A self-starting control method, controller and storage medium of a nuclear-grade chiller

Abstract

The application discloses a kind of self-starting control method, controller and storage medium of nuclear grade chiller, it is related to cooling control field, comprising: in response to the high level signal generated when the normally closed contact of power supply state detection relay closes, the state position of nuclear grade chiller is active shutdown state, sends the first persistent signal of control nuclear grade chiller restart, and in the case where self-checking is not abnormal, and normally closed contact is disconnected within preset period, nuclear grade chiller is self-started in response to the first persistent signal.The application is triggered by the high level signal of normally closed contact closure to place the unit to active shutdown state by controller, avoid the control system to be blocked unit due to set fault state bit, simultaneously, the automatic restart of unit after power recovery is realized by the first persistent signal, without manual reset, the self-starting of nuclear grade chiller after external power failure is realized, the refrigeration recovery rate and operation reliability of unit are improved, and then the operation reliability of nuclear grade chiller is improved.

Description

Technical Field

[0001] This application relates to the field of cooling control technology, and in particular to a self-starting control method, controller and storage medium for nuclear-grade chillers. Background Technology

[0002] Nuclear-grade chillers, as a crucial component of the nuclear island safety building chilled water system (DEL), play a vital role during the normal operation of a nuclear power plant. They are responsible for supplying cold water to the controlled and uncontrolled areas of the nuclear island, as well as the main control room, and performing the safety function of waste heat removal in accident conditions. Given the high importance of nuclear-grade chillers in nuclear power unit accident scenarios, existing technologies mostly employ safety-grade digital control systems to implement the control functions of nuclear-grade chillers, ensuring their reliability.

[0003] However, existing safety-grade digital control systems have problems such as inability to automatically start and slow recovery of cooling when faced with external power outages at nuclear power plants, such as a fault in the main transformer power supply bus that requires switching to the auxiliary transformer power supply bus. This reduces the operational reliability of nuclear-grade chillers. Summary of the Invention

[0004] In view of the above problems, this application provides a self-starting control method, controller, and storage medium for nuclear-grade chillers, to achieve self-starting and rapid recovery of cooling after an external power failure, thereby improving operational reliability. The specific solution is as follows:

[0005] The first aspect of this application provides a self-starting control method for a nuclear-grade chiller unit, applied to the controller of the nuclear-grade chiller unit. The nuclear-grade chiller unit further includes a control cabinet equipped with a power supply status detection relay with normally closed contacts. The self-starting control method for the nuclear-grade chiller unit includes:

[0006] In response to the high-level signal generated when the normally closed contact of the power supply status detection relay closes, the state of the nuclear-grade chiller unit is set to active shutdown state, a first continuous signal for controlling the restart of the nuclear-grade chiller unit is sent, and the normally closed contact is monitored to see if it opens within a preset time period. The start time of the preset time period is the time when the normally closed contact closes. The closing of the normally closed contact of the power supply status detection relay indicates the occurrence of an external power failure fault.

[0007] If no abnormality is found during self-testing and the normally closed contact is opened within the preset time period, the nuclear-grade chiller unit will automatically start in response to the first continuous signal.

[0008] In one possible implementation, if the self-test shows no abnormalities and the normally closed contact does not disconnect within the preset time period, the method further includes:

[0009] Control the backup generator set to start, monitor the first electrical signal of the backup generator set, and output a second continuous signal to control the nuclear-grade chiller unit to remain shut down;

[0010] Under the condition that the first electrical signal is adapted to the preset load conditions, the backup generator set is controlled to switch to the power supply bus of the nuclear-grade chiller unit;

[0011] When the power supply bus is energized, the status bit of the nuclear-grade chiller unit is changed from the active shutdown state to the start state. The second continuous signal is changed from a high-level signal to a low-level signal indicating that the nuclear-grade chiller unit has been released from shutdown. When the normally closed contact is energized and opened, based on the self-test results and operating parameters of the nuclear-grade chiller unit, the equipment of the nuclear-grade chiller unit is controlled to start sequentially.

[0012] In one possible implementation, the equipment of the nuclear-grade chiller unit includes: multiple compressors, lubricating oil pumps corresponding to the compressors, and electronic expansion valves corresponding to the compressors. The step of controlling the sequential startup of each piece of equipment in the nuclear-grade chiller unit based on the self-test results and operating parameters of the nuclear-grade chiller unit includes:

[0013] If no fault record is found in the self-test results, the compressors are started sequentially in ascending order of their cumulative runtime. The start-up operation includes:

[0014] The system controls the start of the lubricating oil pump corresponding to the compressor, and controls the compressor to run from a 0-load state to a first preset partial load state, and calculates the first target load change rate based on the coolant outlet temperature corresponding to the compressor in the operating parameters of the nuclear-grade chiller unit;

[0015] Based on the first target load change rate, the compressor is controlled to operate from the first preset negative load state to the full load state.

[0016] In one possible implementation, the startup operation further includes:

[0017] If at least one of the compressors is operating at full load, and the coolant temperature in the operating parameters of the nuclear-grade chiller unit is less than a preset temperature threshold, for each of the compressors that are not started:

[0018] The lubricating oil pump corresponding to the compressor that is not started is started, and the compressor that is not started is controlled to run from 0 load state to the second part of the preset load state. The second target load change rate is calculated based on the coolant outlet temperature corresponding to the compressor that is not started in the nuclear-grade chiller unit operating parameters.

[0019] The compressors that have been started are controlled to run from the full load state to the second preset load state, and the compressors that have been started and the compressors that have been started are controlled to run from the second preset load state to the full load state based on the second target load change rate.

[0020] In one possible implementation, the startup operation further includes:

[0021] Receive a start-up mode signal, and if the start-up mode signal is a fast start-up, increase the first target load change rate by a preset change rate, or increase the second target load change rate by the preset change rate.

[0022] A second aspect of this application provides a controller for use in a nuclear-grade chiller unit, the nuclear-grade chiller unit further comprising a control cabinet equipped with a power supply status detection relay with normally closed contacts, the controller being configured as follows:

[0023] In response to a high-level signal generated when the normally closed contact of the power supply status detection relay closes, the nuclear-grade chiller unit is set to an active shutdown state. A first continuous signal is sent to control the restart of the nuclear-grade chiller unit, and the normally closed contact is monitored to see if it opens within a preset time period. The start time of the preset time period is the time when the normally closed contact closes. The closing of the normally closed contact of the power supply status detection relay indicates an external power failure. If there are no abnormalities in the self-test and the normally closed contact opens within the preset time period, the nuclear-grade chiller unit automatically starts in response to the first continuous signal.

