Testing system for emergency diesel generator set of nuclear power plant

Abstract

The utility model relates to a test system of a nuclear power plant emergency diesel generating set, which is applied to a diesel generating set comprising a plurality of generators. The test system comprises a synchronous closing module and an additional auxiliary transformer module. The synchronous closing module is connected with the generator and the additional auxiliary transformer module; the additional auxiliary transformer module is connected with an auxiliary power grid of the nuclear power plant; the synchronous switching-on module is switched on after the test system meets the synchronous condition, and electric energy generated by the diesel generating set during test is transmitted to the additional auxiliary transformer module through the synchronous switching-on module, processed by the additional auxiliary transformer module and then transmitted to the auxiliary power supply power grid for consumption. According to the scheme, special mobile load equipment is not needed, and the influence of weather is avoided. The test can also be executed in the unit power operation mode, the nuclear safety risk of power loss of the emergency bus is avoided, and the test time is more flexible. And by using the synchronous closing module, the grid-connected closing process is more stable, and the test safety is improved.

Description

Technical Field

[0001] This utility model relates to the field of generator testing, and in particular to a testing system for emergency diesel generator sets in nuclear power plants. Background Technology

[0002] Emergency diesel generator sets in nuclear power plant units require preventative maintenance every 1.5 years, and their load-bearing capacity must be verified through a full-power test. Additionally, if the maintenance involves disassembly and inspection of moving parts of the diesel engine, a break-in test must be completed before the full-power test. Currently, the electrical energy generated by the emergency diesel generator sets during power tests is primarily utilized in two ways:

[0003] 1. Connect a circuit to the outgoing terminal T of the emergency diesel generator set, and connect it to a mobile load device placed outdoors via a temporary cable. The electrical energy is absorbed by the resistors and reactors inside the mobile load device. Due to the compact structure and large heat dissipation of the mobile load device, its heat dissipation vents are designed to face upwards. In rainy weather, there is a risk of short circuit, which may damage the equipment and induce the emergency diesel generator to experience load shedding.

[0004] Second, energy consumption is achieved through the motor load connected to the plant's emergency busbar. Because conducting tests in the unit's power operation mode carries the risk of emergency busbar de-energization, potentially triggering a nuclear safety accident, tests via the plant's emergency busbar have specific time window requirements, only applicable during the unit's major overhaul shutdown window. However, if a serious defect is discovered during the maintenance or testing of the emergency diesel generator set, it will affect the entire unit's overhaul schedule, resulting in economic losses. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a test system for emergency diesel generator sets in nuclear power plants.

[0006] The technical solution adopted by this utility model to solve its technical problem is: a test system for emergency diesel generator sets in nuclear power plants, applied to diesel generator sets, wherein the diesel generator sets include several generators; the test system includes: a synchronization closing module and an additional auxiliary transformer module;

[0007] The synchronizing closing module is connected to the generator and the auxiliary transformer module, and the auxiliary transformer module is connected to the auxiliary power grid of the nuclear power plant.

[0008] The synchronizing closing module closes after the test system meets the synchronization conditions. The electrical energy generated by the diesel generator set during the test is transmitted to the auxiliary transformer module through the synchronizing closing module, and after being processed by the auxiliary transformer module, it is transmitted to the auxiliary power grid for consumption.

[0009] Furthermore, the test system also includes: a plurality of generator-side circuit breakers, each of the generators being connected to the synchronizing closing module through one of the generator-side circuit breakers.

[0010] Furthermore, the synchronizing closing module includes a data acquisition unit, a grid-connected circuit breaker, and a synchronizing device;

[0011] The grid-connected circuit breaker is connected between the generator and the auxiliary transformer module;

[0012] The acquisition unit is connected to the grid-connected circuit breaker and is used to acquire electrical parameters at both ends of the grid-connected circuit breaker;

[0013] The synchronization device is connected to the acquisition unit and is used to determine whether the electrical parameters meet the synchronization conditions. If so, it outputs the closing command of the grid-connected circuit breaker.

