Centralized chilled water system of nuclear power plant and control method

Abstract

The invention discloses a nuclear power plant centralized chilled water system and a control method, the nuclear power plant centralized chilled water system comprises a controller, and a cold water structure, a differential pressure bypass assembly, a cold storage tank, a temperature instrument, a user system and a flow instrument which are connected with the controller, the cold water structure is connected with the differential pressure bypass assembly in parallel, and one end of the cold water structure is connected with one end of the cold storage tank; the other end of the cold storage tank is connected with a temperature instrument, the temperature instrument is further connected with one end of a user system, the other end of the user system is connected with a flow instrument, and the flow instrument is further connected with the other end of the cold water structure; the differential pressure bypass assembly comprises a differential pressure bypass valve and differential pressure bypass instruments, the differential pressure bypass valve is connected with the cold water structure in parallel, and the differential pressure bypass instruments are arranged at the two ends of the differential pressure bypass valve so that variable flow control over a user system and automatic start and stop of the cold water structure can be achieved, meanwhile, the water capacity is improved, and the start and stop frequency of the cold water structure is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of instrumentation and control equipment for nuclear power plants, and in particular to a centralized chilled water system and a control method for a nuclear power plant. Background Art

[0002] The process systems in different buildings of a nuclear power plant all have cooling load requirements. Compared with distributed chilled water systems, centralized chilled water systems are widely used in third-generation nuclear power plants due to their higher energy efficiency, easy maintenance, space saving and precise control.

[0003] However, the existing nuclear island chilled water system currently generally adopts a constant flow system, which makes it impossible to use variable flow control on the user side, and the cold water structure cannot be automatically started and stopped according to user flow requirements, and the cold water structure is frequently started and stopped under low load. Summary of the invention

[0004] The purpose of the present invention is to provide a centralized chilled water system for a nuclear power plant and a control method thereof, aiming to solve the problems that the existing chilled water system cannot use variable flow control on the user side, the cold water structure cannot be automatically started and stopped according to the user flow demand, and the cold water structure is frequently started and stopped under low load.

[0005] In a first aspect, an embodiment of the present invention provides a centralized chilled water system for a nuclear power plant, comprising a controller, a cold water structure, a pressure differential bypass component, a cold storage tank, a temperature meter, a user system and a flow meter, wherein the controller is connected to the cold water structure, the pressure differential bypass component, the cold storage tank, the temperature meter, the user system and the flow meter; the cold water structure is connected in parallel with the pressure differential bypass component, one end of the cold water structure is connected to one end of the cold storage tank, the other end of the cold storage tank is connected to the temperature meter, the temperature meter is also connected to one end of the user system, the other end of the user system is connected to the flow meter, and the flow meter is also connected to the other end of the cold water structure; wherein the pressure differential bypass component comprises a pressure differential bypass valve and a pressure differential bypass meter, the pressure differential bypass valve is connected in parallel with the cold water structure, and the pressure differential bypass meter is arranged at both ends of the pressure differential bypass valve for measuring the pressure difference at both ends of the pressure differential bypass valve.

[0006] Furthermore, the cold water structure includes a plurality of groups of cold water components, and the plurality of groups of cold water components are connected in parallel with each other;

[0007] The multiple groups of cold water components include multiple water pumps and multiple chillers. One end of each of the multiple water pumps is connected to one end of the corresponding chiller among the multiple chillers, and is also connected to one end of the pressure differential bypass valve. The other end of each of the multiple chillers is connected to the other end of the pressure differential bypass valve, and is also connected to the cold storage tank.

[0008] Furthermore, the user system includes a first user device, a second user device and an electric isolation valve; one end of the first user device is connected to the temperature meter, the other end of the first user device is connected to one end of the electric isolation valve, and the other end of the electric isolation valve is connected to the flow meter; one end of the second user device is connected to the temperature meter, and the other end of the second user device is connected to the flow meter.

[0009] Furthermore, the multiple groups of cold water components include a first chiller, a second chiller, a third chiller and a fourth chiller, and the first chiller, the second chiller, the third chiller and the fourth chiller are connected in parallel; two of the first chiller, the second chiller, the third chiller and the fourth chiller are provided with an emergency power supply.

[0010] Furthermore, each of the multiple chillers includes an evaporator, and an outlet of the evaporator is connected to one end of the cold storage tank.

[0011] Furthermore, it also includes a constant pressure tank, which is connected to each of the multiple water pumps.

[0012] Furthermore, the multiple water pumps include a first water pump, a second water pump, a third water pump and a fourth water pump, one end of the first water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the first water pump is connected to the first chiller; one end of the second water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the second water pump is connected to the second chiller; one end of the third water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the third water pump is connected to the third chiller; one end of the fourth water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the fourth water pump is connected to the fourth chiller.

