A method for regulating the active power of a hydropower station using a secondary frequency modulation amplification gain

Abstract

The present invention discloses a method for regulating the active power of a hydropower station using amplified gain with secondary frequency regulation. When the hydropower station receives a secondary frequency regulation instruction and all judgment conditions are met, all hydropower units participating in the secondary frequency regulation perform amplified gain regulation in the same direction as the secondary frequency regulation instruction: within the gain regulation time threshold, each unit amplifies and updates the single-unit active power setting value based on the single-unit active power distribution value by the same direction of regulation, and the amplification amount is the single-unit active power regulation dead zone multiplied by a set proportional parameter. Under the amplified gain regulation mechanism of the present invention, the more units in the power generation state, the more units participating in the secondary frequency regulation, and the faster the regulation rate. Therefore, compared with the currently commonly used active power regulation method, the present invention can better meet the dispatcher's expectation that the regulation rate is positively correlated with the rated capacity of the power station.

Description

Technical Field

[0001] The invention relates to the technical field of power system automation control, in particular to a method for regulating the active power of a hydropower station through amplified gain with secondary frequency modulation. Background Art

[0002] Grid frequency reflects the balance between power generation and power consumption in the power system. When power generation exceeds power consumption, the grid frequency is above the rated frequency (50Hz). When power generation is lower than power consumption, the grid frequency is lower than the rated frequency. Using the grid frequency as a reference indicator, the power system adjusts power generation and power consumption to bring them back into balance. This regulation primarily involves primary and secondary frequency regulation of power generation.

[0003] Secondary frequency regulation refers to the process whereby, when the grid frequency deviates from the rated frequency by more than the secondary frequency regulation threshold, the dispatcher adjusts the output active power of each grid-connected power station within the control range to restore the grid's generated power and consumed power to a balanced state, ensuring that the difference between the grid frequency and the rated frequency is within the permissible range. This entire process is called secondary frequency regulation. Secondary frequency regulation includes the following steps: 1) The dispatcher calculates the required change in generated power to restore the grid frequency to the rated frequency based on the grid frequency deviation and the grid's "frequency-power" sensitivity coefficient; 2) The dispatcher modifies the active power set values of each grid-connected power station within the control area based on the calculation results and issues power adjustment instructions; 3) After receiving the new active power set value, the AGC distributes the total active power set value of the power station to each unit controlled by the AGC; 4) The active power control system of each unit performs closed-loop feedback adjustment on the unit's active power based on the new single-unit active power set value.

[0004] From the entire secondary frequency regulation process described above, we can see that three key factors influence the quality of secondary frequency regulation: 1) the dispatcher's accurate calculation of the secondary frequency regulation amount; 2) the dispatcher's reasonable allocation of the secondary frequency regulation amount; and 3) the power plant's accurate and rapid execution of the dispatcher's secondary frequency regulation instructions. The first two factors are directly controlled by the dispatcher, while the last is constrained by the power plant's professional expertise and operational management level. To address this issue, the dispatcher implements a series of measures, such as the "Two Detailed Rules" and the "Frequency Regulation Market," to indirectly manage the power plant's secondary frequency regulation performance through metrics. These metrics include regulation delay, regulation rate, and regulation accuracy. Regulation delay reflects the lag between the dispatcher issuing the secondary frequency regulation instruction and the actual change in the power plant's active power. Regulation rate reflects the magnitude of the change in the power plant's active power per unit time during the regulation process. Regulation accuracy reflects the deviation between the power plant's actual active power and the setpoint value issued by the dispatcher after the regulation is completed.

[0005] In order to meet the dispatching management requirements for the secondary frequency regulation quality of power stations, document 1 "A method for controlling the active power output of automatic power generation in a hydropower station" (application publication number CN105914795A), document 2 "A method for preprocessing parameters of automatic power generation active power output control in a hydropower station" (application publication number CN105811473A), document 3 "A method for distributing active power of AGC in a hydropower station based on the combined output model of units" (application publication number CN105870979A), document 4 "A method for modeling a multi-unit combination of hydropower units with multiple operating areas" (application publication number CN106056236A), document 5 "A method for considering complex approximations" (application publication number CN106056236A), document 6 "A method for controlling the active power output of automatic power generation in a hydropower station" (application publication number CN105811473A), document 7 "A method for controlling the active power output of automatic power generation in a hydropower station based on the combined output model of units" (application publication number CN105870979A), document 8 "A method for modeling a multi-unit combination of hydropower units with multiple operating areas" (application publication number CN106056236A), document 9 "A method for modeling a multi-unit combination of hydropower units with multiple operating areas" (application publication number CN106056236A), document 10 "A method for modeling a multi-unit combination of hydropower units with multiple operating areas" (application publication number CN106056236A), document 11 "A method for modeling a multi-unit combination of hydropower units with multiple operating areas" (application publication number CN106056236A), document 12 "A method for modeling a multi-unit combination of hydropower units with multiple operating areas" (application publication number CN106056236A), document 13 Reference 6 "AGC Control Strategy for Hydropower Station with a Single Advisory Bundle" (Proceedings of the Chinese Society of Electrical Engineering, Vol. 37, No. 19), Reference 7 "AGC Algorithm Design and Regulation Performance Evaluation of Hydropower Plants in the Southern Power Grid" (Hydropower and Pumped Storage, Vol. 3, No. 5), Reference 7 "A Method for Active Power Control of Hydropower Units in a Single Advisory Operation Area" (Application Publication No. CN111740452B), and Reference 8 "A Method for Active Power Control of Hydropower Units in a Dual Advisory Operation Area" (Application Publication No. CN111654068B) analyze and study the regulation mechanism of active power of hydropower stations from different perspectives, and their results can meet the operational requirements of dispatching for secondary frequency regulation of hydropower stations under most operating conditions.

[0006] However, the aforementioned literature fails to address the following issue: the dispatcher's expectation of a power plant's secondary frequency regulation rate is positively linearly correlated with the total rated capacity of the plant's generating units. This means that larger rated capacities are expected to provide higher secondary frequency regulation rates. At the same time, due to the closed-loop nature of hydropower plant active power regulation, a deadband must be set to ensure that active power regulation can reach a achievable end condition. This conflict arises when, in a power plant with a large number of operating units and a small secondary frequency regulation amount issued by the dispatcher, the power plant allocates the secondary frequency regulation amount to multiple units for regulation. This can cause the individual active power setpoints of each unit to vary too little, potentially leaving the actual active power output of each unit within the deadband of the setpoint. This can lead to the failure or even weakening of the secondary frequency regulation effect. Alternatively, if the power plant allocates the secondary frequency regulation amount to a single unit, most units will be unable to participate in the secondary frequency regulation, similarly resulting in a significant deviation between the secondary frequency regulation rate and the dispatcher's expectations, thus reducing secondary frequency regulation performance. The manifestation of this problem in engineering practice is that from mid-July to mid-November each year, the secondary frequency regulation performance, especially the regulation rate, of the hydropower stations in the Lancang River Basin shows a significant decline to varying degrees.