[0014] Furthermore, the acquisition unit includes a current transformer subunit and a voltage transformer subunit.

[0015] Furthermore, the test system also includes a converter module connected between the diesel generator set and the synchronizing module, the converter module being used to integrate the output cables of several of the generators.

[0016] Furthermore, the transfer module includes a first transfer box, at least one second transfer box, ... at least one (N-1)th transfer box, at least one Nth transfer box, where N is an integer greater than 1;

[0017] The output terminal of each of the Nth transfer boxes is connected to the input terminal of the (N-1)th transfer box, and the output terminal of the first transfer box is connected to the synchronous closing module;

[0018] Each of the generators is connected to the input terminal of one of the Nth transfer boxes; or, each of the generators is connected to one of the first transfer boxes, one of the second transfer boxes... one of the (N-1)th transfer boxes, or the input terminal of one of the Nth transfer boxes.

[0019] Furthermore, the additional auxiliary transformer module includes an additional auxiliary transformer and a first protection unit;

[0020] The low-voltage side of the auxiliary transformer is connected to the synchronizing closing module, and the high-voltage side of the auxiliary transformer is connected to the auxiliary power grid and the first protection unit.

[0021] Furthermore, the first protection unit includes a grounding switch and a first surge arrester; the additional auxiliary transformer is grounded through the grounding switch and the first surge arrester respectively.

[0022] Furthermore, the synchronous closing module is connected to the medium-voltage busbar of the nuclear power plant, and is connected to the auxiliary transformer module through the medium-voltage busbar.

[0023] Furthermore, a transformer-side circuit breaker is connected between the medium-voltage busbar and the additional auxiliary transformer module;

[0024] A second protection unit is also connected between the transformer-side circuit breaker and the additional auxiliary transformer module. The second protection unit includes a second surge arrester that is grounded and a live display subunit.

[0025] The implementation of this utility model has the following beneficial effects: By transmitting the electrical energy generated by the diesel generator set during testing to the auxiliary power grid through the auxiliary transformer module, it eliminates the need for dedicated mobile load equipment and avoids the influence of weather. Since the auxiliary transformer module is in an unloaded standby state during normal power operation of the nuclear power unit, testing can be performed even in the unit's power operation mode, avoiding the nuclear safety risks of emergency bus power failure. Furthermore, the testing execution time is more flexible, avoiding extended overhaul periods. In addition, using a synchronization module to close the circuit after meeting synchronization conditions makes the grid connection process smoother, improving the safety of the testing process. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0027] Figure 1 This is a structural block diagram of an embodiment of the test system for an emergency diesel generator set in a nuclear power plant according to this utility model;

[0028] Figure 2 This is a structural block diagram of another embodiment of the test system for the nuclear power plant emergency diesel generator set of this utility model;

[0029] Figure 3 This is a schematic diagram of an embodiment of the test system for an emergency diesel generator set in a nuclear power plant according to this utility model;

[0030] Figure 4 This is a schematic diagram of the use of mobile loads in existing technology. Detailed Implementation

[0031] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the terms "first," "second," etc., are used only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0032] This invention relates to a test system for nuclear power plant emergency diesel generator sets. The system is applied to diesel generator sets to utilize the electrical energy generated by each generator during power testing of the nuclear power plant emergency diesel generator sets. The diesel generator set includes several generators, such as one or more diesel generators. The diesel generators can be from LHP, LHQ, LHS, LHR, or LHU systems in nuclear power plants.

[0033] like Figure 1 As shown, in one embodiment of the test system for the nuclear power plant emergency diesel generator set of this utility model, the test system includes: a synchronizing closing module 10 and an additional auxiliary transformer module 20.

[0034] The synchronizing module 10 connects the generator and the auxiliary transformer module 20, which in turn connects to the auxiliary power grid of the nuclear power plant. The synchronizing module 10 closes after the test system meets the synchronization conditions. The electrical energy generated by the diesel generator set during the test is transmitted through the synchronizing module 10 to the auxiliary transformer module 20, processed by the auxiliary transformer module 20, and then transmitted to the auxiliary power grid for consumption.

