Uninterruptible AC power system for operating multiple power plants that include individual small nuclear reactor modules

Abstract

The present invention relates to an AC power uninterruptible system for a plurality of power plants comprising individual small reactor modules, comprising a plurality of power plants each comprising a small reactor, a self-starting generator capable of generating power independently, a main transformer that converts power produced by the individual small reactor into high-voltage power, an in-plant auxiliary transformer that converts a portion of the power produced by the individual small reactor into power for operating the power plant, a high-voltage circuit breaker, and an AC power system that branches the AC power produced by the individual small reactor of each of the plurality of power plants and transmits it to a load through two high-voltage buses.

Description

Technology Field

[0001] The present invention relates to a power system for operating multiple power plants, and specifically, to an AC power uninterruptible system for operating multiple power plants comprising individual small reactor modules. Background Technology

[0002] The safety systems of conventional active nuclear power plants utilize electricity as an essential driving force to perform safety functions in emergencies in preparation for power loss; to this end, they are required to be equipped with emergency diesel generators and backup AC generators. However, in the case of passive nuclear power plants, safety functions are driven by natural forces such as gravity and convection, so electricity is not essential in emergencies. Therefore, passive nuclear power plants, where the systems for achieving safety functions do not require electricity, may be exempt from the application of Article 16 (Sharing of Facilities) of the Rules on Technical Standards for Reactor Facilities, etc., which, in principle, prohibits the sharing of safety-critical structures, systems, and equipment between reactor facilities. However, if it is necessary to supply reliable power for the operation and monitoring of safety functions even during normal operation, an uninterruptible power supply system may be essential. Prior art literature

[0003] (Patent Literature 1) Korean Published Patent Application No. 10-2018-0095547 (August 27, 2018) The problem to be solved

[0004] The present invention aims to provide an uninterruptible power system that shares equipment with an AC power system applied to multiple power plants, including individual small reactor modules, based on a passive power plant that does not require emergency power by performing safety functions using natural forces such as gravity and convection to achieve safety functions.

[0005] However, the problem to be solved by the present invention is not limited thereto and may be expanded in various ways without departing from the spirit and scope of the present invention. means of solving the problem

[0006] According to one embodiment of the present invention, an AC power uninterruptible system for a plurality of power plants comprising individual small reactor modules may include a plurality of power plants each comprising a small reactor, a self-starting generator capable of generating power independently, a main transformer that converts power produced by the individual small reactor into high-voltage power, an in-plant auxiliary transformer that converts a portion of the power produced by the individual small reactor into power for operating the power plant, a high-voltage circuit breaker, and an AC power system that branches the AC power produced by the individual small reactor of each of the plurality of power plants and transmits it to a load through two high-voltage buses.

[0007] Each of the above multiple power plants may include the main transformer, two of the above in-house auxiliary transformers, and two of the above high-voltage circuit breakers.

[0008] A plurality of high-voltage circuit breakers within the aforementioned plurality of power plants are configured as closed loops, and each path of the closed loop may include a switch.

[0009] The above multiple power plants can be configured as an independent power grid capable of starting with the above self-starting generator.

[0010] Each of the aforementioned multiple power plants has an AC power system comprising two in-situ auxiliary transformers and two high-voltage circuit breakers, and each of the two in-situ auxiliary transformers and the two high-voltage circuit breakers is separated into a first series and a second series, and the in-situ auxiliary transformer of the first series and the high-voltage circuit breaker of the first series are connected to the high-voltage busbar of the first series, and the in-situ auxiliary transformer of the second series and the high-voltage circuit breaker of the second series are connected to the high-voltage busbar of the second series, and different types of loads may be connected to each of the high-voltage circuit breakers of the first series and the second series.

[0011] The above AC power uninterruptible system includes a switchyard, and the switchyard can receive power produced from the self-starting generator and the plurality of power plants and supply power to consumers and the plurality of power plants.

