Integrated control method of modular combined box-type substation

Abstract

The application relates to the field of substation automation control and discloses an integrated control method of a modular combined box-type substation, which comprises the following steps: acquiring the spatial coordinates and structural attribute parameters of an electrical function module, and establishing a spatial thermal-electric coupling correlation matrix; loading a standard operation and transient takeover setting value area in a microcomputer protection device; calling the correlation matrix to perform decoupling operation to eliminate environmental thermal deviation, and outputting an equivalent self-heating temperature estimation value; calculating the thermal inertia time margin remaining after reaching a limit alarm temperature, and marking critical and redundant electrical function modules; extracting a life cycle control parameter, and instructing the redundant module to activate the transient takeover setting value area and execute load transfer reconstruction. Through spatial decoupling operation, the thermal conduction interference of adjacent modules is eliminated, an objective heating temperature is obtained, protection device misoperation is avoided, and a redundant module is used to take over a load before thermal overrun, so that power supply continuity is maintained without increasing hardware investment.

Description

Technical Field

[0001] This invention relates to the field of substation automation control technology, specifically to an integrated control method for a modular combined box-type substation. Background Technology

[0002] Prefabricated substations are widely used in power distribution networks due to their compact structure and small footprint. With the increasing integration of internal electrical functional modules, the heat generated during equipment operation accumulates in the relatively enclosed physical space, leading to significant heat conduction and cross-influence between adjacent modules. Existing substation control methods, when performing overload protection and thermal status monitoring, generally rely on the absolute temperature value of a single measuring point or a fixed current setting, failing to incorporate spatial heat conduction effects into their calculations. When a module is operating under high load, the heat it dissipates will transfer to surrounding modules, causing their measured temperatures to rise. In this situation, traditional control logic cannot distinguish between the module's self-heating and the thermal offset transferred from the external environment, easily triggering protection devices before the module itself reaches its thermal tolerance limit, resulting in unnecessary power outages.

[0003] Meanwhile, existing microprocessor-based protection devices typically handle localized overloads or rising temperature trends by directly tripping and disconnecting the load. This control logic fails to consider the thermophysical characteristics of electrical equipment during the heating process, meaning there is a time buffer between the equipment's current state and its reaching the ultimate alarm temperature. Due to the lack of a mechanism to assess this thermophysical time margin, the system cannot determine whether conditions allow for the execution of other control strategies, nor can it utilize other modules within the substation that are under low load and low temperature conditions for temporary load takeover. Therefore, existing methods have a simplistic action logic when dealing with thermal over-limit issues within prefabricated substations, and without increasing external hardware investment, it is difficult to balance equipment thermal operation safety with the continuity of overall power supply. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an integrated control method for modular combined box-type substations, which solves the problem that existing substations cannot comprehensively consider spatial heat distribution and electrical boundaries during local overload, leading to protection malfunctions or thermal damage to equipment.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an integrated control method for a modular combined prefabricated substation, comprising:

[0006] Obtain the three-dimensional spatial relative position coordinates of each electrical functional module and the structural property parameters of the physical isolation medium, and establish a spatial thermoelectric coupling correlation matrix characterizing the heat conduction characteristics between electrical functional modules;

[0007] The microcomputer protection device of the electrical function module is equipped with a standard operating setting area and a transient control setting area;

[0008] Collect the measured ambient temperature of each electrical functional module in operation, call the spatial thermoelectric coupling correlation matrix to perform decoupling operation to remove the ambient thermal offset, and output the estimated equivalent self-heating temperature of each electrical functional module.

[0009] Each electrical function module is taken as a target electrical function module. Based on the estimated equivalent self-heating temperature of the target electrical function module, the remaining thermal inertia time margin before the target electrical function module reaches the preset limit alarm temperature is calculated. The thermal inertia time margins of each target electrical function module are summarized to construct a thermal inertia time margin sequence. The critical electrical function modules and redundant electrical function modules are marked according to the thermal inertia time margin sequence.

[0010] Based on the thermal inertia time margin of the emergency electrical function module, the life cycle control parameters are extracted, the redundant electrical function module is instructed to activate the transient takeover setpoint area, and cross-module load transfer reconfiguration is performed after completing the pre-synchronization verification and parallel capacity verification.

[0011] The core principle of this invention lies in establishing a spatial thermoelectric coupling correlation matrix to associate the heat distribution of the substation's physical space with the electrical setting logic of the microprocessor-based protection device. Matrix operations are used to eliminate the heat transfer effects between adjacent modules, obtaining the heating state of a single module. Combining the obtained heating state with the thermal inertia time margin calculation mechanism, before a single module reaches its limit alarm temperature, redundant electrical functional modules within the system, operating at low load and low temperature, take over overload loads within the thermal inertia time margin, thereby maintaining the substation's power supply continuity without increasing hardware redundancy.

[0012] The aforementioned establishment of a spatial thermoelectric coupling correlation matrix characterizing the heat conduction properties between electrical functional modules includes: writing the body's electrothermal temperature rise conversion coefficient into the main diagonal elements of the spatial thermoelectric coupling correlation matrix, and writing the thermal resistance correction parameter, set in conjunction with structural attribute parameters, into the off-diagonal elements of the spatial thermoelectric coupling correlation matrix. The decoupling operation performed using the spatial thermoelectric coupling correlation matrix to eliminate environmental thermal offsets includes: subtracting the accumulated value of environmental thermal offsets transmitted by surrounding electrical functional modules from the measured environmental temperature of the target electrical functional module based on the thermal resistance correction parameter.

[0013] The above-mentioned loading of standard operating setpoint area and transient takeover setpoint area in the microcomputer protection device of electrical function module includes: setting the action parameters of logic nodes involving transient fault clearing to be completely consistent in the standard operating setpoint area and transient takeover setpoint area, and fixing the consistency parameters in the non-volatile memory of microcomputer protection device; setting the action tolerance threshold of logic nodes involving thermal accumulation effect in transient takeover setpoint area to be greater than that of standard operating setpoint area.

[0014] After outputting the estimated equivalent self-heating temperature of each electrical functional module, the process further includes: comparing the heating power calculated based on the real-time three-phase current effective value theory with the estimated equivalent self-heating temperature of the target electrical functional module; if the deviation between the heating power and the estimated equivalent self-heating temperature exceeds the preset allowable error threshold, marking the thermal state reliability of the target electrical functional module as low reliability; and issuing an instruction to the logic interlocking node of the microcomputer protection device to forcibly interlock the permission to enter the transient control setpoint area.

[0015] The above calculation of the remaining thermal inertia time margin for the target electrical functional module to reach the preset limit alarm temperature based on the estimated equivalent self-heating temperature of the target electrical functional module includes: calculating the expected steady-state maximum temperature by combining the real-time load current RMS value and the base ambient reference temperature; setting the thermal inertia time margin to the maximum safety constant when the expected steady-state maximum temperature is less than or equal to the limit alarm temperature; setting the thermal inertia time margin to zero when the estimated equivalent self-heating temperature is greater than or equal to the limit alarm temperature; and calculating the thermal inertia time margin by using the ratio of the difference between the expected steady-state maximum temperature and the estimated equivalent self-heating temperature to the difference between the expected steady-state maximum temperature and the limit alarm temperature, through logarithmic operation and in combination with the inherent heating time constant of the target electrical functional module.