[0024] In one possible implementation, the controller is further configured as follows:

[0025] If no abnormality is found during self-test and the normally closed contact does not disconnect within the preset time period, the backup generator set is started, the first electrical signal of the backup generator set is monitored, and a second continuous signal is output to control the nuclear-grade chiller unit to remain shut down.

[0026] Under the condition that the first electrical signal is adapted to the preset load conditions, the backup generator set is controlled to switch to the power supply bus of the nuclear-grade chiller unit;

[0027] When the power supply bus is energized, the status bit of the nuclear-grade chiller unit is changed from the active shutdown state to the start state. The second continuous signal is changed from a high-level signal to a low-level signal indicating that the nuclear-grade chiller unit has been released from shutdown. When the normally closed contact is energized and opened, based on the self-test results and operating parameters of the nuclear-grade chiller unit, the equipment of the nuclear-grade chiller unit is controlled to start sequentially.

[0028] In one possible implementation, the equipment of the nuclear-grade chiller unit includes: multiple compressors, lubricating oil pumps corresponding to the compressors, and electronic expansion valves corresponding to the compressors. The controller, when controlling the sequential startup of each piece of equipment in the nuclear-grade chiller unit based on the self-test results and operating parameters of the nuclear-grade chiller unit, is configured as follows:

[0029] If no fault record is found in the self-test results, the compressors are started sequentially in ascending order of their cumulative runtime. The start-up operation includes:

[0030] The system controls the start of the lubricating oil pump corresponding to the compressor, and controls the compressor to run from a 0-load state to a first preset partial load state, and calculates the first target load change rate based on the coolant outlet temperature corresponding to the compressor in the operating parameters of the nuclear-grade chiller unit;

[0031] Based on the first target load change rate, the compressor is controlled to operate from the first preset negative load state to the full load state.

[0032] In one possible implementation, the controller is further configured to perform the startup operation as follows:

[0033] If at least one of the compressors is operating at full load, and the coolant temperature in the operating parameters of the nuclear-grade chiller unit is less than a preset temperature threshold, for each of the compressors that are not started:

[0034] The lubricating oil pump corresponding to the compressor that is not started is started, and the compressor that is not started is controlled to run from 0 load state to the second part of the preset load state. The second target load change rate is calculated based on the coolant outlet temperature corresponding to the compressor that is not started in the nuclear-grade chiller unit operating parameters.

[0035] The compressors that have been started are controlled to run from the full load state to the second preset load state, and the compressors that have been started and the compressors that have been started are controlled to run from the second preset load state to the full load state based on the second target load change rate.

[0036] In one possible implementation, the controller is further configured to perform the startup operation as follows:

[0037] Receive a start-up mode signal, and if the start-up mode signal is a fast start-up, increase the first target load change rate by a preset change rate, or increase the second target load change rate by the preset change rate.

[0038] A third aspect of this application provides a computer storage medium carrying one or more computer programs that, when executed by a controller, enable the controller to implement the self-starting control method for a nuclear-grade chiller unit as described in the first aspect or any implementation thereof.

[0039] By employing the above technical solution, this application provides a self-starting control method, controller, and storage medium for nuclear-grade chillers. This method configures the control cabinet of the nuclear-grade chiller to use a power supply status detection relay with normally closed contacts. The high-level signal generated when the normally closed contacts of the power supply status detection relay close triggers the controller, causing it to set the nuclear-grade chiller to an active shutdown state. This prevents the safety-grade digital control system from locking the nuclear-grade chiller due to setting the state to a fault state. Consequently, the nuclear-grade chiller automatically restarts after the normally closed contacts are energized and disconnected, improving the cooling recovery rate. Furthermore, by configuring the controller to send a first continuous signal to restart the nuclear-grade chiller after detecting an active shutdown state, the self-starting of the nuclear-grade chiller is quickly triggered after a self-test shows no abnormalities and the normally closed contacts open, eliminating the need for manual reset and further improving the cooling recovery rate. Therefore, this application effectively implements the self-starting of nuclear-grade chillers and improves their cooling recovery rate and operational reliability. Attached Figure Description

[0040] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0041] Figure 1 A flowchart of a self-starting control method for a nuclear-grade chiller unit provided in this application;

[0042] Figure 2 This application provides an electrical system diagram of the power supply circuit for a nuclear-grade chiller unit;

[0043] Figure 3 A power supply timing diagram for a backup generator set is provided in this application;

[0044] Figure 4 A schematic diagram of processing logic provided in this application;

[0045] Figure 5 This application provides a schematic diagram of control logic for a purely automatic operation.

[0046] Figure 6 A flowchart of a self-starting control method for a nuclear-grade chiller unit provided in this application;

[0047] Figure 7 This is a schematic diagram of the structure of a controller provided in this application. Detailed Implementation

[0048] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0049] The embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0050] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0051] It should be noted that, in practical applications, this application improves the operational reliability of nuclear-grade chiller units compared to existing control methods. Specifically: Existing nuclear-grade chiller units employ a safety-grade digital control system to implement control functions, with the controller independently powered by an Uninterruptible Power System (UPS). When a nuclear power plant experiences a main transformer trip or main / auxiliary transformer switching due to an external power outage, the electrical equipment of the nuclear-grade chiller unit shuts down due to busbar power loss, while the controller remains energized thanks to the UPS. However, existing technology uses normally open power supply status detection relays to detect the main power supply status. When an external power outage occurs, the normally open contact of the power supply status detection relay de-energizes and opens. At this time, the controller does not receive a normal shutdown command, but only detects the loss of the main power supply signal (continuous low level), thus determining the current state of the nuclear-grade chiller unit as a power fault and setting it to a fault state. After the auxiliary transformer is closed or the main power supply is restored, the fault status continuously blocks the unit's start-up signal, preventing the unit from completing self-tests and automatic restarts. This results in slow recovery of cooling, failing to meet the safety requirements of continuous cooling supply and waste heat removal in the nuclear island's safe building chilled water system, and reducing the operational reliability of the nuclear-grade chiller unit. Furthermore, existing safety-grade digital control systems typically use pulse signals to prevent accidental activation of the nuclear-grade chiller unit. However, when the normally open contacts of the existing power relays open due to external power failure, this pulse signal becomes ineffective. This necessitates manual reset after the auxiliary transformer is closed or the main power supply is restored, further contributing to the slow recovery of cooling in the nuclear-grade chiller unit. This application configures the control cabinet of the nuclear-grade chiller unit with a power supply status detection relay equipped with normally closed contacts. The high-level signal generated when the normally closed contacts of the power supply status detection relay close triggers the controller, causing the controller to set the nuclear-grade chiller unit to an active shutdown state. This avoids the safety-grade digital control system from locking the nuclear-grade chiller unit due to setting the status to a fault state. Furthermore, it enables the nuclear-grade chiller unit to automatically restart after the normally closed contacts are energized and disconnected, improving the cooling recovery rate. Moreover, by configuring the controller to send a first continuous signal to restart the nuclear-grade chiller unit after detecting an active shutdown state, the self-test is normal, and the normally closed contacts open, quickly triggering the self-start of the nuclear-grade chiller unit without manual reset, further improving the cooling recovery rate. Therefore, this application effectively implements the self-starting of the nuclear-grade chiller unit and improves its cooling recovery rate and operational reliability.

