Protection device and control method for standby water feeding pump of high-temperature reactor and nuclear power station

Abstract

The invention relates to the technical field of high-temperature gas cooled reactors, and discloses a high-temperature reactor standby feed pump protection device, a control method and a nuclear power plant. The protection device comprises a first protection module, a second protection module and a current acquisition module; the current acquisition module acquires current signals including a first switch current at the load side of the first power switch, a second switch current at the load side of the second power switch and a neutral point current at the neutral point of the standby feed pump, and outputs the current signals to the first protection module and the second protection module respectively. The first protection module and the second protection module respectively calculate a first differential current value and a second differential current value based on the current signal, and when the first differential current value or the second differential current value exceeds a preset current, the corresponding power switch is driven to cut off the power supply to the standby feed pump. The protection device can accurately detect internal faults of the standby water feeding pump, misoperation caused by transient differential current generated by difference of current transformers under the starting working condition is avoided, and therefore reliability is improved.

Description

Technical Field

[0001] This application relates to the field of high-temperature gas-cooled reactor technology, specifically to a high-temperature reactor backup feedwater pump protection device and control method, and a nuclear power plant. Background Technology

[0002] In related technologies, the main feedwater system of a high-temperature gas-cooled reactor nuclear power plant adopts a configuration combining multiple main feedwater pumps and a common standby pump. The standby feedwater pump is equipped with two independent power switches, each connected to a different busbar section, and an electrical interlocking mechanism prevents simultaneous closing of both switches from causing a loop in the two busbar sections.

[0003] The medium-voltage switchgear for the standby feedwater pump is equipped with differential protection as the main protection, with current sampling points located at the motor neutral point side and the lower terminal of the switchgear circuit breaker. However, when the standby feedwater pump is started by one power supply and the protection device of the other power supply switch is also in use, a large differential current will be generated because current only flows into the protection device on the neutral point side, while there is no current at the lower terminal of the switchgear. This will cause the differential protection of the standby feedwater pump switch to malfunction and send an alarm to the main control room, affecting the monitoring of the operation personnel. Adjusting the differential protection settings will reduce its sensitivity, and it may fail to operate in the event of a fault, which is unacceptable. Summary of the Invention

[0004] This application provides a protection device and control method for a standby feedwater pump in a high-temperature reactor, and a nuclear power plant, to solve the problem of differential protection malfunction during the start-up of the standby feedwater pump in a high-temperature reactor in related technologies.

[0005] In a first aspect, this application provides a protection device for a standby feedwater pump in a high-temperature reactor, comprising: a first protection module electrically connected to a first power switch; a second protection module electrically connected to a second power switch; and a current acquisition module configured to acquire current signals and output them to the first protection module and the second protection module respectively, wherein the current signals include a first switching current on the load side of the first power switch, a second switching current on the load side of the second power switch, and a neutral point current at the neutral point of the standby feedwater pump; the first protection module is configured to calculate a first differential current value based on the current signals, and drive the first power switch to cut off the power supply to the standby feedwater pump when the first differential current value exceeds a preset current value; the second protection module is configured to calculate a second differential current value based on the current signals, and drive the second power switch to cut off the power supply to the standby feedwater pump when the second differential current value exceeds a preset current value.

[0006] Beneficial effects: By setting up a first protection module, a second protection module, and a current acquisition module, and configuring them to calculate the differential current value based on the acquired current signals (including the first switch current, the second switch current, and the neutral point current), the power switch is driven to cut off the power supply when the differential current exceeds the preset value. This enables the protection device to accurately detect internal faults in the standby water pump and avoids maloperation caused by transient differential current generated by the difference in current transformers during startup, thereby improving the reliability and accuracy of the protection device.

[0007] In one optional implementation, the current acquisition module includes: a first current transformer disposed on the load side of the first power switch, the output terminal of the first current transformer being connected to the current input terminals of the first protection module and the second protection module respectively via two independent lines; a second current transformer disposed on the load side of the second power switch, the output terminal of the second current transformer being connected to the current input terminals of the first protection module and the second protection module respectively via two independent lines; and a third current transformer disposed at the neutral point port of the standby water pump, the output terminal of the third current transformer being connected to the current input terminals of the first protection module and the second protection module.