[0016] The above-mentioned marking of critical electrical function modules and redundant electrical function modules based on thermal inertia time margin sequence includes: marking a critical electrical function module when the thermal inertia time margin is less than the lower limit of the danger warning, the lower limit of the danger warning is set to be greater than the sum of the circuit breaker mechanical action delay time, the network communication dead zone time and the setting value switching command processing time; marking a redundant electrical function module when the thermal inertia time margin is greater than the load takeover safety threshold and the real-time load rate has not reached the rated capacity upper limit, the load takeover safety threshold is set to the sum of the system's expected longest loop closing and switching time and the inherent cooling time constant of the redundant electrical function module.

[0017] After the aforementioned redundant electrical function module activates the transient takeover setpoint area, it also includes: synchronously sending the life cycle control parameters to the redundant electrical function module and converting them into local holding control quantities; mapping the local holding control quantities to the initial value of the hardware timer of the internal safety coprocessor of the microcomputer protection device and starting the countdown task; and forcibly disconnecting the closing permission hard contact in the operating circuit of the bus tie circuit breaker when no successful status acknowledgment of the setpoint area switching is received or the countdown task is detected to be zero.

[0018] The above-mentioned cross-module load transfer reconfiguration after completing the pre-synchronization verification and parallel capacity verification includes the following logical branches: When both the pre-synchronization verification and parallel capacity verification meet the set conditions, the system switches to the closed transfer branch, issues a closing command to the bus tie circuit breaker to form a short-time closed-loop parallel connection, and disconnects the incoming circuit breaker of the emergency electrical function module; when the parallel capacity verification passes but the pre-synchronization verification fails, the system switches to the interruption transfer branch, disconnects the incoming circuit breaker of the emergency electrical function module, and issues a closing command to the bus tie circuit breaker when the residual voltage amplitude of the bus is lower than the no-voltage judgment threshold; when the parallel capacity verification fails, the system switches to the over-limit load reduction branch, and disconnects the feeder circuit breakers of the secondary feeder circuits on the emergency electrical function module side in sequence according to the pre-stored feeder priority list.

[0019] The above-mentioned cross-module load transfer and reconstruction, after completing the pre-synchronization verification and parallel capacity verification, also includes the execution of a multi-level safety rollback mechanism: monitoring the hot spot temperature of redundant electrical function modules and local hardware timers; when the local hardware timer count value is cleared or the estimated equivalent self-heating temperature is greater than the secondary thermal warning temperature threshold, extracting the real-time effective load current value of the redundant electrical function module and comparing it with the set long-term safe carrying current threshold; when the real-time effective load current value is greater than the long-term safe carrying current threshold, intercepting the setpoint rollback command and starting the system-level load reduction program; when the real-time effective load current value is less than or equal to the long-term safe carrying current threshold, suspending the transient takeover setpoint area and locking the standard operation setpoint area.

[0020] The above-mentioned thermal monitoring logic for the emergency electrical function module is executed during the execution of the multi-level safety backoff mechanism: the actual temperature drop data of the physical surface at the electrical joints inside the emergency electrical function module is obtained; after the actual temperature drop data of the physical surface continuously decreases and is less than the safety return temperature threshold, and the state maintenance time is greater than the preset observation window time, the interlocking of the emergency electrical function module operation permission control node is released, and the incoming circuit breaker of the emergency electrical function module is closed.

[0021] This invention provides an integrated control method for a modular, prefabricated substation. It offers the following advantages:

[0022] 1. This invention establishes a spatial thermoelectric coupling correlation matrix and uses this matrix for decoupling calculations. This eliminates heat conduction interference between adjacent electrical functional modules in physical space, thereby obtaining an objective estimate of the equivalent self-heating temperature of a single module. This calculation method eliminates the influence of internal environmental temperature deviations in prefabricated substations on the temperature monitoring of individual equipment, avoids premature malfunctions of protection devices due to local heat accumulation, and improves the accuracy of substation thermal status monitoring.

[0023] 2. This invention calculates the thermal inertia time margin for electrical functional modules to reach their limit alarm temperatures and, in conjunction with the pre-loaded transient control settings in the microprocessor protection device, performs cross-module load transfer reconfiguration before a module experiences a thermal over-limit. This control logic utilizes the short-term redundant carrying capacity of low-load modules within the system, replacing the rigid action of directly tripping and disconnecting loads in traditional protection logic, thus maintaining the power supply continuity of the substation without increasing external physical hardware investment.

[0024] 3. This invention incorporates pre-synchronization verification and parallel capacity verification during load transfer and reconfiguration, and implements a multi-level safety rollback mechanism after reconfiguration. By continuously monitoring the temperature, current status, and takeover time of redundant electrical functional modules, the system can promptly lock out the operating status or initiate a load reduction procedure when redundant modules show signs of overload or exceeding temperature limits. This limits the cascading risk of exceeding limits caused by load transfer operations and ensures the safe operation of equipment during dynamic topology switching. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the modular combined box-type substation integrated control method according to an embodiment of the present invention.

[0026] Figure 2 This is a comparison diagram of the thermal state evolution of the target electrical functional modules of the present invention;

[0027] Figure 3 This is a diagram illustrating the cross-module load spatiotemporal transfer process of the present invention;

[0028] Figure 4 This is a schematic diagram of the sub-process of step S30, dynamic margin assessment and module hierarchical logic, in an embodiment of the present invention.

[0029] Figure 5 This is a schematic diagram of the sub-process of the cross-module load transfer routing and branch control logic in step S50 of this embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the sub-process of step S60, the multi-level safety rollback and closed-loop reconstruction mechanism, in an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] See attached document Figure 1 This invention provides an integrated control method for a modular, prefabricated substation, which is implemented based on the substation's underlying hardware architecture. The substation's hardware architecture includes a main controller and multiple electrical function modules. These electrical function modules are physically adjacent and each module contains a microprocessor-based protection device, circuit breaker components, temperature sensors, and sampling transformers.

[0033] The sampling transformers include voltage transformers and current transformers. Circuit breaker components include incoming line circuit breakers, bus tie circuit breakers, and feeder circuit breakers. The main controller is connected to each microprocessor-based protection device via an industrial communication network. This industrial communication network adopts the IEC 61850 protocol standard and is internally divided into a manufacturing message specification communication link and a general object-oriented substation event communication link. The manufacturing message specification communication link is used for setting group control and parameter read / write operations. The general object-oriented substation event communication link is used for status feedback reception and fast interlocking signal transmission.

[0034] This invention provides an integrated control method for a modular, combined prefabricated substation, comprising the following steps:

[0035] S10: Obtain the physical space splicing topology diagram and temperature sensor calibration parameters of each electrical functional module of the prefabricated substation, and establish a spatial thermoelectric coupling correlation matrix; pre-configure two independent setting areas in the microcomputer protection device at the bottom layer of each module of the substation, namely the standard operation setting area and the transient takeover setting area; set the action parameters of the logic nodes involved in transient fault clearing to be completely consistent in the two setting areas and solidify them locally, and only configure a higher action tolerance threshold in the transient takeover setting area for logic nodes involved in thermal accumulation effect;

[0036] S20, during the steady-state operation phase, the main controller collects the electrical operating parameters of each electrical functional module and the measured ambient temperature in real time through the industrial communication network; calls the preset spatial thermoelectric coupling correlation matrix to perform decoupling calculation on the measured temperature of each module, eliminates the ambient thermal offset transmitted from the surrounding modules based on the thermal resistance correction parameter, outputs the estimated equivalent self-heating temperature of each operating electrical functional module and its temperature rise time gradient, and performs data credibility judgment to determine whether to lock the transient takeover permission;

[0037] S30, based on the first-order thermal resistance-capacitance physical model, calculates the expected steady-state maximum temperature of the target electrical function module by combining the real-time load current RMS value; combined with the estimated equivalent self-heating temperature, it uses piecewise constraint equations to calculate the remaining thermal inertia time margin of the target electrical function module before it reaches the limit alarm temperature in real time; the main controller dynamically identifies critical electrical function modules with margins approaching the lower limit of danger and redundant electrical function modules with sufficient margins based on the thermal inertia time margin sequence of all electrical function modules in the station.

