Dual power automatic switching control method and device for hydroelectric power station fire fighting system

Abstract

The application discloses a dual-power automatic switching control method and device for a hydropower station fire-fighting system, and the method comprises the following steps: calculating the load recovery impact equivalent of each fire-fighting load, determining the fire-fighting linkage urgency according to the fire-fighting linkage role and the current environment state, and determining the switching recovery priority value by comprehensively considering the two factors; sorting the fire-fighting loads according to the priority value from high to low, dividing multiple input groups by taking the cumulative load recovery impact equivalent not exceeding the bus allowed pressure drop impact threshold as a constraint, and generating a delay input time sequence; inputting the standby power after the main power fails and sequentially recovering each group of fire-fighting loads; after the switching is completed, collecting the bus voltage sag value, comparing the bus voltage sag value with the estimated maximum pressure drop, and dynamically adjusting the bus allowed pressure drop impact threshold. The application solves the technical problems of excessive bus impact and delayed recovery of important fire-fighting loads during the switching of the existing dual power.

Description

Technical Field

[0001] This invention relates to the field of power supply control technology for hydropower station fire protection, specifically to a dual-power automatic switching control method and device for hydropower station fire protection systems. Background Technology

[0002] The fire protection system of a hydropower station is a core facility for ensuring fire safety in the station's production area, and its power supply reliability directly affects whether fire-fighting equipment can be deployed normally during a fire. According to relevant regulations, fire-fighting loads should be equipped with a dual-power automatic transfer switch at the final distribution box of their power lines. When the main power supply fails, the dual-power transfer switch must switch the fire-fighting load to the backup power supply.

[0003] Currently, automatic switching control for dual power supplies in hydropower stations typically restores all fire-fighting loads simultaneously or sequentially in a fixed order. This approach fails to consider the differences in starting current surges and the urgency of fire-fighting linkages among different fire-fighting loads, easily leading to two problems: First, the combined surge currents from the simultaneous activation of numerous fire-fighting loads can cause the bus voltage to drop beyond permissible limits, affecting the normal operation of other loads and even damaging equipment. Second, the lack of distinction between high-urgency loads for fire-fighting operations and low-urgency loads for auxiliary support may delay the restoration of critical loads, impacting fire response efficiency. Therefore, existing control methods are deficient in both switching safety and load restoration rationality. Summary of the Invention

[0004] In a first aspect, the present invention provides a dual-power automatic switching control method for a hydropower station fire protection system, the method comprising: Obtain the rated power, starting current multiple, impedance per unit length of power supply line, power supply voltage, and line length from the load to the dual power supply switching device for each fire load, and calculate the load recovery impact equivalent for each fire load. The basic weight of the equipment is determined based on the fire linkage role of the fire load, and the regional state coefficient is determined based on the current environmental state. The fire linkage urgency of each fire load is obtained by combining the analysis. Based on the load recovery impact equivalent and the urgency of fire linkage for each of the aforementioned fire loads, the switching and restoration priority value for each of the aforementioned fire loads is determined; The fire loads are sorted from high to low according to the switching and restoration priority value. With the cumulative load restoration impact equivalent not exceeding the preset bus allowable voltage drop impact threshold as a constraint, the sorted fire loads are divided into multiple input groups, and a delayed input sequence is generated between each group. After detecting a main power failure, the backup power supply is activated, and the fire load in each activation group is restored sequentially according to the delayed activation sequence. After the switching operation is completed, the bus voltage sag value is collected, and the bus voltage sag value is compared with the estimated maximum bus voltage drop value before the switching. The preset bus voltage drop impact threshold is adjusted according to the comparison result.

[0005] Secondly, the present invention also provides a dual-power automatic switching control device for a hydropower station fire protection system, the device comprising: The load recovery impact equivalent calculation module is used to obtain the rated power, starting current multiple, power supply line impedance per unit length, power supply voltage, and line length from the load to the dual power supply switching device for each fire load, and to calculate the load recovery impact equivalent for each fire load. The fire linkage urgency determination module is used to determine the basic weight of equipment based on the fire linkage role of the fire load, determine the area state coefficient based on the current environmental state, and obtain the fire linkage urgency of each fire load through analysis. The switching and recovery priority determination module is used to determine the switching and recovery priority value of each fire load by comprehensively considering the load recovery impact equivalent and the urgency of fire linkage for each fire load. The module for dividing the fire loads into input groups and generating the timing sequence is used to sort each fire load from high to low according to the switching and recovery priority value, and to divide the sorted fire loads into multiple input groups with the constraint that the cumulative load recovery impact equivalent does not exceed the preset bus allowable voltage drop impact threshold, and to generate the delayed input timing sequence between each group. The switching execution module is used to switch to the backup power supply after detecting a main power failure, and to restore the fire load in each power-on group in sequence according to the delayed power-on sequence. The threshold adjustment module is used to collect the bus voltage sag value after the switching is completed, compare the bus voltage sag value with the estimated maximum bus voltage drop value before the switching, and adjust the preset bus allowable voltage drop impact threshold according to the comparison result.

[0006] One or more technical solutions provided by this invention have at least the following technical effects or advantages: First, by calculating the load recovery impact equivalent of each fire load, this invention quantifies the contribution of each load to the bus voltage drop when it is put into operation, providing an impact constraint basis for grouped restoration and avoiding the problem of excessive bus voltage drop caused by the superposition of impact current in the traditional simultaneous restoration method.

[0007] Second, this invention combines the roles of fire-fighting linkage with the current environmental conditions to determine the urgency of fire-fighting linkage, so that critical loads such as fire-fighting execution are given priority over auxiliary support loads in the recovery sequence, and the recovery priority can be dynamically adjusted according to the actual state of the fire area, thereby improving the timeliness of fire response.

[0008] Third, this invention divides the load into input groups based on the constraint that the cumulative load recovery impact equivalent does not exceed the bus allowable voltage drop impact threshold. Loads with larger impacts are distributed to different input groups and a delay is set between groups to improve the recovery speed as much as possible while ensuring switching safety.

[0009] Fourth, this invention collects the bus voltage sag value after switching and compares it with the estimated maximum voltage drop. Based on the comparison result, it dynamically adjusts the bus allowable voltage drop impact threshold so that the threshold can adapt to changes in actual operating conditions, thereby improving the rationality and adaptability of subsequent switching decisions. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a flowchart illustrating the automatic switching control method for dual power supplies in a hydropower station fire protection system provided in an embodiment of the present invention. Figure 2 This is a logic diagram of a dual-power automatic switching control device for a hydropower station fire protection system provided in an embodiment of the present invention. Figure 3 This is a structural diagram of the dual-power automatic switching control device for a hydropower station fire protection system provided in an embodiment of the present invention; The diagram is labeled as follows: 11 Load recovery impact equivalent calculation module, 12 Fire alarm linkage urgency determination module, 13 Switching recovery priority value determination module, 14 Activation group division and timing generation module, 15 Switching execution module, and 16 Threshold adjustment module. Detailed Implementation

[0012] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0013] Example 1, as Figure 1 As shown in Figure 2, the present invention provides a dual-power automatic switching control method for a hydropower station fire protection system, the method comprising: S10: Obtain the rated power, starting current multiple, impedance per unit length of power supply line, power supply voltage, and line length from the load to the dual power supply switching device for each fire load, and calculate the load recovery impact equivalent for each fire load; Step S10 provided in this embodiment of the invention includes: Obtain the rated power, supply voltage, and line length from the load of each fire-fighting load to the dual-power switching device; Obtain the starting current multiple of each of the fire loads. The starting current multiple is the ratio of the effective value of the current of the fire load at the moment of startup to the effective value of the rated current. For non-motor fire loads, the starting current multiple is taken as one. Obtain the impedance per unit length of the power supply line for each of the fire-fighting loads, wherein the impedance per unit length of the power supply line is the impedance modulus per unit length of the power supply line where the fire-fighting load is located. The rated current of each of the fire-fighting loads is multiplied by the starting current multiple to obtain the impact current value; Multiplying the inrush current value by the product of the impedance per unit length of the power supply line and the line length of the load from the dual power supply switching device, the line voltage drop value of the fire load is obtained, which is used as the load recovery impact equivalent of the fire load.

[0014] The specific implementation method is as follows: Obtain the rated power and supply voltage of each fire-fighting load. The rated power of a fire-fighting load is the electrical power consumed under rated operating conditions, expressed in kW, and can be directly read from the equipment nameplate parameters. The supply voltage is the power supply voltage required for the fire-fighting load to operate normally. The supply voltage for fire-fighting loads in hydropower stations is primarily AC 380V, with some control equipment using AC 220V. For example, a fire pump has a rated power of 30kW and a supply voltage of 380V.

[0015] Obtain the line length from each fire-fighting load to the dual-power switching device. The line length from the load to the dual-power switching device is the total length of the power supply line from the output terminal of the dual-power switching device to the fire-fighting load, measured in meters (m). This length is determined by the hydropower station fire-fighting power supply system design drawings or on-site measurements. This parameter reflects the impedance of the power supply line; the longer the line, the greater the voltage drop on the line when the load is connected. For example, the line length from the fire pump to the dual-power switching device is 80m.

[0016] Obtain the starting current multiple for each fire-fighting load. The starting current multiple is the ratio of the effective value of the current at the moment of startup to the effective value of the rated current, and is a dimensionless quantity. For motor-type loads, the starting current multiple is determined by the starting method and mechanical characteristics of the motor, and is usually between 5 and 7. Specific values ​​can be obtained from the equipment's technical data or nameplate parameters. For non-motor-type loads, such as fire alarm controllers and gas extinguishing control devices, the starting current is basically equal to the rated current, and the starting current multiple is taken as 1. For example, the fire pump is a direct-start squirrel-cage induction motor, and the starting current multiple is 6.