[0008] Beneficial effects: By connecting the output terminals of the first, second, and third current transformers to the first and second protection modules respectively, comprehensive acquisition and bidirectional distribution of current signals are ensured, providing more complete input data for differential protection, enhancing the protection device's ability to distinguish between normal transient current and fault current under startup conditions, further reducing the possibility of false tripping, and optimizing protection accuracy.

[0009] In one optional implementation, the first protection module is configured to: acquire the first switch current, the second switch current, and the neutral point current; and, when the first power switch is closed and the second power switch is open, calculate the magnitude of the vector difference between the neutral point current and the first switch current as the first differential current value.

[0010] Beneficial effects: By configuring the first protection module to calculate the vector difference between the neutral point current and the first switch current under specific conditions (the first power switch is closed and the second power switch is open) as the first differential current value, targeted differential protection for the first power supply circuit is realized, avoiding interference from non-working power switches, ensuring that the protection only responds to real faults, improving the protection selectivity when the first power supply is in operation, and effectively preventing false tripping caused by starting current.

[0011] In one optional implementation, the second protection module is configured to: acquire the first switch current, the second switch current and the neutral point current; and, when the second power switch is closed and the first power switch is open, calculate the magnitude of the vector difference between the neutral point current and the second switch current as the second differential current value.

[0012] Beneficial effects: By configuring the second protection module to calculate the vector difference between the neutral point current and the second switch current under specific conditions (the second power switch is closed and the first power switch is open) as the second differential current value, precise differential protection of the second power supply circuit is achieved, cross interference is avoided, and the protection device only responds to the fault current when the second power supply is on, which enhances the reliability and scenario adaptability of the protection and reduces the risk of false tripping.

[0013] In one optional implementation, the preset current value is greater than the maximum steady-state differential current amplitude generated by the difference in characteristics of the current transformer when the standby water pump is in start-up condition.

[0014] Beneficial effects: By limiting the preset current value to be greater than the maximum steady-state differential current amplitude caused by the difference in current transformers under the start-up condition of the standby water pump, it is ensured that the protection setting can reliably avoid the normal start-up transient current and only operate when the fault current exceeds the threshold. This fundamentally solves the problem of maloperation of differential protection and improves the stability and setting accuracy of the protection system.

[0015] In one optional embodiment, an electrical interlocking mechanism is provided between the first power switch and the second power switch, so that only one of the power switches is in the closed state at any given time.

[0016] Beneficial effects: By setting an electrical interlock mechanism between the first power switch and the second power switch, it is ensured that only one of the two switches is in the closed state at any given time, which prevents the loop current and conflict caused by the simultaneous supply of power from both power sources, reduces the possibility of malfunction caused by power switching or parallel operation, and enhances the safety and reliability of the system.

[0017] In an optional implementation, the first protection module is further configured to send an alarm signal to the remote control system when the first power switch is driven to cut off the power supply to the backup water pump; the second protection module is further configured to send an alarm signal to the remote control system when the second power switch is driven to cut off the power supply to the backup water pump.

[0018] Beneficial effects: By configuring the first and second protection modules to send alarm signals to the remote control system when the drive power switch cuts off the power supply, real-time remote monitoring and alarm of faults are realized, which facilitates timely response and handling by operation and maintenance personnel, improves the maintainability and operational efficiency of the system, and enhances the initiative of fault management.

[0019] In one optional embodiment, the high-temperature reactor standby feedwater pump protection device further includes: a first energized display device, disposed on the connection line between the first current transformer and the standby pump, configured to display the energized status of the standby feedwater pump in real time when the first power switch is closed; and a second energized display device, connected to the connection line between the second current transformer and the standby pump, configured to display the energized status of the standby feedwater pump in real time when the second power switch is closed.

[0020] Beneficial effects: By setting up first and second live display devices connected to the line between the current transformer and the standby water pump, and displaying the pump's live status in real time when the power switch is closed, intuitive voltage indication is provided, preventing misoperation (such as accidental touch or maintenance), and enhancing on-site safety and status monitoring capabilities.

[0021] In one optional embodiment, the high-temperature reactor standby feedwater pump protection device further includes: a first outgoing surge arrester connected to the connection line between the first current transformer and the standby water pump; and a second outgoing surge arrester connected to the connection line between the second current transformer and the standby water pump.

[0022] Beneficial effects: By connecting the first and second outgoing surge arresters to the lines between the current transformer and the water pump, the overvoltage surges on the load side (such as lightning strikes or switching overvoltages) can be absorbed, protecting the power switch and subsequent circuits from damage, improving the durability and anti-interference ability of the device, and ensuring stable operation of the protection device in harsh environments.

