Emergency power supply system of nuclear power plant

Abstract

The invention discloses an emergency power supply system for a nuclear power plant. The emergency power supply system comprises an emergency diesel generating set, an external auxiliary system and a plurality of internal auxiliary systems, the emergency diesel generator set comprises a plurality of small-power diesel generators with the maximum power not exceeding 2400 KW. The built-in auxiliary systems are in one-to-one correspondence with the small-power diesel generators, and each built-in auxiliary system is integrated in the corresponding small-power diesel generator; the external auxiliary system comprises a fuel oil system and an exhaust system, and the small-power diesel generators are connected with the fuel oil system and the exhaust system respectively. As the maximum power of the small-power diesel generator does not exceed 2400KW, the auxiliary system of the small-power diesel generator is small in volume, and part of the auxiliary system can be integrated in the small-power diesel generator. The small-power diesel generator is simple in structure and high in reliability; and in the power range that the maximum power does not exceed 2400 KW, multiple types can be selected, related technologies, experience, spare parts, tools and the like are universal, and maintenance is convenient.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power technology, and in particular to an emergency power supply system for a nuclear power plant. Background Art

[0002] Emergency diesel generators are used in nuclear power plants as the last power safety barrier of nuclear power plants. When the nuclear power plant loses the plant power supply and the external power grid backup power supply, the emergency diesel generator will automatically start to provide emergency power to the safety facilities of the nuclear power plant. At present, a single reactor in a nuclear power plant is usually equipped with three high-power emergency diesel generators. The rated power of each emergency diesel generator is about 8000KW, and the three high-power emergency diesel generators are arranged in three independent workshops. The high-power emergency diesel generator is usually based on the largest power diesel generator available on the market, and is formed by design potential tapping and upgrading. It has the following defects: it is close to the upper limit of the design benchmark and has certain shortcomings; the structure of the model is complex, especially the external auxiliary support system is complicated, resulting in limited online maintenance, and some models need to be returned to the factory for maintenance; the design and manufacturing are difficult, and the market application volume is small, resulting in slow technology upgrade iteration and poor reliability; there are many and not unified models in existing application, and the technology, experience, spare parts and tools are not universal; the selection of basic models for transformation and upgrading is limited, and currently only one model of diesel engine is suitable for the needs of existing nuclear power lines. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an improved emergency power supply system for a nuclear power plant in view of at least one defect raised by the above-mentioned background technology.

[0004] The technical solution adopted by the present invention to solve its technical problems is: to provide an emergency power supply system for a nuclear power plant, which includes an emergency diesel generator set, an external auxiliary system and multiple built-in auxiliary systems; the emergency diesel generator set includes multiple low-power diesel generators, and the maximum power of each of the low-power diesel generators does not exceed 2400KW; the built-in auxiliary systems correspond to the low-power diesel generators one by one, and each of the built-in auxiliary systems is integrated in the corresponding low-power diesel generator; the external auxiliary system includes a fuel system and an exhaust system, and each of the low-power diesel generators is connected to the fuel system and the exhaust system respectively.

[0005] In some embodiments, the built-in auxiliary system includes a high-temperature water system, a low-temperature water system, a compressed air system, an air intake system, and a lubricating oil system.

[0006] In some embodiments, the fuel system includes a main fuel storage tank, a fuel supply main pipe, a plurality of fuel supply branch pipes, and a plurality of daily fuel tanks;

[0007] The main oil storage tank is connected to the main oil supply pipe, a plurality of the branch oil supply pipes are respectively connected to the main oil supply pipe, and the daily oil tank is connected between the branch oil supply pipe and the small-power diesel generator.

[0008] In some embodiments, a control valve is provided on the oil supply branch pipe, and the control valve controls its own opening and closing according to the liquid level information of the daily oil tank.

[0009] In some embodiments, the fuel system further includes a bypass pipeline, which is connected between the fuel supply main pipe and the daily fuel tank and is arranged in parallel with the fuel supply branch pipe.

[0010] In some embodiments, the nuclear power plant emergency power supply system also includes an electrical primary control system, which includes a parallel bus, and the output ends of each of the small-power diesel generators are respectively connected to the parallel bus, and the parallel bus is connected to the emergency power supply bus of the nuclear power plant.

[0011] In some embodiments, the nuclear power plant emergency power supply system also includes an electrical secondary control system, which includes a parallel control cabinet and multiple controllers. The controllers and the small-power diesel generators are connected one-to-one, and each of the controllers is respectively connected to the parallel control cabinet.

