according to claim 1, characterized in that: The water leakage collection mechanism (2) comprises a water leakage collection pipe (202), a collecting pipe (203) and a water supply pipe (204); the water leakage collection pipe (202) is connected to the technical water supply main pipe (1); the tail end of the water leakage collection pipe (202) is connected to the collecting pipe (203); the collecting pipe (203) is connected to the secondary water inlet pipe (5) of the pure water cooler (4) via the water supply pipe (204); and the electric valve (201) is arranged on the water leakage collection pipe (202).

3. The temperature control system for the pure water system of a giant water-cooled generator set in shutdown state according to claim 2 is characterized in that: A check valve (205) is provided on the water supply pipe (204).

4. The temperature control system for the pure water system of a giant water-cooled generator set in shutdown state according to claim 1 is characterized in that: When the technical water supply main valve (3) is closed, the water filter water supply electric valve (7) upstream of the connection position between the technical water supply main pipe (1) and the technical water supply filter (6) is closed, and the electric valve (201) is opened.

5. The temperature control system for the pure water system of a giant water-cooled generator set in shutdown state according to claim 1 is characterized in that: The connection position between the leaking water collection mechanism (2) and the secondary water inlet pipe (5) of the pure water cooler (4) is arranged upstream of the secondary water inlet main valve (8).

6. A method for regulating the temperature of a pure water system in a shutdown state of a giant water-cooled generator set, characterized in that: The temperature of pure water is regulated by a temperature regulating system for a pure water system of a giant water-cooled generator set in a shutdown state as described in any one of claims 1 to 5. After the unit is shut down, the technical water supply main valve (3) is closed, the electric valve (201) is opened, and the water leakage collection mechanism (2) collects the water leakage of the technical water supply main valve (3) of each unit. The water leakage is led to a pure water cooler (4) through the water leakage collection mechanism (2). Part of the water delivered by the pure water pump (9) in the pure water system is passed into a water inlet of the three-way valve (10), and the other part is delivered to the pure water cooler (4) for cooling. The opening of the three-way valve (10) is adjusted, and the water cooled by the pure water cooler (4) is mixed with the uncooled water delivered by the pure water pump (9) to regulate the temperature of the pure water in the pure water system.

7. The method for regulating the temperature of a pure water system in a shutdown state of a giant water-cooled generator set according to claim 6, characterized in that: After the unit is shut down, when the pit temperature is lower than 40°C or the pure water system temperature is lower than 38°C, the pit heater arranged at the bottom of the generator set will be put into operation. When the pit temperature is greater than 45°C or the pure water system temperature is greater than 39°C, the pit heater will be shut down.

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