Nuclear power plant diesel generator compressed air system

Abstract

The present application relates to a kind of nuclear power plant diesel generator compressed air systems, it includes air compressor unit, starting gas bottle, overspeed protection gas bottle, diesel generator;The volume of starting gas bottle is greater than the volume of overspeed protection gas bottle;The output end of air compressor unit is connected to the input end of starting gas bottle;The output end of starting gas bottle is respectively connected to the input end of overspeed protection gas bottle and diesel generator;The output end of overspeed protection gas bottle is connected to diesel generator.The input end of overspeed protection gas bottle is connected to the output end of starting gas bottle, and starting gas bottle provides gas source for overspeed protection gas bottle.Because the volume of starting gas bottle is greater than the volume of overspeed protection gas bottle, the pressure of starting gas bottle directly connected to air compressor unit reduces slowly, so the starting frequency of air compressor unit can be greatly reduced.At the same time, because the pressure of starting gas bottle reduces slowly, the frequency of triggering pressure alarm system will also be reduced, and the frequency of on-site inspection of operation and maintenance personnel can be reduced, to avoid inconvenience to operation and maintenance personnel.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant diesel generator technology, and more particularly to a compressed air system for a nuclear power plant diesel generator. Background Technology

[0002] As the last line of electrical safety in a nuclear power plant, multiple emergency diesel generators are used. To ensure the safe operation of these generator sets, each unit is equipped with a cooling water system, fuel system, lubrication system, compressed air system, and auxiliary intake and exhaust systems. Typically, the compressed air system of a nuclear power plant's diesel generators (hereinafter referred to as the compressed air system) has two functions: providing the necessary starting compressed air for the diesel generator's startup; and providing the necessary overspeed protection compressed air when the diesel generator is operating at overspeed. Usually, the compressed air system only has one air compressor unit. Therefore, the same air compressor unit is connected to both the starting air cylinder and the overspeed protection air cylinder. The starting air cylinder and the overspeed protection air cylinder are then connected to the diesel generator, providing the necessary compressed air for the generator under the corresponding conditions (startup or overspeed protection). When the pressure in the starting air cylinder or the overspeed protection air cylinder falls below the limit, the air compressor unit automatically starts to replenish the air supply to the cylinder, simultaneously triggering the pressure alarm system to alert maintenance personnel to conduct on-site inspection.

[0003] However, existing compressed air systems for diesel generators in nuclear power plants have several drawbacks. The small capacity of the overspeed protection cylinders and the presence of pipeline leaks lead to frequent starts of the air compressor units to replenish them. According to feedback from one nuclear power plant, the air compressor units need to be started more than 10 times a day. This frequent starting increases equipment failure rates and maintenance costs, thus affecting the reliability of the air supply. Furthermore, it requires maintenance personnel to frequently visit the site for inspections, causing them considerable inconvenience. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an improved compressed air system for a nuclear power plant diesel generator.

[0005] The technical solution adopted by the present invention to solve its technical problem is: to provide a compressed air system for a nuclear power plant diesel generator, which includes an air compressor unit, a starting air cylinder, an overspeed protection air cylinder, and a diesel generator;

[0006] The volume of the starting gas cylinder is greater than the volume of the overspeed protection gas cylinder;

[0007] The output end of the air compressor unit is connected to the input end of the starting gas cylinder; the output end of the starting gas cylinder is connected to the input end of the overspeed protection gas cylinder and the diesel generator respectively; the output end of the overspeed protection gas cylinder is connected to the diesel generator.

[0008] Preferably, the compressed air system of the nuclear power plant's diesel generator also includes a pressure monitoring unit;

[0009] The pressure monitoring unit is connected to the starting gas cylinder and monitors the pressure value inside the starting gas cylinder;

[0010] When the pressure value of the starting gas cylinder is lower than the first preset value, the air compressor unit is turned on to provide gas supply to the starting gas cylinder.

[0011] When the pressure value of the starting gas cylinder is lower than the second preset value, the pressure monitoring unit triggers a low pressure warning alarm;

[0012] Wherein, the first preset value is greater than the second preset value.

