Power supply system for auxiliary power supply of nuclear power station

Abstract

The utility model belongs to the field of nuclear power station external power supply design, and particularly relates to a power supply system of a nuclear power station auxiliary power supply, which comprises a plurality of nuclear power units and at least one standby transformer starting module, and when the nuclear power units cannot work normally, the standby transformer starting module is switched to supply power so as to maintain the operation of a nuclear power station; wherein the nuclear power unit comprises a generator, a main transformer and at least one station transformer; the other end of the main transformer is respectively connected with the station transformer and the generator; one end of the station transformer is connected with the main transformer and the generator, and the other end is connected with at least one load; the standby transformer starting module comprises a standby main transformer and a plurality of standby station transformers, and the parameters of the standby station transformers are consistent with those of the station transformers; the other end of the standby main transformer is connected with the standby station transformer; one end of the standby station transformer is connected with the standby main transformer, and the other end is connected with a plurality of different loads.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of nuclear power plant external power supply design, concretely relates to a power supply system of nuclear power plant auxiliary power supply. BACKGROUND

[0002] At present, nuclear power plant mainly uses 500kV transmission line of external power grid as main power supply to realize nuclear power unit start / stop power supply function through main transformer and high voltage auxiliary transformer, and uses 220kV transmission line of external power grid as auxiliary power supply to realize nuclear power unit emergency or accident shutdown power supply through auxiliary transformer, does not design flexible auxiliary power supply mode such as start standby transformer, makes nuclear power unit and downstream load have higher dependency on important electrical equipment such as main transformer, high voltage auxiliary transformer and auxiliary transformer, thereby leading to long period maintenance window of above-mentioned electrical equipment to become very nervous.Meanwhile, if auxiliary transformer and auxiliary transformer are faulty during nuclear power unit operation, nuclear power unit will be shut down due to loss of external power supply, and nuclear power unit availability is affected. SUMMARY

[0003] In view of above-mentioned defects of prior art, the utility model aims at providing a novel nuclear power plant auxiliary power supply structure, which can keep external power supply of nuclear power plant available during main transformer and auxiliary transformer shutdown of each nuclear power unit, increase level of nuclear power plant power supply structure, and improve reliability and stability of in-station power supply.

[0004] In order to achieve the above object and other related objects, the utility model provides a kind of power supply system of nuclear power plant auxiliary power supply, comprising: several nuclear power units and at least one standby transformer module, and when the nuclear power unit cannot work normally, it is powered by switching for the standby transformer module, to maintain the operation of nuclear power plant;Wherein, the nuclear power unit includes generator, main transformer, and at least one auxiliary transformer;The one end of the main transformer is connected to the power grid, and the other end is connected to the auxiliary transformer and the generator respectively, to step up the power generated by the generator and deliver to the power grid, or step down the power delivered by the power grid and distribute to the load in nuclear power plant through the auxiliary transformer;The one end of the auxiliary transformer is connected to the main transformer and the generator respectively, and the other end is connected to at least one load, to step down the power generated by the generator or the power delivered by the power grid through the main transformer and distribute to each load, maintain the operation of nuclear power plant;The standby transformer module includes standby main transformer and multiple standby auxiliary transformers, and the parameters of the standby auxiliary transformer are consistent with the auxiliary transformer;The one end of the standby main transformer is connected to the power grid, and the other end is connected to the standby auxiliary transformer;The one end of the standby auxiliary transformer is connected to the standby main transformer, and the other end is connected to multiple different loads;When any one nuclear power unit cannot work normally, the power delivered by the power grid is distributed to the load connected to the nuclear power unit through the standby main transformer and the standby auxiliary transformer, to keep the load without power failure.

[0005] According to a specific embodiment of the utility model, the nuclear power unit further includes at least one first switching device, and the auxiliary transformer is connected to a load through one first switching device;The standby transformer module further includes standby first switching device, which is arranged correspondingly with the first switching device in one or more nuclear power units, and the standby auxiliary transformer is connected to a load through one standby first switching device;Wherein, each load in nuclear power plant is connected to the auxiliary transformer of one nuclear power unit through one first switching device, and connected to the standby auxiliary transformer of one standby transformer module through one standby first switching device, to disconnect the corresponding connected first switching device and close the corresponding connected standby first switching device when the nuclear power unit cannot work normally, to switch for the standby transformer module.