[0023] In an optional embodiment, the high-temperature reactor standby feedwater pump protection device further includes: a first grounding switch, connected to the connection line between the first current transformer and the standby water pump, so as to ground the first power switch when the first grounding switch is closed; and a second grounding switch, connected to the connection line between the second current transformer and the standby water pump, so as to ground the second power switch when the second grounding switch is closed.

[0024] Beneficial effects: By setting up first and second grounding switches and connecting them to the line between the current transformer and the water pump, the load side of the power switch can be reliably grounded during maintenance, ensuring the safety of maintenance personnel, providing necessary safety grounding measures, and reducing the risk of electric shock.

[0025] Secondly, this application provides a nuclear power plant including the high-temperature reactor standby feedwater pump protection device of the first aspect above or any corresponding embodiment thereof.

[0026] Thirdly, this application provides a control method for a high-temperature reactor standby feedwater pump protection device, comprising: collecting current signals and outputting them to a first protection module and a second protection module respectively, wherein the current signals include a first switching current on the load side of a first power switch, a second switching current on the load side of a second power switch, and a neutral point current at the neutral point of the standby feedwater pump; calculating a first differential current value based on the current signals, and driving the first power switch to cut off the power supply to the standby feedwater pump when the first differential current value exceeds a preset current value; calculating a second differential current value based on the current signals, and driving the second power switch to cut off the power supply to the standby feedwater pump when the second differential current value exceeds a preset current value.

[0027] In one optional implementation, the step of calculating the first differential current value based on the current signal includes: obtaining the first switch current, the second switch current and the neutral point current; and, when the first power switch is closed and the second power switch is open, calculating the magnitude of the vector difference between the neutral point current and the first switch current as the first differential current value.

[0028] In one optional implementation, the step of calculating the second differential current value based on the current signal includes: obtaining the first switch current, the second switch current and the neutral point current; and, when the second power switch is closed and the first power switch is open, calculating the magnitude of the vector difference between the neutral point current and the second switch current as the second differential current value. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of a protection device according to an embodiment of this application; Figure 2 This is a circuit diagram of a protection device according to an embodiment of this application; Figure 3 This is a schematic diagram of a nuclear power plant module according to an embodiment of this application; Figure 4This is a flowchart illustrating the control method according to an embodiment of this application.

[0031] Explanation of the reference numerals in the figure: 1. Nuclear power plant; 10. High-temperature reactor standby feedwater pump protection device; 20. Standby feedwater pump; 100, First power switch; 200, Second power switch; 300, First protection module; 400, Second protection module; 500, Current acquisition module; 510, First current transformer; 520, Second current transformer; 530, Third current transformer; 610, First live display device; 620, Second live display device; 710, First outgoing surge arrester; 720, Second outgoing surge arrester; 810, First grounding switch; 820, Second grounding switch. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] It is understood that before using the technical solutions disclosed in the various embodiments of this application, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in this application in an appropriate manner in accordance with relevant laws and regulations, and user authorization should be obtained.

[0034] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0035] Reference Figure 1 As shown, according to a first aspect of this application, a protection device 10 for a high-temperature reactor standby feedwater pump 20 is provided, including a first protection module 300, a second protection module 400, and a current acquisition module 500.

[0036] Specifically, the first protection module 300 is electrically connected to the first power switch 100, the second protection module 400 is electrically connected to the second power switch 200, and the current acquisition module 500 is electrically connected to the first power switch 100, the second power switch 200, the first protection module 300, and the second protection module 400.

[0037] The current acquisition module 500 is configured to acquire current signals and output them to the first protection module 300 and the second protection module 400 respectively. The current signals include the first switching current on the load side of the first power switch 100, the second switching current on the load side of the second power switch 200, and the neutral point current of the neutral point of the standby water pump 20. The first protection module 300 is configured to calculate the first differential current value based on the current signal, and drive the first power switch 100 to cut off the power supply to the standby water pump 20 when the first differential current value exceeds the preset current value. The second protection module 400 is configured to calculate the second differential current value based on the current signal. If the second differential current value exceeds the preset current value, it drives the second power switch 200 to cut off the power supply to the standby water pump 20.