[0052] The first aspect of this application provides a self-starting control method for a nuclear-grade chiller unit, applied to the controller of the nuclear-grade chiller unit. The nuclear-grade chiller unit also includes a control cabinet equipped with a power supply status detection relay with normally closed contacts. A flowchart of the self-starting control method for the nuclear-grade chiller unit is shown below. Figure 1As shown, the self-starting control method of this nuclear-grade chiller unit includes:

[0053] S101. In response to the high-level signal generated when the normally closed contact of the power supply status detection relay closes, the state of the nuclear-grade chiller unit is set to active shutdown state, a first continuous signal for controlling the restart of the nuclear-grade chiller unit is sent, and the normally closed contact is monitored to see if it opens within a preset time period. The start time of the preset time period is the time when the normally closed contact closes. The closing of the normally closed contact of the power supply status detection relay indicates the occurrence of an external power failure fault.

[0054] It should be noted that, in practical applications, the controllers of the aforementioned nuclear-grade chiller units can be located in the control cabinet or in a host computer. The control cabinet (Control & Relay, CR) of the aforementioned nuclear-grade chiller is used to house the controllers of various devices in the nuclear-grade chiller unit (such as compressors, electronic expansion valves, lubricating oil pumps, solenoid valves, etc.).

[0055] It should be noted that, in practical applications, the aforementioned power supply status detection relay is used to detect the energized state of the power supply bus. Existing power supply status detection relays for nuclear-grade chillers using safety-grade digital control systems typically employ normally open contacts. The low-level signal generated when the normally open contact of this relay opens triggers a determination of a power failure in the nuclear-grade chiller, setting it to a fault state and locking the chiller to prevent abnormal power-on after subsequent power restoration. This application, however, configures a power supply status detection relay with normally closed contacts and a high-level signal generated when the normally closed contact closes, setting the nuclear-grade chiller to an active shutdown state. This achieves the change from a fault state (locking out the chiller) to an active shutdown state (not locking out the chiller) without modifying the status settings of the safety-grade digital control system, thus avoiding the problem of the chiller being unable to restart automatically due to lockout.

[0056] It should be noted that in practical applications, the aforementioned power supply status detection relay does not interfere with the power-on and power-off of the various devices in the nuclear-grade chiller unit; it is only used to trigger changes in the status bits of the nuclear-grade chiller unit. Specifically, when an external power failure occurs, the various devices in the nuclear-grade chiller unit are powered down, the normally closed contact of the power supply status detection relay closes to generate a high level, triggering the nuclear-grade chiller unit to the active shutdown state, and the nuclear-grade chiller unit is not locked. When the external power failure is resolved, the normally closed contact of the power supply status detection relay opens to generate a low level, triggering the nuclear-grade chiller unit to change its status bit from the active shutdown state to the start state. Since the nuclear-grade chiller unit is not locked, the various devices in the nuclear-grade chiller unit power on and complete self-starting.

[0057] It should be noted that in practical applications, due to the lack of protection against accidental activation, current nuclear-grade chiller units typically use pulse signals for restarting. This necessitates manual triggering of the pulse signal to restart the chiller after power is restored to the power supply bus, which prevents existing chillers from restarting and results in a low cooling recovery rate. This application addresses this by configuring a high-level signal generated when the normally closed contact of the power supply status detection relay closes. Under the condition that the chiller is in an active shutdown state, a first continuous signal is sent to control its restart. This limits the use of the first continuous signal only under the aforementioned external power failure fault, avoiding excessive interference with the control signals of the existing safety-grade digital control system. Simultaneously, it enables rapid restarting of the chiller after the external power failure is resolved, improving the cooling recovery rate.

[0058] In one possible implementation, to facilitate understanding of the aforementioned external power failure, an electrical system diagram of a nuclear-grade chiller's power supply circuit is provided for illustration. For example... Figure 2 The diagram shown is an electrical system diagram of the power supply circuit for a nuclear-grade chiller unit, including: a 500kV power supply bus, a 220kV power supply bus, a main transformer (hereinafter referred to as the main transformer), a plant service transformer (hereinafter referred to as the plant transformer), an auxiliary transformer (hereinafter referred to as the auxiliary transformer), a 10kV plant service main bus, a 10kV plant service auxiliary bus, a 10kV nuclear-grade chiller unit power supply bus, a low-voltage transformer, and a nuclear-grade chiller unit low-voltage power supply bus. The main transformer's receiving end is electrically connected to the 500kV power supply bus, and its transmission end is electrically connected to the receiving end of the plant transformer. The plant transformer's first transmission end is electrically connected to the 10kV plant auxiliary power main bus via a switchgear. The plant transformer's second transmission end is electrically connected to the 10kV nuclear-grade chiller unit power supply bus via a switchgear. The auxiliary transformer's receiving end is electrically connected to the 220kV power supply bus, and its first transmission end is electrically connected to the 10kV plant auxiliary power auxiliary bus via a switchgear. The auxiliary transformer's second transmission end is electrically connected to the 10kV nuclear-grade chiller unit power supply bus via a switchgear. The 10kV nuclear-grade chiller unit power supply bus is electrically connected via a switchgear, a low-voltage transformer, and a switchgear and the nuclear-grade chiller unit's low-voltage power supply bus. The aforementioned switchgear can be a circuit breaker or a combination of a circuit breaker and a disconnector. In fault-free mode, the main transformer supplies power to the low-voltage power supply bus of the nuclear-grade chiller unit, and the power supply circuit of the auxiliary transformer does not supply power to the low-voltage power supply bus of the nuclear-grade chiller unit. In the event of an external power failure, the circuit of the main transformer cannot supply power to the 10kV power supply bus of the nuclear-grade chiller unit, and it is necessary to switch the circuit of the auxiliary transformer to supply power to the 10kV power supply bus of the nuclear-grade chiller unit.

