A comprehensive method for optimizing FM performance indicators

Abstract

The present invention discloses a comprehensive frequency modulation performance index optimization method, firstly, P is calculated by the frequency modulation target instruction issued by the system. Z value, and then use the obtained P Z Calculate the k1 value, and according to the obtained k1 value, Z It is divided into small instructions and large instructions, and the segmented control strategy and fuzzy control strategy are adopted for small instructions and large instructions respectively, among which, a fixed control mode is adopted for small instructions; a fuzzy control mode is adopted for large instructions; by adopting this segmented control strategy and fuzzy control strategy, it is possible to optimize the regulation rate index k1, response time index k2, and regulation accuracy index k3 in the comprehensive frequency regulation performance index k, so as to obtain the maximum comprehensive frequency regulation performance index k, which not only makes the energy storage system output tracking system frequency regulation instructions more reasonable and stable, but also optimizes the calculation of the comprehensive frequency regulation performance index k value through the fuzzy control mode theory, so as to make the most reasonable response, output the best system frequency regulation service, and improve the frequency regulation benefit.

Description

Technical Field

[0001] The present invention relates to a method for a combined unit of an energy storage frequency modulation system to respond to a frequency modulation command, and more particularly to a method for optimizing an integrated frequency modulation performance index. Background Art

[0002] Frequency modulation ancillary service mainly refers to the service in the secondary frequency modulation reserve of a generator that can automatically respond to the area control error (ACE) through an automatic generation control device (AGC), adjust the power generation output in real time at a certain adjustment rate, and meet the ACE control requirements. The frequency modulation command value is automatically generated according to the area control error (ACE), and the frequency modulation command value is allocated by calculating the rated capacity and adjustment rate of different units, which has uncertainty, and its adjustment effect is measured by the frequency modulation mileage. According to the frequency modulation ancillary service market trading rules in the southern region (hereinafter referred to as the frequency modulation trading rules), the winning power generation units in the frequency modulation market can obtain corresponding frequency modulation mileage compensation fees, and the monthly frequency modulation mileage compensation calculation formula is as follows:

[0003]

[0004] Wherein, n is the total number of trading cycles in the frequency modulation market per month, Di is the frequency modulation mileage provided by the power generation unit in the i-th trading cycle, Pi is the mileage settlement price in the i-th trading cycle, and Ki is the average value of the integrated frequency modulation performance index of the power generation unit in the i-th trading cycle. Among them, the integrated frequency modulation performance index is an important index of the frequency modulation adjustment effect, and a higher index value is obtained through the optimization of the energy storage frequency modulation system, and it also affects the other two indexes of the three calculation factors. Therefore, by optimizing and improving the integrated frequency modulation performance index K value, avoiding over-regulation or overshoot when the power generation unit responds to the AGC command, not only can high-quality frequency modulation ancillary services be provided to the power grid, but also higher compensation benefits can be brought to the power generation unit. The integrated frequency modulation performance index K is used to measure the comprehensive performance of the power generation unit in responding to the AGC control command, including three factors: the adjustment rate k1, the response time k2, and the adjustment accuracy k3.

[0005] Currently, there is also a method to improve the k value by optimizing the output command for calculating the integrated frequency modulation performance index k value, but the overall effect is not satisfactory, and the energy storage system and the unit are not combined better, and the effect is average. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies of the prior art and provide a comprehensive frequency modulation performance index optimization method. The comprehensive frequency modulation performance index optimization method can optimize the regulation rate index k1, response time index k2, and regulation accuracy index k3 in the comprehensive frequency modulation performance index k, so as to obtain the maximum comprehensive frequency modulation performance index k. This not only makes the output of the energy storage system track the system frequency modulation command more reasonable and stable, but also optimizes the calculation of the comprehensive frequency modulation performance index k value through the fuzzy control mode theory, so as to make the most reasonable response and output the best quality system frequency modulation service, improving the frequency modulation benefit.