[0038] In these embodiments, by setting up a first protection module 300, a second protection module 400, and a current acquisition module 500, and configuring them to calculate the differential current value based on the acquired current signal, the power switch is driven to cut off the power supply when the differential current exceeds the preset value. This enables the protection device to accurately detect internal faults in the standby water pump 20, and avoids maloperation caused by transient differential current generated by the difference in current transformers during startup, thereby improving the reliability and accuracy of the protection device.

[0039] Reference Figure 2 As shown, in some embodiments of this application, the current acquisition module 500 includes a first current transformer 510, a second current transformer 520, and a third current transformer 530.

[0040] Specifically, the first current transformer 510 is located on the load side of the first power switch 100, the second current transformer 520 is located on the load side of the second power switch 200, and the third current transformer 530 is located at the neutral point port of the standby water pump 20. Furthermore, the output of the first current transformer 510 is connected to the current input of the first protection module 300 and the second protection module 400 via two independent lines; the output of the second current transformer 520 is connected to the current input of the first protection module 300 and the second protection module 400 via two independent lines; and the output of the third current transformer 530 is connected to the current input of the first protection module 300 and the second protection module 400.

[0041] In these embodiments, by connecting the output terminals of the first current transformer 510, the second current transformer 520, and the third current transformer 530 to the first and second protection modules 400 respectively, comprehensive acquisition and bidirectional distribution of current signals are ensured, providing more complete input data for differential protection, enhancing the ability of the protection device to distinguish between normal transient current and fault current under startup conditions, further reducing the possibility of false tripping, and optimizing protection accuracy.

[0042] More specifically, in some embodiments of this application, the first protection module 300 is configured to: acquire the first switch current, the second switch current, and the neutral point current; and, when the first power switch 100 is closed and the second power switch 200 is open, calculate the magnitude of the vector difference between the neutral point current and the first switch current as the first differential current value. In these embodiments, by configuring the first protection module 300 to calculate the magnitude of the vector difference between the neutral point current and the first switch current as the first differential current value under specific conditions (the first power switch 100 is closed and the second power switch 200 is open), targeted differential protection for the first power supply circuit is achieved, avoiding interference from non-operating power switches, ensuring that the protection only responds to real faults, improving the protection selectivity when the first power supply is powered, and effectively preventing false tripping caused by starting current.

[0043] Similar to the first protection module 300, in some embodiments of this application, the second protection module 400 is configured to: acquire the first switch current, the second switch current, and the neutral point current; and, when the second power switch 200 is closed and the first power switch 100 is open, calculate the magnitude of the vector difference between the neutral point current and the second switch current as the second differential current value. In these embodiments, by configuring the second protection module 400 to calculate the magnitude of the vector difference between the neutral point current and the second switch current as the second differential current value under specific conditions (the second power switch 200 is closed and the first power switch 100 is open), precise differential protection for the second power supply circuit is achieved, cross-interference is avoided, and it is ensured that the protection device only responds to the fault current when the second power supply is in operation. This enhances the reliability and scenario adaptability of the protection and reduces the risk of false tripping.

[0044] In the aforementioned embodiment, the preset current value is greater than the maximum steady-state differential current amplitude generated by the difference in current transformer characteristics during the startup of the standby feedwater pump 20. By limiting the preset current value to be greater than the maximum steady-state differential current amplitude generated by the difference in current transformer characteristics during the startup of the standby feedwater pump 20, it is ensured that the protection setting can reliably avoid the normal startup transient current and only operate when the fault current exceeds the threshold. This fundamentally solves the problem of maloperation of differential protection and improves the stability and setting accuracy of the protection system.

[0045] It should be noted that, in the above embodiments, an electrical interlocking mechanism is provided between the first power switch 100 and the second power switch 200, so that only one of the power switches 100 and 200 is in the closed state at any given time. This setting can prevent the loop current and conflicts caused by simultaneous power supply from both power sources, reduce the possibility of malfunctions caused by power switching or parallel operation, and enhance system safety and operational reliability.

[0046] Reference Figure 2 As shown, optionally, in some embodiments of this application, the first protection module 300 is further configured to send an alarm signal to the remote control system when the first power switch 100 is driven to cut off the power supply to the backup water pump 20; the second protection module 400 is further configured to send an alarm signal to the remote control system when the second power switch 200 is driven to cut off the power supply to the backup water pump 20.