[0013] In a second aspect, an embodiment of the present invention provides a control method for a centralized chilled water system of a nuclear power plant, which is applied to a controller in the centralized chilled water system of a nuclear power plant described in the first aspect, and the method includes:

[0014] Obtaining a pressure difference value of a pressure difference bypass instrument in the pressure difference bypass component, and comparing the pressure difference value with a preset pressure difference value to obtain a comparison result;

[0015] When the comparison result is that the pressure difference value is greater than the preset pressure difference value, increasing the opening of the pressure difference bypass valve in the pressure difference bypass assembly;

[0016] When the comparison result is that the pressure difference value is less than the preset pressure difference value, the opening of the pressure difference bypass valve in the pressure difference bypass assembly is reduced.

[0017] Furthermore, the cold water structure in the centralized chilled water system of the nuclear power plant includes multiple groups of cold water components, and the multiple groups of cold water components include multiple water pumps and multiple chillers; the method also includes:

[0018] Real-time monitoring of the flow value of the flow meter and the temperature value of the temperature meter;

[0019] When it is monitored that the flow value of the flow meter increases, starting a target water pump among the plurality of water pumps based on a first starting strategy;

[0020] When it is monitored that the flow value of the flow meter decreases, the plurality of water pumps are shut down based on a preset shut-down strategy.

[0021] Further, starting a target water pump among the plurality of water pumps based on the first starting strategy includes:

[0022] Obtaining the historical operating time of each water pump in the target water pump;

[0023] According to the first sorting rule in the first startup strategy, the historical operating time of each water pump in the target water pumps is processed in descending order to obtain a first operating time sequence;

[0024] The target water pumps are sorted according to the first operating time sequence to obtain sorted target water pumps, and the sorted target water pumps are started in sequence.

[0025] Further, shutting down the plurality of water pumps based on a preset shut-down strategy includes:

[0026] Obtaining historical operating time of the plurality of water pumps;

[0027] Processing the historical operating hours of the plurality of water pumps in ascending order according to the second sorting rule in the preset shutdown strategy to obtain a second operating hour sequence;

[0028] The plurality of water pumps are sorted according to the second operating time sequence to obtain a plurality of sorted water pumps, and the plurality of sorted water pumps are shut down in sequence.

[0029] Furthermore, the method further comprises:

[0030] When it is monitored that only one target chiller among the multiple chillers is in working state, and the outlet water temperature of the evaporator of the target chiller is less than the second temperature threshold, the target chiller is controlled to switch from the working state to the standby state, and the cold storage tank is started;

[0031] When it is monitored that the outlet water temperature of the evaporator of the target chiller is greater than the second temperature threshold, the target chiller is controlled to switch from the standby state to the working state, and the cold storage tank is closed.

[0032] Furthermore, the user system in the centralized chilled water system of the nuclear power plant includes a first user device, a second user device and an electric isolation valve; the method further includes:

[0033] When it is detected that the centralized chilled water system of the nuclear power plant is in a power-off condition, the electric isolation valve connected to the first user equipment is automatically closed.

[0034] The invention discloses a centralized chilled water system for a nuclear power plant and a control method thereof, comprising a controller and a cold water structure connected to the controller, a pressure differential bypass component, a cold storage tank, a temperature meter, a user system and a flow meter. The cold water structure is connected in parallel with the pressure differential bypass component, one end of the cold water structure is connected to one end of the cold storage tank, the other end of the cold storage tank is connected to the temperature meter, the temperature meter is also connected to one end of the user system, the other end of the user system is connected to the flow meter, and the flow meter is also connected to the other end of the cold water structure; the pressure differential bypass component comprises a pressure differential bypass valve and a pressure differential bypass meter, the pressure differential bypass valve is connected in parallel with the cold water structure, and the pressure differential bypass meter is arranged at both ends of the pressure differential bypass valve to realize variable flow control of the user system and automatic start and stop of the cold water structure, while increasing the water capacity and reducing the start and stop frequency of the cold water structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0036] Figure 1 A schematic block diagram of a centralized chilled water system for a nuclear power plant provided by an embodiment of the present invention;

[0037] Figure 2 A first flow chart of a control method for a centralized chilled water system in a nuclear power plant provided by an embodiment of the present invention;

[0038] Figure 3 A second flow diagram of a control method for a centralized chilled water system in a nuclear power plant provided by an embodiment of the present invention;

[0039] Figure 4 A third flow chart of the control method for a centralized chilled water system in a nuclear power plant provided by an embodiment of the present invention.