[0013] Preferably, the first preset value is 35 to 37 bar; and / or, the second preset value is 34 bar.

[0014] Preferably, the air compressor unit stops operating when the pressure value of the starting gas cylinder is higher than a third preset value.

[0015] Preferably, the third preset value is 39 bar.

[0016] Preferably, the pressure monitoring unit includes a pressure sensor and an alarm module;

[0017] The pressure sensor is communicatively connected to the alarm module; the pressure sensor is connected to the starter gas cylinder to monitor the internal pressure value of the starter gas cylinder; when the pressure value of the starter gas cylinder is lower than a second preset value, the alarm module is activated.

[0018] Preferably, the number of air compressor units is two or more;

[0019] The output terminals of two or more air compressor units are respectively connected to the input terminals of the starting gas cylinder; among the two or more air compressor units, one of the air compressor units is the working unit, and the remaining air compressor units are the standby units.

[0020] Preferably, the output ends of two or more air compressor units are connected to the input end of the starting gas cylinder through parallel pipelines; a first isolation valve is provided on the parallel pipelines.

[0021] Preferably, the compressed air system of the nuclear power plant diesel generator further includes an overspeed protection air supply pipeline;

[0022] The output end of the starting gas cylinder and the input end of the overspeed protection gas cylinder are connected through the overspeed protection gas supply pipeline, and a second isolation valve is provided on the overspeed protection gas supply pipeline.

[0023] Preferably, the overspeed protection air supply line is also equipped with a check valve.

[0024] Preferably, the compressed air system of the nuclear power plant diesel generator further includes a first start-up air supply line, a second start-up air supply line, a control air supply line, and a main start-up valve; the number of start-up air cylinders is two; and the number of diesel generators is two.

[0025] One of the starting gas cylinders is connected to one of the diesel generators via the first starting gas supply line;

[0026] Another starting gas cylinder is connected to another diesel generator through the second starting gas supply line;

[0027] The main start valves are respectively installed on the side of the first start air supply line near one of the diesel generators and on the side of the second start air supply line near the other diesel generator.

[0028] One end of the control gas supply line is connected between the first start gas supply line and the second start gas supply line, and the other end of the control gas supply line is connected to the main start valve on the first start gas supply line and the main start valve on the second start gas supply line, respectively.

[0029] The overspeed protection air supply line is connected to the control air supply line.

[0030] Preferably, the control air supply line is equipped with a pressure reducing valve and a start control air valve; the start control air valve is closer to the diesel generator than the pressure reducing valve.

[0031] Preferably, the compressed air system of the nuclear power plant diesel generator further includes a shutdown pipeline connected to the control air supply pipeline, and a shutdown air valve installed on the shutdown pipeline.

[0032] Preferably, the compressed air system of the nuclear power plant diesel generator further includes an output pipeline and an overspeed control air valve installed on the output pipeline;

[0033] The output end of the overspeed protection gas cylinder is connected to the diesel generator through the output pipeline.

[0034] Preferably, the ratio of the volume of the starting gas cylinder to the volume of the overspeed protection gas cylinder is (35:1) to (45:1).

[0035] This invention offers at least the following advantages: By connecting the input end of the overspeed protection cylinder to the output end of the starting cylinder, the starting cylinder provides the air supply to the overspeed protection cylinder. Because the volume of the starting cylinder is larger than that of the overspeed protection cylinder, the pressure of the starting cylinder, which is directly connected to the air compressor unit, decreases more slowly, thus significantly reducing the starting frequency of the air compressor unit. Simultaneously, the slower pressure decrease in the starting cylinder also reduces the frequency of triggering the pressure alarm system, thereby decreasing the frequency of on-site inspections by maintenance personnel and avoiding inconvenience. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0037] Figure 1 This is a schematic diagram of the system connection of the compressed air system of a nuclear power plant diesel generator according to an embodiment of the present invention. Detailed Implementation