[0047] In these embodiments, by configuring the first and second protection modules 400 to send alarm signals to the remote control system when the drive power switch cuts off the power supply, real-time remote monitoring and alarm of faults are realized, which facilitates timely response and handling by operation and maintenance personnel, improves the maintainability and operational efficiency of the system, and enhances the initiative of fault management.

[0048] Reference Figure 2 As shown, optionally, in some embodiments of this application, the high-temperature reactor standby feedwater pump 20 protection device 10 further includes: a first energized display device 610, disposed on the connection line between the first current transformer 510 and the standby pump, configured to display the energized status of the standby feedwater pump 20 in real time when the first power switch 100 is closed; and a second energized display device 620, connected to the connection line between the second current transformer 520 and the standby pump, configured to display the energized status of the standby feedwater pump 20 in real time when the second power switch 200 is closed.

[0049] Specifically, refer to Figure 2 As shown, in some optional embodiments, the live indicator may include an indicator light. The positive terminal of the indicator light is connected to the connection line between the current transformer and the standby water pump via a capacitor, and the negative terminal of the indicator light is grounded. When the first power switch 100 is closed, power is supplied to the standby water pump, which also illuminates the indicator light. The capacitor acts as a voltage regulator to prevent damage to the indicator light.

[0050] In these embodiments, by setting up first and second live display devices 620 connected to the line between the current transformer and the standby water pump 20, and displaying the live status of the water pump in real time when the power switch is closed, intuitive voltage indication is provided, preventing misoperation (such as accidental touch or accidental maintenance), and enhancing on-site safety and status monitoring capabilities.

[0051] Reference Figure 2 As shown, optionally, in some embodiments of this application, the protection device 10 for the high-temperature reactor standby feedwater pump 20 further includes: a first outgoing surge arrester 710, connected to the connection line between the first current transformer 510 and the standby pump; and a second outgoing surge arrester 720, connected to the connection line between the second current transformer 520 and the standby pump.

[0052] Specifically, refer to Figure 2 As shown, the positive terminal of the outgoing surge arrester is connected to the connection line between the current transformer and the standby water pump, and the negative terminal is grounded.

[0053] By connecting the first and second outgoing surge arresters 720 to the current transformer and the water pump, the overvoltage surge on the load side (such as lightning strikes or switching overvoltages) can be absorbed, protecting the power switch and subsequent circuits from damage, improving the durability and anti-interference capability of the device, and ensuring stable operation of the protection device in harsh environments.

[0054] Reference Figure 2 As shown, optionally, in some embodiments of this application, the protection device 10 for the high-temperature reactor standby feedwater pump 20 further includes: a first grounding switch 810, connected to the connection line between the first current transformer 510 and the standby pump, so as to ground the first power switch 100 when the first grounding switch 810 is closed; and a second grounding switch 820, connected to the connection line between the second current transformer 520 and the standby pump, so as to ground the second power switch 200 when the second grounding switch 820 is closed.

[0055] Specifically, refer to Figure 2 As shown, one end of the grounding switch is connected to the connection line between the current transformer and the standby water pump, and the other end is grounded.

[0056] By setting up first and second grounding switches 820 and connecting them to the line between the current transformer and the water pump, reliable grounding of the power switch load side is allowed during maintenance, ensuring the safety of maintenance personnel, providing necessary safety grounding measures, and reducing the risk of electric shock.

[0057] In conjunction with the above embodiments, in some specific embodiments, the main feedwater system of the high-temperature gas-cooled reactor is a shared system for both reactors, consisting of three feedwater pre-pumps, three main feedwater pumps, two high-pressure heaters, and related piping and valves. Each reactor is equipped with one main feedwater pump as the primary operational unit, and each main feedwater pump can deliver 100% of its single-reactor feedwater flow rate to its respective reactor during normal full-load operation. An additional feedwater pump is provided as a common backup, normally in a hot standby state, and immediately activated when any main feedwater pump fails.

[0058] The standby feedwater pump 20 has two power switches, drawing power from the 6kV A / B section busbars respectively. When the first main feedwater pump fails and stops, the standby feedwater pump 20 is powered by the first power switch 100 connected to the 6kV A section. When the second main feedwater pump fails and stops, the standby feedwater pump 20 is powered by the second power switch 200 connected to the 6kV B section. The two switches are electrically interlocked to prevent simultaneous closing from causing a loop in the two busbar sections.