[0040] Among them, the reference numerals in the figures are as follows:

[0041] 10. Cold water structure; 11. Cold water assembly; 111. First water pump; 112. Second water pump; 113. Third water pump; 114. Fourth water pump; 115. First chiller; 116. Second chiller; 117. Third chiller; 118. Fourth chiller; 20. Pressure differential bypass assembly; 21. Pressure differential bypass valve; 22. Pressure differential bypass instrument; 30. Cold storage tank; 40. Temperature instrument; 50. User system; 51. First user equipment; 52. Second user equipment; 53. Electric isolation valve; 60. Flow meter; 70. Constant pressure tank. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0044] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0045] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0046] See also Figure 1 , Figure 1 A schematic block diagram of a centralized chilled water system for a nuclear power plant provided by an embodiment of the present invention. Figure 1As shown, an embodiment of the present invention provides a centralized chilled water system for a nuclear power plant, the system comprising a controller (not shown), a cold water structure 10, a pressure difference bypass component 20, a cold storage tank 30, a temperature instrument 40, a user system 50 and a flow meter 60, the controller is connected to the cold water structure 10, the pressure difference bypass component 20, the cold storage tank 30, the temperature instrument 40, the user system 50 and the flow meter 60; the cold water structure 10 is connected in parallel with the pressure difference bypass component 20, one end of the cold water structure 10 is connected to one end of the cold storage tank 30, The other end of the cold storage tank 30 is connected to the temperature meter 40, and the temperature meter 40 is also connected to one end of the user system 50. The other end of the user system 50 is connected to the flow meter 60, and the flow meter 60 is also connected to the other end of the cold water structure 10; wherein the pressure differential bypass assembly 20 includes a pressure differential bypass valve 21 and a pressure differential bypass meter 22, the pressure differential bypass valve 21 is connected in parallel with the cold water structure 10, and the pressure differential bypass meter 22 is arranged at both ends of the pressure differential bypass valve 21 to measure the pressure difference at both ends of the pressure differential bypass valve 21.

[0047] In this embodiment, in order to ensure that the centralized chilled water system of a nuclear power plant can operate safely and stably when the water demand changes, a pressure differential bypass component 20 is arranged in the centralized chilled water system of the nuclear power plant, wherein the pressure differential bypass component 20 is connected to the controller, and the pressure differential bypass component 20 is connected in parallel with the cold water structure 10; in addition, the pressure differential bypass valve 21 in the pressure differential bypass component 20 is connected in parallel with the cold water structure 10, and the pressure differential bypass instrument 22 in the pressure differential bypass component 20 is arranged at both ends of the pressure differential bypass valve 21 to measure the pressure difference at both ends of the pressure differential bypass valve 21; thereby, the pressure differential value measured by the pressure differential bypass instrument 22 is obtained through the controller, and the pressure differential value measured by the pressure differential bypass instrument 22 is compared with the preset pressure differential value to control the opening of the pressure differential bypass valve 21. Specifically, when the pressure difference value measured by the pressure differential bypass meter 22 is greater than the preset pressure difference value, it means that the amount of water required by the user's equipment structure is reduced. At this time, the pressure differential bypass valve 21 is gradually opened, so that a part of the water supply does not pass through the cold water structure 10, but enters the pressure differential bypass loop through the pressure differential bypass valve 21 to avoid excessive pressure on the cold water structure 10; when the pressure difference value measured by the pressure differential bypass meter 22 is less than the preset pressure difference value, it means that the amount of water required by the user's equipment structure is increased. At this time, the pressure differential bypass valve 21 is gradually reduced or closed, so that more water flows through the cold water structure 10 to meet the water demand of the user's equipment structure; at the same time, the pressure difference value measured by the pressure differential bypass meter 22 needs to be maintained within the preset pressure difference range to ensure that the flow rate through the cold water structure 10 is a constant value. In addition, the centralized chilled water system of the nuclear power plant also optimizes the operating efficiency of the cold water structure 10 and reduces frequent start and stop under low load conditions by setting a cold storage tank 30 between the cold water structure 10 and the temperature instrument 40; specifically, when the controller detects that only one target cold water unit 112 among the multiple cold water units 112 is in working condition, and the temperature instrument 40 detects that the outlet water temperature of the target cold water structure 10 among the multiple cold water structures 10 drops to the preset temperature threshold, it indicates that the current system's cooling demand is lower than the minimum output capacity of a single cold water structure 10, and the target cold water structure 10 is switched from the working state to the standby state; at this time, the cold storage tank 30 is started to release the cold storage capacity stored in the cold storage tank 30, thereby providing cooling for the downstream user equipment structure. After the cold storage tank 30 has been released, that is, when the outlet water temperature of the target cold water structure 10 is monitored to rise to the preset temperature threshold, the target cold water structure 10 is switched from the standby state to the normal operating state, thereby providing cold load for the downstream user equipment structure while storing cold for the cold storage tank 30. The cycle is repeated until the cold load demand of the user equipment structure exceeds 10% of the rated cooling capacity of the single cold water structure 10.In addition, the centralized chilled water system of the nuclear power plant also includes a temperature meter 40, a user system 50 and a flow meter 60; the temperature meter 40 is connected to the cold storage tank 30, and is also connected to one end of the user system 50, and the other end of the user system 50 is connected to the flow meter 60, and the flow meter 60 is also connected to one end of the cold water structure 10, so that the flow demand of the user system 50 can be learned through the flow meter 60; wherein, the controller monitors the flow value of the flow meter 60 and the temperature value of the temperature meter 40 in real time, and determines whether to start or shut down the cold water structure 10 by monitoring the flow value of the flow meter 60 and the temperature value of the temperature meter 40, thereby realizing automatic start and stop of the cold water structure 10.