[0035] In this embodiment, the auxiliary transformer module 20 includes the auxiliary transformer in the nuclear power plant. The synchronizing module 10 is connected to each generator at one end and to the auxiliary transformer module 20 at the other end. After the electrical parameters at both ends meet the synchronization conditions, it closes the circuit, connecting the generator to the auxiliary transformer module 20. This allows the electrical energy generated by the generator to be transmitted to the auxiliary transformer module 20 for voltage conversion, and then transmitted to the auxiliary power grid for consumption. This auxiliary power grid refers to the nuclear power plant's 220kV auxiliary power system, which can supply power to the load through the auxiliary transformer and the auxiliary transformer. The auxiliary transformer is a backup device for the auxiliary transformer and is in an unloaded standby state during normal power operation of the nuclear power unit. Therefore, its participation in the power test of the emergency diesel generator set does not affect the power supply of the unit's auxiliary power supply.

[0036] compared to Figure 4Compared to existing solutions, this invention eliminates the need for dedicated mobile load equipment, thus avoiding the impact of weather conditions. Since the auxiliary transformer module 20 is in an unloaded standby state during normal power operation of the nuclear power unit, tests can be performed even in the unit's power operation mode. This avoids the nuclear safety risks associated with emergency bus power failure and enables power tests of the nuclear power plant's emergency diesel generator sets to be performed 24 / 7 in the nuclear power unit's power mode. The test execution time is more flexible, avoiding extended overhaul periods. Furthermore, the use of the synchronization module 10 for closing the circuit after meeting synchronization conditions makes the grid connection process smoother, improving the safety of the test process.

[0037] Furthermore, such as Figure 3 As shown, the test system also includes several generator-side circuit breakers CB4. Each generator G1 is connected to the synchronizing closing module 10 through a generator-side circuit breaker CB4.

[0038] The generator-side circuit breaker is installed on the output cable of generator G1 and is used to control the opening and closing of the corresponding generator's power output. In a typical test scenario, only one generator participates in the test at a time. In this case, the corresponding generator-side circuit breaker CB4 of the generator participating in the test is closed, while the CB4s of the other generators are open.

[0039] In an optional embodiment, the synchronizing closing module 10 includes a data acquisition unit, a grid-connected circuit breaker CB2, and a synchronizing device.

[0040] The grid-connected circuit breaker CB2 is connected between the generator G1 and the auxiliary transformer module 20. A data acquisition unit is connected to the grid-connected circuit breaker CB2 to collect electrical parameters from both ends of CB2. A synchronizing device is connected to the data acquisition unit to determine whether the electrical parameters meet the synchronization conditions; if so, it outputs a closing command for the grid-connected circuit breaker CB2.

[0041] Optionally, the acquisition unit includes a current transformer subunit and a voltage transformer subunit. The current transformer subunit uses a current transformer, and the voltage transformer subunit uses a voltage transformer. Further, the acquisition unit also includes a grounding switch connected to the voltage transformer to ground it. The current transformer acquires the current parameters across the grid-connected circuit breaker, and the voltage transformer acquires the voltage parameters across the grid-connected circuit breaker. The synchronization device acquires the current and voltage parameters across the grid-connected circuit breaker. If the current parameters and voltage parameters across the grid-connected circuit breaker are equal, the synchronization condition is met, and a closing command for the grid-connected circuit breaker is output.

[0042] This closing command is used to instruct the grid-connected circuit breaker to close and connect to the grid. The grid-connected circuit breaker can operate in either automatic or manual closing mode. Automatic closing: The synchronizing device sends the closing command to the nuclear power plant's control cabinet, which then controls the grid-connected circuit breaker to close automatically according to the command. Manual closing: Operators manually close the grid-connected circuit breaker according to the closing command.