[0006] According to a specific embodiment of the utility model, the standby transformer module further includes quick switching device, to realize the quick switching of closing / disconnecting the first switching device and the corresponding standby first switching device, to keep the load without power failure during switching.

[0007] According to the utility model one concrete embodiment, the start spare transformer module still includes distribution unit, connects between the spare transformer and different load, wherein, the distribution unit passes through closing / opening switch device, to make the spare transformer one or more load power supply.

[0008] According to the utility model one concrete embodiment, when starting the start spare transformer module, one spare transformer only powers one load connected with the spare transformer through the distribution unit.

[0009] According to the utility model one concrete embodiment, the distribution unit includes one spare second switch device, and one end is connected with the power output end of the spare transformer, and the other end is connected with different spare first switch device respectively, wherein, the spare second switch device is configured to make the spare transformer and one spare first switch device in series after closing.

[0010] According to the utility model one concrete embodiment, the distribution unit includes multiple spare second switch devices, and is set up one to one with the spare first switch device, wherein, one end of any one spare second switch device is connected with the power output end of the spare transformer, and the other end is connected with the corresponding spare first switch device.

[0011] According to the utility model one concrete embodiment, the first switch device, the spare first switch device, the spare second switch device all adopt at least one circuit breaker.

[0012] According to the utility model one concrete embodiment, the nuclear power unit still includes second switch device, and is connected between the main transformer and the generator.

[0013] According to the utility model one concrete embodiment, the nuclear power unit still includes third switch device, and is connected between the main transformer and the power grid, and the start spare transformer module still includes spare third switch device, and is connected between the spare main transformer and the power grid.

[0014] The utility model provides a kind of power supply system of nuclear power plant auxiliary power supply, so that the load in nuclear power plant can include two power supply modes, to carry out overhaul when any one nuclear power unit, start spare transformer module can be used as its overhaul power supply and start-stop machine power supply to power corresponding load, so that the maintenance window of nuclear power unit main transformer and plant transformer can be extended, shorten overhaul critical path, improve unit safety and availability.

[0015] Meanwhile, the present application can also replace its operation through start spare transformer module after the plant transformer failure of any one or more nuclear power units in whole plant, maintain the continuous power generation of nuclear power unit, without waiting for plant transformer failure to be eliminated, greatly improve the availability of unit. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structure schematic view of a specific embodiment of the power supply system of the nuclear power plant power supply provided by the utility model;

[0017] Figure 2 An electrical structure view of a specific embodiment of the nuclear power unit provided by the utility model;

[0018] Figure 3 An electrical structure view of a specific embodiment of the standby transformer module provided by the utility model;

[0019] Figure 4 An electrical structure view of another specific embodiment of the standby transformer module provided by the utility model. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The drawings show embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used herein in the specification are only for the purpose of describing the specific embodiments of the present application and are not intended to limit the present application.

[0022] It can be understood that the terms "first", "second", and the like used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of the present application, the first resistor can be referred to as the second resistor, and similarly, the second resistor can be referred to as the first resistor. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0023] It can be understood that "connection" in the following embodiments, if the circuits, modules, units, etc. connected to each other have the transmission of electrical signals or data, it should be understood as "electrically connected", "communicatively connected", etc.

[0024] It can be understood that "at least one" means one or more, and "multiple" means two or more. "At least part of the element" means part or all of the element.

[0025] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It should also be understood that the term "comprising" or "having" etc. specifies the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but does not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, the term "and / or" used in the specification includes any and all combinations of one or more of the associated listed items.

[0026] First of all, it should be noted that in order to enable those skilled in the art to better understand the scheme of the present application, the technical background of the present application is explained accordingly.

[0027] At present, the generator and the main transformer of each unit in a nuclear power plant adopt unit connection, a generator outlet circuit breaker is installed between the generator and the main transformer, and two high-voltage auxiliary transformers are arranged between the generator and the main transformer. At the same time, each unit is provided with an auxiliary transformer for unit accident shutdown, but no start / standby transformer is provided. Therefore, the normal start and stop of the nuclear power unit can only be realized by the main transformer power supply, but when the main transformer fails, the nuclear power unit cannot continue to generate power during the main transformer failure repair.