[0038] S40: Extract the current thermal inertia time margin value of the emergency electrical function module and generate control parameters for constraining the life cycle of the transient takeover setting area of ​​the redundant electrical function module; The main controller sends a command to the microcomputer protection device of the redundant electrical function module to switch to the transient takeover setting area, and converts the life cycle control parameters into the holding control quantity on the local side of the redundant electrical function module through the underlying control link. This holding control quantity is used to establish a local and remote dual pre-locking mechanism.

[0039] S50, after taking over the protection setting area and releasing the interlock, the main controller collects the voltage transformer signals of the parallel busbars on both sides of the bus tie circuit breaker and performs pre-synchronization verification and parallel capacity verification; based on the verification results, it starts the controlled electrical time-space routing mechanism, controls the state machine to enter the closed transfer branch, the open transfer branch or the over-limit load reduction branch, so as to complete the dynamic routing and transfer reconstruction of the load.

[0040] After load transfer and reconfiguration, the S60 main controller monitors the safety boundaries and thermal status of redundant electrical function modules at high frequency. When abnormal conditions such as local countdown reaching zero, temperature rise exceeding limits, or communication interruption are triggered, the system executes an intelligent state rollback mechanism. In the event of communication failure, the underlying safety unit independently closes the loop and disconnects the module. When communication is normal, the system prioritizes assessing the power restoration conditions of critical electrical function modules, avoids secondary power loss through controlled disconnection, and finally instructs the redundant electrical function modules to exit the transient takeover setting area and roll back to the standard operating setting area.

[0041] When implementing the integrated control method for modular combined box-type substations, the specific implementation of step S10 may include the following sub-steps.

[0042] In this embodiment, S101, the main controller acquires the physical space splicing topology diagram of each electrical functional module within the prefabricated substation and the calibration parameters of the internally embedded temperature sensors. The physical space splicing topology diagram includes the three-dimensional spatial relative position coordinates of each electrical functional module within the prefabricated substation shell, as well as the structural property parameters of the physical isolation medium between adjacent modules. As a preferred embodiment, the structural property parameters specifically include the thickness of the metal isolation baffle, the thermal conductivity of the material, and the spatial spacing of the cooling air ducts. The calibration parameters of the temperature sensors include the sensor installation coordinates and the zero-point calibration deviation value. For the data reading method where the main controller imports the structural property parameters and calibration parameters through the factory configuration file or issues them to the field host computer, those skilled in the art can use conventional file parsing and data communication methods. The data reading and storage operations are well-known technologies in the field and will not be elaborated upon here.

[0043] S102, based on the acquired physical space stitching topology map and temperature sensor calibration parameters, a spatial thermoelectric coupling correlation matrix is ​​established. This spatial thermoelectric coupling correlation matrix is ​​a two-dimensional numerical matrix model characterizing the thermodynamic interaction relationships between multiple modules within the substation. The main controller uses this matrix to spatially couple and bind local electrical parameters with thermal field distribution characteristics. Specifically, the main diagonal elements of the spatial thermoelectric coupling correlation matrix store the electrothermal temperature rise conversion coefficient of each electrical functional module. This electrothermal temperature rise conversion coefficient is used to characterize the physical proportion of heat generation power converted to equipment surface temperature rise when a stable operating current is applied to the current-carrying conductor inside the corresponding electrical functional module. Its value is usually pre-calibrated based on the DC resistance and rated heat dissipation area of ​​the main circuit conductor inside each module.

[0044] Meanwhile, the off-diagonal elements of the spatial thermoelectric coupling correlation matrix store thermal resistance correction parameters reflecting the thermal conduction characteristics between physically adjacent modules. These thermal resistance correction parameters are pre-calculated and set based on the structural properties of the physical isolation medium; their actual values ​​are directly proportional to the thermal conductivity of the isolation medium and inversely proportional to the baffle thickness. Through the configuration of these static matrix parameters, the system can quantify the amount of environmental thermal offset transferred from the heat generated by any high-load electrical functional module to adjacent low-load electrical functional modules.

[0045] S103. Two independent setting areas are pre-configured in the internal storage unit of the microprocessor-based protection device at the bottom layer of each electrical functional module in the substation: a standard operating setting area and a transient takeover setting area. To achieve dynamic matching between load status and protection logic, the microprocessor-based protection device implementing this step has an underlying architecture that supports switching between multiple setting configuration areas. Before system operation, the main controller issues setting area switching commands via the industrial communication network, controlling the microprocessor-based protection device to activate different setting areas to adapt to different load flow states. Both setting areas fully contain all the relay protection logic nodes required by the electrical functional module.

[0046] S104 implements differentiated logic-based configuration for protection action parameters in the two sets of setting areas. In specific implementation, the system sets the action parameters of logic nodes involved in transient fault clearing to be completely consistent in both the standard operating setting area and the transient takeover setting area, and solidifies this consistency parameter configuration item in the non-volatile memory of the microprocessor protection device to prevent dynamic modification via the communication link. Logic nodes involved in transient fault clearing specifically include transient overcurrent protection nodes, zero-sequence ground fault protection nodes, and circuit breaker failure protection nodes.

[0047] The aforementioned consistency-based solidification process helps ensure that the substation's ability to quickly clear severe short-circuit faults does not substantially degrade or delay during load space transfers or setting zone switching operations. Based on this, only logic nodes involved in thermal accumulation effects are configured with a higher operational tolerance threshold in the transient takeover setting zone compared to the standard operating setting zone. Logic nodes involved in thermal accumulation effects specifically include thermal overload protection nodes and time-based overcurrent protection nodes.

[0048] The increase in the action tolerance threshold is specifically manifested in the amplification of the heating time constant parameter in the thermal overload protection node by a preset safety margin multiple (such as 1.5 to 2.0 times), or the upward floating configuration of the action current initiation threshold of the inverse time curve in the time overcurrent protection node. This setting is mainly used to allow electrical functional modules in a safe redundancy state to safely take over transient load transfer currents exceeding their rated capacity but not yet endangering their physical thermal limits within a short time window under extreme operating conditions.

[0049] When implementing the integrated control method for modular combined box-type substations, the specific implementation of step S20 may include the following sub-steps.

[0050] In this embodiment, S201, during the steady-state operation phase of the prefabricated substation, the main controller collects multi-dimensional operating data of each electrical functional module in real time through the internal industrial communication network. Specifically, the multi-dimensional operating data includes the effective values ​​of three-phase voltage and three-phase current sampled by voltage and current transformers, and the measured ambient temperature of the electrical functional modules transmitted back by temperature sensors. For analog-to-digital conversion of analog signals and message parsing and extraction based on communication protocols, those skilled in the art can use conventional microprocessor peripherals and communication protocol stack parsing methods. The data sampling and digital filtering processes are well-known technologies in the field and will not be elaborated upon here.