[0038] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0039] The existing diesel generator compressed air system only has one air compressor unit. Therefore, this same air compressor unit is connected to both a starting air cylinder and an overspeed protection air cylinder. When the air compressor unit operates, it stores compressed air in both the starting air cylinder and the overspeed protection air cylinder. These cylinders are then connected to the diesel generator, providing the necessary compressed air for the generator under corresponding conditions (starting or overspeed protection). When the diesel generator receives an emergency start command, the starting air cylinder provides the high-pressure power source required for starting. When the diesel generator operates at overspeed (reaching 112% of rated speed), the overspeed protection air cylinder provides the high-pressure power source required for overspeed shutdown protection. Furthermore, if the pressure in either the starting air cylinder or the overspeed protection air cylinder falls below the limit, the air compressor unit automatically starts to replenish the air supply to either cylinder, simultaneously triggering a pressure alarm system to alert maintenance personnel to conduct on-site inspection.

[0040] In practice, it has been found that due to the small volume of the overspeed protection cylinders and the existence of pipeline leaks, the overspeed protection cylinders frequently experience insufficient pressure and require replenishment, leading to frequent starts of the air compressor units to supply gas to the cylinders. According to feedback from a nuclear power plant system, the air compressor units need to be started more than 10 times a day. Frequent starts of the air compressor units increase equipment failure rates and maintenance costs, thus affecting the reliability of the air supply. Simultaneously, maintenance personnel need to frequently visit the site for inspections, causing considerable inconvenience. Increasing the volume of the overspeed protection cylinders would require corresponding expansion of the air compressor units and modifications to the site layout, making practical operation difficult and incurring significant modification costs.

[0041] Figure 1 An embodiment of the present invention is shown of a nuclear power plant diesel generator compressed air system, which includes an air compressor unit 1, a starting air cylinder 2, an overspeed protection air cylinder 3, and a diesel generator 4.

[0042] Because the amount of compressed air required to start the diesel generator 4 is much greater than the amount of compressed air required for overspeed shutdown protection, the volume of the starting air cylinder 2 is greater than the volume of the overspeed protection air cylinder 3. The ratio of the volume of the starting air cylinder 2 to the volume of the overspeed protection air cylinder 3 can be (35:1) to (45:1).

[0043] The output of air compressor unit 1 is connected to the input of starting gas cylinder 2. The output of starting gas cylinder 2 is connected to the input of overspeed protection gas cylinder 3 and diesel generator 4. The output of overspeed protection gas cylinder 3 is connected to diesel generator 4.

[0044] Because the volume of starting gas cylinder 2 is much larger than that of overspeed protection gas cylinder 3, the input end of overspeed protection gas cylinder 3 is connected to the output end of starting gas cylinder 2 by modifying the pipeline connection. Starting gas cylinder 2 then provides the air supply to overspeed protection gas cylinder 3. Since the volume of starting gas cylinder 2 is larger than that of overspeed protection gas cylinder 3, the pressure of starting gas cylinder 2, which is directly connected to air compressor unit 1, decreases more slowly. This significantly reduces the starting frequency of air compressor unit 1, thereby preventing increased equipment failure rates, higher maintenance costs, and ensuring the reliability of air supply to air compressor unit 1. Simultaneously, the slower pressure decrease in starting gas cylinder 2 also reduces the frequency of triggering the pressure alarm system, decreasing the frequency of on-site inspections by maintenance personnel and minimizing inconvenience.

[0045] The compressed air system of the diesel generator in the nuclear power plant also includes a control unit (not shown). The control unit is connected to the air compressor unit 1 and the starting air cylinder 2, and controls the start and stop of the air compressor unit 1. The control unit can be a microcontroller, computer, or other device with logic control functions.

[0046] Furthermore, in this embodiment, the compressed air system of the nuclear power plant diesel generator also includes a pressure monitoring unit. The pressure monitoring unit is connected to the starting gas cylinder 2, monitors the pressure value inside the starting gas cylinder 2, and feeds it back to the control unit. The pressure value corresponding to triggering the start-up action of the air compressor unit 1 is a first preset value; the pressure value corresponding to triggering the low-pressure alarm is a second preset value. The first preset value is greater than the second preset value.