[0028] Based on the above power supply structure, the present application increases the selectivity of the power supply mode of the nuclear power unit start and stop stage by adding a start / standby transformer common to the whole station, which can greatly increase the repair window of the main transformer and the auxiliary transformer. Even if the auxiliary transformer fails or is under repair, the start / standby transformer can make the nuclear power unit generate power normally, and improve the availability of the nuclear power unit.

[0029] Please refer to Figure 1 The power supply structure of the nuclear power plant auxiliary power supply shown in the figure comprises: a plurality of nuclear power units 10 and a start / standby transformer module 20, to provide two power supply modes to cope with the main transformer and / or auxiliary transformer failure and repair of the nuclear power unit 10, maintain the efficient availability and continuous operation of the nuclear power unit 10, and maintain the normal operation of the nuclear power plant.

[0030] It can be understood here that the nuclear power unit 10 as the basic power generation unit of the nuclear power plant can not only deliver the generated power to the national power grid, but also directly supply the nuclear power plant. Therefore, each nuclear power unit 10 includes a main transformer 11 (main transformer), at least one auxiliary transformer 12 (auxiliary transformer), a generator 13 and other electrical equipment. At the same time, one end of the main transformer 11 is connected to the power grid, and the other end is connected to the auxiliary transformer 12 and the generator 13, respectively, and one end of the auxiliary transformer 12 is connected to the main transformer 11 and the generator 13, respectively, and the other end is connected to the load in the nuclear power plant. Based on the above circuit structure, a nuclear power unit 10 can divide the power generated by the generator 13 into two paths, one of which is boosted by the main transformer 11 and connected to the national power grid, and the other of which is stepped down by the auxiliary transformer 12 and directly supplied to the nuclear power plant.

[0031] It should be added here that although the nuclear power unit 10 can be used for power generation to maintain its normal operation, external power supply is still required to start the reactor and control rod and other equipment during the start-up phase, because the nuclear reactor itself cannot be started directly and requires external power supply to provide the necessary power. Once the nuclear reactor is started and reaches the critical state, it can maintain the reaction by itself and generate enough heat to heat the water to produce steam, which in turn drives the steam turbine generator to generate electricity. Therefore, each nuclear power unit 10 can use the power delivered by the power grid through the main transformer 11 and the auxiliary transformer 12 during the start-up phase to distribute to the corresponding load, i.e. the relevant electrical equipment for starting the generator 13. In turn, the generator 13 can directly supply power to all loads in the nuclear power plant through the auxiliary transformer 12 after starting, and no longer rely on external power grid. In addition, when the generator 13 stops unexpectedly or the reactor needs to be shut down, the nuclear power unit 10 cannot supply power to the load in the nuclear power plant, i.e. the downstream load of the nuclear power plant, such as lighting, monitoring, access control, air conditioning and other equipment. However, the power delivered by the power grid through the main transformer 11 and the auxiliary transformer 12 can still be used to supply power to the corresponding load to maintain the basic operation of the nuclear power plant.

[0032] It should be noted that the load mentioned in this embodiment is the relevant electrical equipment in the nuclear power plant, which is not limited, and usually a corresponding auxiliary transformer is configured to be responsible for and control, for example, one nuclear power unit can be configured with multiple auxiliary transformers to be responsible for multiple different loads. Among them, the number of auxiliary transformers is also not limited and can be configured according to actual needs.

[0033] As can be seen, the nuclear power plant is jointly carried by multiple nuclear power units 10 to operate and generate power. Of course, the number of nuclear power units 10 is not limited and can be configured according to the size of the nuclear power plant.

[0034] Based on the above power supply mode, once the main transformer 11 and the plant transformer 12 in the nuclear power unit 10 stop working, it will cause the load in the nuclear power plant to be powered off, thereby affecting the normal operation of the nuclear power plant. To this end, the embodiment also adds the standby transformer module 20 to provide another power supply mode to cope with the situation that the main transformer 11 and / or the plant transformer 12 in the nuclear power unit 10 cannot work normally. And the standby transformer module 20 includes a standby main transformer 21, a standby plant transformer 22, and a power distribution unit 23. One end of the standby main transformer 21 is connected to the power grid, and the other end is connected to the standby plant transformer 22. One end of the standby plant transformer 22 is connected to the standby main transformer 21, and the other end can be connected to multiple different loads through the power distribution unit 23. Thus, when any one nuclear power unit cannot work normally, the electrical energy after being stepped down by the standby main transformer 21 and the standby plant transformer 22 is distributed to the corresponding load through the power distribution unit 23, so as to keep the load powered on and avoid affecting the operation of the nuclear power plant.