[0007] The technical solution of the present invention to solve the above technical problems is:

[0008] A comprehensive frequency modulation performance index optimization method, wherein the comprehensive frequency modulation performance index k is used to measure the comprehensive performance of the power generation unit in responding to the AGC frequency modulation command, and the calculation formula is as follows:

[0009] k = 0.25 × (2 × k1 + k2 + k3);

[0010] In the formula: k1 is the regulation rate index, which refers to the rate at which the power generation unit responds to the AGC frequency modulation command; k2 is the response time index, which refers to the time delay of the power generation unit in responding to the AGC frequency modulation command; k3 is the regulation accuracy index, which refers to the accuracy of the power generation unit's unit in responding to the AGC frequency modulation command;

[0011] Among them, the arithmetic mean of the comprehensive frequency modulation performance index k of the power generation unit within different time periods is the comprehensive frequency modulation performance index k within the corresponding statistical period;

[0012] The comprehensive frequency modulation performance index optimization method realizes the optimization of the regulation rate index k1, response time index k2, and regulation accuracy index k3 through segmented strategy control and fuzzy control strategy for the AGC frequency modulation command, including the following steps:

[0013] S1. Calculate the P Z value, where P Z is the difference between the output of the energy storage combined unit P L and the target value P4 of the system frequency modulation command, which is expressed by the formula: P Z = |P4 - P L |;

[0014] Substitute the obtained P Z value into the following formula:

[0015]

[0016] When the power generation unit reaches the moment of completing D% of the current AGC frequency modulation command according to the regulation rate calculation threshold time L1, L1 = t i1-t i0 ; where the output rate V of the energy storage combined unit i has the following calculation formula:

[0017]

[0018] Then the calculation formula for the regulation rate index k1 is:

[0019]

[0020] In the formula, t i0 is the starting calculation moment of the calculation period i, that is, the moment when the difference between the output of the power generation unit and the output at the starting moment is greater than the starting calculation set threshold P sd ; t i1 is the ending calculation moment of the calculation period i, that is, to reasonably avoid the target dead zone and truly reflect the regulation rate, the moment when the power generation unit completes the current frequency modulation command D% is selected; D is the ratio from the calculation period to the ending calculation moment, and the system specification fixed value is 70; P i0 is the starting value of the output of the calculation period i, that is, the output of the power generation unit at the starting calculation moment t i0 ; P i1 is the ending value of the output of the calculation period i, that is, the output of the power generation unit at the ending calculation moment t i1 ; P Ti is the regulation rate calculation threshold value. To avoid over-regulation or overshoot of the power generation unit when responding to the AGC frequency modulation command, the current frequency modulation market system sets the maximum value of k1 not to exceed 3;

[0021] S2. According to the calculated k1 value, divide P Z into small commands and large commands. The basis is: when the k1 value is greater than or equal to 1.0, it is a large command; when the k1 value is less than 1.0, it is a small command. After classification, the following strategies are used to control small commands and large commands respectively:

[0022] For the frequency modulation command of the small command, a fixed control mode is adopted; the strategy of the fixed control mode is: after the power generation unit receives the AGC frequency modulation command, the energy storage system immediately responds and outputs to the action dead zone P acut , and reaches the regulation rate calculation threshold value P Ti after L1 seconds according to the fixed control mode output function, and then directly outputs to reach the frequency modulation command target value P4, and cooperates with the unit to output and stabilize at the frequency modulation command target value P4;

[0023] Let P x be the fixed control mode output function of the small command, then

[0024]

[0025] Under the increased AGC frequency modulation command, let P xz be the positive output function of the fixed control mode for small commands, then:

[0026]

[0027] Under the decreased AGC frequency modulation command, let P xf be the negative output function of the fixed control mode for small commands, then

[0028]

[0029] In the formula, P j is the measured value of the unit's real-time output;

[0030] For the frequency modulation response process of large commands, a fuzzy control mode is adopted; the strategy of the fuzzy control mode is: after the power generation unit receives the AGC frequency modulation command, the energy storage system first responds and outputs directly to reach the action dead zone P acut When it reaches, after maintaining for L1 seconds, the combined output of the energy storage and the unit P i approaches the adjustment rate calculation threshold value P Ti , and then responds according to the calculation of the fuzzy control mode output function, rising to more than D% of the frequency modulation command target value P4. Subsequently, it cooperates with the unit to track the frequency modulation command target value P4 until it enters the target dead zone of the frequency modulation command and returns within 10 seconds of entering the target dead zone, waiting for the next AGC frequency modulation command;

[0031] Let P d be the output function of the fuzzy control mode for large commands, then

[0032]

[0033] In the formula: P c is the real-time output of the energy storage system.