[0012] The above AC power system may be configured to supply power through the switchyard from one of the other power plants other than the shut-down power plant to loads that were receiving power from the shut-down small reactor and the power plant when the small reactor and the power plant are shut down.

[0013] The above AC power system can be configured such that, if one of the two in-house auxiliary transformers fails, the power path for the load transmitted by the in-house auxiliary transformer that failed is switched to a high-voltage busbar operating normally within the same power plant to which the in-house auxiliary transformer that failed belongs, through switching of the high-voltage circuit breaker.

[0014] The above AC power system can be configured such that if the high-voltage busbars of both in-house auxiliary transformers within a single power plant are lost, the load transmitted by the in-house auxiliary transformer where the fault occurred is switched to the high-voltage busbar of another power plant through the switching of the high-voltage circuit breaker.

[0015] The above AC power system may be configured to switch to another high-voltage busbar of the same power plant to which the faulty auxiliary transformer belongs, through switching of the high-voltage circuit breaker, in the event that one of the auxiliary transformers in the house load operation becomes unusable. Effects of the invention

[0016] An AC power uninterruptible system for operating multiple power plants, each comprising individual small reactor modules, according to one embodiment of the present invention, can receive power through a high-voltage circuit breaker of another power plant even when the internal power system of one power plant is interrupted, thereby enabling the operation and monitoring of safety functions even in emergencies.

[0017] According to one embodiment of the present invention, an AC power uninterruptible system for operating multiple power plants including individual small reactor modules can receive power from the high-voltage circuit breaker of the same power plant even when one of the in-plant auxiliary transformers of the power plant is unusable, so that in-plant load operation is possible without stopping the generator. Brief explanation of the drawing

[0018] FIG. 1 is a diagram showing the configuration of an AC power uninterruptible system for a plurality of power plants including individual small reactor modules according to one embodiment of the present invention. FIG. 2 is a drawing showing a channel of one integrated power cell included in a DC power system of a power system (10) for a plurality of power plants including individual small nuclear reactor modules according to one embodiment of the present invention. Specific details for implementing the invention

[0019] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the technical spirit and scope of the present invention. In describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention.

[0020] Terms such as "first," "second," etc., may be used to describe various components, but the components are not limited by these terms. The terms may be used solely for the purpose of distinguishing one component from another.

[0021] The terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. While the terms used in this invention have been selected to be as widely used as possible in consideration of their functions within the invention, they may vary depending on the intent of those skilled in the art, case law, or the emergence of new technologies. Furthermore, in specific cases, terms have been arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall content of the invention.

[0022] A singular expression may include a plural expression unless the context clearly indicates otherwise. In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0023] FIG. 1 is a diagram showing the configuration of an AC power uninterruptible system for a plurality of power plants including individual small reactor modules according to one embodiment of the present invention.

[0024] The AC power uninterruptible system (10) illustrated in FIG. 1 is a power system for a plurality of power plants including individual small nuclear reactor modules, and may largely include a self-starting generator (110), a switchyard (120), power plants (130, 140, 150, 160), auxiliary diesel generators (181, 182), and a controller (190).

[0025] The switchyard (120) may include first to fourth switchyards (121, 122, 123, 124), and the switchyard (120) may provide a power transmission path between the self-starting generator (110) and the power plant (130, 140, 150, 160) and between the power plant (130, 140, 150, 160) and the consumer by means of a controller (190).

[0026] Each of the power plants (130, 140, 150, 160) may include a corresponding small reactor module (131, 132, 133, 134).

[0027] The first small reactor module (131) may be composed of a reactor, turbine, generator, and auxiliary equipment for power production and operation of the first power plant (130). The power produced in the first small reactor module (131) is converted into high-voltage power through a main transformer (141) and transmitted to the first switchyard (121), and some of the power can be utilized as power required for the operation of the power plant (130, 140, 150, 160) through an in-plant auxiliary transformer (151, 152) and a high-voltage circuit breaker (161, 162).