[0059] Differential protection is installed as the main protection in the two medium-voltage switchgear cabinets used for the standby water pump 20, namely the first protection module 300 and the second protection module 400. The currents on both sides of the differential protection are taken from the neutral point current transformer of the main water pump motor and the current transformer at the lower end of the switchgear circuit breaker, respectively. When the motor starts, a starting current of 4-8 times the motor's rated current is generated. This current flows through the current transformers on both sides of the motor. Due to individual differences in the transformers, a certain differential current will be generated in the protection device. The protection setting calculation must avoid this current to ensure that the protection does not malfunction during motor startup. However, assuming that the standby first power switch 100 supplies power to the standby water pump 20 to start the motor, if the protection device of the second power switch 200 is also activated at this time, only the neutral point current enters the protection device. Because the current is too large, the protection setting (i.e., the preset current value) cannot be avoided, which will cause the differential protection of the second power switch 200 to malfunction and send an alarm to the main control room, affecting the monitoring of the operation personnel. Adjusting the preset current value required for the differential protection would reduce its sensitivity, potentially causing it to fail to operate in case of a fault, which is unacceptable. Conversely, when the second power switch 200 supplies power to the backup water pump 20 to start the motor, the protection device of the second power switch 200 will also malfunction. Therefore, in this embodiment, the differential current value is calculated using the first switch current, the second switch current, and the neutral point current. Its protection range and sensitivity are consistent with the above method, while effectively solving the problem of malfunction of the protection of one switch when the motor is started by one switch.

[0060] Reference Figure 3 As shown, according to the second aspect of this application, a nuclear power plant 1 is provided, including the high-temperature reactor standby feedwater pump 20 protection device 10 of any of the foregoing embodiments. Since the nuclear power plant 1 includes the high-temperature reactor standby feedwater pump 20 protection device 10 of any of the foregoing embodiments, the nuclear power plant 1 can also achieve all the beneficial effects of the high-temperature reactor standby feedwater pump 20 protection device 10, which will not be repeated here.

[0061] Reference Figure 4 As shown, according to a third aspect of this application, a control method for a protection device 10 of a high-temperature reactor standby feedwater pump 20 is provided, comprising: S1: The current signal is collected and output to the first protection module 300 and the second protection module 400 respectively.

[0062] In step S1, the current signal includes the first switching current on the load side of the first power switch 100, the second switching current on the load side of the second power switch 200, and the neutral point current of the neutral point of the standby water pump 20. S2: Calculate the first differential current value based on the current signal. If the first differential current value exceeds the preset current value, drive the first power switch 100 to cut off the power supply to the standby water pump 20.

[0063] In step S2, the step of calculating the first differential current value based on the current signal includes: obtaining the first switch current, the second switch current and the neutral point current; and when the first power switch 100 is closed and the second power switch 200 is open, calculating the magnitude of the vector difference between the neutral point current and the first switch current as the first differential current value.

[0064] S3: Calculate the second differential current value based on the current signal. If the second differential current value exceeds the preset current value, drive the second power switch 200 to cut off the power supply to the standby water pump 20.

[0065] In step S3, the step of calculating the second differential current value based on the current signal includes: obtaining the first switch current, the second switch current and the neutral point current; and when the second power switch 200 is closed and the first power switch 100 is open, calculating the magnitude of the vector difference between the neutral point current and the second switch current as the second differential current value.

[0066] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A protection device for a standby feedwater pump in a high-temperature reactor, characterized in that, include: The first protection module is electrically connected to the first power switch; The second protection module is electrically connected to the second power switch; as well as The current acquisition module is configured to acquire current signals and output them to the first protection module and the second protection module respectively. The current signals include the first switching current on the load side of the first power switch, the second switching current on the load side of the second power switch, and the neutral point current of the neutral point of the standby water pump. The first protection module is configured to calculate a first differential current value based on the current signal, and drive the first power switch to cut off the power supply to the backup water pump when the first differential current value exceeds a preset current value. The second protection module is configured to calculate a second differential current value based on the current signal, and drive the second power switch to cut off the power supply to the backup water pump when the second differential current value exceeds a preset current value.