[0034] Preferably, in step S2, the real-time output of the energy storage system P c is:

[0035] P c = P i - P j

[0036] In the formula, P i is the output value that the energy storage and the unit should output; P j is the measured value of the unit's real-time output.

[0037] Preferably, the calculation formula for the output value P i that the energy storage and the unit should output in the fuzzy control mode for large commands is:

[0038]

[0039] Simplified according to the relevant setting parameters of a 600MW coal-fired unit as follows:

[0040]

[0041] Where:

[0042] P1 is the output value of the power generation unit at the start; P4 is the target value of the AGC frequency modulation command; t1 starts timing from the moment when the output value of the power generation unit reaches the regulation rate calculation threshold value P Ti ; t2 starts timing from the moment when the response process of the power generation unit increases or decreases with the unit load and reaches |ΔP i | = D% × |P4 - P1| - |P Ti |; β is a constant close to 1. In the fuzzy control mode of a large command, when the combined output ΔP of the power generation unit i ≤ D% × |P i4 - P1| - P Ti In this case, make it infinitely close to the regulation rate calculation threshold value P Ti to avoid reaching the regulation rate calculation threshold value P Ti When starting to calculate the value of k1, determine the value in combination with the actual regulation fluctuation range of the unit. After actual measurement, take 0.9; ΔP i is the potential output value of the energy storage system combined with the unit after L1 seconds, reflecting the ability to reach the dead zone of the AGC frequency modulation command target. Among them,

[0043] The above-mentioned ΔP i is calculated as follows:

[0044]

[0045] Simplified according to the relevant setting parameters of a 600MW coal-fired unit as follows:

[0046]

[0047] Where, P ce is the rated power of the energy storage system, P kj is the rated capacity of the unit, V j is the real-time change rate of the unit load, P L is the output of the energy storage combined unit, P j is the measured value of the real-time output of the unit.

[0048] Preferably, in step S1, when the frequency modulation command is evenly distributed by the average of all the starting units in the plant:

[0049]

[0050] When using a 600MW coal-fired unit, then

[0051]

[0052] Among them, S kj The rated capacity of the power generation unit; the average standard regulation rate V of the AGC power generation unit sv is set to 1.784.

[0053] Preferably, L1 is taken as 4 seconds. When P4 > P1, the action dead zone P acut is taken as 3 MW, and P Ti is taken as 6 MW. When P4 < P1, the action dead zone P acut is taken as -3 MW, and P Ti is taken as -6 MW.

[0054] Preferably, when the power generation unit responds to the AGC frequency modulation command, it preferentially uses the fast response output of the energy storage system. At the moment when the AGC frequency modulation command is issued, it immediately outputs to reach the action dead zone value P acut , so that the response time is close to zero. Since the frequency modulation response speed of the energy storage system is much greater than that of the unit, the optimization effect reaches the best;

[0055] Among them, the calculation formula for the time delay index k2 of the power generation unit's response to the AGC frequency modulation command is:

[0056] k2 = 1 - (power generation unit response delay time / 5 min);

[0057] Among them, the power generation unit response delay time refers to the delay time between the AGC action of the power generation unit and the power generation unit receiving the AGC frequency modulation command;

[0058] When the response is output by the unit, it takes more than 30 seconds to reach the action dead zone. When encountering reverse regulation of the unit, the actual response time will be extended to more than 2 minutes, while the response of the energy storage system is approximately zero seconds, and the k2 value is close to 1.

[0059] Preferably, the optimization strategy for the accuracy k3 of the power generation unit's response to the AGC frequency modulation command is that when P Z is a small command, the power generation unit actively responds to reach the frequency modulation command target value. Within the output capacity range of the energy storage system's rated capacity, the time to track the frequency modulation command target value meets the calculated frequency modulation accuracy conditions; while when P Z is a large command, it is necessary to make the time to track the frequency modulation command target value not meet the requirements of the calculated frequency modulation accuracy conditions and not participate in the k3 calculation, so as to avoid the accuracy of tracking the frequency modulation command target value from decreasing due to insufficient output capacity of the energy storage system. Among them,

[0060] The calculation formula for the accuracy k3 of the power generation unit's response to the AGC frequency modulation command is as follows:

[0061] k3 = 1 - (regulation error of power generation unit / allowable regulation error of power generation unit);

[0062] Among them, the regulation error of the power generation unit refers to the deviation between the actual output value and the command value after the power generation unit responds to the AGC frequency modulation command; the allowable regulation error of the power generation unit is 1.5% of the rated output of the power generation unit.