[0047] For example, the first preset value can be 35-37 bar (absolute pressure). The second preset value can be 34 bar (absolute pressure).

[0048] When the pressure monitoring unit detects that the pressure value of the starting gas cylinder 2 is lower than the first preset value, it sends a corresponding signal to the control unit. The control unit then issues a command to start the air compressor unit 1. After the air compressor unit 1 starts, it provides gas supply to the starting gas cylinder 2. If the gas supply to the starting gas cylinder 2 proceeds normally, the low pressure alarm will not be triggered. When the pressure value of the starting gas cylinder 2 is lower than the second preset value, it likely indicates that the gas supply to the starting gas cylinder 2 has not been successful, and manual intervention is required. In this case, the pressure monitoring unit triggers a low pressure alarm, notifying the maintenance personnel, who will then go to the site to investigate the cause.

[0049] Therefore, the pressure value that triggers the start-up action of air compressor unit 1 is no longer the same as the pressure value that triggers the low-pressure alarm, thus eliminating the interlocking triggering setting between the start-up action of air compressor unit 1 and the alarm action of the pressure monitoring unit. Furthermore, since the first preset value is greater than the second preset value, if the replenishment of gas cylinder 2 proceeds normally, the low-pressure alarm will not be triggered. This significantly reduces the number of times maintenance personnel need to visit the site while ensuring unit safety.

[0050] Furthermore, in this embodiment, the pressure monitoring unit includes a pressure sensor (not shown) and an alarm module (not shown).

[0051] The pressure sensor and alarm module communicate with each other via the control unit. The pressure sensor is connected to the starting gas cylinder 2, monitors the internal pressure value of the starting gas cylinder 2, and feeds it back to the control unit in real time. When the pressure value of the starting gas cylinder 2 is lower than a second preset value, the control unit issues a command to activate the alarm module. The alarm module may include a buzzer, which sounds an alarm when the pressure value of the starting gas cylinder 2 is lower than the second preset value. Alternatively, the alarm module may include an LED display. When the pressure value of the starting gas cylinder 2 is lower than the second preset value, the corresponding alarm information is displayed on the LED display.

[0052] Furthermore, in this embodiment, when the pressure value of the starting gas cylinder 2 is higher than a third preset value, the air compressor unit 1 shuts down. The third preset value can be 39 bar (absolute pressure). For example, when the pressure monitoring unit detects that the pressure value of the starting gas cylinder 2 is lower than a first preset value, it sends a corresponding signal to the control unit. The control unit then issues a command to control the air compressor unit 1 to start. After the air compressor unit 1 starts, it provides gas supply to the starting gas cylinder 2. During the gas supply replenishment process, the pressure value inside the starting gas cylinder 2 gradually increases until it reaches 39 bar (absolute pressure). At this point, the control unit issues a command to control the air compressor unit 1 to stop, and the air compressor unit 1 shuts down accordingly.

[0053] Furthermore, the number of air compressor units 1 is two or more. The output terminals of the two or more air compressor units 1 are respectively connected to the input terminals of the starting air cylinders 2. Among the two or more air compressor units 1, one air compressor unit 1 is the working unit, and the remaining air compressor units 1 are standby units. When the system is running, the working unit operates normally. When the working unit needs maintenance, the working unit is shut down, and the standby units are started and put into operation. In this way, the sufficiency of compressed air supply can be guaranteed in real time, ensuring that the diesel engine can operate safely and stably in real time.

[0054] Furthermore, the output ends of two or more air compressor units 1 are connected to the input end of the starting gas cylinder 2 via the same parallel pipeline 10. A first isolation valve 11 is installed on the parallel pipeline 10. During normal system operation, the first isolation valve 11 is normally closed. The working unit operates normally, providing air to the starting gas cylinder 2 through the parallel pipeline 10. When the working unit is undergoing maintenance, it is shut down, and maintenance personnel open the first isolation valve 11 on the parallel pipeline 10. Another standby unit then starts up, providing air to the starting gas cylinder 2 through the parallel pipeline 10.

