A parallel maintenance method for two rows of electrical panels in a nuclear power unit

Abstract

The present invention provides a method for parallel maintenance of two rows of electrical panels in a nuclear power unit, comprising: determining whether the nuclear power unit meets the functional requirements for performing parallel maintenance of the two rows of electrical panels; if not, sorting out the functional requirements for performing parallel maintenance of the two rows of electrical panels; if satisfied, adding a repower distribution panel as the power source for the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels; and performing parallel maintenance on any two of the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels based on the first maintenance cycle or the second maintenance cycle. The present invention classifies the functional requirements of the nuclear power unit into main system functions that require continuous power supply and auxiliary system functions that require intermittent power supply, and correspondingly selects the cross-power supply or external power supply method for the electrical panels to meet the power supply requirements of the nuclear power unit during the parallel maintenance of the electrical panels, thereby solving the problem of traditional row-by-row serial maintenance occupying the critical path of overhaul, extending the overhaul period, and reducing the flexibility of overhaul.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power operation, and in particular to a method for parallel maintenance of two rows of electrical panels in a nuclear power unit. Background Art

[0002] The electrical panel of a nuclear power unit requires maintenance in full unloading mode. Previous-generation nuclear power units, due to their dual-column safety system configuration (i.e., dual-column electrical panel configuration), generally adopted a cross-column power supply scheme for serial maintenance. This serial maintenance scheme allows for a cross-column power supply overhaul configuration, which offers good applicability. However, with the advancement of nuclear power technology, the new generation of nuclear power technology features three independent and redundant safety systems and corresponding three-column electrical panel configurations. For this three-column electrical panel configuration, traditional serial maintenance of these panels typically occupies the critical overhaul path, extending the overhaul period and reducing overhaul flexibility.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention and does not constitute any limitation to the present invention. Summary of the Invention

[0004] In view of the shortcomings of the prior art mentioned above, the present invention provides a method for parallel maintenance of two rows of electrical panels in a nuclear power unit. The method classifies the functional requirements of each module of the nuclear power unit into the main system function that needs to meet continuous power supply or the auxiliary system function that needs intermittent power supply, and refines the functional requirements of each module to the specific equipment corresponding to each row of electrical panels, and selects other electrical panels for cross-power supply or external power supply to meet the power supply needs of the nuclear power unit during the parallel maintenance of the electrical panels, so as to solve the problem of traditional serial maintenance by row, occupying the key path of overhaul, extending the overhaul period, and reducing the flexibility of overhaul.

[0005] The present invention provides a method for parallel maintenance of two rows of electrical panels in a nuclear power unit, wherein the nuclear power unit comprises a first row of electrical panels, a second row of electrical panels, and a third row of electrical panels. The method for parallel maintenance of the two rows of electrical panels in a nuclear power unit comprises the following steps:

[0006] S100, determining whether the nuclear power unit meets the functional requirements for parallel maintenance of two rows of electrical panels;

[0007] S200: If not, sort out the functional requirements of the nuclear power unit to meet the requirements for parallel maintenance of two rows of electrical panels;

[0008] S300: If the conditions are met, add a repower distribution panel as the power source for the first, second, and third rows of electrical panels;

[0009] S400: Perform parallel maintenance on any two of the first column electrical panels, the second column electrical panels, and the third column electrical panels based on the first maintenance cycle or the second maintenance cycle.

[0010] In one embodiment of the present invention, step S100 includes: obtaining the main system function requirements and auxiliary system function requirements of the nuclear power unit under full unloading conditions; the main system function requirements continue to supply power during the execution of parallel maintenance, and the auxiliary system function requirements intermittently supply power during the execution of parallel maintenance.

[0011] In one embodiment of the present invention, the main system function requirements and the auxiliary system function requirements include one or more of the spent tank related functions, material dumping operation functions, ventilation functions, three waste systems functions, fire protection functions, electrical and instrumentation system functions, and operation and maintenance requirements.