[0063] Preferably, in the fixed control mode, during the response process, it is required that after the output power of the power generation unit enters the dead zone of the frequency modulation command target, it needs to continuously track the target value of the frequency modulation command for at least 40 s or more. When the time to enter the target dead zone meets the calculation condition of the k3 value, the output of the energy storage system should return to zero to prepare for responding to the next frequency modulation command.

[0064] Preferably, the calculation condition of the k3 value, that is, the calculation condition of the frequency modulation accuracy is:

[0065] (1). The power generation unit enters the target dead zone and the continuous duration is greater than 20 s;

[0066] (2). The regulation accuracy calculation duration T accu is calculated starting from the moment when the power generation unit enters the target dead zone, and accumulates up to 40 s at most, that is, the number of effective data calculation points is 41.

[0067] Preferably, in the fuzzy control mode, an automatic and manual optimization mode is set to find the best control strategy among the randomly issued target values of the frequency modulation command, so as to increase the k1 value and thus increase the comprehensive frequency modulation performance index k; the steps are as follows:

[0068] When a k1 value greater than 1.0 is generated in a time period, the k1 value in the subsequent time periods can only be higher than the previous k1 value, otherwise the response process is completed according to the fixed control mode and no k1 value is generated; at the same time, c a variable integer a is added to the P function, with an initial value of zero, and a = ΔP - 19 + 1. After a k1 value calculation is completed, it is re-assigned, then

[0069]

[0070] It can be deduced from the above function that when a k1 value greater than 1.0 is generated in a time period, the subsequent k1 values can only be higher than the previous k1 value. Otherwise, the response process is completed according to the fixed control mode without generating a k1 value. Assuming that the distribution of the frequency modulation command is balanced, then the average value of k1 between 1.0 and 3 is 2, and the k1 value generated according to the listed function will be greater than 2. In addition, it is also possible to switch to the manual control mode to increase the k1 value. According to human experience, an expected value can be proposed, and a more ideal k1 value can be achieved through manual operation. Just assign a value to a. As long as a frequency modulation command target value greater than the expected value appears once in a time period, the requirement can be met, and the expected k1 value can be obtained. Without changing the k2 and k3 values, the comprehensive frequency modulation performance index k of frequency modulation is improved.

[0071] The present invention has the following beneficial effects compared with the prior art:

[0072] 1. The comprehensive frequency modulation performance index optimization method of the present invention controls the frequency modulation command through a segmented strategy, that is, adopts a fixed control mode for small commands and a fuzzy control mode for large commands, so as to optimize the adjustment rate index k1, response time index k2, and adjustment accuracy index k3 in the comprehensive frequency modulation performance index k, and obtain the maximum comprehensive frequency modulation performance index k. This not only makes the output of the energy storage system track the system frequency modulation command more reasonably and stably, but also optimizes the calculation of the comprehensive frequency modulation performance index k value through the fuzzy control mode theory, so as to make the most reasonable response and output the highest-quality system frequency modulation service, improving the frequency modulation revenue.

[0073] 2. After the implementation of the comprehensive frequency modulation performance index optimization method of the present invention, the k value of the comprehensive frequency modulation performance index of the energy storage system can be greatly improved, thereby increasing the frequency modulation income of the energy storage and creating higher utilization value.

[0074] 3. The comprehensive frequency modulation performance index optimization method of the present invention optimizes the frequency modulation command, thereby improving the quality and stability of the output of the energy storage frequency modulation system, reducing unnecessary output losses, prolonging the battery life of the energy storage system, and better providing high-quality system frequency modulation services.