[0055] In this embodiment, there are two air compressor units 1. The output terminals of the two air compressor units 1 are respectively connected to the input terminals of the starting gas cylinder 2.

[0056] In this embodiment, the compressed air system of the nuclear power plant diesel generator also includes an overspeed protection air supply line 30.

[0057] The output end of the starting gas cylinder 2 and the input end of the overspeed protection gas cylinder 3 are connected via an overspeed protection gas supply line 30, which is equipped with a second isolation valve 31. The second isolation valve 31 can be connected to a control unit to control its opening and closing. When the control unit controls the second isolation valve 31 to open, the overspeed protection gas cylinder 3 connects to the starting gas cylinder 2, connecting to a supplementary gas source. When the control unit controls the second isolation valve 31 to close, the overspeed protection gas cylinder 3 is isolated from the starting gas cylinder 2.

[0058] Similarly, a pressure sensor connected to the overspeed protection cylinder 3 can be installed on the overspeed protection gas cylinder 3 or the overspeed protection gas supply line 30. This pressure sensor is connected to the control unit to monitor the internal pressure value of the overspeed protection gas cylinder 3. When the internal pressure value of the overspeed protection gas cylinder 3 is less than the fourth preset value, the control unit issues a command to open the second isolation valve 31, connecting the overspeed protection gas cylinder 3 to the starting gas cylinder 2 and connecting it to the replenishment gas source. When the internal pressure value of the overspeed protection gas cylinder 3 is less than the fifth preset value, it likely indicates that the overspeed protection gas cylinder 3 has not been successfully replenished and requires manual intervention for inspection. In this case, the alarm module sends an alarm message corresponding to the overspeed protection gas cylinder 3 to the maintenance personnel, who then go to the site to check the cause.

[0059] Furthermore, in this embodiment, a check valve 32 is also provided on the overspeed protection gas supply line 30 to prevent gas backflow in the overspeed protection gas supply line 30.

[0060] Furthermore, in this embodiment, the compressed air system of the nuclear power plant diesel generator also includes a first start-up air supply line 51, a second start-up air supply line 52, a control air supply line 53, and a main start-up valve 56. There are two start-up air cylinders 2 and two diesel generators 4. One start-up air cylinder 2 is connected to one of the diesel generators 4 via the first start-up air supply line 51. The other start-up air cylinder 2 is connected to the other diesel generator 4 via the second start-up air supply line 52. The main start-up valve 56 is respectively located on the side of the first start-up air supply line 51 near one of the diesel generators 4 and on the side of the second start-up air supply line 52 near the other diesel generator 4. The first start-up air supply line 51 and the second start-up air supply line 52 are directly connected to the main unit of the diesel generator 4. During the start-up phase of the diesel generator 4, by controlling the opening of the main start-up valve 56, the corresponding start-up air cylinder 2 quickly provides the required air source to the diesel generator 4.

[0061] One end of the control gas supply line 53 is connected between the first start gas supply line 51 and the second start gas supply line 52, and the other end of the control gas supply line 53 is connected to the main start valve 56 on the first start gas supply line 51 and the main start valve 56 on the second start gas supply line 52, respectively.

[0062] Specifically, the control gas supply line 53 includes a first branch bypass 531, a second branch bypass 532, a third branch bypass 533, a fourth branch bypass 534, and a main line 530. The first branch bypass 531 connects the first start gas supply line 51 to the first end of the main line 530. The second branch bypass 532 connects the second start gas supply line 52 to the first end of the main line 530. Both the first branch bypass 531 and the second branch bypass 532 are equipped with check valves 32.

[0063] The third branch bypass 533 is connected between the main start valve 56 of the first start air supply line 51 and the second end of the main line 530, enabling the other end of the control air supply line 53 to be connected to the main start valve 56 on the first start air supply line 51. The fourth branch bypass 534 is connected between the main start valve 56 of the second start air supply line 52 and the second end of the main line 530, enabling the other end of the control air supply line 53 to be connected to the main start valve 56 on the second start air supply line 52.