[0012] In some embodiments, the nuclear power plant emergency power supply system also includes an electrical secondary control system, which includes a first instrument control cabinet, and the first instrument control cabinet is respectively connected to the external auxiliary system and the built-in auxiliary system, and is used to control the operation of the external auxiliary system and the built-in auxiliary system.

[0013] In some embodiments, the nuclear power plant emergency power supply system also includes an electrical secondary control system, which includes a second instrument control cabinet, and the second instrument control cabinet is respectively connected to the external auxiliary system and the built-in auxiliary system, and is used to display parameter information and alarm information of the external auxiliary system and the built-in auxiliary system.

[0014] In some embodiments, the nuclear power plant emergency power supply system also includes a battery pack, and the battery pack and the emergency diesel generator set are respectively arranged in different rooms in the nuclear power plant building. The battery pack is connected to each of the small-power diesel generators to provide power for the starting motor of each of the small-power diesel generators.

[0015] In some embodiments, the nuclear power plant emergency power supply system also includes a 24V conversion cabinet and a 24V switch cabinet, and the 24V conversion cabinet and the 24V switch cabinet are connected by cables to provide 24V control power for each load device.

[0016] In some embodiments, the nuclear power plant emergency power supply system also includes an electrical secondary control system and a fault recorder, the electrical secondary control system includes at least one of a parallel control cabinet, a controller, a first instrument control cabinet and a second instrument control cabinet; a plurality of the controllers are connected one-to-one with the small-power diesel generators, and each of the controllers is connected to the parallel control cabinet; the first instrument control cabinet is connected to the external auxiliary system and the built-in auxiliary system, respectively, for controlling the operation of the external auxiliary system and the built-in auxiliary system; the second instrument control cabinet is connected to the external auxiliary system and the built-in auxiliary system, respectively, for displaying parameter information and alarm information of the external auxiliary system and the built-in auxiliary system; the fault recorder is connected to at least one of the parallel control cabinet, the controller, the first instrument control cabinet and the second instrument control cabinet, for recording faults of electrical parameters.

[0017] In some embodiments, all of the small-power diesel generators are arranged in the same room in the nuclear power plant; and / or, the external auxiliary system is integrated with the auxiliary and support systems of the nuclear power plant.

[0018] In some embodiments, the sum of the rated powers of the small-power diesel generators is greater than the rated power required by the emergency power supply system of the nuclear power plant.

[0019] In some embodiments, the multiple low-power diesel generators include multiple main diesel engines and at least one backup diesel engine, the sum of the rated powers of each of the main diesel engines is greater than or equal to the rated power required by the emergency power supply system of the nuclear power plant, and the sum of the rated powers of each of the main diesel engines and the backup diesel engines is greater than the rated power required by the emergency power supply system of the nuclear power plant.

[0020] In some embodiments, the rated power of the main diesel engine is equal to the rated power of the standby diesel engine.

[0021] The present invention has at least the following beneficial effects: the present invention adopts multiple low-power diesel generators with a maximum power not exceeding 2400KW to replace the high-power emergency diesel generators currently used in the nuclear power field. Since the maximum power of the low-power diesel generator does not exceed 2400KW, the volume of its auxiliary system is relatively small, so some auxiliary systems can be integrated inside the low-power diesel generator as a built-in auxiliary system. In addition, the low-power diesel generator has a simple structure and a large market share, so the technology is improved, upgraded, and iterated quickly, so the reliability is high; within the power range of the maximum power not exceeding 2400KW, there are many optional models, and the relevant technology, experience, spare parts and tools are relatively common, which is convenient for maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

[0023] Figure 1 is a schematic diagram of a fuel system of a nuclear power plant emergency power supply system according to some embodiments of the present invention;

[0024] Figure 2 is a schematic diagram of an electrical primary control system of a nuclear power plant emergency power supply system according to some embodiments of the present invention;

[0025] Figure 3 Schematic diagram of an electrical secondary control system of an emergency power supply system of a nuclear power plant according to some embodiments of the present invention. DETAILED DESCRIPTION