[0007] Therefore, how to effectively control all hydropower station units in power generation to participate in secondary frequency regulation when there are a large number of hydropower stations in operation and the adjustment amount of the dispatching secondary frequency regulation instructions is small, or control some hydropower units in power generation to participate in secondary frequency regulation at a faster rate to meet the dispatching performance requirements for the power station's secondary frequency regulation rate, adjustment delay, and adjustment accuracy, is still a problem to be solved. Summary of the Invention

[0008] The present invention provides a method for regulating the active power of a hydropower station by amplifying gain with secondary frequency modulation. When a dispatching secondary frequency modulation instruction is received, the method can control the hydropower generating units to perform amplifying gain adjustment in the same direction as the secondary frequency modulation instruction within the time threshold of the gain adjustment, so as to achieve a higher regulation rate, a lower regulation delay and a better regulation accuracy.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A method for regulating the active power of a hydropower station using amplified gain in secondary frequency regulation is disclosed. When the hydropower station receives a secondary frequency regulation command, it determines whether the secondary frequency regulation to be performed meets the time interval threshold T, whether the regulation amplitude exceeds a certain proportion of the total rated capacity, and whether the current active power operation range of the AGC hydropower units meets the secondary frequency regulation command. A secondary frequency regulation gain adjustment flag is set to reflect the judgment result. When all the judgment conditions are met, all hydropower units participating in the secondary frequency regulation perform amplified gain adjustment in the same direction as the secondary frequency regulation command.

[0011] The difference between the plant-wide active power setting value of the secondary frequency regulation instruction and the original plant-wide active power setting value of the hydropower station is evenly distributed to each hydropower unit participating in the secondary frequency regulation to obtain the secondary frequency regulation adjustment amount; then, combined with the original single-unit active power distribution value, the single-unit active power distribution value of each unit is obtained and distributed to each unit;

[0012] Within the gain adjustment time threshold T1, which is shorter than the time interval threshold T, each unit amplifies and updates the single-unit active power setting value in the same direction based on the single-unit active power distribution value. The amplification amount is the single-unit active power adjustment dead zone multiplied by the set proportional parameter.

[0013] Each unit performs closed-loop regulation of the active power of the unit according to the updated active power setting value of the unit; when the amplified gain adjustment time reaches the gain adjustment time threshold, the current active power setting value of the unit is set as the active power distribution value of the unit.

[0014] The single-unit active power distribution value of each unit is distributed through the following operations:

[0015] S3100) Calculate the active power distribution value of each hydropower unit

[0016] S3110) Subtracting the original full-plant active power setting value of the hydropower station from the full-plant active power setting value of the secondary frequency modulation instruction to obtain a difference △P between the two;

[0017] S3120) Calculate the secondary frequency regulation value △p allocated to unit i i :

[0018] S3121) If △P is greater than 0, then △p i It is equal to △P divided by the number of units that are in AGC control, in power generation state, and whose single-unit active power setting value is less than the upper limit of the active power operation area;

[0019] S3122) If △P is less than 0, then △p i It is equal to △P divided by the number of units that are in AGC control, in power generation state, and whose single-unit active power setting value is greater than the lower limit of the active power operation zone;

[0020] S3130) Active power distribution value of each unit Perform the calculation:

[0021] S3131) If the secondary frequency regulation value of unit i is △p i >0, the active power distribution value of the unit =min(the original single-unit active power distribution value of the unit + the single-unit secondary frequency regulation value △p i , the upper limit of the active power operation area of the unit);

[0022] S3132) If the secondary frequency regulation value of unit i is △p i <0, the active power distribution value of the unit = max(the original active power distribution value of the unit + the secondary frequency regulation value of the unit △p i , the lower limit of the active power operation area of the unit);

[0023] S3140) summing the active power distribution values of each unit to obtain an updated original active power setting value for the entire hydropower station;

[0024] S3150) Based on the updated original active power setting value of the hydropower station, ΔP is recalculated in the manner described in S3110:

[0025] S3151) If ΔP is not equal to 0, jump to step S3120 to distribute and calculate the secondary frequency modulation adjustment amount again;

[0026] S3152) If △P is equal to 0, the calculation of the distribution of the secondary frequency regulation amount is completed, and the single unit active power distribution value of each hydropower unit is obtained.

[0027] S3200) distributes the active power of each hydropower unit to Sent to the AGC control system of each unit.

[0028] Each unit performs amplified gain adjustment in the same direction as the secondary frequency modulation instruction through the following operations based on the received single-unit active power distribution value:

[0029] S3310) Setting a gain adjustment time threshold T1 that is less than the time interval T;

[0030] If the judgment conditions for the secondary frequency modulation gain adjustment are met, the secondary frequency modulation gain adjustment flag α is set to 1; otherwise, the secondary frequency modulation gain adjustment flag α is set to 0;

[0031] S3320) Setting timer C2 to count the adjustment time of the amplified gain adjustment:

[0032] S3321) If α=1, start timer C2 for timing;

[0033] S3322) If α=0, stop and clear the reset timer C2;

[0034] S3330) Each unit adjusts the secondary frequency gain according to the marker α and the received single unit active power distribution value. Update the active power setting value of a single machine

[0035] S3331) If α=1 and Greater than the current Update for

[0036] S3332) If α=1 and Less than the current Update for

[0037] in is the dead zone of active power regulation of unit i, and k3 is a manually set proportional parameter greater than or equal to 1;

[0038] S3333) If α=0, then Set to

[0039] S3340) Each AGC system operation cycle takes the time t2 of timer C2, and when t2 is greater than or equal to the gain adjustment time threshold T1, updates for At the same time, the timing of timer C2 is stopped and reset; and the secondary frequency modulation gain adjustment flag α is set to 0;

[0040] Each unit is based on the updated single unit active power setting value Perform closed-loop regulation of the active power of a single machine.

[0041] Compared with the prior art, the present invention has the following beneficial technical effects:

[0042] 1. The amplified gain regulation of the present invention allows all hydropower generating units in the generating state to perform gain regulation of the amplified regulation amount in the same direction as the secondary frequency regulation instruction within a shorter period of time. Furthermore, the amplification of the active power regulation amount by each hydropower station unit is calculated based on the dead zone of the active power regulation of each unit and a manually set proportional parameter. Therefore, the more hydropower generating units in the generating state, the more hydropower generating units will participate in the secondary frequency regulation, and the more significant the amplification of the active power regulation of the hydropower station will be. Furthermore, the problem of the dead zone of the active power regulation of each hydropower unit weakening the sensitivity of power regulation is avoided or suppressed.