[0048] Therefore, the above-mentioned embodiment can realize variable flow control of the user system 50 and automatic start and stop of the cold water structure 10, while increasing the water capacity and reducing the start and stop frequency of the cold water structure 10.

[0049] In one embodiment, if Figure 1 As shown, the cold water structure 10 includes multiple groups of cold water components 11, and the multiple groups of cold water components 11 are connected in parallel with each other; the multiple groups of cold water components 11 include multiple water pumps and multiple chillers, one end of each of the multiple water pumps is connected to one end of the corresponding chiller in the multiple chillers, and is also connected to one end of the pressure differential bypass valve 21, the other end of each of the multiple chillers is connected to the other end of the pressure differential bypass valve 21, and is also connected to the cold storage tank 30.

[0050] In this embodiment, the cold water structure 10 includes multiple groups of cold water components 11, and the multiple groups of cold water components 11 are connected in parallel with each other; and the multiple groups of cold water components 11 include multiple water pumps and multiple chillers for driving cold water circulation; wherein, the number of the multiple water pumps and the multiple chillers is the same, and each of the multiple water pumps is correspondingly connected to a corresponding chiller in the multiple chillers, and each of the water pumps is also connected to one end of the pressure differential bypass valve 21, so that water passes through the corresponding chiller for cooling or enters the pressure differential bypass loop. wherein, the number of the multiple water pumps and the multiple chillers can be set according to the actual needs of the user system 50, and is not specifically limited here.

[0051] In one embodiment, if Figure 1 As shown, the user system 50 includes a first user device 51, a second user device 52 and an electric isolation valve 53; one end of the first user device 51 is connected to the temperature meter 40, the other end of the first user device 51 is connected to one end of the electric isolation valve 53, and the other end of the electric isolation valve 53 is connected to the flow meter 60; one end of the second user device 52 is connected to the temperature meter 40, and the other end of the second user device 52 is connected to the flow meter 60.

[0052] In this embodiment, in view of the situation that some users still need chilled water supply under power-off conditions, the user system 50 is divided into a first user device 51 and a second user device 52; wherein, one end of the first user device 51 is connected to the temperature meter 40, and the other end of the first user device 51 is connected to one end of the electric isolation valve 53, and the other end of the electric isolation valve 53 is connected to the flow meter 60; one end of the second user device 52 is connected to the temperature meter 40, and the other end of the second user device 52 is connected to the flow meter 60. Thus, through this setting, when the centralized chilled water system of the nuclear power plant is in a power-off condition, the controller controls the electric isolation valve 53 connected to the first user device 51 to be closed, so that the cooling water of multiple chillers only passes through the second user device 52, providing a cold source for the second user device 52.

[0053] In one embodiment, if Figure 1 As shown, the multiple groups of cold water components 11 include a first chiller 115, a second chiller 116, a third chiller 117 and a fourth chiller 118, and the first chiller 115, the second chiller 116, the third chiller 117 and the fourth chiller 118 are connected in parallel; two of the first chiller 115, the second chiller 116, the third chiller 117 and the fourth chiller 118 are provided with emergency power supplies.

[0054] In this embodiment, the multiple groups of cold water components 11 include four chillers, namely, a first chiller 115, a second chiller 116, a third chiller 117 and a fourth chiller 118, wherein the first chiller 115, the second chiller 116, the third chiller 117 and the fourth chiller 118 are connected in parallel; and two of the first chiller 115, the second chiller 116, the third chiller 117 and the fourth chiller 118 are provided with a diesel engine emergency power supply, so that by providing a diesel engine emergency power supply in two of the chillers, it is ensured that they can be quickly started and provide a stable power supply in the event of a power failure, thereby providing a load for the second user equipment 52 that needs to be guaranteed.