[0028] Each of the main transformers (141, 142, 143, 144) can transmit power to the load through the high-voltage busbars (HVB 1, HVB 2, HVB 3, HVB 4). Subsequently, the high-voltage busbars (HVB 1, HVB 2, HVB 3, HVB 4) can be branched into a first series of high-voltage busbars connected to the in-house auxiliary transformer (151) and the high-voltage circuit breaker board (161), and a second series of high-voltage busbars connected to the in-house auxiliary transformer (152) and the high-voltage circuit breaker board (162). Thus, the four power plants (130, 140, 150, 160) can include eight high-voltage busbars.

[0029] The loads within the power plant (130, 140, 150, 160) can be classified into a first series of loads (L1) and a second series of loads (L2).

[0030] The in-house auxiliary transformer (151) and the high-voltage circuit breaker board (161) within the first power plant (130) can transmit power to the first series load (L1) through the first series high-voltage busbar (HVB 1_1). Additionally, the in-house auxiliary transformer (152) and the high-voltage circuit breaker board (162) within the first power plant (130) can transmit power to the second series load (not shown) within the third power plant (150) through the second series high-voltage busbar (HVB 1_2). Here, the first series load (L1) and the second series load (L2) may include different types.

[0031] The controller (190) can be configured such that, depending on the emergency situation within the power plant (130, 140, 150, 160), the high-voltage busbar connection within the power system (10) is configured such that the loads of the first series within the power plant (130, 140, 150, 160) receive power transmitted from the small reactor module of the power plant to which they belong, and the loads of the second series within the power plant (130, 140, 150, 160) receive power transmitted from the small reactor module of another power plant.

[0032] Additionally, the high-voltage circuit breakers (161 to 168) form a closed loop, and the closed loop may include switches in each loop. That is, switches may be included in the path connecting each of the high-voltage circuit breakers (161 to 168).

[0033] The switching of the high-voltage circuit breaker base of the present specification may include the switching of the switch.

[0034] The controller (190) can control the switch according to the emergency situation within the power plant to change the power transmission path corresponding to each emergency situation.

[0035] In this way, according to one embodiment of the present invention, the AC power system of the power system (10) is cross-connected to each other among the power plants (130, 140, 150, 160), so that even in the event of a failure of at least one of the in-house auxiliary transformers (151 to 158) and the high-voltage circuit breaker boards (161 to 168), each of the power plants (130, 140, 150, 160) can receive power from an adjacent power plant through the switching combination of the high-voltage circuit breaker boards (161 to 168).

[0036] The DC power system within the first power plant (130) may include an integrated power cell (171), and some channels of the integrated power cell (171) may receive and store power through the first series in-house auxiliary transformer (151), the first series high-voltage circuit breaker board (161), and the first series high-voltage busbar (HVB 1_1) within the first power plant (130). Additionally, other channels of the integrated power cell (171) may receive and store power through the second series in-house auxiliary transformer (156), the first series high-voltage circuit breaker board (166), and the second series high-voltage busbar (HVB 3_2) within the third power plant (150). The integrated power cell (171) can be configured to provide highly reliable, uninterrupted DC power to the safety system of the small reactor of the first power plant (130), the emergency recirculation valve (ERV) and emergency depressurization valve (EDV) of the emergency core cooling system, etc., using stored power.

[0037] Additionally, the power system (10) may include a self-starting generator (110) to enable starting and operating a power plant in a remote area without external power sources.

[0038] In addition, the first auxiliary diesel generator (181) and the second auxiliary diesel generator (182) may be included so that power supply is possible even after 72 hours of loss of the system AC power among the off-site power sources.

[0039] The first auxiliary diesel generator (181) supplies power to the channel corresponding to the first series among the channels of the integrated power cells (171 to 174), and the auxiliary diesel generator (182) may be configured to supply power to the channel corresponding to the second series among the channels of the integrated power cells (171 to 174).