[0043] Under the mechanism of amplified gain regulation, the more units in the power generation state, the more units participating in the secondary frequency regulation, and the faster the regulation rate. Therefore, compared with the currently commonly used active power regulation method, the present invention can better meet the dispatcher's expectation that the regulation rate is positively correlated with the rated capacity of the power station.

[0044] 2. The present invention sets strict startup regulation for the secondary frequency modulation gain regulation. The secondary frequency modulation gain regulation is performed only when the secondary frequency modulation regulation instruction is received for the first time, the secondary frequency modulation regulation amplitude is small, and no hydropower unit needs to change the operating range. This can effectively avoid the possible conflict between the logic of the present invention and other conventional logics of the active power regulation function of the hydropower station, thereby improving the safety and easy promotion of the present invention.

[0045] 3. The present invention sets up a secondary frequency modulation calibration adjustment link, which can effectively avoid the problem of decreased regulation accuracy caused by the increase in regulation rate, and further reduce the regulation error on the basis of the active power regulation function of the original hydropower station. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A simulation model of the amplified gain adjustment of the present invention;

[0047] Figure 2 A logic flow chart of the amplified gain adjustment of the present invention;

[0048] Figure 3 A comparative simulation model is provided for the amplified gain regulation of the present invention and the conventional active closed-loop regulation;

[0049] Figure 4 This is a comparison diagram of the simulated adjustment effects of the amplified gain adjustment of the present invention and the conventional active closed-loop adjustment;

[0050] Figure 5 This is the second comparison diagram of the simulated adjustment effects of the amplified gain adjustment of the present invention and the conventional active closed-loop adjustment;

[0051] Figure 6 A logic flow chart of the secondary frequency modulation calibration adjustment of the present invention;

[0052] Figure 7 A simulation model for the secondary frequency modulation calibration adjustment of the present invention;

[0053] Figure 8 It is the simulation adjustment effect of the active power setting value of a single machine with secondary frequency regulation conventional adjustment supplemented by secondary frequency regulation calibration adjustment;

[0054] Figure 9 It is the simulation adjustment effect of the active power value of a single machine with the secondary frequency regulation conventional adjustment supplemented by the secondary frequency regulation calibration adjustment;

[0055] Figure 10 It is a simulation adjustment effect of the total plant active power value with secondary frequency regulation conventional adjustment supplemented by secondary frequency regulation calibration adjustment. DETAILED DESCRIPTION

[0056] The present invention will be described in further detail below with reference to the accompanying drawings.

[0057] The simulation modeling of amplified gain adjustment is as follows Figure 1 As shown, in the model, T y is the servomotor response time constant; T w is the water flow inertia time constant; T a is the unit (load) inertia time constant; T f To adjust the feedback delay, reflect the synchronization delay between the output power and the PID adjustment signal, mainly including the output power measurement, transmission time and PID operation time; n It is the unit (load) static frequency self-regulation (characteristic) coefficient.

[0058] Reference Figure 1 The present invention provides a method for regulating the active power of a hydropower station using amplified gain of secondary frequency modulation. Upon receiving a secondary frequency modulation command, the hydropower station determines whether the secondary frequency modulation to be performed meets the time interval threshold T, whether the modulation amplitude exceeds a certain proportion of the total rated capacity, and whether the current active power operation range of the AGC hydropower generating units meets the secondary frequency modulation command. The method then sets a secondary frequency modulation gain adjustment flag to reflect the judgment result. When all the judgment conditions are met, all hydropower generating units participating in the secondary frequency modulation perform amplified gain adjustment in the same direction as the secondary frequency modulation command.

[0059] The difference between the plant-wide active power setting value of the secondary frequency regulation instruction and the original plant-wide active power setting value of the hydropower station is evenly distributed to each hydropower unit participating in the secondary frequency regulation to obtain the secondary frequency regulation adjustment amount; then, combined with the original single-unit active power distribution value, the single-unit active power distribution value of each unit is obtained and distributed to each unit;

[0060] Within the gain adjustment time threshold T1, which is shorter than the time interval threshold T, each unit amplifies and updates the single-unit active power setting value in the same direction based on the single-unit active power distribution value. The amplification amount is the single-unit active power adjustment dead zone multiplied by the set proportional parameter.

[0061] Each unit performs closed-loop regulation of the active power of the unit according to the updated active power setting value of the unit; when the amplified gain adjustment time reaches the gain adjustment time threshold, the current active power setting value of the unit is set as the active power distribution value of the unit.

[0062] The following is a detailed description of the secondary FM gain adjustment judgment and secondary FM gain adjustment method.

[0063] The method for regulating the active power of a hydropower station by amplifying gain with secondary frequency modulation provided by the present invention can be performed by the following steps:

[0064] S1000) determining whether gain adjustment is required for the secondary frequency modulation instruction, including:

[0065] S1100) Setting a time interval threshold T for starting secondary FM gain adjustment;

[0066] S1200) Upon receiving the secondary frequency modulation instruction, calculating the time interval between the secondary frequency modulation instruction and the last secondary frequency modulation instruction, including:

[0067] S1210) Setting a timer C1 for continuous timing;

[0068] S1220) Each time a new secondary frequency modulation instruction is received, the following operations are performed:

[0069] S1221) reading the time t1 of the timer C1, where t1 is the time interval between the last secondary frequency modulation instruction;

[0070] S1222) Reset timer C1.

[0071] S1300) Calculating the adjustment amplitude threshold for starting secondary frequency modulation gain adjustment, including:

[0072] S1310) Setting a ratio k1 of the adjustment amplitude threshold to the total rated capacity, where k1 is set to be greater than or equal to the active power adjustment accuracy of the hydropower station, and in this embodiment, it is assumed to be 2%;

[0073] S1320) Calculating the total rated capacity of the hydropower station's generating units in the generating state. The total rated capacity is equal to the sum of the rated capacities of the hydropower units in the generating state at the current water head. Assuming that two generating units in the power station are in the generating state, with rated capacities of 300 MW and 200 MW, respectively, the total rated capacity of the generating units in the hydropower station is 500 MW.

[0074] S1330) The adjustment amplitude threshold of the secondary frequency regulation gain adjustment is equal to the total rated capacity of the units in the power generation state of the hydropower station multiplied by k1. Assuming k1 is 2% and the total rated capacity of the units in the power generation state of the hydropower station is 500MW, the adjustment amplitude threshold of the secondary frequency regulation gain adjustment is equal to 500×2%=10MW.