[0017] Obtain the impedance per unit length of the power supply line for each fire-fighting load. The impedance per unit length of the power supply line is the impedance modulus per unit length of the power supply line containing the fire-fighting load, expressed in Ω / km or Ω / m. The impedance modulus is determined by the conductor material, cross-sectional area, and laying method of the power supply line. Hydropower station fire-fighting power supply lines typically use copper-core fire-resistant cables, and their impedance per unit length can be found in the technical parameter tables provided by the cable manufacturer or in an electrical handbook. For example, this fire pump power supply line uses a copper-core cable with a cross-sectional area of ​​25mm², and its impedance per unit length is 0.80Ω / km, which translates to 0.0008Ω / m.

[0018] Calculate the rated current for each fire-fighting load. Rated current equals rated power divided by the supply voltage. For three-phase AC loads, rated current (RMS value) = rated output power ÷ ( (×supply voltage × power factor × efficiency). The power factor and efficiency are determined based on the equipment nameplate parameters or measured data; when the nameplate is not marked and actual measurement conditions are not available, they are estimated based on the typical power factor of 0.85 and typical efficiency of 0.9 for motor loads in hydropower station fire protection loads. For example, the rated power of this fire pump is 30kW, the supply voltage is 380V, the power factor is taken as 0.85, the efficiency is taken as 0.9, and the rated current is 30×1000÷(1.732×380×0.85×0.9)≈59.6A.

[0019] Multiply the rated current by the starting current factor to obtain the inrush current value. The inrush current value is the effective value of the current at the instant the load starts, and the unit is ampere (A). For example, the rated current of this fire pump is 59.6A, the starting current factor is 6, and the inrush current value = 59.6 × 6 = 357.6A.

[0020] Multiplying the inrush current value by the product of the impedance per unit length of the power supply line and the line length from the load to the dual-power switching device yields the line voltage drop value for the fire-fighting load. This line voltage drop is the voltage drop on the power supply line at the moment the load is switched on, measured in volts (V). This is used as the load recovery impact equivalent for the fire-fighting load. The load recovery impact equivalent reflects the contribution of the fire-fighting load to the bus voltage drop when switched on; a larger value indicates a stronger impact on the bus voltage during recovery. For example, if the inrush current value is 357.6A, the impedance per unit length of the power supply line is 0.0008Ω / m, and the line length is 80m, then the load recovery impact equivalent = 357.6 × 0.0008 × 80 ≈ 22.9V.

[0021] After the load recovery impact equivalent of each fire load is calculated, it is stored in the dual power automatic switching controller according to the load number for subsequent use in the division of input groups and the generation of timing.

[0022] The following technical effects were achieved through this step: This step involves obtaining the rated power, supply voltage, starting current multiple, impedance per unit length of the power supply line, and line length of each fire-fighting load. It then calculates the inrush current value of each load and its voltage drop on the line, obtaining the load restoration inrush equivalent. This equivalent combines two key factors: the load's starting characteristics and the power supply line impedance. It quantitatively reflects the contribution of each load to the bus voltage drop when it is put into operation, providing a basis for subsequent grouping and orderly restoration based on the cumulative inrush equivalent. This avoids the problem of excessive bus voltage drop caused by the superposition of inrush currents in traditional simultaneous restoration methods.

[0023] S20: Determine the basic weight of the equipment based on the fire linkage role of the fire load, determine the regional state coefficient based on the current environmental state, and obtain the fire linkage urgency of each fire load through analysis; Step S20 provided in this embodiment of the invention includes: Obtain the fire linkage role of each fire load. The fire linkage role is the linkage function positioning of the fire load in the hydropower station fire protection system. The fire linkage role includes sensing and alarm type, linkage control type, fire extinguishing execution type and auxiliary support type. Obtain the current environmental status of each fire protection zone where the fire load is located, and determine the area status coefficient based on the current environmental status; The basic weight of each fire load is determined according to the fire linkage role, wherein the basic weight of the fire extinguishing execution equipment is greater than the basic weight of the sensing alarm equipment, the basic weight of the sensing alarm equipment is greater than the basic weight of the linkage control equipment, and the basic weight of the linkage control equipment is greater than the basic weight of the auxiliary support equipment. The basic weights of the equipment for each of the fire loads are corrected using the regional state coefficients to obtain the fire linkage urgency of the fire loads.

[0024] This includes obtaining the current environmental state of each fire protection zone where the fire load is located, and determining the area state coefficient based on the current environmental state, including: Obtain the temperature, smoke concentration, and carbon monoxide concentration values ​​within the fire compartment where each of the aforementioned fire loads is located; Obtain the trend values ​​of the temperature, smoke concentration, and carbon monoxide concentration within a preset time period; According to the preset fire risk level classification rules, the basic fire risk level is determined based on the temperature value, the smoke concentration value, and the carbon monoxide concentration value. When the trend of change of at least two of the temperature value, the smoke concentration value and the carbon monoxide concentration value is greater than the preset trend increase threshold, the basic fire risk level will be raised by one level. When the trend values ​​of the temperature value, the smoke concentration value, and the carbon monoxide concentration value are all less than or equal to the preset trend increase threshold, the basic fire risk level is maintained. Based on the final fire risk level, the corresponding regional state coefficient is obtained from the preset regional state coefficient mapping table.

[0025] The specific implementation method is as follows: Obtain the fire linkage role of each fire load. The fire linkage role is the functional positioning of the fire load in the hydropower station fire protection system. According to the different tasks undertaken by the fire load in the automatic fire alarm and fire extinguishing linkage process, they are divided into four categories: sensing and alarm, linkage control, fire extinguishing execution, and auxiliary support.

[0026] Sensing and alarm-related fire protection loads include point-type smoke detectors, point-type heat detectors, linear heat-sensing cables, image-type fire detectors, infrared flame detectors, and manual fire alarm buttons, whose function is to detect fires and issue alarm signals. Linkage and control-related fire protection loads include fire alarm controllers, fire linkage control panels, gas extinguishing control devices, fire broadcast control equipment, audible and visual alarms, and control modules, whose function is to receive alarm signals and drive related equipment to operate according to preset logic. Fire extinguishing execution-related fire protection loads include fire hydrant pumps, water sprinkler pumps, gas extinguishing system start-up solenoid valves, deluge valve solenoid valves, and other equipment that directly executes fire extinguishing actions. Auxiliary and support-related fire protection loads include fire telephones, fire emergency lighting, evacuation signs, fireproof roller shutters, and smoke exhaust fans, which are used to ensure personnel evacuation and fire extinguishing conditions.

[0027] The basic equipment weights for each fire load are determined based on its role in fire-fighting linkage. These basic equipment weights are dimensionless, reflecting the functional importance of the fire load within the fire protection system, and range from 0 to 1. The determination of these basic equipment weights is based on the provisions of the national standard GB 50116-2013 "Code for Design of Automatic Fire Alarm Systems" and the industry standard NB / T 10881-2021 "Code for Design of Automatic Fire Alarm Systems for Hydropower Plants," which specify the fire-fighting linkage control logic and the irreplaceable role of each piece of equipment in the fire-fighting process. Combined with operational experience of hydropower station fire protection systems, the basic equipment weights for the four categories of fire loads are preset as follows: Fire-fighting execution type 0.9, Sensing alarm type 0.7, Linkage control type 0.5, and Auxiliary support type 0.3. This value set satisfies the weight order of fire-fighting execution type being greater than sensing alarm type, sensing alarm type being greater than linkage control type, and linkage control type being greater than auxiliary support type. Firefighting execution equipment directly determines whether a fire can be extinguished or controlled, so it has the highest weight. Although sensing and alarm equipment does not directly extinguish fires, its detection results are a prerequisite for initiating all linkage actions, so it has the next highest weight. Linkage control equipment is responsible for signal transmission and logic control, and its importance is lower than the former two. Auxiliary support equipment only plays a role in specific scenarios, so it has the lowest weight.

[0028] The system acquires the temperature, smoke concentration, and carbon monoxide concentration values ​​within each fire compartment containing a fire load. Each fire compartment is an independent area within the hydropower station building, divided according to fire separation. Temperature, smoke, and carbon monoxide sensors are installed in each compartment, and the sensor signals are connected to a dual-power automatic switching controller or a fire alarm control system. Temperature values ​​are measured in °C, smoke concentration in mg / m³, and carbon monoxide in ppm. For example, a fire pump is located in the gas extinguishing protection zone on the ninth floor of an auxiliary plant building. The current temperature in this fire compartment is 36 °C, the smoke concentration is 0.8 mg / m³, and the carbon monoxide concentration is 15 ppm.

[0029] The system acquires the trend values ​​of temperature, smoke concentration, and carbon monoxide concentration over a preset time period. The trend value is calculated as follows: Trend value = (Current sampled value - Sampled value before the preset time period) ÷ Preset time period. The preset time period is determined based on the sensor response characteristics and the monitoring requirements of the hydropower station's fire protection system for fire development trends, and is set to 5 minutes. This time period length matches the most unfavorable response time of the hydropower station's automatic fire alarm system, enabling the capture of the continuous upward trend of environmental parameters in the early stages of a fire, while avoiding the smoothing of trend information due to excessively large time windows.