[0051] S202, after acquiring basic multi-dimensional operational data, the system enters the thermal field feature extraction stage. The main controller calls the preset spatial thermoelectric coupling correlation matrix to perform thermal island crosstalk decoupling calculation. Within the physical space of the modular substation, the measured ambient temperature of any electrical functional module not only originates from its own load heating but also includes the heat transferred from surrounding high-load electrical functional modules. Based on the principle of physical heat conduction, heat spontaneously transfers from high-temperature areas to low-temperature areas, causing local measurement data to fail to accurately reflect the operating status of the corresponding electrical functional module. To obtain thermal parameters reflecting the true load state of a single module, the main controller, based on the thermal resistance correction parameters in the matrix, removes the ambient thermal offset transferred from surrounding modules from the measured ambient temperature of the target electrical functional module, and then outputs the estimated equivalent self-heating temperature of each operating electrical functional module. The calculation logic of this decoupling process satisfies the following relationship:

[0052] ;

[0053] In the formula, Indicates the target electrical function module Estimated equivalent self-heating temperature; Indicates the target electrical function module The measured ambient temperature; This represents the total number of electrical functional modules included in the spatial thermo-electric coupling correlation matrix calculation within the prefabricated substation; The spatial thermoelectric coupling correlation matrix represents adjacent electrical functional modules. For the target electrical functional module Thermal resistance correction parameters affected by heat conduction; Indicates adjacent electrical function modules The measured ambient temperature; The baseline ambient temperature is typically provided by a temperature and humidity sensor located outside the substation enclosure. As a preferred method, to refine the algorithm logic and avoid numerical anomaly dead zones, when a value is detected... Below When the calculation result of the corresponding cumulative term is forced to zero, it is to avoid generating cold offset compensation that does not conform to the actual physical laws of heating.

[0054] S203: Based on the output of the estimated equivalent self-heating temperature, the main controller calculates the temperature rise time gradient of the corresponding electrical functional module according to the time series of this estimate over multiple consecutive sampling periods. The temperature rise time gradient is obtained by dividing the difference between the estimated equivalent self-heating temperature outputs of two consecutive successfully decoupled calculations by the sampling time interval. This gradient parameter is used to characterize the dynamic aggravation of the current equipment's heating and provides a basis for trend analysis for subsequent safety monitoring.

[0055] S204, based on the above calculation results, the system performs a thermal state data reliability judgment to determine whether to lock out transient takeover permission from the lower level. The data reliability judgment mechanism constitutes the lower-level implementation logic through multi-dimensional anomaly checks. Specifically, the system first checks the communication status bits and range limits of the temperature sensor to check for physical open circuits or short circuits. After the check is correct, the main controller verifies the residuals in the decoupling calculation process and compares the linearity of the heating power theoretically calculated based on the real-time three-phase current effective value with the output equivalent self-heating temperature estimate. If the deviation between the two exceeds the preset allowable error threshold, it indicates that the thermoelectric coupling model has been distorted.

[0056] In the implementation scenario, this allowable error threshold can be pre-calibrated based on the confidence interval of the equipment's factory temperature rise test curve or historical steady-state operating data. Furthermore, the main controller needs to compare the operating feedback status of the environmental control equipment with the changing trend of the temperature rise time gradient. If it detects that the cooling fan is in rated operating condition but the temperature rise time gradient of the estimated equivalent self-heating temperature still shows an unreasonable steep increase, it is determined that the physical-thermal boundary has been violated. When any of the above tests fails, the main controller marks the thermal state confidence level of the target electrical function module as low confidence and issues a command to the logic interlock node of the corresponding microprocessor protection device, forcibly interlocking its permission to enter the transient takeover setting area. This interlock operation helps prevent the protection action threshold from being erroneously relaxed when data is distorted, thereby improving the underlying electrical safety of the system.

[0057] See attached document Figure 4 When implementing the integrated control method for modular combined box-type substations, the specific implementation of step S30 may include the following sub-steps.

[0058] In this embodiment, in step S301, the main controller obtains the real-time effective value of the load current of the electrical functional module based on the first-order thermal resistive-capacitive physical model, and calculates the expected steady-state maximum temperature that the target electrical functional module can achieve under the current load condition through continuous operation, in conjunction with the factory-set rated operating parameters. For the calculation of the transient and steady-state heat transfer processes of the first-order thermal resistive-capacitive physical model, those skilled in the art can use the conventional method of simultaneously solving Joule's law and the thermal balance equation. The basic thermodynamic modeling process is a well-known technique in the field and will not be elaborated here. As a preferred method, the expected steady-state maximum temperature of the target electrical functional module is usually obtained by adding the steady-state temperature rise increment to the base ambient temperature. Further, the value of this steady-state temperature rise increment is calculated by multiplying the square of the ratio of the real-time effective load current to the rated current of the equipment by the factory-calibrated rated temperature rise value of the equipment under rated load.

[0059] After the expected steady-state maximum temperature of the target electrical functional module is calculated, in step S302, combined with the estimated equivalent self-heating temperature output from the previous step, the main controller uses a piecewise constraint equation to calculate in real time the remaining thermal inertia time margin before the target electrical functional module reaches its limit alarm temperature. Since the actual temperature rise of the electrical functional module is constrained by physical boundaries, using a single formula can easily lead to numerical overflow at the critical point. Therefore, the piecewise constraint equation is divided into three boundary judgment logics based on the relative relationship between the current heating state and the system's preset limit alarm temperature. The value of the limit alarm temperature is pre-calibrated and stored based on the factory heat resistance rating of the internal insulation material of the electrical functional module.

[0060] When the expected steady-state maximum temperature of the target electrical functional module is less than or equal to the limit alarm temperature, it indicates that the target electrical functional module will not trigger a thermal over-limit alarm under the current load. At this time, the main controller configures the remaining thermal inertia time margin before the target electrical functional module reaches the limit alarm temperature to the maximum safety constant preset by the system. In the underlying program implementation, this maximum safety constant is often assigned to the maximum unsigned integer value supported by the register or a specific infinite default flag bit. When the estimated current equivalent self-heating temperature of the target electrical functional module is greater than or equal to the limit alarm temperature, it indicates that the equipment is in a state of actual thermal over-limit danger. At this time, the remaining thermal inertia time margin before the target electrical functional module reaches the limit alarm temperature is directly set to zero. When the estimated current equivalent self-heating temperature of the target electrical functional module is less than the limit alarm temperature, and the expected steady-state maximum temperature of the target electrical functional module is greater than the limit alarm temperature, it indicates that the target electrical functional module is continuously heating up towards the over-limit point. At this time, the system calls the transient temperature rise logarithmic equation to calculate the precise remaining time, and its calculation logic satisfies the following relationship:

[0061] ;

[0062] In the formula, This indicates the remaining thermal inertia time margin before the target electrical functional module reaches its limit alarm temperature. This represents the inherent heating time constant of the target electrical functional module, the value of which is pre-calibrated based on the equipment's factory temperature rise test data and stored in the main controller; This indicates the expected steady-state maximum temperature of the target electrical functional module; Indicates the target electrical function module Estimated equivalent self-heating temperature; This indicates the extreme alarm temperature.