[0059] It should be noted that, in practical applications, the duration of the aforementioned preset time period can be set based on the maximum allowable switching time of the nuclear power plant's power supply lines or the minimum load-carrying time of the standby generator set. (As mentioned above...) Figure 2 The electrical system diagram of the power supply circuit of the nuclear-grade chiller unit shown assumes that in the event of an external power outage caused by a fault in the 500kV power supply bus, the time interval between the tripping of the main transformer and the closing of the auxiliary transformer in the nuclear power plant is 1s to 6s. Therefore, the above-mentioned preset time period can be set to 6s.

[0060] S102. If there are no abnormalities during self-test and the normally closed contact is opened within a preset time period, the nuclear-grade chiller unit will automatically start in response to the first continuous signal.

[0061] It should be noted that in practical applications, this application sets the nuclear-grade chiller to an active shutdown state to achieve self-starting of the chiller, preventing it from being locked out. It also configures the chiller to send a first continuous signal to control its restart, thereby improving the cooling recovery rate. However, if the chiller malfunctions due to an external power outage, directly starting it risks failing to restore cooling or even being damaged, severely impacting the operational reliability of both the chiller and the nuclear power plant. Therefore, this application configures the chiller to self-start upon receiving the first continuous signal when there are no abnormalities during self-testing and the normally closed contact opens within a preset time period. This avoids the risk of the chiller failing to start or being damaged due to equipment failure, thus improving the operational reliability of the chiller.

[0062] Those skilled in the art will understand that, in practical application scenarios, the above self-test results can be automatically generated based on the respective self-test processes of the security-level digital control system. This application does not impose too many limitations or elaborate on the specific content of the above self-test results or the specific methods of self-test implementation.

[0063] In one possible implementation, if an anomaly is detected during self-testing, the status of the nuclear-grade chiller unit is set to a system fault state to lock out the nuclear-grade water chiller unit.

[0064] This application configures the control cabinet of the nuclear-grade chiller unit with a power supply status detection relay equipped with normally closed contacts. The high-level signal generated when the normally closed contacts of the power supply status detection relay close triggers the controller, causing the controller to set the nuclear-grade chiller unit to an active shutdown state. This prevents the safety-grade digital control system from locking the nuclear-grade chiller unit due to setting the status to a fault state. Furthermore, it enables the nuclear-grade chiller unit to automatically restart after the normally closed contacts are energized and opened, improving the cooling recovery rate. Moreover, by configuring the controller to send a first continuous signal to restart the nuclear-grade chiller unit after detecting an active shutdown state, the self-test is normal, and the normally closed contacts open, quickly triggering the self-start of the nuclear-grade chiller unit without manual reset, further improving the cooling recovery rate. Therefore, this application effectively implements the self-starting of the nuclear-grade chiller unit and improves its cooling recovery rate and operational reliability.

[0065] In one possible implementation, if the self-test shows no abnormalities and the normally closed contact does not open within a preset time period, the following is also included:

[0066] Control the start-up of the backup generator set, monitor the first electrical signal of the backup generator set, and output a second continuous signal to control the nuclear-grade chiller unit to remain shut down;

[0067] Under the condition that the first electrical signal adapts to the preset load conditions, control the backup generator set to switch to the power supply bus of the nuclear-grade chiller unit;

[0068] When the power supply bus is energized, the status of the nuclear-grade chiller unit is changed from active shutdown to start-up. The second continuous control signal is changed from a high-level signal to a low-level signal indicating that the nuclear-grade chiller unit has been released from shutdown. With the normally closed contact energized and opened, the system controls the sequential startup of each piece of equipment in the nuclear-grade chiller unit based on the self-test results and operating parameters of the nuclear-grade chiller unit.

[0069] It should be noted that in practical applications, the aforementioned backup generator sets can be diesel emergency generator sets, gas turbine emergency generator sets, steam turbine emergency generator sets, etc., used as emergency power generation units when external energy fails and power cannot be restored for an extended period. Since nuclear-grade chillers are responsible for cooling controlled areas, uncontrolled areas, main control areas, and safety injection system equipment under extreme conditions, if a prolonged external power failure prevents the nuclear-grade chiller from restarting, there is a risk of continuous temperature rise in the controlled area, which could seriously affect the safe shutdown of the nuclear reactor. Therefore, this application configures the backup generator set to start when there are no abnormalities during self-testing and the normally closed contacts do not disconnect within a preset time period. This allows the backup generator set to restart the nuclear-grade chiller when an external power failure cannot be quickly resolved, thereby improving the cooling recovery rate of the nuclear-grade chiller and enhancing the operational reliability of both the nuclear-grade chiller and the nuclear power plant.

[0070] It should be noted that, in practical applications, the aforementioned first electrical signal can be a parameter signal characterizing the operational stability of the backup generator set. Taking a diesel emergency generator set as an example, the types of the aforementioned first electrical signal include, but are not limited to: diesel engine speed, diesel engine output line voltage, diesel engine lubricating oil pressure, and diesel engine output current frequency. The aforementioned preset load conditions can be based on the stable operating range corresponding to the type of the corresponding first electrical signal, and this stable operating range can be determined through calibration test results of the backup generator set.

[0071] It should be noted that in practical applications, due to process requirements, the various devices in a nuclear-grade chiller unit need to be started in a specific sequence. For example, the lubricating oil pump needs to start before the compressor to lubricate the system and avoid equipment wear caused by insufficient lubrication. Furthermore, in addition to powering the nuclear-grade chiller unit, the backup generator set may also power high-power equipment such as mains pumps, safety injection pumps, flushing pumps, and drain pumps. Since the backup generator set has limited capacity, simultaneous startup could lead to instability or even tripping and shutdown of the backup generator set, causing the nuclear-grade chiller unit's self-starting to fail. Therefore, this application configures the system to control the sequential startup of each device in the nuclear-grade chiller unit based on the self-test results and operating parameters of the unit when the normally closed contact is disconnected. This gradually increases the load capacity of the backup generator set, thus meeting the process requirements for starting the nuclear-grade chiller unit while avoiding the risk of self-starting failure due to excessive load causing the backup generator to be unable to supply power.