[0012] In one embodiment of the present invention, step S300 includes: supplying power in parallel between the repower distribution panel and the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels, and supplying power in series between the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels.

[0013] In one embodiment of the present invention, the further step includes: using a branch box to connect the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels that are cross-powered in series, and the first row of electrical panels and the second row of electrical panels are connected in parallel with the third row of electrical panels and the re-supply distribution panel via the branch box.

[0014] In one embodiment of the present invention, an air cooling unit is further included. The air cooling unit and the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels are located on a parallel power supply circuit of the repower distribution panel.

[0015] In one embodiment of the present invention, step S400 includes: in a first cycle, performing maintenance on the first row of electrical panels and the low-voltage electrical panels in the second row of electrical panels in series; in a second cycle, performing maintenance on the second row of electrical panels; and in a third cycle, performing maintenance on the third row of electrical panels and the low-voltage electrical panels in the first row of electrical panels in parallel; wherein the first, second, and third rows of electrical panels are maintained using the first maintenance cycle.

[0016] In one embodiment of the present invention, the method further includes: in a fourth cycle, performing maintenance on the low-voltage electrical panels in the first and third rows of electrical panels in parallel; in a fifth cycle, performing maintenance on the second row of electrical panels and the low-voltage electrical panels in the second row of electrical panels in series; in a sixth cycle, performing maintenance on the third row of electrical panels and the low-voltage electrical panels in the first row of electrical panels in parallel; wherein the maintenance of the first, second, and third rows of electrical panels is performed using the second maintenance cycle.

[0017] In one embodiment of the present invention, step S400 further includes: in a first cycle, performing maintenance on the first and third electrical panels in parallel; in a second cycle, performing maintenance on the second electrical panel; and in a third cycle, performing maintenance on the low-voltage electrical panels in each of the first, second, and third electrical panels. The maintenance of the first, second, and third electrical panels is performed using the first maintenance cycle. A seventh cycle is also included, in which the same maintenance steps as in the first cycle are performed.

[0018] In one embodiment of the present invention, the system further includes: in a fourth cycle, concurrently performing maintenance on the first and third electrical panels; in a fifth cycle, performing maintenance on the second electrical panel; and in a sixth cycle, performing maintenance on the low-voltage electrical panels in each of the first, second, and third electrical panels. The maintenance of the first, second, and third electrical panels is performed using the second maintenance cycle. The system further includes a seventh cycle, performing the same maintenance steps as the first cycle.

[0019] The beneficial effects of the present invention are as follows: by classifying the functional requirements of each module of the nuclear power unit into the main system functions that need to meet continuous power supply or the auxiliary system functions that need intermittent power supply, and refining them into the specific equipment corresponding to the power supply of each column of electrical panels, different power supply methods are selected to achieve parallel maintenance of two columns of distribution panels, which shortens the overhaul period compared to the serial maintenance method by column, and further optimizes the overhaul period in conjunction with the pre-inspection cycle strategy, thereby achieving flexible configuration of electrical panel maintenance.

[0020] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and it is clear that a person skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0022] Figure 1 This is a flow chart of the method for parallel maintenance of two rows of electrical panels in a nuclear power unit according to the present invention;

[0023] Figure 2 This is a circuit architecture diagram for parallel maintenance of two rows of electrical panels in one embodiment of the present invention;

[0024] Figure 3 This is a circuit architecture diagram for parallel maintenance of two rows of electrical panels in another embodiment of the present invention;

[0025] Figure 4 This is a flow chart of executing a parallel maintenance strategy for two rows of electrical panels in one embodiment of the present invention;

[0026] Figure 5 The figure is a flow chart of executing a parallel maintenance strategy for two rows of electrical panels in another embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following describes the embodiments of the present invention by means of specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and examples can be combined with each other unless they conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, not to limit the scope of protection of the present invention.