[0026] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0027] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0028] The nuclear power plant emergency power supply system of one embodiment of the present invention comprises an emergency diesel generator set, a plurality of built-in auxiliary systems and an external auxiliary system. The emergency diesel generator set comprises a plurality of low-power diesel generators 40, and the maximum power of each low-power diesel generator 40 does not exceed 2400KW. Specifically, the plurality of low-power diesel generators 40 may refer to at least two low-power diesel generators 40. The number of low-power diesel generators 40 may be determined according to the power of the selected low-power diesel generators 40 and the rated power required by the emergency power supply system of the applied nuclear power plant, and the present invention does not make too many restrictions on this. The "low power" referred to in the low-power diesel generator 40 is mainly relative to the power of the high-power emergency diesel generators currently used in the nuclear power field. The rated power of each low-power diesel generator 40 may be the same or different. For example, for a nuclear power plant with a rated power of 8400kW required for the emergency power supply system, four low-power diesel generators 40 with a rated power of 2200kW may be configured to replace the original high-power diesel generator with a rated power of 8400kW. The small-power diesel generator 40 with a maximum power not exceeding 2400KW can cover almost all diesel generators on the market that are technologically mature and can integrate auxiliary systems into the main engine, that is, can have a built-in auxiliary system.

[0029] The built-in auxiliary system corresponds to the low-power diesel generator 40 one by one, and each built-in auxiliary system is integrated in the corresponding low-power diesel generator 40. The built-in auxiliary system is mainly used to provide working media such as water, air, and lubricating oil for the diesel generator.

[0030] The external auxiliary system includes a fuel system and an exhaust system, and each low-power diesel generator 40 is connected to the fuel system and the exhaust system respectively. The external auxiliary system is mainly used to provide fuel and exhaust paths for the diesel generator.

[0031] That is, the external auxiliary system and the low-power diesel generator 40 are independent of each other, and the external auxiliary system is independently arranged outside the low-power diesel generator 40; the internal auxiliary system is integrated into the low-power diesel generator 40. However, the high-power emergency diesel generators currently used in the nuclear power field have undergone transformation and upgrading, and their external auxiliary systems are complicated and large in size, so they cannot be integrated into the diesel engine.

[0032] In summary, the present invention uses multiple low-power diesel generators 40 with a maximum power not exceeding 2400KW to replace the high-power emergency diesel generators currently used in the nuclear power field. Since the maximum power of the low-power diesel generator 40 does not exceed 2400KW, the volume of its auxiliary system is relatively small, so some auxiliary systems can be integrated into the low-power diesel generator 40 as a built-in auxiliary system. In addition, the low-power diesel generator 40 has a simple structure and a large market share, so the technology is improved, upgraded, and iterated quickly, so the reliability is high; within the power range of the maximum power not exceeding 2400KW, there are many optional models, and the relevant technology, experience, spare parts and tools are relatively common, which is convenient for maintenance.

[0033] As described in the background technology, the three high-power emergency diesel generators currently installed in the nuclear power plant are arranged in three independent workshops due to their large size; in addition, the workshops are also equipped with supporting systems such as civil engineering structures, ventilation and fire protection, communication instruments, and control cabinet cables. Each high-power emergency diesel generator itself is also equipped with 7 auxiliary systems such as an external fuel system, compressed air system, lubricating oil system, high-temperature water system, low-temperature water system, air intake system, and exhaust system, including storage tanks, heat exchangers, pumps, heaters, air compressors, radiators, and other large and complex equipment and their related valves and pipeline accessories. All of these auxiliary systems are externally placed in other workshops. The system is large and complex, inconvenient for operation and maintenance and management, and the cost is high.

[0034] Compared with the prior art, since the present invention uses multiple low-power diesel generators 40 with a maximum power not exceeding 2400KW to replace the high-power emergency diesel generators currently used in the nuclear power field, multiple low-power diesel generators 40 can be centrally arranged in one plant and one room. That is, all the low-power diesel generators 40 are arranged in the same room in the nuclear power plant. In addition, the external auxiliary system and the auxiliary and support system of the nuclear power plant can be integrated together to achieve a set of layout design, and the layout of the emergency power supply system of the nuclear power plant is simplified to the maximum. The auxiliary and support systems of the nuclear power plant include a water supply system, a ventilation and air conditioning system (HVAC), an electrical system, etc. At the same time, the floor height of the nuclear power plant is reduced from 7 floors required by the original high-power diesel engine to 2 floors, and the room only needs to be equipped with a diesel engine hall, a leaking oil tank room, a fire foam room, a gas cylinder room, an oil tank room, an air conditioning room, an electrical room, etc. Compared with the original high-power diesel engine plant layout, the number of rooms required is reduced by more than 50%, which greatly reduces the space required for the diesel engine layout. In some embodiments, the sum of the rated powers of each low-power diesel generator 40 is greater than the rated power required by the emergency power supply system of the nuclear power plant. The rated power required by the emergency power supply system of a nuclear power plant varies depending on the design and scale of the nuclear power plant. For example, for a nuclear power plant with a rated power of 8400kW required by the emergency power supply system, four low-power diesel generators 40 with a rated power of 2200kW can be configured, and the sum of the rated powers of the small-power diesel generators 40 is 8800kW, which is greater than the rated power required by the emergency power supply system. In this way, redundant configuration of the power supply of the emergency power supply system of the nuclear power plant can be achieved, and the reliability of the emergency power supply of the nuclear power plant can be improved.