[0072] To avoid thermal shock and improve the stability of the output current, the backup generator set needs to run until it reaches a stable state after startup before being connected to the load (nuclear-grade chiller). Furthermore, since nuclear-grade chillers contain multiple high-power compressors, if all equipment in the chiller is started simultaneously after power is restored, the limited output of the backup generator set will cause instability or even tripping, leading to the failure of the chiller's self-start. Therefore, this application configures the system to control the sequential startup of each device in the nuclear-grade chiller based on its self-test results and operating parameters, even when the normally closed contacts are disconnected. This gradually increases the load capacity of the backup generator set, thereby avoiding the risk of self-start failure of the chiller.

[0073] In one possible implementation, to facilitate understanding of the execution process of the backup generator set driving the load, a possible implementation and performance description of this application are provided below:

[0074] like Figure 3The diagram shown is a power supply timing diagram for a backup generator set, where the horizontal axis represents time (unit: seconds / s), and the vertical axis represents the status of the nuclear-grade chiller unit, control cabinet, or backup generator set. Figure 5 It can be seen that at 0s, there is an external power failure, the nuclear-grade chiller unit loses power, the control cabinet is powered on, and the backup generator unit stops; at 5s, because the external power failure has not been resolved, the backup generator unit starts, at which time the nuclear-grade chiller unit loses power and the control cabinet is powered on; between 5s and 20s, the backup generator unit operates stably, at which time, because the backup generator unit is not connected to the power supply bus, the nuclear-grade chiller unit loses power and the control cabinet is powered on; at 21.5s, the backup generator unit is connected to the power supply bus, at which time the control cabinet is powered on, and the nuclear-grade chiller unit starts automatically.

[0075] It should be noted that in practical applications, the output current of the backup generator set may experience temporary fluctuations during the sequential startup of the various devices in the nuclear-grade chiller unit. This fluctuation can lead to the controller mistakenly identifying a fault and shutting down the unit due to load power loss. Therefore, the sequential startup control of the nuclear-grade chiller unit based on its self-test results and operating parameters can be achieved using a reset / set (RS) trigger. Specifically:

[0076] like Figure 4 The diagram illustrates the processing logic for a reset / set trigger to sequentially start up various devices. The status bit, the inverted result of the second continuous signal, and the inverted result of the open / closed state of the normally closed contact of the power supply status detection relay communicate with the set terminal of the reset / set trigger via an AND logic gate. The nuclear-grade chiller unit startup status and the second continuous signal communicate with the set terminal of the reset / set trigger via an OR logic gate. The internal logic of this reset / set trigger is as follows: when the set terminal is 1, the reset / set trigger outputs a low-level signal (does not trigger the operation of sequentially starting up the devices of the nuclear-grade chiller unit); when the set terminal is 0 and the reset terminal is 1, the reset / set trigger outputs a high-level signal (triggers the operation of sequentially starting up the devices of the nuclear-grade chiller unit).

[0077] When the status of the nuclear-grade chiller unit is changed from active shutdown to start, the second continuous control signal changes from a high level signal to a low level signal indicating that the nuclear-grade chiller unit has been released from shutdown. After the normally closed contact is energized and opened, the status position corresponds to a high level (1), the second continuous signal corresponds to a low level (0), and the normally closed contact is energized and opened, corresponding to a low level (0). At this time, when each level signal is input to the reset / set trigger, the condition that the set terminal is 0 and the reset terminal is 1 is met, and the operation of sequentially starting each device of the nuclear-grade chiller unit is triggered.

[0078] In one possible implementation, the equipment of the nuclear-grade chiller unit includes: multiple compressors, corresponding lubricating oil pumps for the compressors, and corresponding electronic expansion valves for the compressors. Based on the self-test results and operating parameters of the nuclear-grade chiller unit, the sequential startup of each piece of equipment in the nuclear-grade chiller unit is controlled, including:

[0079] If no fault record is found in the self-test results, start-up operations are performed on each compressor in ascending order of cumulative runtime. The start-up operations include:

[0080] The system controls the start of the lubricating oil pump corresponding to the compressor, and controls the compressor to run from a 0-load state to a first preset partial load state. The system also calculates the first target load change rate based on the coolant outlet temperature of the compressor in the operating parameters of the nuclear-grade chiller unit.

[0081] Based on the first target load change rate, the compressor is controlled to operate from the first preset negative load state to the full load state.

[0082] It should be noted that in practical applications, due to the limitations of their operating principle, nuclear-grade chillers should be started up slowly rather than quickly. This is primarily to ensure smooth refrigerant circulation within the chiller system. Rapid load increases or decreases are not permitted during startup or operation; otherwise, problems such as liquid return, oil leakage, equipment malfunctions, and pipe freezing may occur, potentially triggering the chiller's fault protection program. This results in a longer startup time for existing nuclear-grade chillers to reach normal cooling operation, reducing the cooling recovery rate. Since a shorter cumulative runtime reduces the likelihood of internal compressor malfunctions and allows it to withstand a relatively higher rate of increase in cooling load, this application configures the compressors to start sequentially in ascending order of cumulative runtime, provided there are no fault records in the self-test results. This prioritizes the rapid start-up of compressors with lower malfunction risks to handle the cooling load, reducing the cooling load that compressors with longer cumulative runtimes must handle during startup. Consequently, this approach shortens the startup time of nuclear-grade chillers and improves the cooling recovery rate while ensuring the safe startup and operation of the nuclear-grade chiller unit.

[0083] In one possible implementation, to further avoid damage to the nuclear-grade chiller unit, after the lubricating oil pump corresponding to the control compressor is started, the outlet pressure of the lubricating oil pump can be collected. When the outlet pressure is within the outlet pressure range corresponding to the preset stable operating state of the cooling oil valve, the compressor is controlled to run from the 0 load state to the first preset partial load state, thereby avoiding the instantaneous superposition of compressor and cooling oil pressure impact that could damage the pipeline.

[0084] It should be noted that, in practical applications, the above implementation method for calculating the first target load change rate based on the coolant outlet temperature of the compressor in the operating parameters of a nuclear-grade chiller unit may include the following steps A1 to A3. Step A1: Obtain the current cooling target temperature and trigger step A2.

[0085] Step A2: Calculate the difference between the coolant outlet temperature and the target cooling temperature obtained in step A1. Then trigger step A3.

[0086] Step A3: Find the first target load change rate that matches the difference obtained in step A2 in the preset mapping table.

[0087] It should be noted that the preset mapping table in step A3 above stores the compressor load change rate corresponding to different temperature control ranges. The temperature control ranges and their corresponding compressor load change rates can be obtained through calibration tests.