[0075] S1400) Calculating whether the adjustment amplitude of the secondary frequency modulation adjustment instruction exceeds the adjustment amplitude threshold calculated in S1300, including:

[0076] S1410) Calculate the absolute value of the deviation between the plant-wide active power set value of the secondary frequency regulation instruction and the original plant-wide active power set value of the hydropower station. Assuming that the dispatcher issues the secondary frequency regulation instruction for the new plant-wide active power set value of the hydropower station as 1200MW, and the plant-wide active power set value of the hydropower station before receiving the secondary frequency regulation instruction is 1000MW, then the absolute value of the deviation between the two is 200MW;

[0077] S1420) Calculate the absolute value of the deviation between the plant-wide active power set value of the secondary frequency regulation instruction and the plant-wide active power output value of the hydropower station. Assuming that the secondary frequency regulation instruction issued by the dispatcher is a new plant-wide active power set value of 1200MW for the hydropower station, and the plant-wide active power output value of the hydropower station when receiving the secondary frequency regulation instruction is 990MW, the absolute value of the deviation between the two is 210MW;

[0078] S1430) If the results obtained in S1410 and S1420 are both greater than the adjustment amplitude threshold calculated in S1300, it is considered that the adjustment amplitude of the secondary frequency modulation adjustment instruction exceeds the adjustment amplitude threshold;

[0079] S1440) If the result obtained in S1410 or S1420 is less than or equal to the adjustment amplitude threshold calculated in S1300, it is considered that the adjustment amplitude of the secondary frequency modulation adjustment instruction does not exceed the adjustment amplitude threshold.

[0080] S1500) Determining whether the current active power operation range of each AGC hydropower unit meets the secondary frequency regulation instruction, including:

[0081] S1510) The active power setting values of each hydropower unit not put into AGC control are accumulated and summed. Assuming that there are two units not put into AGC control, and the active power setting values of each unit are 200MW and 250MW respectively, the sum of the active power setting values of each hydropower unit not put into AGC control is 450MW;

[0082] S1520) The upper limit values of the active power operation ranges of the hydropower generating units put into AGC control are accumulated and summed. Assuming that there are three units put into AGC control, and the upper limits of the active power operation ranges are 250MW, 250MW, and 600MW, respectively, the result of the accumulated sum of the upper limit values is 1100MW;

[0083] S1530) The lower limit values of the active power operation ranges of the hydropower units put into AGC control are accumulated and summed. Assuming that there are three units put into AGC control, and the lower limits of the active power operation ranges are 100MW, 100MW, and 400MW, respectively, the result of the accumulated sum of the upper limits is 600MW;

[0084] S1540) adding the result obtained in S1510 and the result obtained in S1520 to obtain the upper limit threshold of secondary frequency regulation of the hydropower station without changing the active power operation zone constraint of the unit. According to the assumptions in S1510 and S1520, the upper limit threshold of secondary frequency regulation of the hydropower station without changing the active power operation zone constraint of the unit is 1550MW;

[0085] S1550) adding the result obtained in S1510 and the result obtained in S1530 to obtain the lower limit threshold of the secondary frequency regulation of the hydropower station without changing the active power operation zone constraint of the unit. According to the assumptions in S1510 and S1530, the lower limit threshold of the secondary frequency regulation of the hydropower station without changing the active power operation zone constraint of the unit is 1050MW;

[0086] S1560) If the secondary frequency regulation instruction is less than or equal to the upper threshold obtained in S1540 and greater than or equal to the lower threshold obtained in S1550, then the current active power operation range of each AGC hydropower unit meets the secondary frequency regulation instruction;

[0087] S1540) If the secondary frequency regulation instruction is greater than the upper threshold obtained in S1540, or less than the lower threshold obtained in S1550, the current active power operation range of each AGC hydropower unit does not meet the secondary frequency regulation instruction.

[0088] According to the S1500 logic, if the current active power operating range of each hydropower station unit does not meet the dispatch secondary frequency regulation instruction, even if the secondary frequency regulation instruction's adjustment range is extremely small, the secondary frequency regulation gain adjustment will not be triggered. This logic is implemented because, if a unit's active power operating range changes when the secondary frequency regulation adjustment range is extremely small, the individual active power setpoints of the units whose active power operating ranges change will undergo a significant change, and this change will inevitably exceed the adjustment range of the secondary frequency regulation instruction. Therefore, to prevent overshoot, the individual active power setpoints of the other units whose active power operating ranges do not change need to be changed in the opposite direction to ensure that the sum of the individual active power setpoints of each unit is equal to the secondary frequency regulation instruction received by the hydropower station, resulting in extremely complex regulation conditions. In this case, introducing the relevant logic mechanism for secondary frequency regulation gain adjustment may lead to unforeseen regulation conflicts or other abnormal situations. Therefore, it is necessary to implement the S1500 logic to determine whether the current active power operating range of each AGC hydropower unit meets the secondary frequency regulation instruction as a constraint for secondary frequency regulation gain adjustment.

[0089] S1600) Determining whether the conditions for secondary frequency modulation gain adjustment are met, including:

[0090] S1610) As described in S1400, determining whether the adjustment amplitude of the secondary frequency modulation adjustment instruction exceeds the adjustment amplitude threshold; if it does not exceed, this condition is met; otherwise, this condition is not met;

[0091] S1620) determining whether the time interval t1 between the secondary frequency modulation instruction obtained in S1200 and the previous secondary frequency modulation instruction exceeds the time interval threshold T described in S1100; if it exceeds, this condition is met; otherwise, this condition is not met;

[0092] S1630) As described in S1500, determine whether the current active power operation range of each AGC hydropower unit meets the secondary frequency regulation instruction. If so, this condition is met; otherwise, this condition is not met;

[0093] S1640) If the conditions described in S1610, S1620, and S1630 are all met, then the conditions for secondary frequency modulation gain adjustment are met; otherwise, the conditions for secondary frequency modulation gain adjustment are not met.

[0094] S1700) If the conditions for secondary frequency modulation gain adjustment are not met, conventional secondary frequency modulation adjustment is performed, i.e., the hydropower station AGC distributes the adjustment amount of the secondary frequency modulation instruction to each hydropower unit under AGC control in a conventional manner, and each hydropower unit then performs conventional single-unit active power closed-loop adjustment, while setting the secondary frequency modulation gain adjustment flag α to 0;

[0095] S1800) If the conditions for secondary frequency modulation gain adjustment are met, secondary frequency modulation gain adjustment is performed according to the method of the present invention, and the secondary frequency modulation gain adjustment flag α is set to 1.

[0096] S2000) Setting amplified gain adjustment to amplify the actual adjustment amount of the closed-loop active power adjustment of a single machine in the same direction;

[0097] Through amplified gain regulation, more hydropower units can be called upon to participate in secondary frequency regulation, but this increases the logical complexity of determining the active power setting value of a single unit;

[0098] The amplified gain adjustment is described in detail below.

[0099] S3000) Figure 2 As shown, the adjustment of the amplified gain adjustment includes the following operations:

[0100] S3100) Calculate the active power distribution value of each hydropower unit

[0101] S3110) Calculating the difference ΔP between the plant-wide active power setting value of the secondary frequency regulation instruction and the original plant-wide active power setting value of the hydropower station, where ΔP is equal to the plant-wide active power setting value of the secondary frequency regulation instruction minus the original plant-wide active power setting value of the hydropower station;

[0102] S3120) Calculate the secondary frequency regulation value △p allocated to each unit i , △p i The secondary frequency regulation amount allocated to unit i includes:

[0103] S3121) If △P is greater than 0, then △p i It is equal to △P divided by the number of units that are put into AGC control, in the generating state, and whose single-unit active power setting value is less than the upper limit of the active power operation area;

[0104] S3122) If △P is less than 0, then △p i It is equal to △P divided by the number of units that are under AGC control, in the generating state, and whose single-machine active power setting value is greater than the lower limit of the active power operating area.