[0064] The control air supply line 53 is equipped with a pressure reducing valve 54 and two start-up control air valves 55. The pressure reducing valve 54 is located on the main line 530 of the control air supply line 53. The two start-up control air valves 55 are respectively located on the third branch bypass 533 and the fourth branch bypass 534. Compressed air from the main line 530 is reduced in pressure by the pressure reducing valve 54 before entering the third branch bypass 533 and the fourth branch bypass 534.

[0065] The overspeed protection air supply line 30 is connected to the main line 530 of the control air supply line 53, and can also be connected between the pressure reducing valve 54 and the first end of the main line 530. The air source for the overspeed protection air supply line 30 comes from compressed air supplied from one of the starting air cylinders 2 and the output of the other starting air cylinder 2 into the main line 530 of the control air supply line 53. Thus, both starting air cylinders 2 can supply air to the overspeed protection air supply line 30, and the two starting air cylinders 2 can serve as backups for each other. When one starting air cylinder 2 fails, the other starting air cylinder 2 can serve as a backup and continue to supply air to the overspeed protection air supply line 30.

[0066] Furthermore, in this embodiment, the compressed air system of the nuclear power plant diesel generator also includes a shutdown pipeline 57 and a shutdown air valve 58. The shutdown air valve 58 is installed on the shutdown pipeline 57, which is connected to the control air supply pipeline 53. The shutdown air valve 58 is connected to the shutdown cylinder 59. The shutdown air valve 58 can also be connected to the control unit. In an emergency, the diesel generator 4 can be quickly shut down by controlling the shutdown air valve 58 to open.

[0067] That is, the compressed air in the control air supply line 53 is reduced in pressure by the pressure reducing valve 54 and then supplied to the two start control air valves 55 on the third branch bypass 533 and the fourth branch bypass 534, as well as the stop air valve 58 on the stop line 57.

[0068] The output end of the overspeed protection gas cylinder 3 is connected to the diesel generator 4 via an output pipe 40. An overspeed control air valve 41 is installed on the output pipe 40. The overspeed control air valve 41 can also be connected to the control unit. By controlling the overspeed control air valve 41 to open, fuel supply to the diesel generator 4 is stopped, thereby gradually reducing the speed until the diesel generator 4 stops operating.

[0069] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features and make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A compressed air system for a nuclear power plant diesel generator, characterized in that, Includes air compressor unit (1), starting gas cylinder (2), overspeed protection gas cylinder (3), and diesel generator (4); The volume of the starting gas cylinder (2) is greater than the volume of the overspeed protection gas cylinder (3); The output end of the air compressor unit (1) is connected to the input end of the starting gas cylinder (2); the output end of the starting gas cylinder (2) is connected to the input end of the overspeed protection gas cylinder (3) and the diesel generator (4); the output end of the overspeed protection gas cylinder (3) is connected to the diesel generator (4). The compressed air system of the nuclear power plant diesel generator also includes an overspeed protection air supply line (30), a first start air supply line (51), a second start air supply line (52), a control air supply line (53), and two main start valves (56). The number of the starting gas cylinders (2) is two; the number of the diesel generators (4) is two; one of the starting gas cylinders (2) is connected to one of the diesel generators (4) through the first starting gas supply line (51); the other starting gas cylinder (2) is connected to the other diesel generator (4) through the second starting gas supply line (52); the two main starting valves (56) are respectively installed on the first starting gas supply line (51) and the second starting gas supply line (52); The control gas supply line (53) includes a first branch bypass (531), a second branch bypass (532), a third branch bypass (533), a fourth branch bypass (534), and a main line (530); the first branch bypass (531) is connected between the first start-up gas supply line (51) and the first end of the main line (530); the second branch bypass (532) is connected between the second start-up gas supply line (52) and the first end of the main line (530); the third branch bypass (533) is connected between the main start valve (56) of the first start-up gas supply line (51) and the second end of the main line (530); the fourth branch bypass (534) is connected between the main start valve (56) of the second start-up gas supply line (52) and the second end of the main line (530). The main pipeline (530) is equipped with a pressure reducing valve (54), and the third branch bypass (533) and the fourth branch bypass (534) are respectively equipped with start control air valves (55). The overspeed protection air supply pipeline (30) is connected between the pressure reducing valve (54) and the first end of the main pipeline (530).