[0088] In one possible implementation, the above startup operation also includes:

[0089] If at least one compressor is running at full load and the coolant temperature in the nuclear-grade chiller unit's operating parameters is lower than a preset temperature threshold, for each compressor that is not started:

[0090] The lubricating oil pump corresponding to the compressor that is not started is started, and the compressor that is not started is controlled to run from 0 load state to the second part of the preset load state. The second target load change rate is calculated based on the coolant outlet temperature of the compressor that is not started in the nuclear-grade chiller unit operating parameters.

[0091] Control each compressor that has been started to run from full load to the second preset load state, and control the compressor that has been started and each compressor that has been started to run from the second preset load state to full load state based on the second target load change rate.

[0092] It should be noted that in practical applications, the preset load conditions in the second part are less than those in the first part. When compressors are both running and not running, there are significant differences in suction pressure, discharge temperature, oil pressure, and refrigerant flow between them. Furthermore, the later a compressor starts, the greater the risk of malfunction. If all compressors are started in the same way, the differences in compressor starting status can easily lead to system malfunctions in the nuclear-grade chiller unit, such as coolant backflow, oil leakage, and vibration, potentially even causing a protective trip and failure to restart automatically. Moreover, if at least one compressor is running at full load and the coolant temperature in the nuclear-grade chiller unit's operating parameters is below the preset temperature threshold, it indicates a large remaining cooling load. If the compressors are still started according to the preset load conditions in the first part, there is a risk that the nuclear-grade chiller unit will trip and shut down due to excessive cooling load. Therefore, this application configures the system to start the lubricating oil pump corresponding to the compressor that is not started when at least one compressor is running at full load and the coolant temperature in the operating parameters of the nuclear-grade chiller is less than a preset temperature threshold. This controls the compressor that is not started to run from a zero-load state to a second preset load state, and controls each compressor that has been started to run from a full-load state to a second preset load state. This reduces the difference in operating environment between the compressor that is started and the compressors that have been started, thereby reducing disturbances and improving the self-starting reliability of the nuclear-grade chiller.

[0093] In one possible implementation, the above startup operation also includes:

[0094] Receive the start-up mode signal, and if the start-up mode signal is fast start, increase the first target load change rate to a preset change rate, or increase the second target load change rate to a preset change rate.

[0095] It should be noted that in practical application scenarios, due to the need for rapid start-up of nuclear-grade chillers, this application increases the first target load change rate by a preset change rate or the second target load change rate by a preset change rate when the start-up mode signal is rapid start-up, thereby increasing the rate at which the compressor reaches full load.

[0096] It should be noted that the researchers of this application conducted prototype testing using the self-starting control method for a nuclear-grade chiller unit provided in the first aspect of this application. Under slow start-up conditions, the nuclear-grade chiller unit takes approximately 40 minutes to reach full load operation from start-up. Specifically, the first compressor to start takes 2 minutes to reach the first preset load state (10%), the first target load change rate is 6% / min, and this compressor takes 15 minutes to reach full load. The remaining three compressors take a total of 6 minutes to start in a single run. Under rapid start-up conditions, the nuclear-grade chiller unit takes approximately 20 minutes to reach full load operation from start-up. With the load change rate increased to 15% / min after adding the preset change rate, the already started compressors take 6 minutes to reach full load.

[0097] It should be noted that in practical applications, the above-mentioned start-up mode signal can be switched. The switching methods include: manual / automatic mode switching, purely manual operation, and purely automatic operation. Specifically:

[0098] Manual / Automatic Mode Switching Operation: To facilitate operation by operators, the operation interface of the nuclear-grade chiller unit is set with two modes: manual mode switching and automatic mode switching. If the operator needs to manually intervene in the fast or slow start mode of the unit, the manual mode can be selected. If the operator needs to control the program to determine the start mode automatically, the automatic mode can be used.

[0099] Manual Operation: When the operator manually selects the unit's start-up mode, they can limit the fast or slow mode of the nuclear-grade chiller unit by clicking the fast start and slow start selection buttons on the manual mode panel. The unit's default initial state is slow start mode. If it is necessary to switch to fast start mode, the operator can manually switch between fast and slow start modes on the screen.

[0100] Fully automatic operation: When the operator sets the unit startup mode to automatic mode, the control system will automatically determine the unit startup mode based on the current status of the unit.

[0101] In one possible implementation, the control logic for the above-mentioned fully automatic operation can use the rising edge of the power supply status detection relay as a trigger condition for switching to fast start. When the nuclear chiller unit shuts down or experiences a fault alarm, the fast start mode is exited, and the system switches to the start mode that meets the requirements. A schematic diagram of the control logic for the above-mentioned fully automatic operation can be shown below. Figure 5 As shown:

[0102] In manual mode, when the fast start mode or slow start mode is triggered (triggered by two AND gates respectively), the corresponding start mode signal is output (the fast start mode triggers the corresponding fast start mode signal, and the slow start mode triggers the corresponding slow start mode signal).

[0103] In automatic mode, if the nuclear chiller unit is shut down for longer than the preset time, and the power supply status detection relay is closed and there is no fault (triggered by an AND gate), a fast start mode signal is output to trigger the corresponding fast start mode. If any condition is not met and there is no fault, a slow start mode signal is output.

[0104] To facilitate the explanation of the self-starting control method for a nuclear-grade chiller unit provided in the first aspect and any implementation thereof of this application, a possible implementation of this application is described herein:

[0105] like Figure 6 The diagram shown is a flowchart of a self-starting control method for a nuclear-grade chiller unit:

[0106] Step S601: In response to the high-level signal generated when the normally closed contact of the power supply status detection relay closes, the state of the nuclear-grade chiller unit is set to active shutdown state, and a first continuous signal controlling the restart of the nuclear-grade chiller unit is sent. Step S602 is then triggered.

[0107] Step S602: Determine whether the preset time period has ended. If yes, trigger step S603; otherwise, trigger step S602.

[0108] Step S603: Determine whether the normally closed contact of the power supply status detection relay is open. If yes, trigger step S604; otherwise, trigger step S605.

[0109] Step S604: Determine if there is a fault in the self-test result. If yes, trigger step S606; otherwise, trigger step S607.

[0110] Step S605: Determine if there is a fault in the self-test result. If yes, trigger step S606; otherwise, trigger step S608.

[0111] Step S606, fault report.

[0112] In step S607, the nuclear-grade chiller unit automatically starts in response to the first continuous signal.

[0113] Step S608: Control the backup generator set to start, monitor the first electrical signal of the backup generator set, and output a second continuous signal to control the nuclear-grade chiller unit to remain shut down. If the first electrical signal matches the preset load conditions, control the backup generator set to switch to the power supply bus of the nuclear-grade chiller unit. And trigger step S609.