[0105] S3130) The active power distribution value p of each unit i AGC Perform calculations, including:

[0106] S3131) If the secondary frequency regulation value of unit i is △p i >0, the active power distribution value of the unit =min(the original single-unit active power distribution value of the unit + the single-unit secondary frequency regulation value △p i , the upper limit of the active power operation area of the unit);

[0107] S3132) If the secondary frequency regulation value of unit i is △p i <0, the active power distribution value of the unit = max(the original active power distribution value of the unit + the secondary frequency regulation value of the unit △p i , the lower limit of the active power operation area of the unit).

[0108] S3140) summing the active power distribution values of each unit to obtain an updated original active power setting value for the entire hydropower station;

[0109] S3150) Recalculate ΔP in the manner described in S3110:

[0110] S3151) If ΔP is not equal to 0, jump to step S3120 to distribute and calculate the secondary frequency modulation adjustment amount again;

[0111] S3152) If △P is equal to 0, the calculation of the distribution of the secondary frequency regulation amount is completed, and the single unit active power distribution value of each hydropower unit is obtained.

[0112] Assume that there are 5 units in the hydropower station in power generation state and all are under AGC control. The active power distribution values of each unit are 295, 290, 280, 295, and 295MW respectively. The active power operation range is 100-300MW. The newly received secondary frequency regulation instruction has a plant-wide active power setting value of 1495MW. According to the logic of S3100 of the present invention, the active power distribution value of each unit is calculated. The process is shown in the following table.

[0113] Unit / MW Before allocation First allocation Second allocation 3rd distribution Active power distribution value of unit 1 295 300 300 300 Active power distribution value of unit 2 290 298 300 300 Active power distribution value of unit 3 280 288 292.5 295 Active power distribution value of unit 4 295 300 300 300 Active power distribution value of unit 5 295 300 300 300 Active power distribution value of the whole plant 1455 1486 1492.5 1495 △P 40 9 2.5 0 Number of units that can participate in allocation 5 units 2 units 1 unit 1 unit <![CDATA[△p i ]]> 8 4.5 2.5 0

[0114] S3200) distributes the active power of each hydropower unit to Send to each unit control system;

[0115] S3300) Each unit receives the single unit active power distribution value Perform amplifier gain adjustment, including:

[0116] S3310) Setting a gain adjustment time threshold T1 for secondary FM amplification gain adjustment. The gain adjustment time threshold set in S3310 should be less than the time interval threshold T for starting secondary FM gain adjustment set in S1100.

[0117] If the judgment conditions for the secondary frequency modulation gain adjustment are met, the secondary frequency modulation gain adjustment flag α is set to 1; otherwise, the secondary frequency modulation gain adjustment flag α is set to 0;

[0118] S3320) Set timer C2 to count the adjustment time of the secondary frequency modulation amplification gain adjustment:

[0119] S3321) If α=1, start timer C2 for timing;

[0120] S3322) If α=0, stop and clear the reset timer C2;

[0121] S3330) Each unit adjusts the secondary frequency gain according to the marker α and the received single unit active power distribution value. Update the active power setting value of a single machine include:

[0122] S3331) If α=1 and Greater than the current This indicates that this frequency modulation needs to increase active power regulation, so The update further amplifies the adjustment amount, Updated to in is the dead zone of active power regulation of unit i, and k3 is a manually set proportional parameter greater than or equal to 1;

[0123] S3332) If α=1 and This indicates that this frequency regulation needs to reduce active power regulation, so The update further amplifies the adjustment amount, Updated to

[0124] S3333) If α = 0, then Updated to Make adjustments,

[0125] Each unit is based on the updated single unit active power setting value Perform closed-loop regulation of active power of a single machine;

[0126] In step S3300, all hydropower generating units in the power generation state perform amplifying gain adjustment in the same direction as the secondary frequency regulation instruction, and the amplification of active power regulation by each hydropower station unit is calculated based on the dead zone of active power regulation of each unit and the manually set proportional parameter k3. Therefore, the more hydropower generating units in the power generation state, the more hydropower generating units will participate in the secondary frequency regulation, and the more obvious the amplification of the active power regulation of the hydropower station will be, thus ensuring the positive correlation between the secondary frequency regulation rate of the power station and the rated capacity of the power station.

[0127] S3340) Each system operation cycle takes the time t2 of timer C2. When t2 is greater than or equal to the time threshold of the secondary frequency modulation amplification gain adjustment described in S3310, the timing of timer C2 is stopped and the timer C2 is reset to zero; and the timer C2 is set. At the same time, the secondary frequency modulation gain adjustment flag α is set to 0;

[0128] Whenever the active power setting value of each unit After the update, each unit performs closed-loop adjustment of the active power of each unit based on it.

[0129] In order to demonstrate the advantages of the present invention, a simulation model is constructed to compare the regulation effects of the secondary frequency modulation amplification gain regulation of the present invention and the conventional single-unit active power closed-loop regulation of the hydropower unit. Figure 3 As shown (the upper part of the figure is the existing adjustment, and the lower part is the adjustment of the present invention; by comparison, it can be seen that the present invention has added a link to amplify the adjustment amount); T in the model y is the servomotor response time constant; T w is the water flow inertia time constant; T a is the unit (load) inertia time constant; T f To adjust the feedback delay, reflect the synchronization delay between the output power and the PID adjustment signal, mainly including the output power measurement, transmission time and PID operation time; n It is the unit (load) static frequency self-regulation (characteristic) coefficient.

[0130] Assuming that the dead zone of the unit active power regulation is 10MW, k3 is 1.5, and the time threshold of the secondary frequency modulation amplification gain regulation is 4 seconds, when the regulation amount is 8MW and 15MW, the simulation regulation effect of the secondary frequency modulation amplification gain regulation and the conventional single-unit active power closed-loop regulation of the hydropower unit is compared. Figure 4 、 Figure 5 As shown, Figure 4 For the regulation effect of 8MW, Figure 5 The regulating effect is 15MW; Figure 4 、 Figure 5 It can be seen that the secondary frequency modulation amplification gain regulation of the present invention has a very obvious effect in ensuring the regulation quality and improving the regulation rate under the condition of small load regulation.

[0131] The secondary frequency modulation gain adjustment of the present invention may lead to an increase in the error within the allowable range of the adjustment accuracy, so it is necessary to perform a secondary frequency modulation calibration adjustment at the end of the secondary frequency modulation to further reduce the adjustment error and improve the adjustment accuracy.