[0063] Based on the above segmented calculation results, in step S303, the main controller aggregates the calculation data of each electrical functional module to construct a thermal inertia time margin sequence for all electrical functional modules in the station. Based on this sequence, the main controller dynamically identifies critical electrical functional modules with margins approaching the lower limit of danger, as well as redundant electrical functional modules with sufficient margins. In specific implementation scenarios, the criterion for determining critical electrical functional modules is that the remaining thermal inertia time margin before the target electrical functional module reaches its limit alarm temperature is less than the preset lower limit of danger warning.

[0064] The setting of this lower limit for hazard warning needs to comprehensively consider the overhead of underlying hardware actions. Its lower limit is configured to be greater than the sum of the circuit breaker's mechanical action delay time, network communication dead zone time, and setting switching command processing time, ensuring that the system retains a basic intervention window before irreversible thermal damage to the equipment occurs. Simultaneously, when the remaining thermal inertia time margin before the target electrical function module reaches its extreme alarm temperature is greater than the preset load takeover safety threshold, and its real-time load rate has not reached the rated capacity limit, it is marked as a redundant electrical function module. To ensure the feasibility of the takeover process, the selection of the aforementioned load takeover safety threshold must have a clear physical basis. Its value is typically configured as the sum of the system's expected longest loop-closing switching time and the inherent cooling time constant of the redundant electrical function module itself. This inherent cooling time constant can be derived from the heat dissipation area of ​​the electrical function module and the external convective heat transfer coefficient, or directly adopted from the test constant of the factory natural cooling test. This hierarchical marking mechanism based on dynamic time margin provides direct data support at the physical state level for subsequent cross-module load safety transfer and control authority handover.

[0065] When implementing the integrated control method for modular combined box-type substations, the specific implementation of step S40 may include the following sub-steps.

[0066] In this embodiment, after the system completes the hierarchical marking of the critical electrical function module and the redundant electrical function module, the handover procedure for protection control authority is triggered. S401, the main controller extracts the current thermal inertia time margin value of the critical electrical function module and generates control parameters based on this time value to constrain the transient setpoint survival period of the redundant electrical function module. Due to the transmission time of the substation's internal industrial communication network and the mechanical action delay time of the circuit breaker, the survival period control parameters are usually not directly equivalent to the remaining thermal limit time of the critical electrical function module.

[0067] As a preferred approach, the specific numerical configuration of the lifecycle control parameters is the difference between the current thermal inertia time margin of the critical electrical function module and the system communication delay tolerance and mechanical action margin compensation value. In practice, the aforementioned system communication delay tolerance is calibrated based on the maximum message forwarding hop delay and protocol stack processing cycle of the switch in the industrial communication network, while the mechanical action margin compensation value is taken from the maximum inherent tripping time in the factory mechanical characteristic test record of the circuit breaker corresponding to the redundant electrical function module. This parameter deduction configuration based on physical execution time helps to reserve a basic system state rollback operation window and prevents the time span for redundant electrical function modules to take over high loads from exceeding the limit.

[0068] Along with the generation of control parameters, in step S402, the main controller sends a command to the microprocessor-based protection device corresponding to the redundant electrical function module to switch to the transient takeover setting area. At the specific communication implementation level, the main controller executes this switching command using the manufacturing message specification communication link in the industrial communication network. Upon receiving the manufacturing message specification message containing the switching authentication code, the microprocessor-based protection device of the redundant electrical function module suspends the currently active standard operating setting area in the underlying storage area and simultaneously loads and activates the transient takeover setting area. Based on the aforementioned steps of solidifying and differentiating the protection action parameters, the activated transient takeover setting area can maintain the basic short-circuit protection fault clearing capability while granting the redundant electrical function module the tolerance to withstand short-term severe overloads.

[0069] To limit the runtime of redundant electrical function modules under relaxed protection threshold conditions, in step S403, the main controller synchronously sends lifecycle control parameters to the redundant electrical function modules via the underlying general-purpose object-oriented substation event communication link. The microprocessor-based protection device of the redundant electrical function module receives these parameters and converts them into a local holding control quantity. In the underlying hardware implementation, this holding control quantity is specifically mapped to the initial value of a hardware timer in the internal safety coprocessor of the microprocessor-based protection device. Upon confirming the activation of the transient takeover setting zone, the microprocessor-based protection device uses this initial hardware timer value to start an internal countdown task. This countdown task runs independently using the microprocessor-based protection device's own hardware crystal oscillator clock, without relying on the main controller's network communication heartbeat messages for maintenance.

[0070] Based on the coordinated interaction between the aforementioned state switching actions and control parameters, S404, the system constructs a dual pre-locking mechanism covering both local and remote characteristics. At the remote software control level, after issuing the setpoint zone switching command, the main controller enters a logical waiting state. When it receives a successful setpoint zone switching status acknowledgment from the redundant electrical function module microprocessor protection device via the general object-oriented substation event communication link, the system releases the software closing lockout logic for the bus tie circuit breaker.

[0071] Meanwhile, at the local hardware control level, if the system detects that the hardware timer inside the redundant electrical function module has failed to start successfully, or that the countdown task has reached zero, the underlying control circuit of the microprocessor protection device will forcibly disconnect the closing permission hard contact in the bus tie circuit breaker's operating circuit. As a preferred approach, this hardware-software interlocking architecture ensures that the system only grants cross-module load transfer operation permissions after confirming that the redundant electrical function module has completed the setting zone switching and established time constraint boundaries. This mechanism is primarily used to prevent equipment from tripping due to sudden overloads under standard operating setting zones.

[0072] See attached document Figure 5 When implementing the integrated control method for modular combined box-type substations, the specific implementation of step S50 may include the following sub-steps.

[0073] In this embodiment, after the redundant electrical function module's protection setting area is successfully taken over and the phase-locking logic is released, the main controller plans the cross-module transfer path for the electrical load. Specifically, in S501, the main controller collects the voltage transformer signals of the busbars to be connected in parallel on both sides of the bus tie circuit breaker, and performs pre-synchronization verification and parallel capacity verification accordingly. As a preferred method, the pre-synchronization verification specifically compares the amplitude difference, phase angle difference, and frequency difference of the voltages on both busbars. The system requires that the deviation values ​​of the above parameters be less than the preset synchronization allowable threshold. This synchronization allowable threshold is usually pre-calibrated based on the withstand capability of the rotating motors and inductive loads in the substation against closing impact.

[0074] To provide clear implementation guidance, this threshold can be configured as follows: voltage amplitude difference not exceeding 5% of rated voltage, phase angle difference not exceeding 10 degrees, and frequency difference not exceeding 0.2 Hz. Simultaneously conducted parallel capacity verification is used to assess the physical load-bearing capacity of redundant electrical functional modules at the moment of takeover. The main controller retrieves the current operating load current of the redundant electrical functional modules and the load current to be transferred from the emergency electrical functional modules, calculates the phasor sum of the two in the electrical network, and determines whether this phasor sum exceeds the maximum transient safe current set by the redundant electrical functional modules in the transient takeover setting zone. In specific implementation scenarios, the specific value of this maximum transient safe current is taken from the operating current activation threshold configured in the time overcurrent protection node of the aforementioned transient takeover setting zone, and multiplied by a reliability derating factor less than 1 (typically ranging from 0.85 to 0.95).