[0055] In one embodiment, if Figure 1 As shown, each of the multiple chillers includes an evaporator, and the outlet of the evaporator is connected to one end of the cold storage tank 30.

[0056] In this embodiment, each of the multiple chillers is provided with an evaporator, which utilizes the evaporation heat absorption principle of the refrigerant to lower the temperature of the water, thereby cooling the water entering the chiller from the water pump, and then transporting the low-temperature cooled water to the cold storage tank 30 for storage and to the first user device 51 and the second user device 52 to meet the cooling needs.

[0057] In one embodiment, if Figure 1 As shown, a constant pressure tank 70 is also included, and the constant pressure tank 70 is connected to each of the multiple water pumps.

[0058] In this embodiment, in order to maintain the pressure stability in the centralized chilled water system of the nuclear power plant, the centralized chilled water system of the nuclear power plant further includes a constant pressure tank 70, wherein the constant pressure tank 70 is connected to each of the multiple water pumps. In specific implementation, before at least one of the multiple water pumps is started, a certain amount of water is pre-stored in the constant pressure tank 70 to ensure that at least one of the multiple water pumps can immediately obtain the required water flow when it is started. In addition, when at least one of the multiple water pumps is running, if the pressure of the centralized chilled water system of the nuclear power plant drops, the constant pressure tank 70 will release the water stored therein to replenish it, so as to ensure the stable operation of the water pump.

[0059] In one embodiment, the multiple water pumps include a first water pump 111, a second water pump 112, a third water pump 113 and a fourth water pump 114, one end of the first water pump 111 is connected to the constant pressure tank and the pressure differential bypass valve 21, and the other end of the first water pump 111 is connected to the first chiller 115; one end of the second water pump 112 is connected to the constant pressure tank and the pressure differential bypass valve 21, and the other end of the second water pump 112 is connected to the second chiller 116; one end of the third water pump 113 is connected to the constant pressure tank and the pressure differential bypass valve 21, and the other end of the third water pump 113 is connected to the third chiller 117; one end of the fourth water pump 114 is connected to the constant pressure tank and the pressure differential bypass valve 21, and the other end of the fourth water pump 114 is connected to the fourth chiller 118.

[0060] In this embodiment, the multiple water pumps in this embodiment specifically include a first water pump 111, a second water pump 112, a third water pump 113, and a fourth water pump 114; wherein, one end of the first water pump 111 is connected to both the constant pressure tank and the pressure differential bypass valve 21, the other end of the first water pump 111 is connected to one end of the first chiller 115, and the other end of the first chiller 115 is connected to the cold storage tank 30; one end of the second water pump 112 is connected to both the constant pressure tank and the pressure differential bypass valve 21, the other end of the second water pump 112 is connected to one end of the second chiller 116, and the other end of the second chiller 116 is connected to the cold storage tank 30. connection; one end of the third water pump 113 is connected to both the constant pressure tank and the pressure differential bypass valve 21, the other end of the third water pump 113 is connected to one end of the third chiller 117, and the other end of the third chiller 117 is connected to the cold storage tank 30; one end of the fourth water pump 114 is connected to both the constant pressure tank and the pressure differential bypass valve 21, the other end of the fourth water pump 114 is connected to one end of the fourth chiller 118, and the other end of the fourth chiller 118 is connected to the cold storage tank 30; thereby, water is pushed through the corresponding chiller for cooling by any water pump among the multiple water pumps, and the cooled cold water is then transmitted to the user system 50.

[0061] See also Figure 2 , Figure 2 The first flow chart of the control method of the centralized chilled water system of a nuclear power plant provided by the embodiment of the present invention is as follows. Figure 2 As shown, an embodiment of the present invention further provides a control method for a centralized chilled water system of a nuclear power plant, which is applied to a controller in a centralized chilled water system of a nuclear power plant, wherein the centralized chilled water system of a nuclear power plant further comprises a cold water structure, a pressure difference bypass component, a cold storage tank, a temperature instrument, a user system and a flow meter, wherein the controller is connected to the cold water structure, the pressure difference bypass component, the cold storage tank, the temperature instrument, the user system and the flow meter; the method comprises:

[0062] S110, obtaining a pressure difference value of a pressure difference bypass instrument in the pressure difference bypass assembly, and comparing the pressure difference value with a preset pressure difference value to obtain a comparison result;

[0063] S120, when the comparison result is that the pressure difference value is greater than the preset pressure difference value, increasing the opening of the pressure difference bypass valve in the pressure difference bypass assembly;

[0064] S130. When the comparison result is that the pressure difference value is less than the preset pressure difference value, reducing the opening of the pressure difference bypass valve in the pressure difference bypass assembly.