[0030] For example, the current temperature at the sampling time is 36℃, and the temperature 5 minutes ago was 31℃, so the temperature change trend value is (36-31)÷5=1.0℃ / min; the current smoke concentration is 0.8mg / m³, and the smoke concentration 5 minutes ago was 0.2mg / m³, so the smoke concentration change trend value is (0.8-0.2)÷5=0.12mg / (m³·min); the current carbon monoxide concentration is 15ppm, and the carbon monoxide concentration 5 minutes ago was 5ppm, so the carbon monoxide concentration change trend value is (15-5)÷5=2.0ppm / min.

[0031] Based on the preset fire risk level classification rules, the basic fire risk level is determined according to temperature, smoke concentration, and carbon monoxide concentration. The preset fire risk level classification rules adopt a graded threshold method: the fire risk level is divided into four levels: Level I (normal), Level II (concern), Level III (early warning), and Level IV (alarm). The threshold for each level is determined according to the recommended range of fire early warning threshold in NB / T 10881-2021 and detector alarm threshold in GB 50116-2013.

[0032] The temperature thresholds are as follows: Level I corresponds to a temperature less than 40℃, Level II corresponds to a temperature between 40℃ and 55℃, Level III corresponds to a temperature between 55℃ and 70℃, and Level IV corresponds to a temperature greater than 70℃. The smoke concentration thresholds are as follows: Level I corresponds to a smoke concentration less than 1.0 mg / m³, Level II corresponds to a smoke concentration between 1.0 mg / m³ and 3.0 mg / m³, Level III corresponds to a smoke concentration between 3.0 mg / m³ and 6.0 mg / m³, and Level IV corresponds to a smoke concentration greater than 6.0 mg / m³. The carbon monoxide concentration thresholds are as follows: Level I corresponds to a carbon monoxide concentration less than 30 ppm, Level II corresponds to a carbon monoxide concentration between 30 ppm and 60 ppm, Level III corresponds to a carbon monoxide concentration between 60 ppm and 120 ppm, and Level IV corresponds to a carbon monoxide concentration greater than 120 ppm.

[0033] Based on the corresponding levels for temperature, smoke concentration, and carbon monoxide concentration, the highest level is taken as the basic fire risk level. For example, if the current temperature of this fire compartment is 36℃, the smoke concentration is 0.8mg / m³, and the carbon monoxide concentration is 15ppm, then the basic fire risk level is determined to be Level I.

[0034] When the trend of change in at least two of the temperature, smoke concentration, and carbon monoxide concentration values ​​exceeds a preset trend increase threshold, the basic fire risk level is raised by one level. The preset trend increase threshold is determined based on the measurement noise level of each sensor and the statistical lower limit of the rate of increase of parameters in the early stages of a fire. The measurement noise of the temperature sensor is approximately 0.3℃ / min, and the rate of temperature increase in the early stages of a fire is typically not less than 1℃ / min; therefore, the temperature trend increase threshold is set to 1℃ / min. The measurement noise of the smoke concentration sensor is approximately 0.02 mg / (m³·min), and the rate of smoke concentration increase in the early stages of a fire is typically not less than 0.05 mg / (m³·min); therefore, the smoke concentration trend increase threshold is set to 0.05 mg / (m³·min). The measurement noise of the carbon monoxide concentration sensor is approximately 1 ppm / min, and the rate of carbon monoxide concentration increase in the early stages of a fire is typically not less than 3 ppm / min; therefore, the carbon monoxide concentration trend increase threshold is set to 3 ppm / min.

[0035] When at least two of the three trend values ​​exceed their respective trend increase thresholds, it indicates that the environmental parameters within the fire compartment are showing a simultaneous increase in multiple parameters, a precursor to fire, and the basic fire risk level is raised by one level. For example, the temperature trend value in this fire compartment is 1.0℃ / min, just reaching the temperature trend increase threshold of 1℃ / min, but not exceeding it; the smoke concentration trend value is 0.12 mg / (m³·min), exceeding the smoke concentration trend increase threshold of 0.05 mg / (m³·min); and the carbon monoxide concentration trend value is 2.0 ppm / min, not exceeding the carbon monoxide concentration trend increase threshold of 3 ppm / min. Only the smoke concentration trend value exceeds its corresponding threshold, failing to meet the condition that at least two values ​​exceed the threshold. Therefore, the basic fire risk level remains unchanged, and the final fire risk level remains Level I.

[0036] If the temperature change trend value of the fire compartment is 1.5℃ / min, the smoke concentration change trend value is 0.08mg / (m³·min), and the carbon monoxide concentration change trend value is 2.0ppm / min, then at least two of the trend values ​​are greater than the threshold, and the basic fire risk level is increased by one level from Level I, with the final fire risk level being Level II. When the trend values ​​of temperature, smoke concentration, and carbon monoxide concentration are all less than or equal to the preset trend increase threshold, the basic fire risk level remains unchanged.

[0037] Based on the final fire risk level, the corresponding regional state coefficient is obtained from a pre-set regional state coefficient mapping table. This pre-set mapping table is determined according to the differentiated recovery requirements for different fire risk areas in the hydropower station's fire load recovery strategy, specifically: Level I fire risk corresponds to a regional state coefficient of 1.0; Level II fire risk corresponds to a regional state coefficient of 1.2; Level III fire risk corresponds to a regional state coefficient of 1.5; and Level IV fire risk corresponds to a regional state coefficient of 1.8. The regional state coefficient is a dimensionless multiplicative correction factor, ranging from 1.0 to 1.8. Level I represents the normal state, with a regional state coefficient of 1.0, which does not change the relative magnitude of the equipment foundation weight. The regional state coefficients increase progressively from Level II to Level IV, indicating that the higher the fire risk in the fire compartment, the more urgent the fire load recovery in that area should be. For example, the final fire risk level of this fire compartment is Level I, and the regional state coefficient obtained from the mapping table is 1.0.

[0038] The regional state coefficients for each fire load are determined based on the current environmental conditions. Each fire load is then bound to the aforementioned regional state coefficient according to its fire compartment for subsequent adjustments.

[0039] The basic weights of equipment for each fire load are adjusted using a regional state coefficient to obtain the urgency of fire linkage for that fire load. The adjustment method is to multiply the basic weight of the equipment by the regional state coefficient, i.e., urgency of fire linkage = basic weight of equipment × regional state coefficient. The urgency of fire linkage reflects the degree of urgency at which power needs to be restored to the fire load under the current fire condition; a higher value indicates a higher priority for restoration. For example, the aforementioned fire pump belongs to the fire extinguishing execution category, has a basic weight of 0.9, and its regional state coefficient in the fire compartment is 1.0, so its urgency of fire linkage = 0.9 × 1.0 = 0.9. If the regional state coefficient of the fire compartment is adjusted to 1.5, then the urgency of fire linkage = 0.9 × 1.5 = 1.35, indicating a significant increase in the urgency of restoring the fire pump. This process is repeated for all fire loads to obtain the urgency of fire linkage for each fire load.

[0040] The following technical effects were achieved through this step: This step categorizes fire loads into four types based on fire-fighting linkage roles, employing the analytic hierarchy process (AHP) to assign differentiated basic weights to equipment, reflecting the varying importance of different functional equipment in the fire-fighting process. By collecting temperature, smoke concentration, and carbon monoxide concentration values ​​within fire compartments, the trend values ​​of each parameter over a preset time period are calculated. A tiered threshold method is then used to determine the basic fire risk level. When multiple parameters rise simultaneously, the risk level is adjusted upwards, and a regional state coefficient is obtained from a preset mapping table. Multiplying the regional state coefficient by the equipment's basic weight yields the fire-fighting linkage urgency, comprehensively reflecting the functional importance of equipment and the degree of regional fire risk.

[0041] Firefighting equipment already has a high urgency level under normal circumstances, and this urgency is further amplified in areas with increased fire risk. It is crucial to ensure that critical loads in the fire area are restored first, preventing auxiliary equipment from being restored before firefighting equipment. The urgency of fire linkage serves as a core input for subsequent switchover and restoration priority calculations, constraining the restoration order from both functional importance and regional fire risk dimensions, thereby improving the rationality of restoration decisions and the timeliness of firefighting response.

[0042] S30: Determine the switching and restoration priority value of each fire load by comprehensively considering the load restoration impact equivalent and the urgency of fire linkage for each fire load; Step S30 provided in this embodiment of the invention includes: Obtain the load recovery impact equivalent of each fire load, and take the maximum value among all the load recovery impact equivalents of the fire loads as the reference value of the maximum impact equivalent; The load recovery impact equivalent of each fire load is normalized based on the maximum impact equivalent reference value to obtain the load recovery impact normalized value of the fire load. Based on the urgency of fire linkage for each fire load and the normalized value of the load recovery impact of each fire load, the switching and recovery priority value of each fire load is calculated and obtained.

[0043] The specific implementation method is as follows: Obtain the load recovery impact equivalent for each fire-fighting load. The load recovery impact equivalent has been calculated in step S10 and stored in the dual-power automatic switching controller, organized by fire-fighting load number. For example, a hydropower station fire-fighting system includes five typical fire-fighting loads: fire hydrant pumps, water sprinkler pumps, fire alarm controllers, gas extinguishing control panels, and fire emergency lighting, numbered L1 to L5 respectively. Calculated in step S10, the load recovery impact equivalents for each fire-fighting load are as follows: L1 fire hydrant pump 22.9V, L2 water sprinkler pump 20.6V, L3 fire alarm controller 5.2V, L4 gas extinguishing control panel 3.8V, and L5 fire emergency lighting 2.1V.