[0040] For the plant start-up of the multiple power plants (130, 140, 150, 160) shown in Fig. 1, the plants can be started using external power or a self-starting generator (110).

[0041] In normal operation, some of the power produced by each of the small reactor modules (131, 132, 133, 134) shown in FIG. 1 can be transmitted to a first series load in its own power plant, a second series load in another power plant, and some channels of an integrated power cell (171 to 174), and the remaining power can be transmitted through a line connected to a switchyard (120).

[0042] In the event of a partial small reactor module (131, 132, 133, 134) or a plant shutdown, the load that was receiving power from the shut-down plant may receive power from one of the other plants other than the shut-down plant via the switchyard (120).

[0043] In the event of a fault in a small reactor module (131, 132, 133, 134) or a main transformer (141, 142, 143, 144), only the high-voltage side circuit breaker of the main transformer (141, 142, 143, 144) is opened (tripped), so power from another power plant can be supplied via the switchyard (120) without switching of the high-voltage circuit breaker board (161 to 169), that is, without switching of the high-voltage busbar.

[0044] If an accident occurs in one of the in-house auxiliary transformers (151, 152) of the first power plant (130), the controller (190) can switch the high-voltage bus connected to the load supplied by the in-house auxiliary transformer where the accident occurred to another high-voltage bus within the first power plant (130) by switching the high-voltage circuit breaker boards (161 and 162).

[0045] If both high-voltage busbars of the in-house auxiliary transformers (151, 152) of the first power plant (130) are lost, the high-voltage busbars of another power plant can be switched by switching to the high-voltage circuit breaker boards (163 to 169) of the controller (190).

[0046] There may be cases where all power plants (130 to 160) are operating under internal load due to the loss of all transmission lines connected to the switchyard (120), or cases where the circuit breaker of the switchyard (120) connected to some power plants is opened, causing internal load operation. In such cases, when one of the internal auxiliary transformers of a power plant operating under internal load becomes unusable, the internal load operation may be possible without stopping the power plant by switching to another high-voltage busbar within the same power plant through the switching of the high-voltage circuit breaker.

[0047] In the event of a loss of offsite power, the power system (10) attempts house load operation, and if all power plants (130 to 160) fail to perform house load operation and the generator circuit breaker (not shown) opens, the integrated power cell (171 to 174) can supply DC power (battery) to the accident monitoring equipment and the emergency recirculation valve (ERV) and emergency pressure reducing valve (EDV) of the emergency core cooling system.

[0048] Since the integrated power cell (171 to 174) is equipped with a passive safety system capable of performing safety-related functions for 72 hours without AC power supply, a separate Emergency Diesel Generator may not be required.

[0049] On the other hand, the power system (10) must demonstrate that it can maintain core cooling and the integrity of the containment building area for a specific period of time in the event of a Station Blackout, that is, an accident in which both the power produced by the main generator and the power supply from the outside are cut off (however, the battery can still supply power). In the case of the i-SMR, since it is equipped with a passive safety system capable of performing safe-related functions for 72 hours without the supply of DC power as well as AC power, an alternative AC power source (AAC) may not be necessary in preparation for a Station Blackout (SBO).

[0050] FIG. 2 is a drawing showing a channel of one integrated power cell included in a DC power system of a power system (10) for a plurality of power plants including individual small nuclear reactor modules according to one embodiment of the present invention.

[0051] As shown in FIG. 2, each of the integrated power cells (171 to 174) included in the DC power system (10) can be composed of channels A, B, C, and D.

[0052] Each of channels A, B, C, and D (210, 220, 230, 240) of the integrated power cell (200) may include one battery, two chargers (e.g., a charger and a backup charger) and one DC control panel.