[0065] In this embodiment, the pressure difference value of the pressure difference bypass instrument in the pressure difference bypass assembly is obtained, and the pressure difference value is compared with the preset pressure difference value to obtain a comparison result, so as to adjust the valve opening of the electric bypass valve according to the comparison result; wherein, when the comparison result is that the pressure difference value is greater than the preset pressure difference value, it means that the amount of water required by the user equipment structure is reduced. At this time, the opening of the pressure difference bypass valve in the pressure difference bypass assembly is increased, so that a part of the water supply does not pass through the cold water structure, but directly enters the pressure difference bypass loop through the pressure difference bypass valve to avoid excessive pressure on the cold water structure. When the comparison result is that the pressure difference value is less than the preset pressure difference value, it means that the amount of water required by the user equipment structure is increased. At this time, the opening of the pressure difference bypass valve in the pressure difference bypass assembly is reduced, so that more water flows through the cold water structure to meet the water demand of the user equipment structure. At the same time, the pressure difference value measured by the pressure difference bypass instrument needs to be kept within the preset pressure difference range to ensure that the flow through the cold water structure is a constant value, thereby ensuring the safe and normal operation of the centralized chilled water system of the nuclear power plant.

[0066] In one embodiment, if Figure 3 As shown, the cold water structure in the centralized chilled water system of the nuclear power plant includes multiple groups of cold water components, and the multiple groups of cold water components include multiple water pumps and multiple chillers; the method also includes:

[0067] S210, monitoring the flow value of the flow meter and the temperature value of the temperature meter in real time;

[0068] S220, when it is monitored that the flow value of the flow meter increases, starting a target water pump among the multiple water pumps based on a first starting strategy;

[0069] S230: When it is monitored that the flow value of the flow meter decreases, the plurality of water pumps are shut down based on a preset shut-down strategy.

[0070] In this embodiment, the flow value of the flow meter is monitored in real time to obtain the flow demand of the current user system, and the temperature value of the entire circuit in the system is obtained through the temperature meter. Specifically, if the flow value of the flow meter is monitored to increase, the target water pump among the multiple water pumps is started based on the first startup strategy; and when the temperature value of the temperature meter is monitored to be greater than the first temperature threshold, it means that after starting the target water pump, the entire circuit in the system is still overheated. At this time, the remaining water pumps among the multiple water pumps except the target water pump are started based on the second startup strategy to meet the user's cooling needs; in addition, if the flow value of the flow meter is monitored to decrease, the multiple water pumps are closed based on the preset shutdown strategy. Therefore, the automatic start and stop of multiple water pumps and cold water components corresponding to the multiple water pumps can be realized through the above embodiment.

[0071] In one embodiment, starting a target water pump among the plurality of water pumps based on a first starting strategy includes:

[0072] Obtaining the historical operating time of each water pump in the target water pump;

[0073] According to the first sorting rule in the first startup strategy, the historical operating time of each water pump in the target water pumps is processed in descending order to obtain a first operating time sequence;

[0074] The target water pumps are sorted according to the first operating time sequence to obtain sorted target water pumps, and the sorted target water pumps are started in sequence.

[0075] In this embodiment, starting the target water pump among the multiple water pumps based on the first starting strategy specifically includes: obtaining the historical operating time of each water pump among the target water pumps; performing descending processing on the historical operating time of each water pump among the target water pumps according to the first sorting rule to obtain a first operating time sequence; sorting the target water pumps according to the first operating time sequence to obtain sorted target water pumps, and starting the sorted target water pumps in sequence. For example: the multiple water pumps include the first water pump, the second water pump, the third water pump and the fourth water pump; the target water pumps include the first water pump, the second water pump and the third water pump; and the historical operating time of the first water pump is 20 minutes, the historical operating time of the second water pump is 30 minutes and the historical operating time of the third water pump is 40 minutes, then the first water pump, the second water pump and the third water pump are started in sequence; thereby giving priority to starting the water pump and the chiller with the shortest operating time, so that all water pumps and chillers can be used relatively evenly, thereby extending the service life of the entire system.

[0076] In one embodiment, shutting down the plurality of water pumps based on a preset shut-down strategy includes:

[0077] Obtaining historical operating time of the plurality of water pumps;

[0078] Processing the historical operating hours of the plurality of water pumps in ascending order according to the second sorting rule in the preset shutdown strategy to obtain a second operating hour sequence;

[0079] The plurality of water pumps are sorted according to the second operating time sequence to obtain a plurality of sorted water pumps, and the plurality of sorted water pumps are shut down in sequence.