[0035] It can be understood here that although the plant transformer in a nuclear power unit 10 can also connect multiple loads as corresponding power supply lines responsible for powering the loads, the standby transformer module 20 can be shared by multiple nuclear power units 10 as a common standby power supply mode, that is, the standby plant transformer 22 can be connected to multiple loads corresponding to the power supply of different nuclear power units 10 through the power distribution unit 23, so as to continue to power the load through the power distribution unit 23 when the main transformer and / or the plant transformer of any one nuclear power unit cannot work normally. For example, assuming that the nuclear power plant has A, B, and C three nuclear power units, and each nuclear power unit is connected to different loads, that is, A is responsible for powering load X, B is responsible for powering load Y, and C is responsible for powering load Z, and the standby plant transformer 22 of the standby transformer module 20 can be connected to loads X, Y, and Z through the power distribution unit 23, so as to keep the power supply of load X uninterrupted by connecting the standby plant transformer 22 and load X through the power distribution unit 23 when the main transformer and / or the plant transformer of A cannot work, or keep the power supply of load Y uninterrupted by connecting the standby plant transformer 22 and load Y through the power distribution unit 23 when the main transformer and / or the plant transformer of B cannot work, or keep the power supply of load Z uninterrupted by connecting the standby plant transformer 22 and load Z through the power distribution unit 23 when the main transformer and / or the plant transformer of C cannot work.

[0036] It should be noted that, since the standby transformer 22 is redundantly arranged as the transformer 12, the parameters of the standby transformer 22 also need to be consistent, such as working parameters, device model parameters, and the like, that is, the standby transformer 22 and the transformer are basically identical. In addition, the parameters of the main transformer and the transformer in each nuclear power unit are usually consistent, and therefore, the start standby transformer module 20 can be shared by multiple nuclear power units 10 as a common standby power supply mode, so as to switch the power supply mode of the load by using the start standby transformer module 20 when any nuclear power unit 10 cannot work normally. In addition, the standby main transformer 21 is not limited, and it can be understood that the main transformer not only needs to step down the power transmitted by the power grid and then transmit it to the transformer, but also needs to step up the power generated by the generator and then transmit it to the power grid, and the standby main transformer only needs to step down the power of the power grid and then transmit it to the standby transformer when the main transformer and / or the transformer in the nuclear power unit cannot work, so as to keep the load without power failure. The actual role of the main transformer is different, and accordingly, it does not need to be completely consistent, and can be set according to actual needs.

[0037] In a specific embodiment, the electrical structure of a nuclear power unit 10 can refer to Figure 2 It can be understood that in actual application, some switching devices still need to be matched to form the electrical circuit of the nuclear power unit 10. Therefore, the first switching device, that is, the circuit breaker 001JA, is arranged between the transformer 12 and the load, which is used to close / open the power supply circuit between the transformer 12 and the load, that is, to close the power supply of the load by the nuclear power unit 10 through the transformer 12 thereof, and to open to stop the power supply of the nuclear power unit 10. In the figure, LGA, LGD, LGE, and LGF all represent the load. In addition, the second switching device, that is, the circuit breaker GCB, is arranged between the generator 13 and the main transformer 11, and the third switching device, that is, the circuit breaker CB1, is arranged between the main transformer 11 and the power grid, thereby ensuring the electrical safety of the nuclear power unit.

[0038] The electrical structure of the start standby transformer module 20 can refer to Figure 3As shown, some switch devices are still needed to configure the electrical circuit of the standby transformer module 20. Therefore, a standby third switch device, i.e., a circuit breaker CB2, is arranged between the standby main transformer 21 and the power grid. Meanwhile, switch devices can also be used for the distribution unit 23, for example, the same number of standby second switch devices, i.e., circuit breakers 101JS, can be arranged according to the number of loads that need to be connected to the standby plant transformer 22. If any one load needs to be powered, the corresponding 101JS on the corresponding line is closed, or if any multiple loads need to be powered, the corresponding 101JS on the corresponding multiple lines is closed. Alternatively, the standby second switch device can directly use a multi-way selector switch, so that the power supply line between the standby plant transformer 22 and the corresponding one or more loads is connected according to the actual demand, and power supply is performed. In addition, a standby first switch device, i.e., a circuit breaker 102JA, is arranged between the standby second switch device and the load, which corresponds to the first switch device 001JA.