[0053] Channel A (210) and Channel C (230) of the integrated power cell (200) may be configured to receive power through the first series of lines of the non-safety-grade auxiliary power system. Meanwhile, Channel B (220) and Channel D (240) may be configured to receive power through the second series of lines.

[0054] The batteries of Channel A (210) and Channel B (220) can be designed for a 72-hour duty and can power the reactor safety system, some engineered safety equipment related to accident mitigation, and post-accident monitoring equipment for 0 to 24 hours. Additionally, they can power the post-accident monitoring equipment for 24 to 72 hours.

[0055] The batteries of Channel C (220) and Channel D (240) can be designed for 24-hour operation and can supply power to the reactor safety system, some engineering safety equipment related to accident mitigation, and post-accident monitoring equipment.

[0056] The operating duty of the batteries in channels A, B, C, and D (210, 220, 230, 240) of the integrated power cell (200) can be changed according to the type of load connected to each channel.

[0057] Embodiments of the present invention may be further explained using the following content.

[0058] 1. An AC power uninterruptible system for multiple power plants including individual small reactor modules, comprising: multiple power plants each including a small reactor; a self-starting generator capable of generating power independently; a main transformer that converts power produced by the individual small reactor into high-voltage power; an in-plant auxiliary transformer that converts a portion of the power produced by the individual small reactor into power for operating the power plant; a high-voltage circuit breaker; and an AC power system that branches the AC power produced by the individual small reactor of each of the multiple power plants and transmits it to a load through two high-voltage buses.

[0059] 2. Each of the above multiple power plants may include the main transformer, two of the above in-house auxiliary transformers, and two of the above high-voltage circuit breakers.

[0060] 3. The multiple high-voltage circuit breakers within the multiple power plants are configured as closed loops, and each path of the closed loop may include a switch.

[0061] 4. The above multiple power plants may be configured as an independent power grid capable of being started by the above self-starting generator.

[0062] 5. Each of the above multiple power plants includes two in-situ auxiliary transformers and two high-voltage circuit breakers, and each of the two in-situ auxiliary transformers and the two high-voltage circuit breakers is separated into a first series and a second series, and the in-situ auxiliary transformer of the first series and the high-voltage circuit breaker of the first series are connected to the high-voltage busbar of the first series, and the in-situ auxiliary transformer of the second series and the high-voltage circuit breaker of the second series are connected to the high-voltage busbar of the second series, and different types of loads may be connected to each of the first series and the high-voltage circuit breakers of the second series.

[0063] 6. The above AC power uninterruptible system includes a switchyard, and the switchyard can receive power produced from the self-starting generator and the plurality of power plants and supply power to consumers and the plurality of power plants.

[0064] 7. The above AC power system may be configured to supply power through the switchyard from one of the other power plants other than the shut-down power plant to loads that were receiving power from the shut-down small reactor and the power plant when the small reactor and the power plant are shut down.

[0065] 8. The above AC power system may be configured such that, if one of the two in-house auxiliary transformers fails, the power path for the load transmitted by the in-house auxiliary transformer that failed is switched to a high-voltage busbar operating normally within the same power plant to which the in-house auxiliary transformer that failed belongs, through switching of the high-voltage circuit breaker.

[0066] 9. The above AC power system may be configured to switch to the high-voltage bus of another power plant through switching of the high-voltage circuit breaker for the load transmitted by the faulty in-plant auxiliary transformer when the high-voltage bus of both in-plant auxiliary transformers within one power plant is lost.