[0114] Step S609: When the power supply bus is powered on, the status of the nuclear-grade chiller unit is changed from the active shutdown state to the start state. The second continuous signal is changed from a high-level signal to a low-level signal indicating that the nuclear-grade chiller unit has been released from shutdown. With the normally closed contact energized and disconnected, based on the self-test results and operating parameters of the nuclear-grade chiller unit, the equipment of the nuclear-grade chiller unit is started sequentially.

[0115] It should be noted that, in practical application scenarios, steps S601 to S604 are as described above. Figure 1 One possible implementation of step S101 shown above, and step S607 is as described above. Figure 1 One possible implementation of step S102 shown. A second aspect of this application provides a controller applied to a nuclear-grade chiller unit. The nuclear-grade chiller unit further includes a control cabinet equipped with a power supply status detection relay with normally closed contacts. The controller is configured to:

[0116] In response to the high-level signal generated when the normally closed contact of the power supply status detection relay closes, the nuclear-grade chiller unit is set to an active shutdown state. A first continuous signal is sent to control the restart of the nuclear-grade chiller unit, and the normally closed contact is monitored to see if it closes within a preset time period. The start time of the preset time period is the time when the normally closed contact closes. The closing of the normally closed contact of the power supply status detection relay indicates the occurrence of an external power failure. If there are no abnormalities in the self-test and the normally closed contact opens within the preset time period, the nuclear-grade chiller unit automatically starts in response to the first continuous signal.

[0117] In one possible implementation, the controller provided in the second aspect of this application is further configured as follows:

[0118] If there are no abnormalities during self-test and the normally closed contact does not disconnect within the preset time period, control the backup generator set to start, monitor the first electrical signal of the backup generator set, and output a second continuous signal to control the nuclear-grade chiller unit to remain shut down.

[0119] Under the condition that the first electrical signal adapts to the preset load conditions, control the backup generator set to switch to the power supply bus of the nuclear-grade chiller unit;

[0120] When the power supply bus is energized, the status of the nuclear-grade chiller unit is changed from active shutdown to start-up. The second continuous control signal is changed from a high-level signal to a low-level signal indicating that the nuclear-grade chiller unit has been released from shutdown. With the normally closed contact energized and opened, the system controls the sequential startup of each piece of equipment in the nuclear-grade chiller unit based on the self-test results and operating parameters of the nuclear-grade chiller unit.

[0121] In one possible implementation, the equipment of the nuclear-grade chiller unit includes: multiple compressors, corresponding lubricating oil pumps for the compressors, and corresponding electronic expansion valves for the compressors. The controller, when controlling the sequential startup of each piece of equipment in the nuclear-grade chiller unit based on the self-test results and operating parameters of the nuclear-grade chiller unit, is configured as follows:

[0122] If no fault record is found in the self-test results, start-up operations are performed on each compressor in ascending order of cumulative runtime. The start-up operations include:

[0123] The system controls the start of the lubricating oil pump corresponding to the compressor, and controls the compressor to run from a 0-load state to a first preset partial load state. The system also calculates the first target load change rate based on the coolant outlet temperature of the compressor in the operating parameters of the nuclear-grade chiller unit.

[0124] Based on the first target load change rate, the compressor is controlled to operate from the first preset negative load state to the full load state.

[0125] In one possible implementation, the controller provided in the second aspect of this application is further configured to perform the startup operation as follows:

[0126] If at least one compressor is running at full load and the coolant temperature in the nuclear-grade chiller unit's operating parameters is lower than a preset temperature threshold, for each compressor that is not started:

[0127] The lubricating oil pump corresponding to the compressor that is not started is started, and the compressor that is not started is controlled to run from 0 load state to the second part of the preset load state. The second target load change rate is calculated based on the coolant outlet temperature of the compressor that is not started in the nuclear-grade chiller unit operating parameters.

[0128] Control each compressor that has been started to run from full load to the second preset load state, and control the compressor that has been started and each compressor that has been started to run from the second preset load state to full load state based on the second target load change rate.

[0129] In one possible implementation, the controller provided in the second aspect of this application is further configured to perform the startup operation as follows:

[0130] Receive the start-up mode signal, and if the start-up mode signal is fast start, increase the first target load change rate to a preset change rate, or increase the second target load change rate to a preset change rate.

[0131] A third aspect of this application provides a computer storage medium carrying one or more computer programs, which, when executed by a controller, enable the controller to implement the self-starting control method for a nuclear-grade chiller unit as described in the first aspect or any implementation thereof.

[0132] The structural diagram of the controller provided in the second aspect of this application is as follows: Figure 7 As shown. The controller in the embodiments of this application may include, but is not limited to, fixed terminals such as mobile phones, laptops, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Figure 7 The controller shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0133] like Figure 7 As shown, the controller may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 702 or a program loaded from a storage device 708 into a random access memory (RAM) 703. When the controller is powered on, the RAM 703 also stores various programs and data required for controller operation. The processing device 701, ROM 702, and RAM 703 are interconnected via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0134] Typically, the following devices can be connected to I / O interface 705: input devices 706 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 707 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 708 including, for example, memory cards, hard drives, etc.; and communication devices 709. Communication device 709 allows the controller to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 7 A controller with various devices is shown; however, it should be understood that implementation or possession of all the devices shown is not required. More or fewer devices may be implemented alternatively.

[0135] It should also be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, in the device embodiment drawings provided in this application, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines.

[0136] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware, or it can be implemented by special-purpose hardware including application-specific integrated circuits, special-purpose CPUs, special-purpose memory, special-purpose components, etc. Generally, any function performed by a computer program can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be diverse, such as analog circuits, digital circuits, or special-purpose circuits. However, for this application, software program implementation is more often the preferred implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, training equipment, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0137] In the above embodiments, the implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, in the form of a computer program product.

[0138] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

Claims

1. A self-starting control method for a nuclear-grade chiller unit, characterized in that, A controller for a nuclear-grade chiller unit, the nuclear-grade chiller unit further comprising a control cabinet with a power supply status detection relay having normally closed contacts, and a self-starting control method for the nuclear-grade chiller unit comprising: In response to the high-level signal generated when the normally closed contact of the power supply status detection relay closes, the state of the nuclear-grade chiller unit is set to active shutdown state, a first continuous signal for controlling the restart of the nuclear-grade chiller unit is sent, and the normally closed contact is monitored to see if it opens within a preset time period. The start time of the preset time period is the time when the normally closed contact closes. The closing of the normally closed contact of the power supply status detection relay indicates the occurrence of an external power failure fault. If no abnormality is found during self-testing and the normally closed contact is opened within the preset time period, the nuclear-grade chiller unit will automatically start in response to the first continuous signal.