[0035] Further, in some embodiments, the plurality of low-power diesel generators 40 include a plurality of main diesel engines and at least one standby diesel engine. The sum of the rated powers of the main diesel engines is greater than or equal to the rated power required by the emergency power supply system of the nuclear power plant. The sum of the rated powers of the main diesel engines and the standby diesel engines is greater than the rated power required by the emergency power supply system of the nuclear power plant. For example, for a nuclear power plant with a rated power of 8400kW required for the emergency power supply system, five low-power diesel generators 40 can be configured, each with a rated power of 2200kW, of which four low-power diesel generators 40 are used as main diesel engines, and the sum of the rated powers of the main diesel engines is 8800kW, which is slightly greater than the rated power required by the emergency power supply system. The remaining one low-power diesel generator 40 is used as a standby diesel engine. Thus, when one of the main diesel engines fails for maintenance, the standby diesel engine can be enabled without affecting the normal operation of the diesel generator set. Furthermore, the rated power of the main diesel engine is equal to that of the standby diesel engine, which allows for greater flexibility in load distribution; the same spare parts and maintenance standards can be used, reducing spare parts inventory costs and management complexity; operators only need to be familiar with equipment of one power, reducing training costs and the risk of operational errors. Of course, in some other embodiments, the rated power of the main diesel engine and the rated power of the standby diesel engine may not be equal.

[0036] In summary, the present invention adopts N low-power main diesel engines with a maximum power not exceeding 2400KW and X low-power standby diesel engines with a maximum power not exceeding 2400KW to replace the high-power emergency diesel generators currently used in the nuclear power field. The configuration concept of the main diesel engines is: the total power load required by the nuclear power plant is evenly distributed to N low-power main diesel engines. Usually, N low-power main diesel engines use diesel generators of the same model and power. The total output power of these main diesel engines should be greater than and as close as possible to the original high-power diesel engine. The value of N should not be too large, that is, the minimum rated power of each low-power main diesel engine should not be too small. The configuration concept of X is: redundant configuration based on the power, model, and function requirements of each low-power main diesel engine. Usually, the main diesel engine and the standby diesel engine can be of the same model. The number of X low-power standby diesel engines can be appropriately increased or decreased according to user safety and operation and maintenance requirements. The redundantly configured X low-power standby diesel engines can realize flexible maintenance of diesel generator sets.

[0037] In some embodiments, the built-in auxiliary system includes a high-temperature water system, a low-temperature water system, a compressed air system, an intake system, and a lubricating oil system. Among them, the high-temperature water system is mainly used to cool the heat-generating components, improve the fuel combustion efficiency, preheat the diesel engine, heat the lubricating oil, etc.; the low-temperature water system is mainly used to cool the engine oil, cool the supercharged air, maintain a suitable intake temperature, etc.; the compressed air system is mainly used to start the diesel engine, drive pneumatic tools (such as pneumatic wrenches, pneumatic picks), etc.; the intake system is mainly used to guide air inlet, filter air impurities, increase power by supercharging, cool the supercharged air, control the intake process, etc.; the lubricating oil system is mainly used to provide flowing lubricating oil inside the diesel engine, which plays the role of lubricating parts to reduce friction, cooling and lowering the temperature, keeping parts clean, sealing moving parts, preventing rust and corrosion, absorbing vibration and buffering, etc.

[0038] Since the present invention uses multiple low-power diesel generators 40 with a maximum power not exceeding 2400KW to replace the high-power emergency diesel generators currently used in the nuclear power field, the external auxiliary systems only have the fuel system and the exhaust system, and the remaining auxiliary systems - high-temperature water system, low-temperature water system, compressed air system, intake system, and lubricating oil system are integrated in the low-power diesel generator 40 body as built-in auxiliary systems. In this way, taking four 2200kW main diesel engines and one 2200kW standby diesel engine as an example, the number of equipment in the auxiliary system of the nuclear power plant emergency power supply system is reduced from 44 to 14, and the number of power supply equipment required by the auxiliary system is reduced from 30 to 2, which greatly reduces the number of equipment configurations of the diesel engine auxiliary system and greatly reduces the equipment operation and maintenance costs.