[0075] Based on the comprehensive judgment results of the aforementioned pre-verification, the system controls the internal state machine to enter the corresponding load transfer branch. In step S502, if both the synchronization verification and parallel capacity verification meet the set conditions, the state machine enters the closed transfer branch. Under this branch, the system performs a transfer operation without interrupting power supply to ensure the continuity of sensitive loads. The specific action logic is as follows: the main controller issues a closing command to the bus tie circuit breaker, causing the emergency electrical function module and the redundant electrical function module's busbars to form a short-term closed-loop parallel operation condition.

[0076] After the system confirms the closure of the bus tie circuit breaker's closing contact, it immediately disconnects the incoming circuit breaker corresponding to the emergency electrical function module, completing the uninterrupted transfer of load across modules. To prevent through-circuit faults or excessive internal circulating currents during loop operation, the system initiates the parallel overtime forced disconnection interlocking logic the instant the bus tie circuit breaker is closed. If the parallel operation time exceeds the system's set loop-closing limit dead time, the logic node of the underlying microprocessor protection device will forcibly disconnect the bus tie circuit breaker. To ensure the safety of the physical boundary, the value of this loop-closing limit dead time must be strictly less than the short-time withstand current assessment time of the substation bus tie equipment, while avoiding the action step difference time of the upstream line protection.

[0077] When facing non-ideal operating conditions such as actual power grid fluctuations, if the parallel capacity verification passes but the pre-synchronization verification fails, in S503, the state machine switches to the interruption transfer branch. Under this branch, the system abandons the loop switching and instead executes switching logic with a short-term power outage. The main controller first disconnects the incoming circuit breaker of the emergency electrical function module, cutting off its external power input. After the disconnection operation is completed, the system continuously monitors the residual voltage of the bus on the emergency electrical function module side. When the amplitude of the residual bus voltage fed back by the voltage transformer decays to below the preset no-voltage judgment threshold, the main controller then issues a closing command to the bus tie circuit breaker to restore power supply. This no-voltage judgment threshold is usually configured as 10% to 15% of the rated voltage to prevent the inrush current caused by the reverse phase of the residual voltage from causing physical damage to the insulation layer of the transformer inside the prefabricated substation.

[0078] Under extreme operating conditions, when a substation is under heavy load, causing the parallel capacity verification to fail, it indicates that the redundant electrical function modules, even with relaxed protection thresholds, are still unable to independently carry all the loads to be transferred. At this point, in state S504, the state machine enters the over-limit load reduction branch. Under this branch, the system prioritizes the continuous operation of core-level loads. The main controller, based on the feeder priority list pre-configured in non-volatile memory, sequentially issues commands to disconnect the feeder circuit breakers of the secondary feeder circuits on the side of the emergency electrical function modules until the remaining loads to be transferred meet the constraints of the parallel capacity verification.

[0079] During implementation, considering the inherent communication and mechanical time overhead of tiered load shedding, the system concurrently monitors the real-time thermal inertia time margin of the emergency electrical function module during load shedding operations. Once this margin is detected to fall below the circuit breaker's mechanical action delay time, the system will directly terminate the load shedding process and forcibly instruct the emergency electrical function module to perform independent disconnection and shutdown to avoid thermal overrun leading to equipment burnout.

[0080] If the load shedding process is successfully completed, the system will reselect whether to execute a closed transfer branch or an open transfer branch based on the current result of the pre-synchronization check. If the hard constraints of capacity verification still cannot be met after removing all secondary loads, the system will interrupt the current cross-module load transfer process to prevent the fault range from expanding. It will then instruct the critical electrical function module to perform an independent disconnect shutdown and trigger the state machine of the redundant electrical function module to enter the synchronization backoff sequence. This multi-branch collaborative routing mechanism is beneficial for supporting the orderly reconfiguration of loads based on real-time electrical boundaries when the substation faces a localized thermal crisis.

[0081] See attached document Figure 6 When implementing the integrated control method for modular combined box-type substations, the specific implementation of step S60 may include the following sub-steps.

[0082] In this embodiment, after the cross-module load transfer is completed, the redundant electrical function module is in the dominant operating condition of the transient takeover setpoint zone, and the system then enters the takeover cycle monitoring phase. In step S601, the safety coprocessor of the microprocessor protection device inside the redundant electrical function module continuously decrements the local hardware timer according to pre-set control parameters. During the countdown, the main controller synchronously monitors the real-time load current and hotspot temperature of the critical nodes of the redundant electrical function module. Once the hardware timer count is cleared, or the main controller determines that the estimated equivalent self-heating temperature of the redundant electrical function module is greater than the set secondary thermal warning temperature threshold, the system will immediately trigger a multi-level safety fallback mechanism to prevent the redundant electrical function module from evolving into a new critical electrical function module due to prolonged operation beyond its rated conditions. In the lower-level configuration, the aforementioned secondary thermal warning temperature threshold is typically set to 90% to 95% of the extreme alarm temperature to reserve a communication and logic processing buffer before the equipment reaches the physical damage threshold.

[0083] As a preferred approach, the multi-level safety backoff mechanism requires a mandatory physical condition verification of the local load status before executing the software-level setpoint zone switch. In step S602, the microprocessor-based protection device of the redundant electrical function module extracts the current real-time effective load current value and compares it with the long-term safe carrying current threshold set within the standard operating setpoint zone. This long-term safe carrying current threshold is typically set to no more than 1.05 to 1.1 times the rated operating current of the electrical function module to ensure the thermal balance of the equipment over its long lifespan. If the current real-time effective load current value exceeds this threshold, directly executing the setpoint zone backoff will trigger a protection threshold overrun and cause a false trip. In this case, the microprocessor-based protection device will actively intercept the setpoint zone backoff command and send an overrun alarm signal to the upper-level main controller via a message-based communication link, prompting the main controller to activate the system-level load reduction program to forcibly reduce the underlying load.

[0084] In practice, if the real-time effective load current value still fails to drop below the long-term safe carrying current threshold after system-level load shedding, the microprocessor-based protection device will directly trigger the backup overload protection to trip in order to prevent thermal collapse of redundant electrical functional modules. Conversely, if the real-time effective load current value has naturally fallen back or decreased below the threshold after load shedding, it indicates that the system's electrical state has met the conditions for rollback. The microprocessor-based protection device suspends the transient takeover setting area in the underlying non-volatile memory, reactivates and locks the standard operating setting area, thereby completing the disturbance-free restoration of protection action sensitivity.

[0085] When faced with extreme operating conditions such as sudden short-circuit faults or severe overloads that cannot be effectively mitigated by load reduction, the system activates a closed-loop disconnection mechanism at the hardware and physical execution levels. S603: When a redundant electrical function module detects an internal through-short-circuit fault current during takeover, or fails to successfully switch back to the standard operating setpoint after the system's preset delay tolerance time following the hardware timer being reset to zero, the underlying tripping logic matrix of the microprocessor-based protection device will be directly activated.

[0086] This logic node outputs a trip level to the operating circuit and simultaneously forces the disconnection of the bus tie circuit breaker and the incoming circuit breaker of the redundant electrical function module itself, achieving physical isolation of the fault energy source. The aforementioned delay tolerance time value needs to be set based on the thermodynamic inverse-time characteristic curve of the redundant electrical function module under the current overload multiple to ensure that the equipment does not exceed its thermophysical limits. Regarding the feature extraction and trip matrix configuration of the underlying microprocessor protection device for short-circuit current, those skilled in the art can implement it using conventional overcurrent instantaneous protection or differential protection principles. The basic action signal chain design is a well-known technology in this field and will not be elaborated upon here.