[0132] Secondary frequency modulation calibration adjustment, its logic flow is as follows Figure 6 As shown, the simulation modeling is as follows Figure 7 As shown; T in the modely is the servomotor response time constant; T w is the water flow inertia time constant; T a is the unit (load) inertia time constant; T f To adjust the feedback delay, reflect the synchronization delay between the output power and the PID adjustment signal, mainly including the output power measurement, transmission time and PID operation time; n It is the unit (load) static frequency self-regulation (characteristic) coefficient.

[0133] S4000) performs the following operations for secondary frequency calibration:

[0134] S4100) Determine whether the time interval between the last reception of the secondary frequency modulation instruction is long enough:

[0135] S4110) Setting a time threshold for calibration adjustment, the time threshold being approximately equal to the approximate time required from the hydropower station receiving the secondary frequency regulation instruction to each hydropower unit completing the first closed-loop adjustment of the active power of the single unit;

[0136] S4120) reading the time t1 of the timer C1 set in S1200;

[0137] S4130) If t1 is greater than or equal to the calibration adjustment time threshold, continue to step S4200;

[0138] S4140) If t1 is less than the time threshold for calibration adjustment, jump back to step S4100 and execute again.

[0139] S4200) Determining whether the active power regulation of the power station is basically completed, including:

[0140] S4210) Setting a fluctuation determination threshold for completion of single-unit active power regulation, the fluctuation determination threshold being equal to a periodic variation in the actual value of the single-unit active power due to random fluctuations after the hydropower unit completes single-unit active power regulation;

[0141] S4220) Set an array containing n elements for each unit Where n is a manually set parameter;

[0142] S4230) Each AGC system cycle Perform calculations, It is equal to the absolute value of the difference between the actual active power output value of the unit i collected in this cycle and the actual active power output value of the unit i collected in the previous cycle;

[0143] S4240) Each AGC system cycle assigns the values of the elements in the array in sequence.

[0144] S4250) After n AGC system cycles, determine whether the active power of each unit is regulated, including:

[0145] S4251) Perform weighted average calculation on the array elements of unit i set in S4220

[0146] in is the jth element in the array of unit i;

[0147] Assume that the array length set by S4230 is 5, arrive They are 10MW, 10MW, 20MW, 20MW, and 10MW respectively;

[0148] The calculation result is

[0149] S4252) If the fluctuation weighted average value obtained in S4251 is less than the fluctuation judgment threshold for completing the single-machine active power regulation set in S4210, then the single-machine active power regulation of unit i is completed;

[0150] S4253) If the result obtained in S4251 is greater than or equal to the threshold for determining whether the single-machine active power regulation is complete set in S4210, the single-machine active power regulation of unit i is not complete;

[0151] S4260) If there is more than one unit that has not completed the single-machine active power regulation, jump back to step S4100 and execute again.

[0152] S4270) If no more than one unit has completed single-unit active power regulation, then:

[0153] S4271) If there is one unit that has not completed single-unit active power adjustment, then select this unit as the unit to perform calibration adjustment, and continue to step S4300;

[0154] S4272) If there are zero units that have not completed single-machine active power adjustment, calculate the absolute value of the difference between the single-machine active power setting value and the single-machine active power actual value of all AGC units, and select the unit with the largest absolute value of the difference as the unit to perform calibration adjustment, and continue to execute step S4300.

[0155] S4300) Determining the adjustment accuracy of the secondary frequency modulation, including:

[0156] S4310) setting a calibration accuracy threshold, wherein the calibration accuracy threshold is set to be between 1.5% and 0.5%;

[0157] S4320) Calculate the absolute value of the difference between the plant-wide active power setting value and the plant-wide active power actual value. Assuming that the plant-wide active power setting value is 1000MW and the plant-wide active power actual value is 1020MW, the absolute value of the difference between the two is equal to 20MW.

[0158] S4330) Calculate the total rated power of all generating units in power generation. Assuming there are four generating units generating power, each with a rated power of 500 MW, the total rated power is 2000 MW.

[0159] S4340) calculating the error ratio of the secondary frequency modulation, the error ratio being equal to the absolute value of the difference obtained in S4320 divided by the sum of the rated powers obtained in S4330. Based on the assumptions in S4320 and S4330, the error ratio is equal to 20 ÷ 2000 = 1%;

[0160] S4350) comparing the error ratio obtained in S4340 with the accuracy threshold of the calibration adjustment set in S4310, including:

[0161] S4351) If the error ratio obtained in S4340 is greater than the accuracy threshold set in S4310, executing step S4400 to perform calibration adjustment;

[0162] S4352) If the error ratio obtained in S4340 is less than or equal to the accuracy threshold set in S4310, the secondary frequency modulation calibration adjustment is terminated.

[0163] S4400) Calculating the pre-allocated active power value of each unit of the unit that performs calibration adjustment, which is equal to the plant-wide active power setting value minus the actual active power values of each unit of the units that do not perform calibration adjustment;

[0164] Assume that the total plant active power setpoint is 1000 MW, there are four units in generating state, the active power setpoint of each unit is 250 MW, and the actual active power values of each unit are 259, 251, 241, and 243 MW, respectively. Unit 1 is the unit performing calibration and adjustment. Therefore, its pre-allocated active power value is 1000-251-241-243=265 MW.

[0165] S4500) comparing the pre-allocated active power value of the unit to be calibrated and adjusted obtained in S4400 with the upper and lower limits of the active power operation range of the unit, including:

[0166] S4510) If the pre-allocated active power value of the unit being calibrated is greater than or equal to the lower limit of the active power operating range of the unit and less than or equal to the upper limit of the active power operating range of the unit, then:

[0167] S4511) will perform calibration and adjustment of the unit active power setting value Set to the pre-allocated active power value of a single machine obtained by S4400;

[0168] S4512) will not perform calibration adjustment of the unit active power setting value Set to the actual active power value of a single machine, that is p i is the actual active power output value of single machine i;

[0169] S4513) Set the active power setting value of each hydropower unit Sent to the control system of each unit for closed-loop regulation of the active power of each unit.

[0170] S4520) If the pre-allocated active power value of a single unit of the unit performing calibration adjustment is less than the lower limit of the active power operating range of the unit, or is greater than the upper limit of the active power operating range of the unit, it indicates that the calibration adjustment does not meet the execution conditions, and the secondary frequency calibration adjustment is terminated.

[0171] use Figure 7 The simulation model shown in the figure simulates the regulation effect of the conventional regulation of secondary frequency regulation supplemented by calibration regulation. Assuming that 4 units participate in the regulation, the dead zone of the unit active power regulation is 10MW, the regulation amount of the secondary frequency regulation instruction is 1500MW, and the regulation amounts allocated to the 4 units are 450, 400, 350, and 300MW respectively, the simulation regulation effect is as follows: Figures 8-10 As shown, Figure 8 、 Figure 9 、 Figure 10 They are the changes in the active power setting value of each unit, the changes in the actual active power value of each unit, and the changes in the actual active power value of the entire plant.