[0039] like Figure 1 As shown, in some embodiments, the fuel system mainly includes a main oil storage tank 10, a main oil supply pipe 20, multiple oil supply branch pipes 21 and multiple daily oil tanks 11. The main oil storage tank 10 is connected to the main oil supply pipe 20, multiple oil supply branch pipes 21 are respectively connected to the main oil supply pipe 20, and the daily oil tank 11 is connected between the oil supply branch pipe 21 and the low-power diesel generator 40. Specifically, as Figure 1In the illustrated embodiment, each low-power diesel generator 40 is assigned a daily oil tank 11, and each daily oil tank 11 is assigned an oil supply branch pipe 21. That is, the number of oil supply branch pipes 21, the number of daily oil tanks 11 and the number of low-power diesel generators 40 are consistent. Of course, in some other embodiments, the number of oil supply branch pipes 21, the number of daily oil tanks 11 and the number of low-power diesel generators 40 may also be inconsistent. The main oil storage tank 10, the oil supply main pipe 20, the oil supply branch pipe 21, the daily oil tank 11 and the low-power diesel generator 40 are connected in sequence. The main oil storage tank 10 and the daily oil tank 11 are mainly used to store fuel oil. The fuel oil output from the main oil storage tank 10 flows from the oil supply main pipe 20 to each oil supply branch pipe 21, and then flows to the daily oil tank 11 for storage. The fuel oil required for the operation of the low-power diesel generator 40 is provided by the daily oil tank 11. In this way, fuel can be provided to a plurality of small-power diesel generators 40 at the same time through at least one main oil storage tank 10 and one oil supply main pipe 20, thereby simplifying the fuel system.

[0040] like Figure 1 In the illustrated embodiment, the fuel system further includes at least one fuel supply pump 30 , which is disposed on the fuel supply main pipe 20 and is mainly used to provide power for the fuel to flow from the fuel supply main pipe 20 to the daily fuel tank 11 .

[0041] Furthermore, if Figure 1 As shown, in some embodiments, a control valve 31 is provided on the oil supply branch pipe 21. Specifically, the control valve 31 refers to a valve that can be used for automatic control, such as a solenoid valve, a pneumatic actuator valve, a hydraulic valve, etc. The control valve 31 controls its own opening and closing according to the liquid level information of the daily oil tank 11. That is, the control valve 31 controls the connection and isolation between the oil supply branch pipe 21 and the daily oil tank 11 according to the liquid level information of the daily oil tank 11. For example, a liquid level sensor (not shown) can be provided on the daily oil tank 11, and the liquid level sensor is connected to the control valve 31 for communication. The liquid level sensor monitors the liquid level information of the fuel inside the daily oil tank 11 in real time. When the liquid level information received by the liquid level sensor is less than the first preset threshold value, the control valve 31 is opened, the oil supply branch pipe 21 and the daily oil tank 11 remain connected, and the fuel can be input into the daily oil tank 11 from the oil supply branch pipe 21. On the contrary, when the liquid level information received by the liquid level sensor is greater than the second preset threshold value, the control valve 31 is closed, the oil supply branch pipe 21 and the daily oil tank 11 are kept isolated, and the fuel cannot be input into the daily oil tank 11 from the oil supply branch pipe 21, thereby stopping the fuel supply to the daily oil tank 11. In this way, the fuel inlet of the daily oil tank 11 can be automatically controlled, thereby ensuring that only one set of oil supply modules is needed, and fuel can be provided to multiple low-power diesel generators 40 at the same time through at least one main oil storage tank 10 and one oil supply main pipe 20, and the liquid level height of the daily oil tank 11 can be accurately controlled, thereby avoiding the use of multiple independent fuel systems and simplifying the fuel system.

[0042] Furthermore, if Figure 1 As shown, in some embodiments, the fuel system further includes a bypass line 22, which is connected between the fuel supply main pipe 20 and the daily fuel tank 11 and is arranged in parallel with the fuel supply branch pipe 21. Once the control valve 31 fails and needs to be repaired, the system can switch to the bypass line 22 to continue to ensure the fuel supply to the daily fuel tank 11, thereby not affecting the safe operation of the diesel engine.