[0087] During the parallel cycle of load takeover and status rollback performed by redundant electrical function modules, the system conducts closed-loop thermal status monitoring for the critical electrical function modules that have already undergone disconnection and shutdown operations. In step S604, the main controller acquires the actual physical surface temperature drop data from temperature sensors located at the electrical connectors inside the critical electrical function modules and cross-validates and compares it with the natural cooling decay curve of a first-order thermal resistive-capacitive physical model under zero current input boundary. The system is set to release the hardware and software lockout of the critical electrical function module's operating permission control node when both the actual detected temperature and the theoretically calculated temperature continuously decrease below the safe return temperature threshold, and this state is maintained for more than a preset observation window time.

[0088] Setting an observation window time is used to prevent temperature rebound caused by incomplete dissipation of deep insulation hotspots. This time value is typically configured to be 1 to 2 times the inherent cooling time constant of the equipment. Simultaneously, to ensure that the equipment's insulation material remains within a stable and safe range, the safe return temperature threshold is specifically configured in the following embodiment as 60% of the sum of the equipment's base ambient reference temperature and the factory-permitted temperature rise limit. After successful verification and release of the interlock, the main controller recloses the incoming circuit breaker of the emergency electrical function module according to the preset substation recovery sequence, and smoothly transfers the load temporarily stored on the redundant electrical function module side back through a loop-closing switching operation, ultimately completing the closed-loop reconstruction of the entire prefabricated substation's thermal distribution and electrical routing.

[0089] Specific application examples:

[0090] To further clarify the technical details and practical effects of the modular combined prefabricated substation integrated control method proposed in this invention, the following section combines a typical 10kV modular combined prefabricated substation's actual operation scenario with reference to... Figure 2 and Figure 3 Please provide a detailed explanation.

[0091] Assume this prefabricated substation contains two adjacent, interconnected electrical functional modules: Module A (powering the main industrial load) and Module B (powering the auxiliary office area). The pre-calibrated and stored extreme alarm temperatures (…) The temperature is set to 95℃, that is... Figure 2 The horizontal dashed line in the diagram. The rated operating current of both module A and module B is 100A. Basic ambient reference temperature (…). The temperature is 35℃.

[0092] In this embodiment, the evolution of the system's operating state is as follows:

[0093] Steady-state operation and sudden overload phase (horizontal axis of the chart: 0-10 minutes):

[0094] like Figure 3 As shown, the substation operates in steady state from 0 to 10 minutes. Module A carries a current of 100A, and module B carries a current of 50A. At the 10-minute mark, the actual load current of module A suddenly increases to 150A. Figure 2 As shown, affected by the overload current, the equipment evaluation temperature of module A began to show an exponential upward trend; at the same time, affected by the heat conduction in the physical space, the measured ambient temperature of module B also passively increased.

[0095] Heat island decoupling and dynamic margin assessment phase (horizontal axis of chart 10-20 minutes):

[0096] The main controller calls a preset spatial thermoelectric coupling correlation matrix to perform decoupling operations, and the calculation logic satisfies the following relationship:

[0097] ;

[0098] In the formula, Indicates the target electrical function module Estimated equivalent self-heating temperature; Indicates the target electrical function module The measured ambient temperature; This represents the total number of electrical functional modules included in the spatial thermo-electric coupling correlation matrix calculation within the prefabricated substation; The spatial thermoelectric coupling correlation matrix represents adjacent electrical functional modules. For the target electrical functional module Thermal resistance correction parameters affected by heat conduction; Indicates adjacent electrical function modules The measured ambient temperature; This indicates the baseline environmental reference temperature.

[0099] Based on the above calculations, the system eliminated the environmental thermal offset from the measured temperature of module B, determined that it met the load takeover conditions, and marked it as a redundant electrical function module. Simultaneously, the main controller calculated the expected steady-state maximum temperature of module A under a 150A load (…). If the temperature exceeds the alarm limit, the system will use the following logarithmic equation to calculate the remaining time:

[0100] ;

[0101] In the formula, This indicates the remaining thermal inertia time margin before the target electrical functional module reaches its limit alarm temperature. This represents the inherent heating time constant of the target electrical functional module; This indicates the expected steady-state maximum temperature of the target electrical functional module; This indicates the extreme alarm temperature.

[0102] Calculation results show that the thermal inertia time margin of module A is approaching the lower limit of the danger warning, and the system marks it as a critical electrical function module.

[0103] Comparison of the effects of proactive load transfer across modules and traditional tripping (horizontal axis of the chart: 20-25 minutes):

[0104] The control effect of this embodiment differs significantly from that of the prior art at this stage:

[0105] Controlled transfer of the present invention: such as Figure 2 As shown, at the 20th minute (when the device evaluation temperature of module A is approximately 79°C), the system issues a setpoint zone switching command and completes the pre-synchronization verification. Figure 3 As indicated by the "Trigger Takeover Transfer" arrow, the system executes a closed-loop transfer operation: the current in module A drops from 150A to 0A, while the current in module B jumps from 50A to 200A. During this process, the load is transferred without power interruption. Because the heat source is cut off, Figure 2 The temperature of the emergency module A in this invention began to drop after 20 minutes and did not continue to approach the limit alarm temperature.

[0106] Traditional power tripping methods: If the control method of this invention is not used, such as... Figure 2 As shown by the solid-line block curve, the temperature of the target module will continue to rise. At the 25-minute mark, the device temperature rises to approximately 86°C. Due to prolonged exposure to a 1.5 times overload current, the underlying conventional inverse-time overcurrent protection is physically triggered. Figure 3As indicated by the arrow for "traditional protection physical trip", the target module current drops to 0A instantly, causing a passive power outage.

[0107] Safety rollback and reconstruction phase (40 minutes after the horizontal axis of the chart):

[0108] After load transfer, redundant module B maintains power supply via the transient takeover setpoint. The main controller continuously monitors the cooling status of critical module A. For example... Figure 2 As shown, at the 40th minute, the equipment assessment temperature of Critical Module A had dropped to approximately 49°C, meeting the conditions for safe return.

[0109] like Figure 3 As indicated by the arrow "Triggering Load Relocation Recovery," the main controller executes the loop-closing switching operation again. Module A resumes carrying 100A current, while the current of module B drops back to 50A. Subsequently, redundant module B exits the transient takeover setting range and returns to the standard operating setting range. The substation completes the dynamic routing and transfer reconfiguration of the load, restoring to the initial steady state.

[0110] In summary, combining Figure 2 and Figure 3 The data shows that the method of the present invention can achieve uninterrupted power transfer of load across physical space before its temperature reaches the physical limit or triggers the tripping of traditional protection, thus avoiding the long-term power outage problem caused by traditional modular box-type substations when facing local overload.