[0028] See also Figures 1 to 5 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, the terms such as position and quantitative relationship quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0029] See also Figure 1 The present invention provides a method for parallel maintenance of two rows of electrical panels in a nuclear power unit, wherein the nuclear power unit includes a first row of electrical panels, a second row of electrical panels, and a third row of electrical panels. The method for parallel maintenance of two rows of electrical panels in a nuclear power unit includes the following steps:

[0030] S100, determining whether the nuclear power unit meets the functional requirements for parallel maintenance of two rows of electrical panels;

[0031] S200: If not, sort out the functional requirements of the nuclear power unit to meet the requirements for parallel maintenance of two rows of electrical panels;

[0032] S300: If the conditions are met, add a repower distribution panel as the power source for the first, second, and third rows of electrical panels;

[0033] S400: Perform parallel maintenance on any two of the first column electrical panels, the second column electrical panels, and the third column electrical panels based on the first maintenance cycle or the second maintenance cycle.

[0034] Furthermore, step S100 includes: obtaining the main system function requirements and auxiliary system function requirements of the nuclear power unit under the complete unloading condition; the main system function requirements are continuous power supply during the parallel maintenance process, and the auxiliary system function requirements are intermittent power supply during the parallel maintenance process.

[0035] Specifically, in an embodiment of the present invention, the two power supplies of the nuclear power unit, that is, the electrical panel, need to provide corresponding repowering capabilities to meet some functional requirements of the nuclear power unit when carrying out maintenance operations. For this, it is first necessary to sort out the functional requirements of each module of the nuclear power unit, sort out the unit-level safety functions and operating functions under the complete unloading condition, and the operation and maintenance party sorts out the power demand of the maintenance activities and the experience feedback of the same type of units. Then, the sorted functional requirements are refined and decomposed, and the functional requirements of each module of the nuclear power unit are classified into the main system functions and related auxiliary system functions (such as water supply, power supply, cold source, etc.) that should be implemented. These main system functions and auxiliary system functions must meet different power supply requirements of continuous power supply or intermittent power supply, and be refined to the specific equipment corresponding to each column of electrical panel power supply. In this way, the power supply requirements of the nuclear power unit are met during the parallel maintenance of the electrical panel.

[0036] It should be noted that maintenance of the electrical panels in nuclear power units includes routine maintenance and overhaul. Routine maintenance can be performed without power outages. This type of work typically targets smaller equipment or system components, requiring the shutdown of some terminal devices on the panel for inspection, cleaning, commissioning, or component replacement. Overhauls involving larger or more complex operations often require shutting down the entire electrical panel in a train. However, some terminal devices in nuclear power units must remain operational, so appropriate measures must be taken to ensure their power supply needs during the overhaul of the corresponding panel.

[0037] See also Figure 2 In one embodiment, step S300 includes: supplying power in parallel between the repower distribution panel and the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels, and supplying power in series between the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels.

[0038] Furthermore, it also includes an air-cooling unit, which is located on a parallel power supply circuit of the repower distribution board with the first row of electrical panels, the second row of electrical panels and the third row of electrical panels.

[0039] Specifically, in the embodiment of the present invention, the first row of electrical panels, the second row of electrical panels and the third row of electrical panels can correspond to the attached Figure 2During maintenance outages, the LKA, LKB, and LKC shown in the figure are replaced by the newly added LKD, LKG, and LKH, respectively. That is, LKD, LKG, and LKH correspond to the first, second, and third rows of electrical panels, respectively. In this embodiment of the present invention, compared to the previously used LKA, LKB, and LKC solution, the cross-power supply circuits between LKA and LKC, and between LKB and LKC, are eliminated. Instead, a repower distribution panel 1LKZ is added, connected in parallel with the three rows of electrical panels. In this parallel power supply circuit, a series cross-power supply is provided between LKD, LKG, and LKH to meet the power supply needs of each row of panels. Furthermore, the air-cooled units in the nuclear power plant are also powered by the repower distribution panel 1LKZ, ensuring the safety of the nuclear power plant during parallel maintenance operations on two rows of electrical panels.