[0067] 10. The above AC power system may be configured to switch to another high-voltage busbar of the same power plant to which the faulty auxiliary transformer belongs, through switching of the high-voltage circuit breaker, for the load transmitted by the faulty auxiliary transformer in the event of the failure of one of the auxiliary transformers in the house load operation. Explanation of the symbols

[0068] 10: AC Power Uninterruptible System 110: Self-starting power generation 120: Switchyard 130, 140, 150, 160: Power Plant 131, 132, 133, 134: Small reactors 141, 142, 143, 144: Transformer 151, 152, 153, 154, 155, 156, 157, 158: In-house auxiliary transformers 161, 162, 163, 164, 165, 166, 167, 168: High-voltage circuit breaker base 171, 172, 173, 174: Integrated Power Cell 181, 182: Auxiliary diesel generator 190: Controller HVB 1_1, HVB 1_2, HVB 3_2: High-voltage busbars L1: 1st series load L2: 2nd series load

Claims

Claim 1 An AC power uninterruptible system for multiple power plants comprising individual small reactor modules, comprising: multiple power plants each comprising a small reactor; a self-starting generator capable of generating power independently; a main transformer that converts power produced by the individual small reactors into high-voltage power; and an on-site auxiliary transformer and a high-voltage circuit breaker that convert a portion of the power produced by the individual small reactors into power for operating the power plants. An AC power uninterruptible system for multiple power plants including individual small reactor modules, comprising an AC power system that branches AC power produced by each of the individual small reactors of the multiple power plants and transmits it to loads through two high-voltage buses, wherein the AC power system is configured to supply power through a switchyard from one of the other power plants other than the shut-down power plant to loads receiving power from the shut-down small reactor and the power plant when the small reactor and the power plant are shut down, and wherein the AC power system is configured to switch the power path to a high-voltage bus operating normally within the same power plant to which the faulty small reactor belongs, through switching of a high-voltage circuit breaker, for loads transmitted by the faulty small reactor when one of the two in-plant auxiliary transformers fails. Claim 2 An AC power uninterruptible system for a plurality of power plants, wherein each of the plurality of power plants comprises an individual small reactor module comprising the main transformer, two of the in-plant auxiliary transformers, and two of the high-voltage circuit breakers. Claim 3 An AC power uninterruptible system for multiple power plants, comprising individual small reactor modules, wherein, in claim 1, multiple high-voltage circuit breakers within the multiple power plants are configured as closed loops and each path of the closed loop includes a switch. Claim 4 In paragraph 3, an AC power uninterruptible system for a plurality of power plants comprising individual small reactor modules, wherein the plurality of power plants are configured as independent power grids capable of being started by the self-starting generator. Claim 5 An AC power uninterruptible system for a plurality of power plants comprising individual small reactor modules, wherein each of the plurality of power plants comprises an AC power system including two in-plant auxiliary transformers and two high-voltage circuit breakers, each of the two in-plant auxiliary transformers and the two high-voltage circuit breakers is separated into a first series and a second series, the in-plant auxiliary transformer of the first series and the high-voltage circuit breaker of the first series are connected to a high-voltage busbar of the first series, the in-plant auxiliary transformer of the second series and the high-voltage circuit breaker of the second series are connected to a high-voltage busbar of the second series, and different types of loads are connected to each of the high-voltage circuit breakers of the first series and the second series. Claim 6 In paragraph 5, the above AC power uninterruptible system comprises a switchyard, and the switchyard is an AC power uninterruptible system for multiple power plants comprising individual small reactor modules that receive power produced from the self-starting generator and the multiple power plants and supply power to consumers and the multiple power plants. Claim 7 An AC power uninterruptible system for multiple power plants including individual small reactor modules, wherein, in the first paragraph, the AC power system is configured to switch to the high-voltage bus of another power plant through switching of the high-voltage circuit breaker for the load transmitted by the faulty in-plant auxiliary transformer when the high-voltage bus of both in-plant auxiliary transformers within one power plant is lost. Claim 8 An AC power uninterruptible system for multiple power plants including individual small reactor modules, wherein, in claim 7, the AC power system is configured to switch to another high-voltage busbar of the same power plant to which the faulty auxiliary transformer belongs, through switching of the high-voltage circuit breaker, for the load transmitted by the faulty auxiliary transformer, when one of the house load transformers becomes unusable during house load operation.

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