[0044] The maximum value among the load recovery impact equivalents of all fire-fighting loads is taken as the reference value for the maximum impact equivalent. Specifically, the load recovery impact equivalents of all fire-fighting loads are iterated and the maximum value is obtained by comparison. For example, the maximum value among the load recovery impact equivalents of the above five fire-fighting loads is 22.9V, corresponding to the L1 fire hydrant pump, so the reference value for the maximum impact equivalent is taken as 22.9V.

[0045] The load recovery impact equivalent of each fire load is normalized based on the maximum impact equivalent reference value to obtain the normalized value of the load recovery impact for that fire load. The normalization process involves dividing the load recovery impact equivalent of each fire load by the maximum impact equivalent reference value. The result is a dimensionless quantity with a value ranging from 0 to 1. A larger value indicates a more significant contribution to the bus voltage drop when the load is put into operation. For example, the normalized value of the load recovery impact of the L1 fire hydrant pump is 22.9V ÷ 22.9V = 1.00, the normalized value of the load recovery impact of the L2 water sprinkler pump is 20.6V ÷ 22.9V ≈ 0.90, the normalized value of the load recovery impact of the L3 fire alarm controller is 5.2V ÷ 22.9V ≈ 0.23, the normalized value of the load recovery impact of the L4 gas extinguishing control panel is 3.8V ÷ 22.9V ≈ 0.17, and the normalized value of the load recovery impact of the L5 fire emergency lighting is 2.1V ÷ 22.9V ≈ 0.09.

[0046] Based on the urgency of fire linkage for each fire load and the normalized value of the load recovery impact, the switching recovery priority value of each fire load is calculated. Switching recovery priority value = urgency of fire linkage × (1 + impact attenuation factor ÷ normalized value of load recovery impact). The switching recovery priority value is a dimensionless quantity, reflecting the priority of the fire load in the dual-power switching process; a larger value indicates a higher priority for activation. The impact attenuation factor is used to suppress excessive amplification of the priority value of small impact loads. Its value is determined based on the distribution of the normalized value of load recovery impact in historical switching events, and is taken as one-tenth of the minimum value of the normalized value of load recovery impact in historical switching events. For example, if the minimum value of the normalized value of load recovery impact in the most recent 20 switching events is 0.1, then the impact attenuation factor is 0.1 × 0.1 = 0.01.

[0047] For example, the fire linkage urgency and load recovery impact normalized value of each fire load are the same as those mentioned above, with an impact attenuation factor of 0.1. The fire linkage urgency of the L1 fire hydrant pump is 0.9, the load recovery impact normalized value is 1.00, and the switching recovery priority value is 0.9 × (1 + 0.1 ÷ 1.00) = 0.9 × 1.1 = 0.99; the fire linkage urgency of the L2 water sprinkler pump is 0.9, the load recovery impact normalized value is 0.90, and the switching recovery priority value is 0.9 × (1 + 0.1 ÷ 0.90) = 0.9 × 1.111 ≈ 1.00; the fire linkage urgency of the L3 fire alarm controller is 0.5, the load recovery impact normalized value is 0.23, and the switching recovery priority value is 0.9 × (1 + 0.1 ÷ 0.90) = 0.9 × 1.111 ≈ 1.00. Priority weight = 0.5 × (1 + 0.1 ÷ 0.23) = 0.5 × 1.435 ≈ 0.72; The fire linkage urgency of the L4 gas extinguishing control panel is 0.6, the load restoration impact normalized value is 0.17, and the switching restoration priority weight = 0.6 × (1 + 0.1 ÷ 0.17) = 0.6 × 1.588 ≈ 0.95; The fire linkage urgency of the L5 fire emergency lighting is 0.3, the load restoration impact normalized value is 0.09, and the switching restoration priority weight = 0.3 × (1 + 0.1 ÷ 0.09) = 0.3 × 2.111 ≈ 0.63. The above priority values ​​are sorted from largest to smallest as follows: L2 water sprinkler pump (1.00), L1 fire hydrant pump (0.99), L4 gas extinguishing control panel (0.95), L3 fire alarm controller (0.72), L5 fire emergency lighting (0.63).

[0048] Iterate through all fire loads, calculate the priority value for switching and recovery, and store the corresponding results according to the fire load number for use in subsequent input group division and timing generation.

[0049] The following technical effects were achieved through this step: This step normalizes the impact equivalent of all fire-fighting loads using the maximum impact equivalent as a reference, making the relative magnitudes of impacts from different loads comparable. The switching and recovery priority value is obtained by dividing the urgency of fire-fighting linkage by the impact normalization value, comprehensively reflecting the urgency of recovery and the impact risk. Loads with higher priority values ​​are those with high urgency and low impact risk, and can be restored first while ensuring busbar safety. This avoids concentrated deployment of high-impact loads and delays in the restoration of critical loads, providing a quantitative ranking basis for subsequent orderly restoration.

[0050] S40: Sort each of the fire loads from high to low according to the switching and restoration priority value, and divide the sorted fire loads into multiple input groups with the constraint that the cumulative load restoration impact equivalent does not exceed the preset bus allowable voltage drop impact threshold, and generate the delayed input sequence between each group. Step S40 provided in this embodiment of the invention includes: Obtain the preset allowable voltage drop impact threshold for the busbar; The fire loads are sorted in descending order of their switching and restoration priority to obtain a restoration sequence. The fire loads are sequentially taken from the recovery sequence, and the load recovery impact equivalent of the taken current fire loads is added to the cumulative load recovery impact equivalent of the current input group. When the cumulative load recovery impact equivalent of the current input group is less than or equal to the bus allowable voltage drop impact threshold, the current fire load is assigned to the current input group. When the cumulative load recovery impact equivalent of the current input group is greater than the allowable voltage drop impact threshold of the bus, the division of the current input group ends, the current fire load is taken as the first fire load of the next input group, and the cumulative load recovery impact equivalent of the next input group is initialized to the load recovery impact equivalent of the current fire load. The remaining fire loads in the recovery sequence are processed in sequence until all fire loads are assigned to the corresponding input group. The resulting multiple input groups are arranged in the order of division. For two adjacent input groups, an inter-group delay is generated between the completion of the recovery of the previous input group and the start of the recovery of the next input group. The inter-group delays are then concatenated to obtain the delayed input sequence.

[0051] The specific implementation method is as follows: Obtain the preset allowable voltage drop impact threshold for the busbar. The allowable voltage drop impact threshold for the busbar is the maximum voltage drop that the standby power supply busbar is allowed to experience during the switching of fire-fighting loads, expressed in volts (V). This threshold is determined as follows: According to the national standard GB / T 12326-2008 "Power Quality Voltage Fluctuations and Flicker," the maximum allowable voltage fluctuation for a 380V busbar generally does not exceed 10% of the rated voltage, i.e., 38V. Considering the sensitivity of the already activated load to the busbar voltage during the switching of fire-fighting loads at the hydropower station, and with a safety margin, 10% of the rated voltage is taken as the theoretical limit, and then multiplied by a safety factor of 0.8, resulting in the allowable voltage drop impact threshold for the busbar: 380V × 10% × 0.8 = 30.4V, rounded down to 30V. For example, in this embodiment, the preset allowable voltage drop impact threshold for the busbar is 30V.

[0052] The fire loads are sorted in descending order of their switching and restoration priority values ​​to obtain a restoration sequence. Specifically, the switching and restoration priority values ​​of each fire load calculated in step S30 are read from the dual-power automatic transfer controller and sorted in descending order of their values. During sorting, if the switching and restoration priority values ​​of two fire loads are equal, their fire linkage urgency is further compared, and the one with the greater fire linkage urgency is ranked first; if they are still equal, the load restoration impact equivalent is compared, and the one with the smaller impact is ranked first.

[0053] For example, the switching and restoration priority values ​​of the five typical fire loads obtained in step S30 are as follows: L1 fire hydrant pump 0.99, L2 water sprinkler pump 1.00, L3 fire alarm controller 0.72, L4 gas extinguishing control panel 0.95, and L5 fire emergency lighting 0.63. After sorting from high to low, the restoration order sequence is: L2 water sprinkler pump, L1 fire hydrant pump, L4 gas extinguishing control panel, L3 fire alarm controller, and L5 fire emergency lighting.

[0054] Fire loads are sequentially retrieved from the recovery sequence and grouped according to the rule that the cumulative load recovery impact equivalent does not exceed the busbar allowable voltage drop impact threshold. Specifically, the initial value of the cumulative load recovery impact equivalent of the current group is set to 0. Starting from the first position in the recovery sequence, the current fire loads are retrieved sequentially, and their load recovery impact equivalent is read. For example, the load recovery impact equivalents of each fire load in the recovery sequence are: L2 water sprinkler pump 20.6V, L1 fire hydrant pump 22.9V, L4 gas extinguishing control panel 3.8V, L3 fire alarm controller 5.2V, and L5 fire emergency lighting 2.1V. The busbar allowable voltage drop impact threshold is 30V. The processing procedure is as follows: Remove the L2 water spray pump. Its load recovery impact equivalent is 20.6V. Add it to group 1: 0V + 20.6V = 20.6V, which is less than the threshold of 30V. L2 is assigned to group 1, and the cumulative value of group 1 is 20.6V.

[0055] Remove the L1 fire hydrant pump. Its load recovery impact equivalent is 22.9V. Add it to Group 1: 20.6V + 22.9V = 43.5V, which is greater than the threshold of 30V. End the Group 1 division and set L1 as the first fire load of Group 2. The cumulative initialization of Group 2 is 22.9V.

[0056] Remove the L4 gas extinguishing control panel. The load recovery impact equivalent is 3.8V. Add it to group 2: 22.9V + 3.8V = 26.7V, which is less than the threshold of 30V. L4 is then assigned to group 2, and group 2 has a cumulative value of 26.7V.