2. The high-temperature reactor standby feedwater pump protection device according to claim 1, characterized in that, The current acquisition module includes: The first current transformer is located on the load side of the first power switch, and the output terminal of the first current transformer is connected to the current input terminals of the first protection module and the second protection module through two independent lines respectively. The second current transformer is located on the load side of the second power switch. The output side of the second current transformer is connected to the current input terminals of the first protection module and the second protection module respectively through two independent lines. A third current transformer is installed at the neutral point port of the standby water pump, and the output terminal of the third current transformer is connected to the current input terminals of the first protection module and the second protection module.

3. The high-temperature reactor standby feedwater pump protection device according to claim 1, characterized in that, The first protection module is configured as follows: The first switch current, the second switch current, and the neutral point current are obtained. When the first power switch is closed and the second power switch is open, the magnitude of the vector difference between the neutral point current and the first switch current is calculated and used as the first differential current value.

4. The high-temperature reactor standby feedwater pump protection device according to claim 1, characterized in that, The second protection module is configured as follows: The first switch current, the second switch current, and the neutral point current are obtained. When the second power switch is closed and the first power switch is open, the magnitude of the vector difference between the neutral point current and the second switch current is calculated and used as the second differential current value.

5. The high-temperature reactor standby feedwater pump protection device according to claim 1, characterized in that, The preset current value is greater than the maximum steady-state differential current amplitude generated by the difference in characteristics of the current transformer when the standby water pump is in start-up condition.

6. The high-temperature reactor standby feedwater pump protection device according to any one of claims 1 to 5, characterized in that, An electrical interlocking mechanism is provided between the first power switch and the second power switch so that only one of the power switches is in the closed state at any given time.

7. The high-temperature reactor standby feedwater pump protection device according to any one of claims 1 to 5, characterized in that, The first protection module is also configured to send an alarm signal to the remote control system when the first power switch is driven to cut off the power supply to the backup water pump. The second protection module is also configured to send an alarm signal to the remote control system when the second power switch is driven to cut off the power supply to the backup water pump.

8. The high-temperature reactor standby feedwater pump protection device according to any one of claims 2 to 5, characterized in that, The high-temperature reactor standby feedwater pump protection device also includes: The first energized display device is installed on the connection line between the first current transformer and the standby water pump, and is configured to display the energized status of the standby water pump in real time when the first power switch is closed. The second energized display device is connected to the connection line between the second current transformer and the standby water pump, and is configured to display the energized status of the standby water pump in real time when the second power switch is closed.

9. The high-temperature reactor standby feedwater pump protection device according to any one of claims 2 to 5, characterized in that, The high-temperature reactor standby feedwater pump protection device also includes: The first outgoing surge arrester is connected to the connection line between the first current transformer and the standby water pump. The second outgoing surge arrester is connected to the connection line between the second current transformer and the standby water pump.

10. The high-temperature reactor standby feedwater pump protection device according to any one of claims 2 to 5, characterized in that, The high-temperature reactor standby feedwater pump protection device also includes: A first grounding switch is connected to the connection line between the first current transformer and the standby water pump, so as to ground the first power switch when the first grounding switch is closed. The second grounding switch is connected to the connection line between the second current transformer and the standby water pump, so as to ground the second power switch when the second grounding switch is closed.

11. A nuclear power plant, characterized in that, Includes the high-temperature reactor standby feedwater pump protection device as described in any one of claims 1 to 10.

12. A control method for a standby feedwater pump protection device for a high-temperature reactor, characterized in that, include: The collected current signals are output to the first protection module and the second protection module respectively. The current signals include the first switching current on the load side of the first power switch, the second switching current on the load side of the second power switch, and the neutral point current of the neutral point of the standby water pump. Calculate the first differential current value based on the current signal, and drive the first power switch to cut off the power supply to the backup water pump when the first differential current value exceeds the preset current value. The second differential current value is calculated based on the current signal. If the second differential current value exceeds the preset current value, the second power switch is driven to cut off the power supply to the standby water pump.

13. The control method according to claim 12, characterized in that, The step of calculating the first differential current value based on the current signal includes: The first switch current, the second switch current, and the neutral point current are obtained. When the first power switch is closed and the second power switch is open, the magnitude of the vector difference between the neutral point current and the first switch current is calculated and used as the first differential current value.

14. The control method according to claim 12, characterized in that, The step of calculating the second differential current value based on the current signal includes: The first switch current, the second switch current, and the neutral point current are obtained. When the second power switch is closed and the first power switch is open, the magnitude of the vector difference between the neutral point current and the second switch current is calculated and used as the second differential current value.

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