[0040] Please note that, please refer to Figure 2 As shown, blue segments represent newly added circuits, black segments represent existing circuits and panels, and yellow segments represent eliminated existing circuits. In this embodiment of the present invention, the first, second, and third rows of panels correspond to LKA, LKB, and LKC, respectively. The third row of panels, LKC, is located between the first and second rows of panels, LKA and LKB. This means that when performing parallel maintenance on two rows of panels, either the first and third rows of panels or the second and third rows of panels can be maintained in parallel.

[0041] See also Figure 3 In one embodiment, the method further includes: using a branch box to connect the first column electrical panel, the second column electrical panel, and the third column electrical panel that are cross-powered in series, and the first column electrical panel and the second column electrical panel are connected in parallel with the third column electrical panel and the re-power distribution panel through the branch box.

[0042] Specifically, see Figure 2 As shown, the black line segments connecting the modules represent the original circuit structure, the red line segments represent the DC power supply of the two sets of protection devices to meet the national standard requirements, and the blue line segments represent the repowering needs of several terminal devices such as network-related cabinets that power the corresponding electrical panel loads. In this embodiment of the present invention, the first row of electrical panels, the second row of electrical panels, and the third row of electrical panels can respectively correspond to the attached Figure 3The LAM, LAN, and LLP in the diagrams respectively include the electrical equipment on each row of electrical panels, such as network-related cabinets, and the corresponding row's power supply. For example, when simultaneously overhauling the first and second rows of electrical panels, the electrical equipment on the LAM and LAN rows are powered by connecting to the power supply of the third row of electrical panels, LLP, through a pre-installed tap box. A double-cut switch or a reserved repower supply interface is also provided in the circuit between the third row of electrical panels, LLP, and the tap box. For example, a repower distribution panel 9LK* can be connected to the circuit through this interface. This allows the power supply from the third row of electrical panels, LLP, to serve as separate power sources for the two sets of protective devices in the first row of electrical panels, LAM, and LAN, respectively, meeting national standards.

[0043] Furthermore, the functional requirements of the main system and the auxiliary system include one or more of the spent tank related functions, material dumping operation functions, ventilation functions, three waste systems functions, fire protection functions, electrical and instrumentation system functions and operation and maintenance requirements.

[0044] More specifically, in an embodiment of the present invention, the spent fuel pool-related functions in each module of a nuclear power unit include a spent fuel pool cooling circuit, which requires ensuring the operability of the two spent fuel pool cooling circuits powered by two rows of electrical panels. The maintenance requirements of the two rows of electrical panels are met by cross-powering the power supplies of the first and second rows of electrical panels, or by cross-powering the power supplies of the third row of electrical panels with the power supplies of the first and second rows of electrical panels. When each row of electrical panels is undergoing maintenance, to meet the operability requirements of the spent fuel pool cooling circuit, the overhaul of each row of electrical panels can be moved to routine maintenance operations. Similarly, when one row of electrical panels is undergoing overhaul, the pump corresponding to the spent fuel pool cooling circuit can be restored online using external power supply, thereby ensuring normal power supply to the spent fuel pool cooling circuit during the overhaul.

[0045] Spent fuel pool-related functions also require that the reactor refueling index and the corresponding spent fuel compartment monitored by one electrical panel row be continuously online. When the reactor building of a nuclear power unit is empty of fuel assemblies, one of the electrical panels must be operational to ensure the cooling circuits for the spent fuel pool, which are divided between the two electrical panels, remain operational. This requirement is met by ensuring that the heat exchangers operating in the two electrical panels can be cross-fed by the cooling water system of the terminal equipment on one of the electrical panels (that is, cooling water from either electrical panel row can supply cooling water to the heat exchangers in either row).

[0046] Spent pool-related functions also include local cooling of the heat exchanger's corresponding cooling pump room. Under fully unloaded reactor conditions, the heat exchanger pump room temperature must be maintained to meet requirements, allowing intermittent operation of the local cooling function in the heat exchanger cooling pump room. The power supply for the cooling units in the heat exchanger cooling pump room is the same as that for the heat exchanger pumps. This allows the electrical panels that power these units to be moved to routine maintenance to ensure they remain operational during overhauls. Alternatively, during the overhaul phase, the corresponding pumps can be restored online using external power supplies.