[0057] Remove the L3 fire alarm controller. The load recovery impact equivalent is 5.2V. Accumulate it to Group 2: 26.7V + 5.2V = 31.9V, which is greater than the threshold of 30V. End the Group 2 division and set L3 as the first fire load in Group 3. The cumulative initialization of Group 3 is 5.2V.

[0058] Remove L5 fire emergency lighting. The load restoration impact equivalent is 2.1V. Add it to group 3: 5.2V + 2.1V = 7.3V, which is less than the threshold of 30V. L5 is then assigned to group 3, and group 3 accumulates to 7.3V.

[0059] All fire loads have been processed, resulting in three input groups: Input Group 1 includes the L2 water sprinkler pump, with a cumulative load recovery impact equivalent of 20.6V; Input Group 2 includes the L1 fire hydrant pump and the L4 gas extinguishing control panel, with a cumulative load recovery impact equivalent of 26.7V; Input Group 3 includes the L3 fire alarm controller and the L5 fire emergency lighting, with a cumulative load recovery impact equivalent of 7.3V. The cumulative load recovery impact equivalent of each group does not exceed the busbar's allowable voltage drop impact threshold of 30V, meeting safety constraints. The resulting input groups are arranged in the order of their division: Input Group 1, Input Group 2, and Input Group 3.

[0060] For two adjacent load groups, an inter-group delay is generated between the completion of the recovery of the previous load group and the start of the recovery of the next load group. The inter-group delay is determined by taking the maximum value of the starting inrush current decay time constant of all fire loads in the two adjacent groups as the base delay, and then multiplying it by a safety factor. The starting inrush current decay time constant is determined by the motor parameters and power supply line parameters of the load, and is usually between 1s and 3s. To ensure that the starting inrush current of the previous load group completely decays to the steady-state level and the bus voltage recovers to stability, a safety factor of 1.5 is taken, so the base delay is approximately 3s × 1.5 = 4.5s, rounded to 5s. Therefore, in this embodiment, the inter-group delay between adjacent load groups is uniformly taken as 5s. For example, after the recovery of load group 1 is completed, there is a 5s delay before the recovery of load group 2 begins; after the recovery of load group 2 is completed, there is a 5s delay before the recovery of load group 3 begins.

[0061] The delays between each group are sequentially concatenated to obtain the delayed activation sequence. The delayed activation sequence includes the load composition of each activation group, the order of restoration, and the delay time between adjacent activation groups. For example, in this embodiment, the delayed activation sequence is as follows: Activation of group 1 (L2 water sprinkler pump) begins at 0 seconds; activation of group 2 (L1 fire hydrant pump, L4 gas extinguishing control panel) begins at 5 seconds; and activation of group 3 (L3 fire alarm controller, L5 fire emergency lighting) begins at 10 seconds. Within each activation group, each fire load is activated sequentially or simultaneously according to the order in the restoration sequence. The specific activation method can be determined by the dual-power automatic switching controller based on the operating characteristics of the load switching mechanism.

[0062] The following technical effects were achieved through this step: This step is based on the priority order of the switching and recovery, with the cumulative load recovery impact equivalent not exceeding the busbar's allowable voltage drop impact threshold as a hard constraint. The fire load is divided into multiple activation groups. Loads with high priority and smaller impact are assigned to earlier activation groups, while high-impact loads are distributed to subsequent activation groups, ensuring that the impact on the busbar from each activation group is within the allowable range. The inter-group delay is determined based on the decay time of the starting inrush current, ensuring that the impact of the previous group completely decays before the next group is restored, avoiding the superposition of impacts that could lead to excessive busbar voltage drop. The activation group division and delay sequence work together to ensure the safety of the dual-power switching process while maximizing the speed of fire load recovery.

[0063] S50: After detecting a main power failure, switch on the backup power supply and restore the fire load in each power-on group in sequence according to the delayed power-on sequence; Step S50 provided in this embodiment of the invention includes: Collect the effective value of the main power supply voltage. When the effective value of the main power supply voltage is lower than the preset power failure judgment threshold and the duration reaches the preset power failure confirmation time, the main power supply is determined to be in failure. After determining that the main power supply has failed, a closing command is sent to the backup power circuit breaker to put the backup power supply into use. After the backup power supply is switched on, the fire loads in each subsequent power-on group are restored in sequence according to the order of delay between each group in the delay power-on sequence, until the fire loads in all power-on groups are restored to power.

[0064] The specific implementation method is as follows: The effective value of the main power supply voltage is collected. This effective value is acquired by a voltage transformer installed on the incoming side of the automatic transfer switch (ATS). After calculation based on the effective value, it serves as the input for power failure detection, with the unit of measurement being V. The acquisition period is consistent with the control period of the ATS controller, set to 20 ms. The ATS is located at the final distribution box of the hydropower station's fire-fighting load distribution line, with the main power supply incoming line being AC 380V. For example, the effective value of the main power supply voltage in the current sampling period is 356V.

[0065] The effective value of the main power supply voltage is compared with a preset power failure threshold. The power failure threshold is determined based on the rated voltage of the main power supply and the adaptability range of the fire load to the supply voltage. According to the requirements of the national standard GB / T 14048.11 "Low-voltage switchgear and controlgear - Part 6-1: Multifunctional electrical transfer switches" for the operating characteristics of automatic transfer switches when the main power supply voltage is abnormal, an undervoltage state is considered when the effective value of the main power supply voltage is lower than 85% of the rated voltage. In this embodiment, the rated voltage of the main power supply is 380V, and the power failure threshold is 380V × 85% = 323V. For example, the current effective value of the main power supply voltage is 356V, which is higher than the power failure threshold of 323V, and the main power supply is in a normal state.

[0066] The main power supply voltage RMS value is continuously monitored. When the RMS value falls below the power failure threshold and the duration reaches the preset power failure confirmation time, the main power supply is deemed to have failed. The preset power failure confirmation time is used to distinguish between permanent power failure and transient voltage drops. Based on the requirements of GB / T 14048.11 for the maloperation of automatic transfer switches under voltage fluctuation and flicker conditions, and considering the sensitivity of hydropower station fire load to power supply continuity, the power failure confirmation time is set to 3 seconds. This time is longer than the duration of common instantaneous power grid disturbances, which avoids misjudgment due to short-term voltage dips, while ensuring that power failure confirmation and switching procedures are initiated within 3 seconds of a real power failure. For example, at time t0, the RMS value of the main power supply voltage drops from 356V to 298V, below the power failure threshold of 323V, and timing begins; at t0+3s, the RMS value is still 295V, and the duration reaches 3 seconds, confirming a main power failure.

[0067] Upon determining that the main power supply has failed, a closing command is sent to the backup power circuit breaker. The backup power circuit breaker is an electrically operated mechanism within the dual-power automatic transfer switch. Upon receiving the closing command, it drives the backup power circuit to close, enabling the backup power supply to be used. The closing command is sent by the dual-power automatic transfer controller via hardwiring or fieldbus. For example, after confirming the main power supply failure at t0+3s, the dual-power automatic transfer controller immediately sends a closing command to the backup power circuit breaker via hardwiring. The backup power circuit breaker completes the closing action within 200ms, and the backup power supply is connected to the bus.

[0068] After the backup power supply is switched on, the fire loads in each subsequent activated group are restored sequentially according to the order of delays between groups in the delayed activation sequence. Specifically, the dual-power automatic transfer controller reads the delayed activation sequence generated in step S40 and restores the fire loads of each group in sequence, starting from the first activated group. The delayed activation sequence generated in step S40 is as follows: Activation group 1 (L2 water sprinkler pump), Activation group 2 (L1 fire hydrant pump, L4 gas extinguishing control panel), Activation group 3 (L3 fire alarm controller, L5 fire emergency lighting), with a 5-second delay between adjacent groups.

[0069] For example, 0 seconds after the backup power supply is switched on, the terminal contactor of the L2 water sprinkler pump in control group 1 is engaged, restoring power supply; from 0 seconds to 5 seconds, the L2 starting inrush current decays, and the bus voltage stabilizes; at 5 seconds, the terminal contactors of the L1 fire hydrant pump and the L4 gas extinguishing control panel in control group 2 are engaged sequentially, restoring power supply; at 10 seconds, the terminal contactors of the L3 fire alarm controller and the L5 fire emergency lighting in control group 3 are engaged, restoring power supply. At this point, all fire loads have been restored to power, and the switchover and restoration process is complete.

[0070] The following technical effects were achieved through this step: This step uses the main power supply voltage effective value being lower than the power failure judgment threshold and continuously reaching the power failure confirmation time as the criterion, taking into account both the sensitivity and reliability of power failure detection and avoiding false switching caused by instantaneous voltage fluctuations; after confirming the power failure, a backup power supply closing command is issued in a timely manner to shorten the power supply interruption time for fire loads; after the backup power supply is closed, the loads of each input group are restored in strict accordance with the delayed input sequence generated by S40, so that the actual restoration process is consistent with the optimized calculation results, ensuring that the bus impact does not exceed the limit while achieving orderly restoration of fire loads.

[0071] S60: After the switching is completed, the bus voltage sag value is collected, and the bus voltage sag value is compared with the estimated maximum bus voltage drop value before the switching. The preset bus voltage drop impact threshold is adjusted according to the comparison result.