[0043] like Figure 2 As shown, in some embodiments, the emergency power supply system of the nuclear power plant also includes an electrical primary control system, which includes a parallel bus 50, and the output ends of each low-power diesel generator 40 are respectively connected to the parallel bus 50, and the parallel bus 50 is connected to the emergency power bus 51 of the nuclear power plant. That is, the parallel bus 50 is connected between the emergency power bus 51 of the nuclear power plant and each low-power diesel generator 40, serving as an intermediate bridge for power transmission. The emergency power bus 51 of the nuclear power plant is also called the LHA / B bus. The emergency power bus 51 of the nuclear power plant is connected to the dedicated safety facilities of the nuclear power plant to provide emergency power supply for the safety facilities of the nuclear power plant. The safety facilities of the nuclear power plant include a safety injection system (RIS), a containment spray system (EAS), an auxiliary water supply system (ASG), a containment isolation system (EIE), an emergency lighting system (ELS), etc. The parallel bus 50 is used to complete the power collection on the emergency diesel generator set side and then transmit the power to the emergency power bus 51 of the nuclear power plant, and then the emergency power bus 51 transmits the power to the dedicated safety facilities of the nuclear power plant. This simplifies the power output control of multiple low-power diesel generators 40.

[0044] Specifically, Figure 2 In the illustrated embodiment, the electrical primary control system further includes a first output line 52, a second output line 53 and a plurality of controllers 61. Each low-power diesel generator 40 is connected to the parallel bus 50 via a first output line 52, on which a circuit breaker 54 is disposed. The parallel bus 50 is connected to the emergency power bus 51 via a second output line 53, on which a circuit breaker 54 is also disposed. The parallel bus 50 is also connected to a voltage transformer cabinet (PT cabinet) 55, a fixed test load 56, a mobile power supply 57 and a factory power supply 58.

[0045] like Figure 3As shown, in some embodiments, the emergency power supply system of the nuclear power plant also includes an electrical secondary control system, which includes at least one parallel control cabinet 60 and multiple controllers 61. The controllers 61 are connected to the small-power diesel generators 40 in a one-to-one correspondence. That is, the number of controllers 61 can be consistent with the number of small-power diesel generators 40, and each small-power diesel generator 40 is allocated a controller 61. Each controller 61 is connected to the parallel control cabinet 60. The parallel control cabinet 60 is mainly used to coordinate and control the operation of the entire system and realize the logical control of the system, including the input and removal of units, priority setting, etc. Each controller 61 is used to realize the control functions such as start and stop, excitation, speed regulation, paralleling, protection, etc. of the corresponding small-power diesel generator 40. That is, the electrical secondary control system adopts the "main control + sub-control" architecture, collects the relevant information of multiple small-power diesel generators 40 and centrally controls them, and reduces the interface with the centralized control system of the nuclear power plant.

[0046] like Figure 3 As shown, in some embodiments, the electrical secondary control system further includes a first instrument control cabinet 62 and a second instrument control cabinet 63. The first instrument control cabinet 62 is connected to the external auxiliary system and the built-in auxiliary system respectively, and is used to control the operation of the external auxiliary system and the built-in auxiliary system. That is, the first instrument control cabinet 62 is used to control the operation of the fuel system, the exhaust system, the high-temperature water system, the low-temperature water system, the compressed air system, the intake system, and the lubricating oil system. The second instrument control cabinet 63 is connected to the external auxiliary system and the built-in auxiliary system respectively, and is used to display the parameter information and alarm information of the external auxiliary system and the built-in auxiliary system. Specifically, a display screen, a control panel and other human-machine interaction interfaces can be set on the second instrument control cabinet 63, and the parameter information and alarm information of the external auxiliary system and the built-in auxiliary system can be displayed through the human-machine interaction interface. Of course, in some other embodiments, only one instrument control cabinet can be set to control the operation of the external auxiliary system and the built-in auxiliary system, and to display related information.

[0047] Specifically, the parallel control cabinet 60, the first instrument control cabinet 62 and the second instrument control cabinet 63 can adopt non-safety-level control cabinets or PLC control cabinets (programmable control cabinets) to reduce costs. At the same time, in some embodiments, the control equipment can be configured from the following three aspects to further ensure the optimization of the electrical secondary control system:

[0048] First, in some embodiments, the nuclear power plant emergency power supply system may also include a battery pack (not shown), which is connected to each low-power diesel generator 40 of the diesel generator set to provide power for the starter motor of each low-power diesel generator 40, ensuring that the diesel engine can be started quickly. The battery pack is placed in a dedicated room in the nuclear power plant, that is, the battery pack and the emergency diesel generator set are respectively arranged in different rooms in the nuclear power plant, so as to achieve high temperature protection of the battery pack and convenient operation and maintenance of the diesel generator set body, and further ensure the optimization of the electrical secondary control system.