[0172] pass Figure 8 、 Figure 9 、 Figure 10 It can be seen that the secondary frequency modulation calibration adjustment of the present invention has the effect of significantly reducing adjustment error and improving adjustment accuracy.

[0173] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are within the scope of the invention as claimed.

Claims

1. A method for regulating the active power of a hydropower station by amplifying gain with secondary frequency modulation, characterized in that: When a hydropower station receives a secondary frequency regulation instruction, it determines whether the secondary frequency regulation to be performed meets the time interval threshold T, whether the regulation amplitude exceeds a certain proportion of the total rated capacity, and whether the current active power operation range of the AGC hydropower unit meets the secondary frequency regulation instruction. It then sets the secondary frequency regulation gain adjustment flag to reflect the judgment result. When all the judgment conditions are met, all hydropower units participating in the secondary frequency regulation perform amplified gain adjustment in the same direction as the secondary frequency regulation instruction: The difference between the plant-wide active power setting value of the secondary frequency regulation instruction and the original plant-wide active power setting value of the hydropower station is evenly distributed to each hydropower unit participating in the secondary frequency regulation to obtain the secondary frequency regulation adjustment amount; Combined with the original single-machine active power distribution value, the single-machine active power distribution value of each unit is obtained and distributed to each unit; Within the gain adjustment time threshold T1, which is shorter than the time interval threshold T, each unit amplifies and updates the single-unit active power setting value in the same direction based on the single-unit active power distribution value. The amplification amount is the single-unit active power adjustment dead zone multiplied by the set proportional parameter. Each unit performs closed-loop regulation of the active power of the unit according to the updated active power setting value of the unit; when the amplified gain adjustment time reaches the gain adjustment time threshold, the current active power setting value of the unit is set as the active power distribution value of the unit.

2. The method for regulating the active power of a hydropower station by amplifying gain with secondary frequency modulation according to claim 1, characterized in that: The time interval threshold T is: S1100) Setting a time interval threshold T for starting secondary FM gain adjustment; S1200) When receiving the scheduled secondary frequency modulation instruction, calculate the time interval between the previous secondary frequency modulation instruction and the scheduled secondary frequency modulation instruction: Set a continuous timing timer C1. Every time a new secondary frequency modulation instruction is received, read the time t1 of the timer C1. t1 is the time interval between the last secondary frequency modulation instruction. After reading the time, reset the timer C1. If the time interval t1 exceeds the time interval threshold T, the time interval requirement is met; The method for determining whether the adjustment range exceeds a certain proportion of the total rated capacity is: S1300) Calculate the adjustment amplitude threshold for starting secondary frequency modulation gain adjustment: S1310) Setting a ratio k1 of the adjustment amplitude threshold to the rated capacity, where k1 is set to be greater than or equal to the active power adjustment accuracy of the hydropower station; S1320) calculating the total rated capacity of the hydropower station's generating units in power generation mode, where the total rated capacity is equal to the sum of the rated capacities of all hydropower generating units in power generation mode at the current water head; S1330) The adjustment amplitude threshold of the secondary frequency regulation gain adjustment is equal to the total rated capacity of the generating units of the hydropower station in the generating state multiplied by k1; S1400) Compare whether the adjustment amplitude of the secondary frequency adjustment instruction exceeds the adjustment amplitude threshold: S1410) Calculating the absolute value of the deviation between the plant-wide active power setting value of the secondary frequency regulation instruction and the original plant-wide active power setting value of the hydropower station; S1420) Calculating the absolute value of the deviation between the plant-wide active power set value of the secondary frequency regulation instruction and the plant-wide active power actual value of the hydropower station; S1430) If the results obtained in S1410 and S1420 are both greater than the adjustment amplitude threshold calculated in S1300, it is considered that the adjustment amplitude of the secondary frequency modulation adjustment instruction exceeds the adjustment amplitude threshold; S1440) If the result obtained in S1410 or S1420 is less than or equal to the adjustment amplitude threshold calculated in S1300, it is considered that the adjustment amplitude of the secondary frequency modulation adjustment instruction does not exceed the adjustment amplitude threshold; Whether the current active power operation range of each AGC hydropower unit meets the secondary frequency regulation instruction is: S1510) accumulating and summing the active power setting values of each hydropower unit not put into AGC operation; S1520) accumulating and summing the upper limits of the active power operation ranges of the AGC hydropower generating units; S1530) accumulating and summing the lower limits of the active power operation ranges of the AGC hydropower generating units; S1540) adding the result obtained in S1510 and the result obtained in S1520 to obtain the upper limit threshold of secondary frequency regulation of the hydropower station without changing the active power operation zone constraint of the unit; S1550) adding the result obtained in S1510 and the result obtained in S1530 to obtain the lower limit threshold of the secondary frequency regulation of the hydropower station without changing the active power operation zone constraint of the unit; S1560) If the secondary frequency regulation instruction is less than or equal to the upper threshold obtained in S1540 and greater than or equal to the lower threshold obtained in S1550, then the current active power operation range of each AGC hydropower unit meets the secondary frequency regulation instruction; S1540) If the secondary frequency regulation instruction is greater than the upper threshold obtained in S1540, or less than the lower threshold obtained in S1550, then the current active power operation range of each AGC hydropower unit does not meet the secondary frequency regulation instruction; If the judgment conditions for secondary frequency modulation gain adjustment are met, the secondary frequency modulation gain adjustment flag α is set to 1; Otherwise, the secondary frequency modulation gain adjustment flag α is set to 0.

3. The method for regulating the active power of a hydropower station by amplifying gain with secondary frequency modulation according to claim 1, characterized in that: The single-unit active power distribution value of each unit is distributed through the following operations: S3100) Calculate the active power distribution value of each hydropower unit S3110) Subtracting the original full-plant active power setting value of the hydropower station from the full-plant active power setting value of the secondary frequency modulation instruction to obtain a difference △P between the two; S3120) Calculate the secondary frequency regulation value △p allocated to unit i i : S3121) If △P is greater than 0, then △p i It is equal to △P divided by the number of units that are in AGC control, in power generation state, and whose single-unit active power setting value is less than the upper limit of the active power operation area; S3122) If △P is less than 0, then △p i It is equal to △P divided by the number of units that are in AGC control, in power generation state, and whose single-unit active power setting value is greater than the lower limit of the active power operation zone; S3130) Active power distribution value of each unit Perform the calculation: S3131) If the secondary frequency regulation value of unit i is △p i >0, the active power distribution value of the unit =min(the original single-unit active power distribution value of the unit + the single-unit secondary frequency regulation value △p i , the upper limit of the active power operation area of the unit); S3132) If the secondary frequency regulation value of unit i is △p i <0, the active power distribution value of the unit = max(the original active power distribution value of the unit + the secondary frequency regulation value of the unit △p i , the lower limit of the active power operation area of the unit); S3140) summing the active power distribution values of each unit to obtain an updated original active power setting value for the entire hydropower station; S3150) Recalculate △P based on the updated original active power setting value of the hydropower station: S3151) If ΔP is not equal to 0, jump to step S3120 to distribute and calculate the secondary frequency modulation adjustment amount again; S3152) If △P is equal to 0, the calculation of the distribution of the secondary frequency regulation amount is completed, and the single unit active power distribution value of each hydropower unit is obtained. S3200) distributes the active power of each hydropower unit to Sent to the AGC control system of each unit.