[0080] In this embodiment, shutting down the multiple water pumps based on the preset shutdown strategy specifically includes: obtaining the historical operating time of the multiple water pumps; processing the historical operating time of the multiple water pumps in ascending order according to the second sorting rule to obtain a second operating time sequence; sorting the multiple water pumps according to the second operating time sequence to obtain the sorted multiple water pumps, and shutting down the sorted multiple water pumps in sequence. For example: the multiple water pumps include the first water pump, the second water pump, the third water pump and the fourth water pump; wherein the historical operating time of the first water pump is 20 minutes, the historical operating time of the second water pump is 30 minutes, the historical operating time of the third water pump is 40 minutes, and the historical operating time of the fourth water pump is 50 minutes, then shut down the fourth water pump, the third water pump, the second water pump and the first water pump in sequence, so as to give priority to shutting down the water pumps and chillers with the longest operating time, so as to avoid the water pumps and chillers running for a long time will reduce the efficiency and increase the energy consumption.

[0081] In one embodiment, if Figure 4 As shown, the user system includes a first user device, a second user device and an electric isolation valve; the method also includes:

[0082] S310, when it is monitored that only one target chiller among the multiple chillers is in working state, and the outlet water temperature of the evaporator of the target chiller is less than the second temperature threshold, controlling the target chiller to switch from the working state to the standby state, and starting the cold storage tank;

[0083] S320: When it is monitored that the outlet water temperature of the evaporator of the target chiller is greater than the second temperature threshold, the target chiller is controlled to switch from the standby state to the working state, and the cold storage tank is closed.

[0084] In this embodiment, in order to avoid the problem of frequent start and stop of chillers under low load, the outlet water temperature of the state machines of the multiple chillers is monitored. When it is monitored that only one target chiller among the multiple chillers is in working state, and the outlet water temperature of the evaporator of the target chiller is less than the second temperature threshold, it means that the cooling demand of the current system is lower than the minimum output capacity of a single chiller. At this time, the controller in the centralized chilled water system of the nuclear power plant controls the target chiller to switch from working state to standby state to avoid energy waste and excessive wear of the target chiller; and starts the cold storage tank, which continues to provide cold for the downstream user system; when the cold stored in the cold storage tank is released, that is, it is detected that the outlet water temperature of the evaporator of the target chiller is greater than the second temperature threshold, the target chiller is controlled to switch from the standby state to the working state, and the cold storage tank is closed; at this time, the target chiller provides cold load for the downstream user system and stores cold for the cold storage tank. The waiting cycle is repeated until the cooling load demand of the user system exceeds 10% of the rated cooling capacity of a single chiller. Therefore, through the above embodiment, the water capacity of the system is increased, the start-stop frequency of the chiller is reduced, and the system failure rate is reduced.

[0085] In one embodiment, the method further comprises:

[0086] When it is detected that the centralized chilled water system of the nuclear power plant is in a power-off condition, the electric isolation valve connected to the first user equipment is automatically closed.

[0087] In this embodiment, the controller detects the working status of the centralized chilled water system of the nuclear power plant in real time. When it is monitored that the centralized chilled water system of the nuclear power plant is in a power-off condition, the electric isolation valve connected to the first user device is automatically closed, so that the cooling water of multiple chillers does not pass through the first user device but only passes through the second user device, thereby providing a cold source for the second user device.

[0088] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A centralized chilled water system for a nuclear power plant, characterized in that: The system includes a controller, a cold water structure, a pressure differential bypass component, a cold storage tank, a temperature meter, a user system and a flow meter. The controller is connected to the cold water structure, the pressure differential bypass component, the cold storage tank, the temperature meter, the user system and the flow meter. The cold water structure is connected in parallel with the pressure differential bypass component, one end of the cold water structure is connected to one end of the cold storage tank, the other end of the cold storage tank is connected to the temperature meter, the temperature meter is also connected to one end of the user system, the other end of the user system is connected to the flow meter, and the flow meter is also connected to the other end of the cold water structure. The pressure differential bypass component includes a pressure differential bypass valve and a pressure differential bypass meter. The pressure differential bypass valve is connected in parallel with the cold water structure, and the pressure differential bypass meter is arranged at both ends of the pressure differential bypass valve to measure the pressure difference at both ends of the pressure differential bypass valve.

2. The centralized chilled water system for a nuclear power plant according to claim 1, characterized in that: The cold water structure comprises a plurality of groups of cold water components, and the plurality of groups of cold water components are connected in parallel with each other; The multiple groups of cold water components include multiple water pumps and multiple chillers. One end of each of the multiple water pumps is connected to one end of the corresponding chiller among the multiple chillers, and is also connected to one end of the pressure differential bypass valve. The other end of each of the multiple chillers is connected to the other end of the pressure differential bypass valve, and is also connected to the cold storage tank.