[0049] Secondly, in some embodiments, the emergency power supply system of the nuclear power plant may also include a 24V conversion cabinet (not shown) and a 24V switch cabinet (not shown). The 24V conversion cabinet and the 24V switch cabinet are connected by cables, and the two are used together to provide 24V control power for each load device. Specifically, the 24V conversion cabinet is an electrical device for converting input power into a 24V DC power supply. The 24V switch cabinet is an electrical device used in a low-voltage power distribution system, mainly used to control and distribute 24V DC power. Among them, the 24V conversion cabinet is mainly used to convert input power (such as AC 220V or higher voltage DC power supply) into a stable 24V DC power supply; the 24V conversion cabinet may include power modules, rectifiers, filters, and voltage stabilizers to ensure the stability and reliability of the output voltage. The 24V switch cabinet is mainly used to distribute the 24V DC power supply to each load device, and provide overload, short circuit protection, and switch control functions. The 24V switch cabinet may include multiple branch circuits for connecting sensors, controllers, actuators, and other equipment. The 24V conversion cabinet and the 24V switch cabinet can be connected to the electrical primary control system and the electrical secondary control system respectively. The load equipment can include a parallel control cabinet 60, a first instrument control cabinet 62, a second instrument control cabinet 63, a controller 61, etc.

[0050] Third, in some embodiments, the emergency power supply system of the nuclear power plant may further include a fault recorder (not shown). The fault recorder is also called a fault recorder cabinet. The fault recorder is connected to at least one of the controller 61, the parallel control cabinet 60, the first instrument control cabinet 62 and the second instrument control cabinet 63 to record the faults of important electrical parameters.

[0051] In summary, the present invention has at least the following beneficial effects:

[0052] (1) Use N low-power main diesel engines with a maximum power of no more than 2400KW and X low-power standby diesel engines with a maximum power of no more than 2400KW to replace the high-power emergency diesel generators currently used in the nuclear power field; the redundant X low-power standby diesel engines can meet the needs of daily maintenance, so that the operation of the nuclear power plant is not restricted by the time limit for diesel engine return to the factory for maintenance, which greatly improves the flexibility and economy of equipment maintenance and well meets user needs; at the same time, the design of multiple low-power main diesel engines + low-power standby diesel engines greatly simplifies the configuration of the auxiliary system, greatly reduces the equipment required for the auxiliary system, reduces the operation and maintenance costs, and reduces the space required for the plant layout, simplifying the grid-connected control process;

[0053] At the same time, the small-power diesel generator 40 has high reliability, a large market share, and fast technical improvement and iteration. Moreover, within the power range required by existing nuclear power plants, the small-power diesel generator 40 has many optional power versions, a large design margin, and unrestricted equipment supply channels. It has well solved many problems of existing large diesel engines in nuclear power plants, such as few power versions, close to the upper limit of the design benchmark, complex models, and complicated auxiliary support systems, which lead to limited online maintenance (some models need to be returned to the factory for maintenance), difficult design and manufacturing, small market application, slow technical upgrade iteration, multiple and non-uniform application models, non-universal technology, experience, spare parts and tools, and limited selection.

[0054] (2) An innovatively designed supporting fuel system can simultaneously supply fuel to multiple low-power diesel generators 40 through at least one main oil storage tank 10 and one fuel supply main pipe 20, thus simplifying the fuel system;

[0055] (3) The innovative design of the electrical primary control system and the electrical secondary control system improves the success rate and reliability of the system startup and grid connection. It is understandable that the above embodiments only express the preferred implementation of the present invention, and the description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present invention; it should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention; therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the scope of the claims of the present invention.

Claims

1. A nuclear power plant emergency power supply system, characterized in that: include: An emergency diesel generator set, the emergency diesel generator set comprising a plurality of low-power diesel generators (40), the maximum power of each of the low-power diesel generators (40) not exceeding 2400KW; A plurality of built-in auxiliary systems, wherein the built-in auxiliary systems correspond to the low-power diesel generators (40) one by one, and each of the built-in auxiliary systems is integrated into the corresponding low-power diesel generator (40); An external auxiliary system comprises a fuel system and an exhaust system, and each of the low-power diesel generators (40) is connected to the fuel system and the exhaust system respectively.

2. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The built-in auxiliary system includes a high-temperature water system, a low-temperature water system, a compressed air system, an air intake system, and a lubricating oil system.

3. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The fuel system comprises a main oil storage tank (10), an oil supply main pipe (20), a plurality of oil supply branch pipes (21) and a plurality of daily oil tanks (11); The main oil storage tank (10) is connected to the main oil supply pipe (20), a plurality of the oil supply branch pipes (21) are respectively connected to the main oil supply pipe (20), and the daily oil tank (11) is connected between the oil supply branch pipes (21) and the low-power diesel generator (40).

4. The nuclear power plant emergency power supply system according to claim 3, characterized in that: The oil supply branch pipe (21) is provided with a control valve (31), and the control valve (31) controls its own opening and closing according to the liquid level information of the daily oil tank (11).

5. The nuclear power plant emergency power supply system according to claim 4, characterized in that: The fuel system further comprises a bypass pipeline (22), wherein the bypass pipeline (22) is connected between the fuel supply main pipe (20) and the daily fuel tank (11), and is arranged in parallel with the fuel supply branch pipe (21).

6. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The nuclear power plant emergency power supply system also includes an electrical primary control system, which includes a parallel bus (50), to which the output ends of the small-power diesel generators (40) are respectively connected, and the parallel bus (50) is connected to an emergency power supply bus (51) of the nuclear power plant.

7. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The nuclear power plant emergency power supply system also includes an electrical secondary control system, which includes a parallel control cabinet (60) and a plurality of controllers (61). The controllers (61) and the low-power diesel generators (40) are connected in a one-to-one correspondence, and each of the controllers (61) is respectively connected to the parallel control cabinet (60).

8. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The nuclear power plant emergency power supply system also includes an electrical secondary control system, which includes a first instrument control cabinet (62). The first instrument control cabinet (62) is connected to the external auxiliary system and the internal auxiliary system respectively, and is used to control the operation of the external auxiliary system and the internal auxiliary system.

9. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The nuclear power plant emergency power supply system also includes an electrical secondary control system, which includes a second instrument control cabinet (63). The second instrument control cabinet (63) is connected to the external auxiliary system and the internal auxiliary system respectively, and is used to display parameter information and alarm information of the external auxiliary system and the internal auxiliary system.

10. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The nuclear power plant emergency power supply system also includes a battery pack, wherein the battery pack and the emergency diesel generator set are respectively arranged in different rooms in the nuclear power plant building, and the battery pack is connected to each of the low-power diesel generators (40) to provide power for the starting motor of each of the low-power diesel generators (40).

11. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The nuclear power plant emergency power supply system also includes a 24V conversion cabinet and a 24V switch cabinet. The 24V conversion cabinet and the 24V switch cabinet are connected by cables to provide 24V control power for each load device.

12. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The nuclear power plant emergency power supply system further comprises an electrical secondary control system and a fault recorder, wherein the electrical secondary control system comprises at least one of a parallel control cabinet (60), a controller (61), a first instrument control cabinet (62) and a second instrument control cabinet (63); A plurality of the controllers (61) are connected to the low-power diesel generators (40) in a one-to-one correspondence, and each of the controllers (61) is connected to the parallel control cabinet (60); the first instrument control cabinet (62) is connected to the external auxiliary system and the internal auxiliary system, respectively, and is used to control the operation of the external auxiliary system and the internal auxiliary system; the second instrument control cabinet (63) is connected to the external auxiliary system and the internal auxiliary system, respectively, and is used to display parameter information and alarm information of the external auxiliary system and the internal auxiliary system; The fault recorder is connected to at least one of the parallel control cabinet (60), the controller (61), the first instrument control cabinet (62) and the second instrument control cabinet (63), and is used to record faults of electrical parameters.

13. The nuclear power plant emergency power supply system according to claim 1, characterized in that: All of the low-power diesel generators (40) are arranged in the same room in the nuclear power plant; And / or, the external auxiliary system is integrated with the auxiliary and support systems of the nuclear power plant.

14. The nuclear power plant emergency power supply system according to claim 1, characterized in that: The sum of the rated powers of the various low-power diesel generators (40) is greater than the rated power required by the emergency power supply system of the nuclear power plant.

15. The nuclear power plant emergency power supply system according to claim 14, characterized in that: The plurality of low-power diesel generators (40) include a plurality of main diesel engines and at least one standby diesel engine, the sum of the rated powers of the main diesel engines being greater than or equal to the rated power required by the emergency power supply system of the nuclear power plant, and the sum of the rated powers of the main diesel engines and the standby diesel engines being greater than the rated power required by the emergency power supply system of the nuclear power plant.

16. The nuclear power plant emergency power supply system according to claim 15, characterized in that: The rated power of the main diesel engine is equal to the rated power of the standby diesel engine.

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