Claims

1. An integrated control method of a modular combined box-type substation, characterized by, include: Obtain the three-dimensional spatial relative position coordinates of each electrical functional module and the structural property parameters of the physical isolation medium, and establish a spatial thermoelectric coupling correlation matrix characterizing the thermal conduction characteristics between the electrical functional modules; The microcomputer protection device of the electrical function module is equipped with a standard operating setting area and a transient control setting area; Collect the measured ambient temperature of each of the electrical functional modules in operation, call the spatial thermoelectric coupling correlation matrix to perform decoupling operation to remove the ambient thermal offset, and output the estimated equivalent self-heating temperature of each of the electrical functional modules. Each of the electrical functional modules is taken as a target electrical functional module. Based on the estimated equivalent self-heating temperature of the target electrical functional module, the remaining thermal inertia time margin before the target electrical functional module reaches the preset limit alarm temperature is calculated. The thermal inertia time margins of each target electrical functional module are summarized to construct a thermal inertia time margin sequence. The critical electrical functional modules and redundant electrical functional modules are marked according to the thermal inertia time margin sequence. Based on the thermal inertia time margin of the critical electrical function module, the survival cycle control parameters are extracted, the redundant electrical function module is instructed to activate the transient takeover setpoint area, and cross-module load transfer reconstruction is performed after completing the pre-synchronization verification and parallel capacity verification.

2. The integrated control method of a modular combined box-type substation according to claim 1, characterized by, Establishing a spatial thermoelectric coupling correlation matrix characterizing the thermal conduction properties between the electrical functional modules includes: The body electrothermal temperature rise conversion coefficient is written into the main diagonal elements of the spatial thermoelectric coupling correlation matrix, and the thermal resistance correction parameter set in combination with the structural attribute parameters is written into the off-diagonal elements of the spatial thermoelectric coupling correlation matrix. The process of decoupling and eliminating environmental thermal offset by calling the spatial thermoelectric coupling correlation matrix includes: subtracting the accumulated value of environmental thermal offset transmitted by surrounding electrical functional modules from the measured environmental temperature of the target electrical functional module based on the thermal resistance correction parameter.

3. The integrated control method for a modular combined prefabricated substation according to claim 1, characterized in that, The standard operating setpoint area and transient control setpoint area loaded in the microcomputer protection device of the electrical function module include: The logic node action parameters involving transient fault clearing are set to be completely consistent in the standard operation setting area and the transient takeover setting area, and the consistency parameters are stored in the non-volatile memory of the microcomputer protection device. The logic node involved in the thermal accumulation effect is set in the transient control setpoint region with an action tolerance threshold greater than that in the standard operation setpoint region.

4. The integrated control method for a modular combined prefabricated substation according to claim 1, characterized in that, After outputting the estimated equivalent self-heating temperature of each of the aforementioned electrical functional modules, the method further includes: By comparing the heat generation power calculated based on the real-time three-phase current effective value theory with the estimated equivalent self-heating temperature of the target electrical function module, if the deviation between the heat generation power and the estimated equivalent self-heating temperature exceeds the preset allowable error threshold, the thermal state reliability of the target electrical function module is marked as low reliability level. A command is sent to the logic interlock node of the microcomputer protection device to forcibly lock out permission to enter the transient control setpoint area.

5. The integrated control method for a modular combined prefabricated substation according to claim 1, characterized in that, The remaining thermal inertia time margin before the target electrical function module reaches the preset limit alarm temperature is calculated based on the estimated equivalent self-heating temperature of the target electrical function module, including: The expected steady-state maximum temperature is calculated by combining the real-time RMS value of the load current with the base ambient reference temperature. When the expected steady-state maximum temperature is less than or equal to the limit alarm temperature, the thermal inertia time margin is set to the maximum safety constant. When the estimated equivalent self-heating temperature is greater than or equal to the extreme alarm temperature, the thermal inertia time margin is set to zero. When the estimated equivalent self-heating temperature is less than the limit alarm temperature and the expected steady-state maximum temperature is greater than the limit alarm temperature, the transient temperature rise logarithmic equation is invoked to calculate the thermal inertia time margin.

6. The integrated control method for a modular combined prefabricated substation according to claim 1, characterized in that, Based on the thermal inertia time margin sequence, the critical electrical function modules and redundant electrical function modules are marked as follows: When the thermal inertia time margin is less than the lower limit of the hazard warning, it is marked as an emergency electrical function module. The lower limit of the hazard warning is set to be greater than the sum of the circuit breaker mechanical action delay time, the network communication dead time, and the setting value switching instruction processing time. When the thermal inertia time margin is greater than the load takeover safety threshold and the real-time load rate does not reach the rated capacity limit, it is marked as a redundant electrical function module. The load takeover safety threshold is set as the sum of the system's expected longest loop-closing switching time and the inherent cooling time constant of the redundant electrical function module.

7. The integrated control method for a modular combined prefabricated substation according to claim 1, characterized in that, After the redundant electrical function module activates the transient takeover setpoint area as described in the instruction, it also includes: The lifecycle control parameters are synchronously sent to the redundant electrical function module and converted into local holding control quantities. The local holding control quantities are mapped to the initial value of the hardware timer of the internal safety coprocessor of the microcomputer protection device and the countdown task is started. If no successful status confirmation of setting zone switching is received or the countdown task is detected to be zero, the closing permission hard contact in the bus tie circuit breaker operation circuit shall be forcibly disconnected.

8. The integrated control method for a modular combined prefabricated substation according to claim 1, characterized in that, After completing the pre-synchronization verification and parallel capacity verification, the cross-module load transfer reconstruction includes the following logical branches: When both the pre-synchronization check and the parallel capacity check meet the set conditions, the circuit breaker is switched to a closed transfer branch, and a closing command is sent to the bus tie circuit breaker to form a short-time closed-loop parallel connection, disconnecting the incoming circuit breaker of the emergency electrical function module. When the parallel capacity verification passes and the pre-synchronization verification fails, the process switches to the interruption transfer branch, disconnects the incoming circuit breaker of the emergency electrical function module, and issues a closing command to the bus tie circuit breaker when the residual voltage amplitude of the bus is lower than the no-voltage judgment threshold. If the parallel capacity verification fails, the process switches to the overload reduction branch and disconnects the feeder circuit breakers of the secondary feeder circuits on the side of the emergency electrical function module in sequence according to the pre-stored feeder priority list.

9. The integrated control method for a modular combined box-type substation according to claim 1, characterized in that, After completing the pre-synchronization verification and parallel capacity verification, and performing cross-module load transfer and reconstruction, the process also includes executing a multi-level safety rollback mechanism: Monitor the hot spot temperature and local hardware timer of the redundant electrical function module. When the local hardware timer count value is cleared or the estimated value of the equivalent self-heating temperature is greater than the secondary thermal warning temperature threshold, extract the real-time effective load current value of the redundant electrical function module and compare it with the set long-term safe carrying current threshold. When the real-time effective load current value is greater than the long-term safe carrying current threshold, the set value zone rollback command is intercepted and the system-level load reduction program is started. When the real-time effective load current value is less than or equal to the long-term safe carrying current threshold, the transient takeover setting zone is suspended and the standard operation setting zone is locked.

10. The integrated control method for a modular combined prefabricated substation according to claim 9, characterized in that, The thermal monitoring logic of the critical electrical function module is executed during the execution of the multi-level safety fallback mechanism: Acquire the actual temperature drop data of the physical surface at the electrical connector located inside the emergency electrical function module. After the actual temperature drop data of the physical surface continuously decreases and is less than the safe return temperature threshold, and the state is maintained for a longer than the preset observation window time, release the lockout of the emergency electrical function module operation permission control node and close the incoming circuit breaker of the emergency electrical function module.

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