2. The self-starting control method for nuclear-grade chillers according to claim 1, characterized in that, If no abnormality is found during self-testing and the normally closed contact does not disconnect within the preset time period, the system further includes: Control the backup generator set to start, monitor the first electrical signal of the backup generator set, and output a second continuous signal to control the nuclear-grade chiller unit to remain shut down; Under the condition that the first electrical signal is adapted to the preset load conditions, the backup generator set is controlled to switch to the power supply bus of the nuclear-grade chiller unit; When the power supply bus is energized, the status bit of the nuclear-grade chiller unit is changed from the active shutdown state to the start state. The second continuous signal is changed from a high-level signal to a low-level signal indicating that the nuclear-grade chiller unit has been released from shutdown. When the normally closed contact is energized and opened, based on the self-test results and operating parameters of the nuclear-grade chiller unit, the equipment of the nuclear-grade chiller unit is controlled to start sequentially.

3. The self-starting control method for nuclear-grade chillers according to claim 2, characterized in that, The nuclear-grade chiller unit includes: multiple compressors, corresponding lubricating oil pumps for the compressors, and corresponding electronic expansion valves for the compressors. The step of controlling the sequential startup of each piece of equipment in the nuclear-grade chiller unit based on its self-test results and operating parameters includes: If no fault record is found in the self-test results, the compressors are started sequentially in ascending order of their cumulative runtime. The start-up operation includes: The system controls the start of the lubricating oil pump corresponding to the compressor, and controls the compressor to run from a 0-load state to a first preset partial load state, and calculates the first target load change rate based on the coolant outlet temperature corresponding to the compressor in the operating parameters of the nuclear-grade chiller unit; Based on the first target load change rate, the compressor is controlled to operate from the first preset negative load state to the full load state.

4. The self-starting control method for nuclear-grade chillers according to claim 3, characterized in that, The startup operation also includes: If at least one of the compressors is operating at full load, and the coolant temperature in the operating parameters of the nuclear-grade chiller unit is less than a preset temperature threshold, for each of the compressors that are not started: The lubricating oil pump corresponding to the compressor that is not started is started, and the compressor that is not started is controlled to run from 0 load state to the second part of the preset load state. The second target load change rate is calculated based on the coolant outlet temperature corresponding to the compressor that is not started in the nuclear-grade chiller unit operating parameters. The compressors that have been started are controlled to run from the full load state to the second preset load state, and the compressors that have been started and the compressors that have been started are controlled to run from the second preset load state to the full load state based on the second target load change rate.

5. The self-starting control method for nuclear-grade chillers according to claim 4, characterized in that, The startup operation also includes: Receive a start-up mode signal, and if the start-up mode signal is a fast start-up, increase the first target load change rate by a preset change rate, or increase the second target load change rate by the preset change rate.

6. A controller, characterized in that, Applied to nuclear-grade chiller units, the nuclear-grade chiller unit also includes a control cabinet equipped with a power supply status detection relay with normally closed contacts, the controller being configured as follows: In response to the high-level signal generated when the normally closed contact of the power supply status detection relay closes, the state of the nuclear-grade chiller unit is set to active shutdown state, a first continuous signal for controlling the restart of the nuclear-grade chiller unit is sent, and the normally closed contact is monitored to see if it opens within a preset time period. The start time of the preset time period is the time when the normally closed contact closes. The closing of the normally closed contact of the power supply status detection relay indicates the occurrence of an external power failure fault. If no abnormality is found during self-testing and the normally closed contact is opened within the preset time period, the nuclear-grade chiller unit will automatically start in response to the first continuous signal.

7. The controller according to claim 6, characterized in that, The controller is also configured to: If no abnormality is found during self-test and the normally closed contact does not disconnect within the preset time period, the backup generator set is started, the first electrical signal of the backup generator set is monitored, and a second continuous signal is output to control the nuclear-grade chiller unit to remain shut down. Under the condition that the first electrical signal is adapted to the preset load conditions, the backup generator set is controlled to switch to the power supply bus of the nuclear-grade chiller unit; When the power supply bus is energized, the status bit of the nuclear-grade chiller unit is changed from the active shutdown state to the start state. The second continuous signal is changed from a high-level signal to a low-level signal indicating that the nuclear-grade chiller unit has been released from shutdown. When the normally closed contact is energized and opened, based on the self-test results and operating parameters of the nuclear-grade chiller unit, the equipment of the nuclear-grade chiller unit is controlled to start sequentially.

8. The controller according to claim 7, characterized in that, The nuclear-grade chiller unit includes: multiple compressors, a lubricating oil pump corresponding to each compressor, and an electronic expansion valve corresponding to each compressor. The controller, when controlling the sequential startup of each piece of equipment in the nuclear-grade chiller unit based on the unit's self-test results and operating parameters, is configured as follows: If no fault record is found in the self-test results, the compressors are started sequentially in ascending order of their cumulative runtime. The start-up operation includes: The system controls the start of the lubricating oil pump corresponding to the compressor, and controls the compressor to run from a 0-load state to a first preset partial load state, and calculates the first target load change rate based on the coolant outlet temperature corresponding to the compressor in the operating parameters of the nuclear-grade chiller unit; Based on the first target load change rate, the compressor is controlled to operate from the first preset negative load state to the full load state.

9. The controller according to claim 8, characterized in that, The controller is also configured to perform the startup operation as follows: If at least one of the compressors is operating at full load, and the coolant temperature in the operating parameters of the nuclear-grade chiller unit is less than a preset temperature threshold, for each of the compressors that are not started: The lubricating oil pump corresponding to the compressor that is not started is started, and the compressor that is not started is controlled to run from 0 load state to the second part of the preset load state. The second target load change rate is calculated based on the coolant outlet temperature corresponding to the compressor that is not started in the nuclear-grade chiller unit operating parameters. The compressors that have been started are controlled to run from the full load state to the second preset load state, and the compressors that have been started and the compressors that have been started are controlled to run from the second preset load state to the full load state based on the second target load change rate.

10. A computer storage medium, characterized in that, The storage medium carries one or more computer programs that, when executed by the controller, enable the controller to implement the self-starting control method for nuclear-grade chillers as described in any one of claims 1 to 5.

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