4. A method for regulating active power of a hydropower station using a secondary frequency modulation amplified gain as claimed in claim 1 or 3, characterized in that: Each unit performs amplified gain adjustment in the same direction as the secondary frequency modulation instruction through the following operations based on the received single-unit active power distribution value: S3310) setting a gain adjustment time threshold T1 that is less than the time interval threshold T; If the judgment conditions for the secondary frequency modulation gain adjustment are met, the hydropower station sets the secondary frequency modulation gain adjustment flag α to 1; otherwise, the hydropower station sets the secondary frequency modulation gain adjustment flag α to 0; the hydropower station sends the secondary frequency modulation gain adjustment flag to each hydropower unit; S3320) Setting timer C2 to count the adjustment time of the amplified gain adjustment: S3321) If α=1, start timer C2 for timing; S3322) If α=0, stop and clear the reset timer C2; S3330) Each unit adjusts the secondary frequency gain according to the marker α and the received single unit active power distribution value. Update the active power setting value of a single machine S3331) If α=1 and Greater than the current Update for S3332) If α=1 and Less than the current Update for in is the dead zone of active power regulation of unit i, and k3 is a manually set proportional parameter greater than or equal to 1; S3333) If α=0, then Set to Each unit is based on the updated single unit active power setting value Perform closed-loop regulation of active power of a single machine; S3340) Each AGC system operation cycle takes the time t2 of timer C2, and when t2 is greater than or equal to the gain adjustment time threshold T1, updates for At the same time, the timing of timer C2 is stopped and reset; and the secondary frequency modulation gain adjustment flag α is set to 0; Whenever the active power setting value of each unit After the update, each unit performs closed-loop adjustment of the active power of each unit based on it.

5. The method for regulating active power of a hydropower station by amplifying gain with secondary frequency modulation according to claim 1 or 4, characterized in that: After the amplifier gain adjustment, a secondary frequency modulation calibration adjustment is performed, including the following operations: S4100) Determine whether the time interval between the last received secondary frequency modulation instruction is long enough: S4110) Setting a time threshold for calibration adjustment, the time threshold being equal to the time required from the hydropower station receiving the secondary frequency regulation instruction to each hydropower unit completing the first closed-loop adjustment of the active power of the single unit; S4120) Setting a timer and reading the interval time t1 from the last secondary frequency modulation; S4130) If t1 is greater than or equal to the calibration adjustment time threshold, continue to step S4200; S4140) If t1 is less than the calibration adjustment time threshold, jump back to step S4100 and execute again; S4200) Determine whether the active power regulation of the power station is basically completed: S4210) Setting a fluctuation determination threshold for completion of single-unit active power regulation, the fluctuation determination threshold being equal to the periodic variation of the actual value of the single-unit active power due to random fluctuations after each hydropower unit completes single-unit active power regulation; S4220) Set an array containing n elements for each unit Where n is a manually set parameter; S4230) Each AGC system cycle Perform calculations, It is equal to the absolute value of the difference between the actual active power output value of the unit i collected in this cycle and the actual active power output value of the unit i collected in the previous cycle; S4240) Each AGC system cycle assigns the values of each element in the array in sequence. S4250) n AGC system cycles to determine whether the active power of each unit is regulated: S4251) Perform weighted average calculation on the array elements of unit i in is the jth element in the array of unit i; S4252) If the fluctuation average weighted value obtained in S4251 is less than the fluctuation judgment threshold, the single-unit active power regulation of unit i is completed; S4253) If the fluctuation average weighted value obtained in S4251 is greater than or equal to the fluctuation judgment threshold, then the single-machine active power regulation of unit i is not completed; S4260) If there is more than one unit for which single-unit active power regulation has not been completed, the process returns to step S4100 and proceeds again. S4270) If no more than one unit has completed single-unit active power regulation, then: S4271) If there is one unit that has not completed single-unit active power adjustment, then select this unit as the unit to perform calibration adjustment, and continue to step S4300; S4272) If there are no units that have not completed single-unit active power adjustment, calculate the absolute value of the difference between the single-unit active power set value and the single-unit active power actual value of all AGC units, select the unit with the largest absolute value of the difference as the unit to perform calibration adjustment, and continue to step S4300; S4300) Determine the adjustment accuracy of the secondary frequency modulation: S4310) setting a calibration accuracy threshold between 1.5% and 0.5%; S4320) Calculating the absolute value of the difference between the set value of the plant-wide active power and the actual value of the plant-wide active power; S4330) calculating the sum of the rated powers of all units in a power generation state; S4340) calculating an error ratio of the secondary frequency modulation, where the error ratio is equal to the absolute value of the difference obtained in S4320 divided by the sum of the rated powers obtained in S4330; S4350) Compare the error ratio with the calibration accuracy threshold: S4351) If the error ratio is greater than the calibration accuracy threshold, executing step S4400 to perform calibration adjustment; S4352) If the error ratio is less than or equal to the calibration accuracy threshold, then the secondary frequency modulation calibration adjustment is terminated; S4400) Calculating the pre-allocated active power value of each unit of the unit that performs calibration adjustment, which is equal to the plant-wide active power setting value minus the actual active power values of each unit of the units that do not perform calibration adjustment; S4500) Compare the obtained pre-allocated active power value of the unit performing calibration and adjustment with the upper and lower limits of the active power operation range of the unit: S4510) If the pre-allocated active power value of the unit being calibrated is greater than or equal to the lower limit of the active power operating range of the unit and less than or equal to the upper limit of the active power operating range of the unit, then: S4511) will perform calibration and adjustment of the unit active power setting value Set to the pre-allocated value of active power for a single machine; S4512) will not perform calibration adjustment of the unit active power setting value Set to the actual active power value of a single machine, that is p i is the actual active power output value of single machine i; S4513) Set the active power setting value of each hydropower unit Send to each unit control system for closed-loop regulation of active power of each unit; S4520) If the pre-allocated active power value of a single unit of the unit performing calibration adjustment is less than the lower limit of the active power operating range of the unit, or is greater than the upper limit of the active power operating range of the unit, it indicates that the calibration adjustment does not meet the execution conditions, and the secondary frequency calibration adjustment is terminated.

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