[0047] Similarly, in the fuel unloading function of a nuclear power unit, the fuel assembly activities and corresponding nuclear safety risks are defined to determine whether they involve the movement of irradiated fuel assemblies. Based on this, maintenance operations for terminals required by irradiated fuel assemblies, such as fans, heaters, and emergency exhaust valves, are staggered across different rows of electrical panels. This means that, while parallel maintenance is performed for the first and third rows of electrical panels, and for the second and third rows of electrical panels, when the irradiated fuel assemblies involved in the fuel unloading function belong to terminals on the first and second rows of panels, respectively, maintenance operations are staggered across the two rows of panels. However, when the irradiated fuel assemblies belong to terminals on the third row of panels, parallel maintenance can be performed.

[0048] Ventilation requirements for nuclear power units can be categorized as normal and maintenance electrical panel requirements, depending on whether they are required during daily operation. Ventilation system terminal equipment includes the non-controlled area of ​​the safety building corresponding to the three electrical panel rows of the nuclear power units, the cooling water and nuclear island fire water pump rooms, the generator building, the service water pump room, and the refrigeration system.

[0049] For example, during complete reactor unloading of a nuclear power plant, ensuring that the temperature in the non-controlled areas of the safety building meets requirements allows for intermittent operation of the normal ventilation functions of the air-cooled units and the cooling functions of the pump room air conditioning units. For example, for maintenance train power supply, the heaters supplied by each train electrical panel can be adjusted from the original LKA / B / C to LKD / G / H to meet power supply and winter antifreeze requirements of the nuclear power unit. LKZ power can also be added to LKD / G / H. During routine maintenance of LKD / G / H, the panel can be maintained without downtime during the overhaul. Alternatively, by adding a repower supply, a separate power supply line can be provided to each train electrical panel load, such as the heater.

[0050] Thus, in an embodiment of the present invention, the functional requirements of the main system requiring continuous power supply and the functional requirements of the auxiliary system requiring intermittent power supply are divided into items requiring continuous power supply or intermittent power supply according to the specific requirements of the spent pool-related functions, material unloading operation functions, ventilation functions, three waste systems functions, fire protection functions, electrical instrumentation system functions, and the needs of the operation and maintenance party corresponding to each module of the nuclear power unit. The functional requirements of the corresponding power supply items are moved to daily maintenance, and two rows of electrical panels undergoing parallel maintenance are powered by a third row of electrical panels, and external power supplies are added to meet the power supply requirements of the corresponding functional requirements of each module of the nuclear power unit. This will not be elaborated here.

[0051] See also Figure 4 In one embodiment, step S400 includes: in a first cycle, serially performing maintenance on the first row of electrical panels and the low-voltage electrical panels in the second row of electrical panels; in a second cycle, performing maintenance on the second row of electrical panels; in a third cycle, performing maintenance on the third row of electrical panels and the low-voltage electrical panels in the first row of electrical panels in parallel; wherein the first, second, and third rows of electrical panels are maintained using a first maintenance cycle. It also includes: in a fourth cycle, performing maintenance on the low-voltage electrical panels in the first and third rows of electrical panels in parallel; in a fifth cycle, serially performing maintenance on the second row of electrical panels and the low-voltage electrical panels in the second row of electrical panels; in a sixth cycle, performing maintenance on the third row of electrical panels and the low-voltage electrical panels in the first row of electrical panels in parallel; wherein the first, second, and third rows of electrical panels are maintained using a second maintenance cycle. It also includes a seventh cycle, in which the same maintenance steps as in the first cycle are performed.