[0043] In other embodiments, the electrical parameters collected by the acquisition unit can vary according to actual needs. For example, the voltage and frequency at both ends of the grid-connected circuit breaker can be collected, and the acquisition unit will change accordingly. In other embodiments, a synchronizing device with electrical parameter measurement function can also be used, eliminating the need for an acquisition unit, such as the SYN 5100 synchronizing device.

[0044] Furthermore, such as Figure 2 As shown, the test system also includes a converter module 30 connected between the diesel generator set and the synchronizing module 10. The converter module 30 is used to integrate the output cables of several generators G1.

[0045] When a diesel generator set has more than one generator, if each generator is directly connected to the synchronizing module 10 via an output cable, these cables will occupy a lot of space and increase wiring complexity and cost. Using the adapter module 30 to integrate the output cables of all generators and then connecting them to the synchronizing module 10 via a unified cable can reduce the space occupied, cost, and wiring complexity.

[0046] It is understandable that when there is only one generator in the diesel generator set, the adapter module 30 may not be required.

[0047] Specifically, the switching module 30 includes a first switching box K1, at least one second switching box K2, ... at least one (N-1)th switching box, and at least one Nth switching box, where N is an integer greater than 1. The output of each Nth switching box is connected to the input of one (N-1)th switching box, and the output of the first switching box K1 is connected to the synchronizing closing module 10. Each generator is connected to the input of one Nth switching box; or, each generator is connected to one first switching box, one second switching box, ... one (N-1)th switching box, or the input of one Nth switching box.

[0048] The hierarchy and number of transfer boxes in the transfer module 30 can be determined according to actual needs. The output terminal of each transfer box is connected to the input terminal of the previous transfer box, and the input terminal of the last transfer box (i.e., the Nth transfer box) is connected to the generator. When there are enough last-level transfer boxes, all generators can be connected to the last-level transfer boxes through generator-side circuit breakers; when there are not enough last-level transfer boxes, some generators can be connected to the previous level transfer boxes through generator-side circuit breakers. In another embodiment, when the number of generators is small, only one first transfer box can be set up, and all generators can be connected to the input terminal of this first transfer box. The electrical energy generated by the generator is output to the synchronous closing module 10 sequentially through each level of transfer box.

[0049] Furthermore, the auxiliary transformer module 20 includes an auxiliary transformer T1 and a first protection unit. The low-voltage side of the auxiliary transformer T1 is connected to the synchronizing closing module 10, and the high-voltage side of the auxiliary transformer T1 is connected to the auxiliary power grid and the first protection unit.

[0050] Specifically, the first protection unit includes a grounding switch Q1 and a first surge arrester SPD1; the auxiliary transformer is grounded through both the grounding switch Q1 and the first surge arrester SPD1. The grounding switch Q1 and the first surge arrester SPD1 are used to protect the auxiliary transformer and ensure the safe conduct of the test.

[0051] In an optional embodiment, the synchronizing module 10 is connected to the medium-voltage busbar of the nuclear power plant, and then connected to the auxiliary transformer module 20 via the medium-voltage busbar. In this embodiment, the generator's electrical energy is transmitted to the auxiliary transformer module 20 via the nuclear power plant's medium-voltage busbar. This test system is not directly connected to the nuclear power unit's auxiliary power system, and does not change the wiring method of the auxiliary power system or affect its operation during the test. Furthermore, this test system can be used as a permanent test system, allowing power tests to be conducted simply by switching on and off each circuit breaker.

[0052] Furthermore, a transformer-side circuit breaker CB1 is connected between the medium-voltage busbar and the auxiliary transformer module 20. A second protection unit is also connected between the transformer-side circuit breaker CB1 and the auxiliary transformer module 20. The second protection unit includes a second surge arrester SPD2 that is grounded and a live display subunit.