[0039] It should be noted here that the plant transformer usually uses the power generated by the generator to supply power to multiple loads connected thereto synchronously. However, when the nuclear power unit fails or cannot work normally, the power supply mode of the load is switched by enabling the standby transformer module. Once the standby transformer module is used for power supply, a special situation occurs, and at this time, it is not necessary to maintain uninterrupted power supply to all loads, but only to maintain uninterrupted power supply to the load that can maintain the basic operation of the nuclear power plant. Generally, the relatively important electrical equipment of the nuclear power plant is distributed to different nuclear power units for power supply. Therefore, although the plant transformer of the nuclear power unit supplies power to multiple loads under normal circumstances, in fact, only the power supply to the relatively important load needs to be maintained uninterrupted when a special situation occurs.

[0040] Therefore, the distribution unit 23 is only used to select which load needs to be redundantly arranged by the standby plant transformer 22 to prevent the load from suddenly losing power. When the standby transformer module 20 is configured with multiple standby plant transformers 22, redundant power supply configuration for multiple loads can be achieved. The actual power supply mode of the load is determined by the first switch device and the standby first switch device, i.e., the first switch device is closed and the standby first switch device is opened, and the nuclear power unit 10 normally supplies power. The first switch device is opened and the standby first switch device is closed, and the standby transformer module 20 supplies power. Correspondingly, as shown in Figure 3 As shown, one end of the standby second switch device, i.e., the circuit breaker 101JS, is connected to the power supply output end of the standby plant transformer 22, and the other end is connected to the standby first switch device, i.e., the circuit breaker 102JA. Of course, since the power supply output end of the standby plant transformer 22 is connected to the power grid through the standby third switch device, i.e., the circuit breaker CB2, the power supply output end of the standby plant transformer 22 is connected to the power grid through the standby third switch device, i.e., the circuit breaker CB2. Figure 3The distribution unit 23 in the above-mentioned nuclear power plant is composed of multiple circuit breakers, that is, each power supply output of the standby plant transformer 22 is connected to the standby first switching device through a standby second switching device, or one power supply output is connected to multiple different standby first switching devices through multiple standby second switching devices. If the distribution unit 23 adopts a multi-way selection switch, one end of the multi-way selection switch is connected to the power supply output of the standby plant transformer 22, and the other end is connected to different standby first switching devices respectively.

[0041] Based on the above-mentioned power supply mode, each load of the nuclear power plant can be configured as follows: each load is connected to the plant transformer of one nuclear power unit through a first switching device, and is connected to the standby plant transformer of one standby transformer module through a standby first switching device, so that when the nuclear power unit cannot work normally, the corresponding connected first switching device is disconnected, and the corresponding connected standby first switching device is closed, to switch to the standby transformer module for power supply.

[0042] As can be seen, the nuclear power plant can be built based on the electrical structure of the nuclear power unit and the standby transformer module, so that the power supply wiring of the load can be distributed at the initial stage of building the plant, that is, the input of the plant transformer and the input of the standby plant transformer need to be connected respectively, and the on-off of the switching device determines which power supply mode to use.

[0043] Specifically, in actual application, the nuclear power unit 10 and the standby transformer module 20 shown in the above-mentioned nuclear power plant are taken as an example, and the standby transformer module can be used to switch the power supply source of the load under the following working conditions. Figure 2 and Figure 3