3. The centralized chilled water system for a nuclear power plant according to claim 1, characterized in that: The user system includes a first user device, a second user device and an electric isolation valve; one end of the first user device is connected to the temperature meter, the other end of the first user device is connected to one end of the electric isolation valve, and the other end of the electric isolation valve is connected to the flow meter; one end of the second user device is connected to the temperature meter, and the other end of the second user device is connected to the flow meter.

4. The centralized chilled water system for a nuclear power plant according to claim 2, characterized in that: The multiple groups of cold water components include a first chiller, a second chiller, a third chiller and a fourth chiller, and the first chiller, the second chiller, the third chiller and the fourth chiller are connected in parallel; two of the first chiller, the second chiller, the third chiller and the fourth chiller are provided with emergency power supplies.

5. The centralized chilled water system for a nuclear power plant according to claim 2, characterized in that: Each of the plurality of chillers comprises an evaporator, and an outlet of the evaporator is connected to one end of the cold storage tank.

6. The centralized chilled water system for a nuclear power plant according to claim 4, characterized in that: It also includes a constant pressure tank, which is connected to each of the multiple water pumps.

7. The centralized chilled water system for a nuclear power plant according to claim 6, characterized in that: The multiple water pumps include a first water pump, a second water pump, a third water pump and a fourth water pump, one end of the first water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the first water pump is connected to the first chiller; one end of the second water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the second water pump is connected to the second chiller; one end of the third water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the third water pump is connected to the third chiller; one end of the fourth water pump is connected to the constant pressure tank and the pressure differential bypass valve, and the other end of the fourth water pump is connected to the fourth chiller.

8. A control method for a centralized chilled water system in a nuclear power plant, applied to a controller in a centralized chilled water system in a nuclear power plant according to any one of claims 1 to 7, characterized in that: The method comprises: Obtaining a pressure difference value of a pressure difference bypass instrument in the pressure difference bypass component, and comparing the pressure difference value with a preset pressure difference value to obtain a comparison result; When the comparison result is that the pressure difference value is greater than the preset pressure difference value, increasing the opening of the pressure difference bypass valve in the pressure difference bypass assembly; When the comparison result is that the pressure difference value is less than the preset pressure difference value, the opening of the pressure difference bypass valve in the pressure difference bypass assembly is reduced.

9. The control method for a centralized chilled water system of a nuclear power plant according to claim 8, characterized in that: The cold water structure in the centralized chilled water system of the nuclear power plant includes multiple groups of cold water components, and the multiple groups of cold water components include multiple water pumps and multiple chillers; the method also includes: Real-time monitoring of the flow value of the flow meter and the temperature value of the temperature meter; When it is monitored that the flow value of the flow meter increases, starting a target water pump among the plurality of water pumps based on a first starting strategy; When it is monitored that the flow value of the flow meter decreases, the plurality of water pumps are shut down based on a preset shut-down strategy.

10. The control method for a centralized chilled water system of a nuclear power plant according to claim 9, characterized in that: The starting a target water pump among the plurality of water pumps based on the first starting strategy comprises: Obtaining the historical operating time of each water pump in the target water pump; According to the first sorting rule in the first startup strategy, the historical operating time of each water pump in the target water pumps is processed in descending order to obtain a first operating time sequence; The target water pumps are sorted according to the first operating time sequence to obtain sorted target water pumps, and the sorted target water pumps are started in sequence.

11. The control method for a centralized chilled water system of a nuclear power plant according to claim 9, characterized in that: The method of shutting down the plurality of water pumps based on a preset shut-down strategy includes: Obtaining historical operating time of the plurality of water pumps; Processing the historical operating hours of the plurality of water pumps in ascending order according to the second sorting rule in the preset shutdown strategy to obtain a second operating hour sequence; The plurality of water pumps are sorted according to the second operating time sequence to obtain a plurality of sorted water pumps, and the plurality of sorted water pumps are shut down in sequence.

12. The control method for a centralized chilled water system of a nuclear power plant according to claim 9, characterized in that: The method further comprises: When it is monitored that only one target chiller among the multiple chillers is in working state, and the outlet water temperature of the evaporator of the target chiller is less than the second temperature threshold, the target chiller is controlled to switch from the working state to the standby state, and the cold storage tank is started; When it is monitored that the outlet water temperature of the evaporator of the target chiller is greater than the second temperature threshold, the target chiller is controlled to switch from the standby state to the working state, and the cold storage tank is closed.

13. The control method for a centralized chilled water system of a nuclear power plant according to claim 12, characterized in that: The user system in the centralized chilled water system of the nuclear power plant includes a first user device, a second user device and an electric isolation valve; the method further includes: When it is detected that the centralized chilled water system of the nuclear power plant is in a power-off condition, the electric isolation valve connected to the first user equipment is automatically closed.

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