[0072] Step S60 provided in this embodiment of the invention includes: After the switchover is completed, the bus voltage sag value is collected, wherein the bus voltage sag value is the maximum drop in bus voltage relative to rated voltage during the standby power supply activation process; Obtain the estimated maximum bus voltage drop value before switching. The estimated maximum bus voltage drop value before switching is calculated based on the maximum value of the cumulative load recovery impact equivalent in each of the input groups and the preset voltage drop conversion coefficient before switching is executed. The bus voltage sag is compared with the estimated maximum bus voltage drop before the switchover. When the bus voltage sag is greater than the estimated maximum bus voltage drop before the switchover, the allowable bus voltage drop impact threshold is adjusted based on the switching and recovery priority of all fire loads in the input group that actually caused the maximum voltage drop. When the bus voltage sag is less than or equal to the estimated maximum bus voltage drop before the switchover, the preset allowable bus voltage drop threshold is increased by a preset adjustment step size.

[0073] Wherein, when the bus voltage sag is greater than the estimated maximum bus voltage drop before the switchover, the allowable bus voltage drop impact threshold is adjusted based on the switching and recovery priority of all fire loads in the activated group that actually caused the maximum voltage drop, including: Obtain the switching recovery priority value of all fire loads in the input group that actually causes the maximum pressure drop during the switching process, and calculate the arithmetic mean of the switching recovery priority values ​​of all fire loads in the input group as the average priority value of the high-impact group. When the average priority value of the high-impact group is greater than the preset high-priority threshold, it is determined that the voltage drop is caused by the concentrated input of high-priority loads, and the preset bus allowable voltage drop impact threshold is increased according to the preset adjustment step size. When the average priority value of the high-impact group is less than or equal to the preset high-priority threshold, it is determined that the voltage drop is caused by the dispersed input of low-priority loads, and the preset bus allowable voltage drop impact threshold is reduced according to the preset adjustment step size.

[0074] The specific implementation method is as follows: After the switchover is completed, the bus voltage sag is collected. The bus voltage sag is the maximum drop in bus voltage relative to the rated voltage during the standby power supply activation process, measured in volts (V). The bus voltage sag is collected as follows: within the time window from the standby power supply closing to the completion of the full restoration of all activated power supply groups, the effective bus voltage value is continuously collected at a sampling period of 20ms, the same as the control cycle of the dual-power automatic transfer controller. The bus voltage sag is then taken as the value with the largest absolute difference from the rated voltage of 380V.

[0075] For example, during the execution of step S50 in this embodiment, the dual power supply automatic switching controller continuously collects the bus voltage from the time the backup power supply is closed to the time the group 3 is restored. The lowest effective value of the voltage is 338V and the rated voltage is 380V. Therefore, the bus voltage sag is 380V-338V=42V.

[0076] Obtain the estimated maximum bus voltage drop value before switching. The estimated maximum bus voltage drop value before switching is calculated based on the maximum cumulative load recovery impact equivalent in each input group and a preset voltage drop conversion factor before the switching is executed. The voltage drop conversion factor is used to convert the load recovery impact equivalent (in V) into the bus voltage sag amplitude (in V). Its physical meaning is the proportional relationship between the voltage drop generated on the line impedance by the load initiation impact and the bus voltage sag. The voltage drop conversion factor is obtained as follows: During the on-site commissioning phase before the dual-power automatic transfer switch is put into operation, a single-load input test is conducted on a typical load, and the line voltage drop value and bus voltage sag value corresponding to the load recovery impact equivalent are measured simultaneously. The ratio of the two is calculated, and the average value of multiple tests is taken as the voltage drop conversion factor.

[0077] For example, in this embodiment, the voltage drop conversion factor is taken as 1.2, which means that the sag of the load restoration impact equivalent on the bus is about 1.2 times its line voltage drop value. In step S40, the maximum value of the cumulative load restoration impact equivalent of each input group appears in input group 2, which is 26.7V. Therefore, the estimated maximum voltage drop value of the bus is 26.7V × 1.2 = 32.04V, which is taken as 32.0V.

[0078] The bus voltage sag is compared with the estimated maximum bus voltage drop before switching. In this embodiment, the bus voltage sag is 42V, and the estimated maximum bus voltage drop before switching is 32V. 42V is greater than 32V, which satisfies the condition that the bus voltage sag is greater than the estimated maximum bus voltage drop before switching. Therefore, the threshold adjustment process based on priority features is initiated.

[0079] Obtain the switching and recovery priority values ​​of all fire-fighting loads within the switching group that actually caused the maximum voltage drop during the switching process. The switching group that actually caused the maximum voltage drop is determined by analyzing the bus voltage drop amplitude at the recovery time of each switching group during the switching process, and the switching group with the largest voltage drop amplitude is selected.

[0080] For example, during this switchover, the bus voltage drop was 10V when switch group 1 recovered, 30V when switch group 2 recovered, and 8V when switch group 3 recovered. Therefore, switch group 2 actually caused the largest voltage drop. Switch group 2 includes the L1 fire hydrant pump (priority value 0.99) and the L4 gas extinguishing control panel (0.95). The average priority value of the high-impact group is calculated as (0.99 + 0.95) / 2 = 0.97.

[0081] The arithmetic mean of the switching and recovery priority values ​​of all fire loads within the input group is calculated and used as the average priority value of the high-impact group. In this embodiment, there is only one load, the L1 fire hydrant pump, in input group 3, and the average priority value of the high-impact group is 0.90.

[0082] Obtain a preset high-priority threshold. The high-priority threshold is used to distinguish whether the voltage drop exceeding the limit is caused by concentrated input of high-priority loads or dispersed input of low-priority loads. This threshold is determined based on the correlation statistics between different priority load combinations and bus voltage drop exceeding the limit in historical switching events. Specifically, the average priority value of the input group causing the largest voltage drop in each of the last 20 switching events is calculated, and the top 50% percentile of the corresponding bus voltage drop exceeding events is used as the high-priority threshold. When there are fewer than 20 historical switching events, the default high-priority threshold of 1.5 is used. For example, in the last 20 switching events, there were 8 voltage drop exceeding events. The average priority values ​​of the high-impact groups corresponding to these 8 events, sorted from smallest to largest, are [0.60, 0.70, 0.75, 0.80, 0.90, 1.00, 1.10, 1.20]. The top 50% percentile corresponds to the 4th value, i.e., 0.80, so the high-priority threshold is set to 0.80. In this embodiment, the average priority value of the high-impact group is 0.675, which is less than the high-priority threshold of 0.80. Therefore, it is determined that the voltage drop exceeding the limit is caused by the concentrated input of high-priority loads. The allowable voltage drop impact threshold of the bus is increased according to the preset adjustment step size.

[0083] The preset adjustment step size is determined based on the typical adjustment range of the bus voltage drop impact threshold. The adjustment step size is 5% of the current threshold value. This percentage is determined based on the standard deviation of the deviation between the bus voltage sag and the estimated maximum voltage drop during the last 10 dual-power supply switching processes. This standard deviation is approximately 2.5% of the initial threshold value. To ensure that the threshold adjustment gradually approaches a reasonable value while avoiding excessive single adjustments that could cause oscillations in the grouping strategy, twice this standard deviation is used as the adjustment step size, i.e., 5% of the current threshold value. The current bus voltage drop impact threshold is 30V, and the adjustment step size = 30V × 5% = 1.5V. Due to the determination that high-priority loads are being concentrated, the bus voltage drop impact threshold is increased from 30V to 30V + 1.5V = 31.5V.

[0084] When the bus voltage sag exceeds the estimated maximum bus voltage drop before switching, and the average priority value of the high-impact group is less than or equal to the high-priority threshold, it is determined that the voltage drop exceedance is caused by the dispersed connection of low-priority loads. In this case, the allowable bus voltage drop impact threshold is reduced according to the preset adjustment step size. For example, if the average priority value of the high-impact group is 0.675 in a certain switching, which is less than the threshold of 0.80, then the threshold is adjusted to 30V-1.5V=28.5V.

[0085] When the bus voltage sag is less than or equal to the estimated maximum bus voltage drop before switching, it indicates that the actual impact has not exceeded the estimate, and the current allowable bus voltage drop impact threshold still has a margin. At this time, the allowable bus voltage drop impact threshold is increased according to the preset adjustment step size to gradually improve recovery efficiency. The increased threshold is the original threshold plus the adjustment step size; if the increased threshold exceeds the preset upper limit, the upper limit is used. The preset upper limit is determined based on the allowable voltage fluctuation limit of the bus: the maximum allowable voltage fluctuation of a 380V bus generally does not exceed 10% of the rated voltage, i.e., 38V; considering model estimation errors and safety margins, the upper limit is taken as 12% of the rated voltage, i.e., 380V × 12% = 45.6V, rounded to 46V. For example, if the bus voltage dip is 22V, which is less than the estimated maximum bus voltage drop of 32.0V before switching, and the adjustment step is 1.5V, then the bus allowable voltage drop impact threshold will be increased from 30V to 31.5V; if the current threshold is already 45V, the theoretical value after the increase is 46.5V, which exceeds the upper limit of the threshold of 46V, then the upper limit of the threshold of 46V will be taken.

[0086] The adjusted bus allowable voltage drop impact threshold is stored in the dual power supply automatic switching controller and used as the constraint value in step S40 during the next dual power supply switching process.