[0044] ​Case one, the normal start and stop stage of the nuclear power unit. When the nuclear power unit is normally stopped, the GCB can be disconnected, and the main transformer is sent to the power plant through the power plant A and the power plant B to supply power to the load LGA, LGD, LGE and LGF. At this time, the 001JA can be disconnected through the quick switching device and the 102JA can be quickly closed. It can be understood here that in the present embodiment, in order to avoid the load being powered off when the 001JA is closed / disconnected and the 102JA is closed / disconnected, the quick switching device is used to realize quick switching, thereby ensuring the reliability of power supply and maintaining the continuous operation of the nuclear power station. At this time, the power supply of the load is switched from the nuclear power unit to the standby transformer module, and the CB1 can be disconnected by the operation and maintenance personnel, so that the main transformer, the power plant A and the power plant B are completely withdrawn, and the corresponding maintenance can be carried out. When the nuclear power unit is normally started, the standby transformer module can meet the demand of supplying power to all loads in the starting stage of the nuclear power unit. Therefore, the nuclear power unit can be replaced by the standby transformer module to supply power to the load until the nuclear power unit has the grid-connected condition. When the main transformer, the power plant A and the power plant B have the live condition, the CB1 can be closed by the operation and maintenance personnel, and then the 102JA can be disconnected and the 001JA can be quickly closed through the quick switching device. At this time, the power supply of the load is switched from the standby transformer module to the nuclear power unit, and finally the generator is connected to the grid through the closed GCB to generate power through the main transformer.

[0045] Case two, when the main transformer, the power plant or other causes tripping accidents in the nuclear power unit, the CB1 and the GCB are immediately disconnected. At this time, the 001JA can be disconnected and the 102JA can be quickly closed through the quick switching device, and the power supply of the load is switched from the nuclear power unit to the standby transformer module, so as to ensure that the downstream load of the LGA, the LGD, the LGE and the LGF is not powered off, avoid the nuclear power unit to occur plant auxiliary switching, and improve the reliability of the external power supply of the unit.

[0046] Case three, when the power plant of the nuclear power unit fails, the CB1 and the GCB are immediately disconnected. Similarly, the 001JA can be disconnected and the 102JA can be quickly closed through the quick switching device, and the power supply of the load is switched from the nuclear power unit to the standby transformer module, so as to ensure that the downstream load of the LGA, the LGD, the LGE and the LGF is not powered off. At this time, the operation and maintenance personnel can quickly isolate the faulty power plant, and on this basis, the unit can close the CB1 and the GCB to make the generator connected to the grid to generate power, thereby ensuring the high efficiency and availability of the nuclear power unit and continuously generating power to the outside.

[0047] In addition, the standby transformer module designed in the present application is common to the whole nuclear power station, and can switch the power supply mode of the power supply load of a certain unit in the whole plant through the standby transformer module according to the operation demand of each nuclear power unit in the whole plant. For example, see Figure 4As shown, taking the No. 1 and No. 2 nuclear power units as examples, the start standby module will be switched from supplying power to the load supplied by the No. 1 unit to supplying power to the load supplied by the No. 2 unit. The No. 1 unit first disconnects 102JA through the quick switching device and quickly closes 001JA, at this time, the power supply mode of the load supplied by the No. 1 unit is switched to the power supply of the No. 1 unit itself, and the start standby module is in an idle state, if the No. 2 unit has a power supply demand at this time, the power supply line originally supplying power to the load of the No. 1 unit can be switched to the power supply line supplying power to the load of the No. 2 unit by using the power distribution unit in the start standby module, that is, 101JS is pushed out, and then 201JS is pushed in. At this time, the start standby module has the condition of supplying power to the load of the No. 2 unit. Similarly, when the No. 2 unit appears the situation as in the above section, the same operation can be used to change the power supply line of the start standby module.

[0048] It also needs to be explained that the start standby module mentioned in the present application is not limited to one, for example, one corresponding start standby module can be configured for a certain number of nuclear power units, to pre-redundantly set the power supply mode of a part of the load, to ensure that the downstream load does not power off. At the same time, the switch device mentioned in the above embodiment is not limited to one circuit breaker, and in actual application, multiple circuit breakers can be included, and the modification and decoration of the embodiments of the present application by those skilled in the art without departing from the spirit of the present application still falls within the scope of the patent application of the present application.

[0049] In summary, the present application provides a power supply system of a nuclear power plant auxiliary power source, so that the load in the nuclear power plant can include two power supply modes, so that when any one nuclear power unit is overhauled, the start standby module can be used as the overhauling power source and the start-stop unit power source to supply power to the corresponding load, thereby prolonging the maintenance window of the nuclear power unit main transformer and the plant transformer, shortening the overhauling critical path, and improving the safety and availability of the unit.

[0050] At the same time, after the plant transformer of any one or more nuclear power units in the whole plant fails, the start standby module can replace its operation to maintain the continuous power generation of the nuclear power unit, without waiting for the plant transformer failure to be eliminated, greatly improving the availability of the unit.