[0052] Specifically, the 3C / 6C maintenance contents of the electrical panel may include cleaning, appearance, tightness and busbar insulation inspection of the distribution panel, lubrication of the drawer guide wheel; inspection and cleaning of the transformer body, insulation resistance and DC resistance measurement, tightness inspection of the incoming and outgoing line electrical connections, inspection and calibration of the transformer temperature controller, and transformer adjustment characteristics inspection (LO system); cleaning and inspection of the circuit breaker, mechanical and electrical characteristics inspection, and replacement of the switch lubricating oil (grease); cleaning and inspection of the contactor, electrical characteristics inspection; cleaning and appearance inspection of the switch mechanism, and lubrication; calibration of relays, transmitters, and meters; inspection of the secondary circuit of the distribution panel: cleaning of the equipment, inspection of cables, terminals and wiring; calibration of the remote tripping and closing intermediate relays and the undervoltage unloading intermediate relays in each compartment; protection group test and circuit inspection; calibration of instruments and transmitters, etc., which are not specifically limited here.

[0053] More specifically, the electrical panel pre-inspection cycle is 3C / 6C, and the maintenance arrangement of the electrical panel will be more flexible. Figure 4As shown in the figure, referring to the strategic planning for optimizing the electrical panel pre-inspection cycle to 3C / 6C in a nuclear power unit project, the overhaul still requires the concurrent inspection of "one electrical panel + another electrical panel (LV) * panel inverter and LV * 3701TB (the power supply cabinet number of the DCS system that supplies the loads in the low-voltage electrical panel) + possible corrective maintenance." This reduces the overhaul duration by 1.5 days per round.

[0054] See also Figure 5 In one embodiment, step S400 further includes: in a first cycle, performing maintenance on the first and third electrical panels in parallel; in a second cycle, performing maintenance on the second electrical panel; in a third cycle, performing maintenance on the low-voltage electrical panels in each of the first, second, and third electrical panels; wherein the maintenance of the first, second, and third electrical panels is performed using a first maintenance cycle. It further includes: in a fourth cycle, performing maintenance on the first and third electrical panels in parallel; in a fifth cycle, performing maintenance on the second electrical panel; in a sixth cycle, performing maintenance on the low-voltage electrical panels in each of the first, second, and third electrical panels; wherein the maintenance of the first, second, and third electrical panels is performed using a second maintenance cycle. It further includes a seventh cycle, in which the same maintenance steps as in the first cycle are performed.

[0055] Specifically, in the embodiment of the present invention, when the parallel maintenance of two rows of electrical panels is realized, the electrical panel pre-inspection cycle is superimposed as 3C / 6C, as shown in the attached Figure 5 As shown, a "long-long-short" maintenance strategy can be implemented: "First cycle: parallel overhaul of columns A and C; second cycle: overhaul of column B; third cycle: no electrical panel overhaul (i.e., the power supply cabinet number of the DCS power supply system for the loads supplied by the LV* panel inverter and LV*3701TB low-voltage electrical panel). Ultra-short overhauls can be planned for the third and sixth cycles, each overhaul round adding at least two days to the path schedule. This maximizes the flexibility of electrical panel overhaul. Therefore, it is essential to simultaneously promote parallel electrical panel overhauls and optimize pre-inspection cycles.

[0056] In summary, the present invention provides a method for parallel maintenance of two rows of electrical panels in a nuclear power unit. The method classifies the functional requirements of each module of the nuclear power unit into the main system function that needs to meet continuous power supply or the auxiliary system function that needs intermittent power supply, and refines the functional requirements to the specific equipment corresponding to each row of electrical panels to select other electrical panels for cross-power supply or external power supply. This meets the power supply needs of the nuclear power unit during the execution of parallel maintenance of the electrical panels, and cooperates with the pre-inspection cycle strategy to further optimize the overhaul period and realize flexible configuration of electrical panel maintenance.