[0053] The auxiliary transformer T1 adopts a Yn,d11 connection mode. The transformer-side circuit breaker CB1 controls the connection and disconnection between the auxiliary transformer module 20 and the medium-voltage busbar, thereby controlling the test. The live-line display subunit displays the energization status between the auxiliary transformer module and the medium-voltage busbar. The live-line display subunit includes an indicator light L1 and a capacitor C1. Capacitor C1 is grounded through indicator light L1. When the indicator light is lit, it indicates that the auxiliary transformer module is energized between the auxiliary transformer module and the medium-voltage busbar, allowing monitoring of whether the energy consumption process of the test is proceeding normally.

[0054] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A test system for an emergency diesel generator set of a nuclear power plant, characterized in that, The application is applied to diesel generator set, which comprises several generators; the test system comprises: a synchronization closing module and an additional auxiliary transformer module; The synchronization closing module is connected with the generator and the additional auxiliary transformer module, and the additional auxiliary transformer module is connected with the auxiliary power grid of the nuclear power plant; The synchronization closing module is closed after the test system meets the synchronization condition, the electric energy generated by the diesel generator set during the test is transmitted to the additional auxiliary transformer module through the synchronization closing module, and is transmitted to the auxiliary power grid for consumption after being processed by the additional auxiliary transformer module.

2. The test system for emergency diesel generating units of a nuclear power plant according to claim 1, characterized in that, The test system further comprises: several generator-side circuit breakers, and each generator is connected with the synchronization closing module through a generator-side circuit breaker.

3. The test system for emergency diesel generating units of a nuclear power plant according to claim 1, characterized in that, The synchronization closing module comprises an acquisition unit, a grid-connected circuit breaker and a synchronization device; The grid-connected circuit breaker is connected between the generator and the additional auxiliary transformer module; The acquisition unit is connected with the grid-connected circuit breaker and is used for acquiring electrical parameters at both ends of the grid-connected circuit breaker; The synchronization device is connected with the acquisition unit and is used for judging whether the electrical parameters meet the synchronization condition, and if yes, outputs a closing instruction of the grid-connected circuit breaker.

4. The test system for emergency diesel generating units of a nuclear power plant according to claim 3, characterized in that, The acquisition unit comprises a current mutual inductance subunit and a voltage mutual inductance subunit.

5. The test system for emergency diesel generating units of a nuclear power plant according to claim 1, characterized in that, The test system further comprises: a switching module connected between the diesel generator set and the synchronization closing module, and the switching module is used for integrating output cables of the generators.

6. The test system for emergency diesel generating units of nuclear power plants according to claim 5, characterized in that, The switching module comprises a first switching box, at least one second switching box, at least one N-1 switching box and at least one N switching box, wherein N is an integer greater than 1; The output end of each N switching box is connected with the input end of one N-1 switching box, and the output end of the first switching box is connected with the synchronization closing module; Each generator is connected with the input end of one N switching box, or each generator is connected with the input end of one first switching box, one second switching box, one N-1 switching box or one N switching box.

7. The test system for emergency diesel generating units of nuclear power plants according to claim 1, characterized in that, The additional auxiliary transformer module comprises an additional auxiliary transformer and a first protection unit; The low-voltage side of the additional auxiliary transformer is connected with the synchronization closing module, and the high-voltage side of the additional auxiliary transformer is connected with the auxiliary power grid and the first protection unit.

8. The test system for emergency diesel generating units of nuclear power plants according to claim 7, characterized in that, The first protection unit comprises a grounding knife switch and a first arrester, and the additional auxiliary transformer is grounded through the grounding knife switch and the first arrester respectively.

9. The test system for emergency diesel generating units of nuclear power plants according to claim 1, characterized in that, The synchronization closing module is connected with the medium-voltage bus of the nuclear power plant, and the additional auxiliary transformer module is connected through the medium-voltage bus.

10. The test system for emergency diesel generating units of nuclear power plants according to claim 9, characterized in that, A transformer-side circuit breaker is connected between the medium-voltage bus and the additional auxiliary transformer module; A second protection unit is further connected between the transformer-side circuit breaker and the additional auxiliary transformer module, and the second protection unit comprises a second arrester and a live display subunit which are grounded respectively.

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