[0087] The following technical effects were achieved through this step: This step involves collecting the actual bus voltage sag value after the switchover is completed and comparing it with the estimated maximum voltage drop value before the switchover. This enables online closed-loop adjustment of the bus's allowable voltage drop impact threshold. When the actual sag exceeds the estimate, the cause of the exceedance is determined based on the average priority value of the high-impact group: the threshold is increased to improve recovery efficiency when high-priority loads are concentrated, and decreased to strengthen impact constraints when low-priority loads are dispersed; when the actual sag does not exceed the estimate, the threshold is increased to gradually improve the recovery speed. Through this dynamic adjustment mechanism, the bus's allowable voltage drop impact threshold can be automatically corrected based on the actual situation of each switchover, making subsequent recovery grouping decisions more closely aligned with the actual bus voltage withstand capability, achieving a dynamic balance between safety and recovery efficiency.

[0088] Example 2, as Figure 3 As shown, based on the same inventive concept provided in Embodiment 1, this embodiment of the invention also provides a dual-power automatic switching control device for a hydropower station fire protection system, the device comprising: The load recovery impact equivalent calculation module 11 is used to obtain the rated power, starting current multiple, power supply line unit length impedance, power supply voltage and the line length of the load from the dual power supply switching device for each fire load, and to calculate the load recovery impact equivalent of each fire load. The fire linkage urgency determination module 12 is used to determine the basic weight of the equipment based on the fire linkage role of the fire load, determine the area state coefficient based on the current environmental state, and obtain the fire linkage urgency of each fire load through analysis. The switching and recovery priority determination module 13 is used to determine the switching and recovery priority value of each fire load by comprehensively considering the load recovery impact equivalent and the urgency of fire linkage of each fire load; The input group division and timing generation module 14 is used to sort each of the fire loads from high to low according to the switching and recovery priority value, and divide the sorted fire loads into multiple input groups with the cumulative load recovery impact equivalent not exceeding the preset bus allowable voltage drop impact threshold as a constraint, and generate the delayed input timing sequence between each group. The switching execution module 15 is used to switch on the backup power supply after detecting a main power failure, and to restore the fire load in each power-on group in sequence according to the delayed power-on sequence. The threshold adjustment module 16 is used to collect the bus voltage sag value after the switching is completed, compare the bus voltage sag value with the estimated maximum bus voltage drop value before the switching, and adjust the preset bus allowable voltage drop impact threshold according to the comparison result.

[0089] In one embodiment, the load recovery impact equivalent calculation module 11 is further used to obtain the rated power, supply voltage and load distance of each of the fire loads from the dual power supply switching device. Obtain the starting current multiple of each of the fire loads. The starting current multiple is the ratio of the effective value of the current of the fire load at the moment of startup to the effective value of the rated current. For non-motor fire loads, the starting current multiple is taken as one. Obtain the impedance per unit length of the power supply line for each of the fire-fighting loads, wherein the impedance per unit length of the power supply line is the impedance modulus per unit length of the power supply line where the fire-fighting load is located. The rated current of each of the fire-fighting loads is multiplied by the starting current multiple to obtain the impact current value; Multiplying the inrush current value by the product of the impedance per unit length of the power supply line and the line length of the load from the dual power supply switching device, the line voltage drop value of the fire load is obtained, which is used as the load recovery impact equivalent of the fire load.

[0090] In one embodiment, the fire linkage urgency determination module 12 is further used to obtain the fire linkage role of each fire load. The fire linkage role is the linkage function positioning of the fire load in the hydropower station fire protection system. The fire linkage role includes sensing alarm type, linkage control type, fire extinguishing execution type and auxiliary support type. Obtain the current environmental status of each fire protection zone where the fire load is located, and determine the area status coefficient based on the current environmental status; The basic weight of each fire load is determined according to the fire linkage role, wherein the basic weight of the fire extinguishing execution equipment is greater than the basic weight of the sensing alarm equipment, the basic weight of the sensing alarm equipment is greater than the basic weight of the linkage control equipment, and the basic weight of the linkage control equipment is greater than the basic weight of the auxiliary support equipment. The basic weights of the equipment for each of the fire loads are corrected using the regional state coefficients to obtain the fire linkage urgency of the fire loads.

[0091] Obtain the temperature, smoke concentration, and carbon monoxide concentration values ​​within the fire compartment where each of the aforementioned fire loads is located; Obtain the trend values ​​of the temperature, smoke concentration, and carbon monoxide concentration within a preset time period; According to the preset fire risk level classification rules, the basic fire risk level is determined based on the temperature value, the smoke concentration value, and the carbon monoxide concentration value. When the trend of change of at least two of the temperature value, the smoke concentration value and the carbon monoxide concentration value is greater than the preset trend increase threshold, the basic fire risk level will be raised by one level. When the trend values ​​of the temperature value, the smoke concentration value, and the carbon monoxide concentration value are all less than or equal to the preset trend increase threshold, the basic fire risk level is maintained. Based on the final fire risk level, the corresponding regional state coefficient is obtained from the preset regional state coefficient mapping table.

[0092] In one embodiment, the switching recovery priority determination module 13 is further configured to obtain the load recovery impact equivalent of each of the fire loads, and use the maximum value among the load recovery impact equivalents of all fire loads as the maximum impact equivalent reference value. The load recovery impact equivalent of each fire load is normalized based on the maximum impact equivalent reference value to obtain the load recovery impact normalized value of the fire load. Based on the urgency of fire linkage for each fire load and the normalized value of the load recovery impact of each fire load, the switching and recovery priority value of each fire load is calculated and obtained.

[0093] In one embodiment, the input group division and timing generation module 14 is also used to obtain a preset bus allowable voltage drop impact threshold. The fire loads are sorted in descending order of their switching and restoration priority to obtain a restoration sequence. The fire loads are sequentially taken from the recovery sequence, and the load recovery impact equivalent of the taken current fire loads is added to the cumulative load recovery impact equivalent of the current input group. When the cumulative load recovery impact equivalent of the current input group is less than or equal to the bus allowable voltage drop impact threshold, the current fire load is assigned to the current input group. When the cumulative load recovery impact equivalent of the current input group is greater than the allowable voltage drop impact threshold of the bus, the division of the current input group ends, the current fire load is taken as the first fire load of the next input group, and the cumulative load recovery impact equivalent of the next input group is initialized to the load recovery impact equivalent of the current fire load. The remaining fire loads in the recovery sequence are processed in sequence until all fire loads are assigned to the corresponding input group. The resulting multiple input groups are arranged in the order of division. For two adjacent input groups, an inter-group delay is generated between the completion of the recovery of the previous input group and the start of the recovery of the next input group. The inter-group delays are then concatenated to obtain the delayed input sequence.

[0094] In one embodiment, the switching execution module 15 is further configured to collect the effective value of the main power supply voltage. When the effective value of the main power supply voltage is lower than a preset power failure determination threshold and the duration reaches a preset power failure confirmation time, the main power supply is determined to be in power failure. After determining that the main power supply has failed, a closing command is sent to the backup power circuit breaker to put the backup power supply into use. After the backup power supply is switched on, the fire loads in each subsequent power-on group are restored in sequence according to the order of delay between each group in the delay power-on sequence, until the fire loads in all power-on groups are restored to power.

[0095] In one embodiment, the threshold adjustment module 16 is further configured to collect the bus voltage sag value after the switching execution is completed, wherein the bus voltage sag value is the maximum drop in bus voltage relative to rated voltage during the standby power supply commissioning process. Obtain the estimated maximum bus voltage drop value before switching. The estimated maximum bus voltage drop value before switching is calculated based on the maximum value of the cumulative load recovery impact equivalent in each of the input groups and the preset voltage drop conversion coefficient before switching is executed. The bus voltage sag is compared with the estimated maximum bus voltage drop before the switchover. When the bus voltage sag is greater than the estimated maximum bus voltage drop before the switchover, the allowable bus voltage drop impact threshold is adjusted based on the switching and recovery priority of all fire loads in the input group that actually caused the maximum voltage drop. When the bus voltage sag is less than or equal to the estimated maximum bus voltage drop before the switchover, the preset allowable bus voltage drop threshold is increased by a preset adjustment step size.

[0096] Obtain the switching recovery priority value of all fire loads in the input group that actually causes the maximum pressure drop during the switching process, and calculate the arithmetic mean of the switching recovery priority values ​​of all fire loads in the input group as the average priority value of the high-impact group. When the average priority value of the high-impact group is greater than the preset high-priority threshold, it is determined that the voltage drop is caused by the concentrated input of high-priority loads, and the preset bus allowable voltage drop impact threshold is increased according to the preset adjustment step size. When the average priority value of the high-impact group is less than or equal to the preset high-priority threshold, it is determined that the voltage drop is caused by the dispersed input of low-priority loads, and the preset bus allowable voltage drop impact threshold is reduced according to the preset adjustment step size.

Claims

1. A dual-power automatic switching control method for a hydropower station fire protection system, characterized in that, include: Obtain the rated power, starting current multiple, impedance per unit length of power supply line, power supply voltage, and line length from the load to the dual power supply switching device for each fire load, and calculate the load recovery impact equivalent for each fire load. The basic weight of the equipment is determined based on the fire linkage role of the fire load, and the regional state coefficient is determined based on the current environmental state. The fire linkage urgency of each fire load is obtained by combining the analysis. Based on the load recovery impact equivalent and the urgency of fire linkage for each of the aforementioned fire loads, the switching and restoration priority value for each of the aforementioned fire loads is determined; The fire loads are sorted from high to low according to the switching and restoration priority value. With the cumulative load restoration impact equivalent not exceeding the preset bus allowable voltage drop impact threshold as a constraint, the sorted fire loads are divided into multiple input groups, and a delayed input sequence is generated between each group. After detecting a main power failure, the backup power supply is activated, and the fire load in each activation group is restored sequentially according to the delayed activation sequence. After the switching operation is completed, the bus voltage sag value is collected, and the bus voltage sag value is compared with the estimated maximum bus voltage drop value before the switching. The preset bus voltage drop impact threshold is adjusted according to the comparison result.

2. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 1, characterized in that, The process of obtaining the rated power, starting current multiple, impedance per unit length of the power supply line, power supply voltage, and line length from the load to the dual-power switching device for each fire load, and calculating the load recovery impact equivalent for each fire load, includes: Obtain the rated power, supply voltage, and line length from the load of each fire-fighting load to the dual-power switching device; Obtain the starting current multiple of each of the fire loads. The starting current multiple is the ratio of the effective value of the current of the fire load at the moment of startup to the effective value of the rated current. For non-motor fire loads, the starting current multiple is taken as one. Obtain the impedance per unit length of the power supply line for each of the fire-fighting loads, wherein the impedance per unit length of the power supply line is the impedance modulus per unit length of the power supply line where the fire-fighting load is located. The rated current of each fire-fighting load is multiplied by the starting current multiple to obtain the impact current value; Multiplying the inrush current value by the product of the impedance per unit length of the power supply line and the line length of the load from the dual power supply switching device, the line voltage drop value of the fire load is obtained, which is used as the load recovery impact equivalent of the fire load.

3. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 1, characterized in that, The process of determining the basic weight of equipment based on the fire linkage role of the fire load, determining the area state coefficient based on the current environmental state, and obtaining the fire linkage urgency of each fire load through analysis includes: Obtain the fire linkage role of each fire load. The fire linkage role is the linkage function positioning of the fire load in the hydropower station fire protection system. The fire linkage role includes sensing and alarm type, linkage control type, fire extinguishing execution type and auxiliary support type. Obtain the current environmental status of each fire protection zone where the fire load is located, and determine the area status coefficient based on the current environmental status; The basic weight of each fire load is determined according to the fire linkage role, wherein the basic weight of the fire extinguishing execution equipment is greater than the basic weight of the sensing alarm equipment, the basic weight of the sensing alarm equipment is greater than the basic weight of the linkage control equipment, and the basic weight of the linkage control equipment is greater than the basic weight of the auxiliary support equipment. The basic weights of the equipment for each of the fire loads are corrected using the regional state coefficients to obtain the fire linkage urgency of the fire loads.

4. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 1, characterized in that, The step of obtaining the current environmental status of each fire protection zone where the fire load is located, and determining the area status coefficient based on the current environmental status, includes: Obtain the temperature, smoke concentration, and carbon monoxide concentration values ​​within the fire compartment where each of the aforementioned fire loads is located; Obtain the trend values ​​of the temperature, smoke concentration, and carbon monoxide concentration within a preset time period; According to the preset fire risk level classification rules, the basic fire risk level is determined based on the temperature value, the smoke concentration value, and the carbon monoxide concentration value. When the trend of change of at least two of the temperature value, the smoke concentration value and the carbon monoxide concentration value is greater than the preset trend increase threshold, the basic fire risk level will be raised by one level. When the trend values ​​of the temperature value, the smoke concentration value, and the carbon monoxide concentration value are all less than or equal to the preset trend increase threshold, the basic fire risk level is maintained. Based on the final fire risk level, the corresponding regional state coefficient is obtained from the preset regional state coefficient mapping table.

5. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 1, characterized in that, The method of determining the switching and restoration priority value of each fire load by comprehensively considering the load restoration impact equivalent and the urgency of fire linkage for each fire load includes: Obtain the load recovery impact equivalent of each fire load, and take the maximum value among all the load recovery impact equivalents of the fire loads as the reference value of the maximum impact equivalent; The load recovery impact equivalent of each fire load is normalized based on the maximum impact equivalent reference value to obtain the load recovery impact normalized value of the fire load. Based on the urgency of fire linkage for each fire load and the normalized value of the load recovery impact of each fire load, the switching and recovery priority value of each fire load is calculated and obtained.

6. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 1, characterized in that, The process involves sorting the fire loads from highest to lowest according to their switching and restoration priority values, and, with the cumulative load restoration impact equivalent not exceeding a preset busbar allowable voltage drop impact threshold as a constraint, dividing the sorted fire loads into multiple activation groups and generating a delayed activation sequence between each group, including: Obtain the preset allowable voltage drop impact threshold for the busbar; The fire loads are sorted in descending order of their switching and restoration priority to obtain a restoration sequence. The fire loads are sequentially taken from the recovery sequence, and the load recovery impact equivalent of the taken current fire loads is added to the cumulative load recovery impact equivalent of the current input group. When the cumulative load recovery impact equivalent of the current input group is less than or equal to the bus allowable voltage drop impact threshold, the current fire load is assigned to the current input group. When the cumulative load recovery impact equivalent of the current input group is greater than the allowable voltage drop impact threshold of the bus, the division of the current input group ends, the current fire load is taken as the first fire load of the next input group, and the cumulative load recovery impact equivalent of the next input group is initialized to the load recovery impact equivalent of the current fire load. The remaining fire loads in the recovery sequence are processed in sequence until all fire loads are assigned to the corresponding input group. The resulting multiple input groups are arranged in the order of division. For two adjacent input groups, an inter-group delay is generated between the completion of the recovery of the previous input group and the start of the recovery of the next input group. The inter-group delays are then concatenated to obtain the delayed input sequence.

7. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 1, characterized in that, The step of switching on backup power after detecting a main power failure and restoring the fire load in each switching group sequentially according to the delayed switching sequence includes: Collect the effective value of the main power supply voltage. When the effective value of the main power supply voltage is lower than the preset power failure judgment threshold and the duration reaches the preset power failure confirmation time, the main power supply is determined to be in failure. After determining that the main power supply has failed, a closing command is sent to the backup power circuit breaker to put the backup power supply into use. After the backup power supply is switched on, the fire loads in each subsequent power-on group are restored in sequence according to the order of delay between each group in the delay power-on sequence, until the fire loads in all power-on groups are restored to power.

8. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 1, characterized in that, After the switching operation is completed, the bus voltage sag value is collected, and the bus voltage sag value is compared with the estimated maximum bus voltage drop value before the switching. Based on the comparison result, the preset allowable bus voltage drop impact threshold is adjusted, including: After the switchover is completed, the bus voltage sag value is collected, wherein the bus voltage sag value is the maximum drop in bus voltage relative to rated voltage during the standby power supply activation process; Obtain the estimated maximum bus voltage drop value before switching. The estimated maximum bus voltage drop value before switching is calculated based on the maximum value of the cumulative load recovery impact equivalent in each of the input groups and the preset voltage drop conversion coefficient before switching is executed. The bus voltage sag is compared with the estimated maximum bus voltage drop before the switchover. When the bus voltage sag is greater than the estimated maximum bus voltage drop before the switchover, the allowable bus voltage drop impact threshold is adjusted based on the switching and recovery priority of all fire loads in the input group that actually caused the maximum voltage drop. When the bus voltage sag is less than or equal to the estimated maximum bus voltage drop before the switchover, the preset allowable bus voltage drop threshold is increased by a preset adjustment step size.

9. The dual-power automatic switching control method for a hydropower station fire protection system according to claim 8, characterized in that, When the bus voltage sag is greater than the estimated maximum bus voltage drop before the switchover, the allowable bus voltage drop impact threshold is adjusted based on the switching and recovery priority of all fire loads in the activated group that actually caused the maximum voltage drop, including: Obtain the switching recovery priority value of all fire loads in the input group that actually causes the maximum pressure drop during the switching process, and calculate the arithmetic mean of the switching recovery priority values ​​of all fire loads in the input group as the average priority value of the high-impact group. When the average priority value of the high-impact group is greater than the preset high-priority threshold, it is determined that the voltage drop is caused by the concentrated input of high-priority loads, and the preset bus allowable voltage drop impact threshold is increased according to the preset adjustment step size. When the average priority value of the high-impact group is less than or equal to the preset high-priority threshold, it is determined that the voltage drop is caused by the dispersed input of low-priority loads, and the preset bus allowable voltage drop impact threshold is reduced according to the preset adjustment step size.

10. A dual-power automatic switching control device for a hydropower station fire protection system, characterized in that, For implementing the dual-power automatic switching control method for a hydropower station fire protection system according to any one of claims 1 to 9, the apparatus comprises: The load recovery impact equivalent calculation module is used to obtain the rated power, starting current multiple, power supply line impedance per unit length, power supply voltage, and line length from the load to the dual power supply switching device for each fire load, and to calculate the load recovery impact equivalent for each fire load. The fire linkage urgency determination module is used to determine the basic weight of equipment based on the fire linkage role of the fire load, determine the area state coefficient based on the current environmental state, and obtain the fire linkage urgency of each fire load through analysis. The switching and recovery priority determination module is used to determine the switching and recovery priority value of each fire load by comprehensively considering the load recovery impact equivalent and the urgency of fire linkage for each fire load. The module for dividing the fire loads into input groups and generating the timing sequence is used to sort each fire load from high to low according to the switching and recovery priority value, and to divide the sorted fire loads into multiple input groups with the constraint that the cumulative load recovery impact equivalent does not exceed the preset bus allowable voltage drop impact threshold, and to generate the delayed input timing sequence between each group. The switching execution module is used to switch to the backup power supply after detecting a main power failure, and to restore the fire load in each power-on group in sequence according to the delayed power-on sequence. The threshold adjustment module is used to collect the bus voltage sag value after the switching is completed, compare the bus voltage sag value with the estimated maximum bus voltage drop value before the switching, and adjust the preset bus allowable voltage drop impact threshold according to the comparison result.

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