[0051] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A power supply system for nuclear power plant auxiliary power, characterized in that, include: The nuclear power plant has several nuclear power units and at least one start-up and standby transformer module, and when the nuclear power units fail to operate normally, the power supply is switched to the start-up and standby transformer module to maintain the operation of the nuclear power plant. The nuclear power unit includes a generator, a main transformer, and at least one auxiliary transformer. One end of the main transformer is connected to the power grid, and the other end is connected to the plant service transformer and the generator respectively, so as to step up the electrical energy generated by the generator and transmit it to the power grid, or to step down the electrical energy transmitted from the power grid and distribute it to the load in the nuclear power plant through the plant service transformer; One end of the plant service transformer is connected to the main transformer and the generator respectively, and the other end is connected to at least one load, so as to distribute the electrical energy generated by the generator or the electrical energy transmitted by the grid through the main transformer to each load after voltage reduction, so as to maintain the operation of the nuclear power plant. The standby transformer module includes a standby main transformer and multiple standby plant transformers, and the parameters of the standby plant transformers are consistent with those of the plant transformers. One end of the backup main transformer is connected to the power grid, and the other end is connected to the backup plant transformer; One end of the standby plant transformer is connected to the standby main transformer, and the other end is connected to multiple different loads; When any nuclear power unit fails to operate normally, the power supplied by the grid is distributed to the loads connected to the nuclear power unit through the backup main transformer and the backup plant service transformer to keep the loads powered.

2. The power supply system for nuclear power plant auxiliary power supply according to claim 1, characterized in that, The nuclear power unit also includes at least one first switching device, and the plant transformer is connected to a load through one of the first switching devices; The standby transformer module also includes a standby first switching device, which is configured to correspond to the first switching device in one or more nuclear power units, and the standby plant transformer is connected to a load through one of the standby first switching devices; Each load in the nuclear power plant is connected to a nuclear power unit’s auxiliary transformer via a first switching device, and to a backup auxiliary transformer of a standby transformer module via a backup first switching device. When the nuclear power unit is unable to operate normally, the corresponding first switching device is disconnected and the corresponding backup first switching device is closed to switch the power supply to the standby transformer module.

3. The power supply system for nuclear power plant auxiliary power supply according to claim 2, characterized in that, The standby transformer module also includes a fast switching device to enable rapid switching between the first switching device and the corresponding backup first switching device to close / open, so as to keep the load powered during the switching process.

4. The power supply system for nuclear power plant auxiliary power supply according to claim 2, characterized in that, The standby transformer module also includes a power distribution unit, which is connected between the standby plant transformer and different loads; The power distribution unit enables the standby plant transformer to supply power to one or more loads by closing / opening switching devices.

5. The power supply system for nuclear power plant auxiliary power supply according to claim 4, characterized in that, When the standby transformer module is activated, one of the standby plant transformers supplies power to only one load connected to the standby plant transformer through the power distribution unit.

6. The power supply system for nuclear power plant auxiliary power supply according to claim 5, characterized in that, The power distribution unit includes a backup second switching device, one end of which is connected to the power output terminal of the backup plant transformer, and the other end is connected to different backup first switching devices respectively. The backup second switching device is configured to connect only the backup plant transformer and a backup first switching device in series after being closed.

7. The power supply system for nuclear power plant auxiliary power supply according to claim 4, characterized in that, The power distribution unit includes multiple backup second switching devices, which are configured one-to-one with the backup first switching devices; In this configuration, one end of any of the backup second switching devices is connected to the power output terminal of the backup plant transformer, and the other end is connected to the corresponding backup first switching device.

8. The power supply system for nuclear power plant auxiliary power supply according to claim 7, characterized in that, The first switching device, the backup first switching device, and the backup second switching device each employ at least one circuit breaker.

9. The power supply system for nuclear power plant auxiliary power supply according to claim 1, characterized in that, The nuclear power unit also includes a second switching device connected between the main transformer and the generator.

10. The power supply system for nuclear power plant auxiliary power supply according to claim 1, characterized in that, The nuclear power unit also includes a third switching device connected between the main transformer and the power grid; The backup transformer module also includes a backup third switching device, which is connected between the backup main transformer and the power grid.

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