[0057] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for parallel maintenance of two rows of electrical panels in a nuclear power unit, wherein the nuclear power unit comprises a first row of electrical panels, a second row of electrical panels, and a third row of electrical panels, characterized in that: The method for parallel maintenance of two rows of electrical panels of a nuclear power unit comprises the following steps: S100, determining whether the nuclear power unit meets the functional requirements for performing parallel maintenance of two rows of electrical panels; S200: If not, sort out the functional requirements of the nuclear power unit to meet the requirements for parallel maintenance of two rows of electrical panels; S300: If the conditions are met, add a repower distribution panel as the power source for the first column of electrical panels, the second column of electrical panels, and the third column of electrical panels; S400: Perform parallel maintenance on any two of the first column electrical panels, the second column electrical panels, and the third column electrical panels based on a first maintenance cycle or a second maintenance cycle.

2. The maintenance method according to claim 1, characterized in that: The S100 step includes: obtaining the main system function requirements and auxiliary system function requirements of the nuclear power unit under the complete unloading condition; the main system function requirements continuously supply power during the parallel maintenance process, and the auxiliary system function requirements intermittently supply power during the parallel maintenance process.

3. The maintenance method according to claim 2, characterized in that: The functional requirements of the main system and the functional requirements of the auxiliary system include one or more of the spent tank related functions, material dumping operation functions, ventilation functions, three waste systems functions, fire protection functions, electrical and instrumentation system functions and operation and maintenance requirements.

4. The maintenance method according to claim 1, characterized in that: The step S300 includes: Power is supplied in parallel between the repower distribution panel and the first, second and third electrical panels, and in series between the first, second and third electrical panels.

5. The maintenance method according to claim 4, characterized in that: Also includes: A branch box is used to connect the first column of electrical panels, the second column of electrical panels and the third column of electrical panels that are cross-powered in series. The first column of electrical panels and the second column of electrical panels are connected in parallel with the third column of electrical panels and the re-power distribution panel through the branch box.

6. The maintenance method according to claim 4, characterized in that: It also includes an air cooling unit, which is located on a parallel power supply circuit of the repower distribution board with the first column of electrical panels, the second column of electrical panels, and the third column of electrical panels.

7. The maintenance method according to claim 1, characterized in that: The step S400 includes: In a first cycle, the maintenance of the first column of electrical panels and the maintenance of the low-voltage electrical panels in the second column of electrical panels are performed in series; In the second cycle, the second column of electrical panels is inspected; In the third cycle, the maintenance of the low-voltage electrical panels in the third row of electrical panels and the first row of electrical panels is performed in parallel; The first column electrical panel, the second column electrical panel, and the third column electrical panel are inspected and maintained using the first inspection cycle.

8. The maintenance method according to claim 7, characterized in that: Also includes: In the fourth cycle, the maintenance of the low-voltage electrical panels in the first column of electrical panels and the third column of electrical panels is performed in parallel; In the fifth cycle, the overhaul of the second column electrical panel and the overhaul of the low-voltage electrical panel in the second column electrical panel are performed in series; In the sixth cycle, the maintenance of the low-voltage electrical panels in the third column and the first column of electrical panels is performed in parallel; The second maintenance cycle is used to perform maintenance on the first column electrical panel, the second column electrical panel, and the third column electrical panel.

9. The maintenance method according to claim 1, characterized in that: The step S400 further includes: In a first cycle, the first column of electrical panels and the third column of electrical panels are inspected in parallel; In the second cycle, the second column of electrical panels is inspected; In a third cycle, performing maintenance on each of the low-voltage electrical panels in the first column of electrical panels, the second column of electrical panels, and the third column of electrical panels; The first column electrical panel, the second column electrical panel, and the third column electrical panel are inspected and maintained using the first inspection cycle.

10. The maintenance method according to claim 9, characterized in that: Also includes: In the fourth cycle, the maintenance of the first column electrical panel and the third column electrical panel is performed in parallel; In the fifth cycle, the second column electrical panel is overhauled; In a sixth cycle, performing maintenance on each of the low-voltage electrical panels in the first column of electrical panels, the second column of electrical panels, and the third column of electrical panels; The second maintenance cycle is used to perform maintenance on the first column electrical panel, the second column electrical panel, and the third column electrical panel.

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