2. The compressed air system for a nuclear power plant diesel generator according to claim 1, characterized in that, The compressed air system of a nuclear power plant's diesel generator also includes a pressure monitoring unit; The pressure monitoring unit is connected to the starting gas cylinder (2) and monitors the pressure value inside the starting gas cylinder (2); When the pressure value of the starting gas cylinder (2) is lower than the first preset value, the air compressor unit (1) is turned on to provide gas supply to the starting gas cylinder (2); When the pressure value of the starting gas cylinder (2) is lower than the second preset value, the pressure monitoring unit triggers a low pressure warning alarm; Wherein, the first preset value is greater than the second preset value.

3. The compressed air system for a nuclear power plant diesel generator according to claim 2, characterized in that, The first preset value is 35~37 bar; and / or, the second preset value is 34 bar.

4. The compressed air system for a nuclear power plant diesel generator according to claim 2, characterized in that, When the pressure value of the starting gas cylinder (2) is higher than the third preset value, the air compressor unit (1) stops operating.

5. The compressed air system for a nuclear power plant diesel generator according to claim 4, characterized in that, The third preset value is 39 bar.

6. The compressed air system for a nuclear power plant diesel generator according to claim 2, characterized in that, The pressure monitoring unit includes a pressure sensor and an alarm module; The pressure sensor is communicatively connected to the alarm module; the pressure sensor is connected to the starter gas cylinder (2) to monitor the internal pressure value of the starter gas cylinder (2); when the pressure value of the starter gas cylinder (2) is lower than the second preset value, the alarm module is activated.

7. The compressed air system for a nuclear power plant diesel generator according to claim 1, characterized in that, The number of air compressor units (1) is two or more; The output ends of two or more air compressor units (1) are respectively connected to the input end of the starting gas cylinder (2); among the two or more air compressor units (1), one of the air compressor units (1) is the working unit, and the remaining air compressor units (1) are the standby units.

8. The compressed air system for a nuclear power plant diesel generator according to claim 7, characterized in that, The output ends of two or more air compressor units (1) are connected to the input end of the starting gas cylinder (2) through a parallel pipeline (10); a first isolation valve (11) is provided on the parallel pipeline (10).

9. The compressed air system for a nuclear power plant diesel generator according to claim 1, characterized in that, The overspeed protection air supply line (30) is equipped with a second isolation valve (31).

10. The compressed air system for a nuclear power plant diesel generator according to claim 9, characterized in that, The overspeed protection air supply line (30) is also equipped with a check valve (32).

11. The compressed air system for a nuclear power plant diesel generator according to any one of claims 1-10, characterized in that, The start-up control air valve (55) is closer to the diesel generator (4) than the pressure reducing valve (54).

12. The compressed air system for a nuclear power plant diesel generator according to any one of claims 1-10, characterized in that, The compressed air system of the nuclear power plant diesel generator also includes a shutdown line (57) connected to the control air supply line (53) and a shutdown air valve (58) installed on the shutdown line (57).

13. The compressed air system for a nuclear power plant diesel generator according to any one of claims 1-10, characterized in that, The compressed air system of the nuclear power plant diesel generator also includes an output pipeline (40) and an overspeed control air valve (41) installed on the output pipeline (40). The output end of the overspeed protection gas cylinder (3) is connected to the diesel generator (4) through the output pipeline (40).

14. The compressed air system for a nuclear power plant diesel generator according to any one of claims 1-10, characterized in that, The ratio of the volume of the starting gas cylinder (2) to the volume of the overspeed protection gas cylinder (3) is (35:1) to (45:1).

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