[0075] 4. The comprehensive frequency modulation performance index optimization method of the present invention can improve the k value of the comprehensive frequency modulation performance index of the auxiliary service of the energy storage frequency modulation system, which is theoretically close to the highest limit value 2 of the frequency modulation system, so that the k value can be increased by more than 30% after being put into production.

[0076] 5. The comprehensive frequency modulation performance index optimization method of the present invention adopts the fuzzy control calculation theory to optimize the combined unit output frequency modulation command of the energy storage system to the best. This not only helps the output of the energy storage system to track the system frequency modulation command more reasonably and stably, but also optimizes the calculation of the comprehensive frequency modulation performance index through the fuzzy control model theory, making the most reasonable response and outputting high-quality system frequency modulation services. Description of the Drawings

[0077] Figure 1 It is a process diagram of the power generation unit responding to the frequency regulation command.

[0078] Figure 2 It is a control strategy logic block diagram of the comprehensive frequency regulation performance index optimization method of the present invention.

[0079] Figure 3 It is for P xz (19 MW) positive output function diagram of the fixed control mode.

[0080] Figure 4 It is a mode response process diagram for a large command of -25 MW.

[0081] Figure 5 It is a mode response process diagram for the critical point.

[0082] Figure 6 It is a mode response process diagram for a large command of -45 MW. Detailed Implementation Manner

[0083] The present invention will be further described in detail below in conjunction with embodiments and the drawings, but the implementation manners of the present invention are not limited thereto.

[0084] See Figure 1-6 , in this embodiment, a 600 MW unit with a supporting energy storage system of 20 MW capacity is taken as an example to introduce the comprehensive frequency regulation performance index optimization method of the present invention.

[0085] 1. Related variables and calculation rules involved in the frequency regulation trading rules:

[0086] See Figure 1 , Figure 1 It is a process diagram of the power generation unit responding to the frequency regulation command: at time T1, the output of the power generation unit is P1. At this time, the system issues a frequency regulation command, and the target output is P4. After a certain response time, at time T2, the output of the power generation unit reaches P2, which is greater than the dead band of the power generation unit for the first time and maintains for U3 seconds, then it is considered that the power generation unit starts to effectively respond to the frequency regulation command; at time T3, the actual output of the power generation unit reaches P3, which reaches the target output dead band for the first time, then it is considered that the power generation unit completes the response to the frequency regulation command and enters the adjustment accuracy calculation time until time T4 reaches the maximum calculation duration of the adjustment accuracy or the system issues a new frequency regulation command again.

[0087] The following is for the starting time T start , the starting output P start , the action dead band P sdeadb , the target dead band P ddeadb , the response action time T schg , the response action output P schg, Enter the target deadband output P acut , Target output P des , Adjustment precision duration T accu are introduced as follows:

[0088] (1), Starting time T start : The time when the system issues the frequency modulation command, corresponding to Figure 1 T1 in

[0089] (2), Starting output P start : The output of the power generation unit at the starting time, corresponding to Figure 1 P1 in

[0090] (3), Action deadband P sdeadb : The threshold value at which the power generation unit starts to actually respond to the frequency modulation command. For a 600MW coal-fired unit, its set value is taken as 3MW according to the system requirements.

[0091] (4), Target deadband P ddeadb : The threshold value at which the power generation unit reaches the frequency modulation target command. For a 600MW coal-fired unit, its set value is taken as 3MW according to the system requirements.

[0092] (5), Response action time T schg : The time when the difference between the output of the power generation unit and the starting output is greater than the action deadband for the first time and remains for U3 seconds (it is considered that the power generation unit truly responds to the frequency modulation command), regarded as the effective response command time, corresponding to Figure 1 T2 in

[0093] (6), Response action output P schg : The output of the power generation unit at the response action time, corresponding to Figure 1 P2 in

[0094] (7), Enter target deadband time T acut : In the case of the response action time being valid, the time when the difference between the output of the power generation unit and the target output is less than the target deadband for the first time, regarded as the effective entry into the target deadband time, corresponding to Figure 1 T3 in

[0095] (8), Enter target deadband output P acut : The output of the power generation unit at the time of entering the target deadband, corresponding to Figure 1 P3 in

[0096] (9), Target output P des : The output target value for the frequency modulation command issued to the power generation unit, corresponding to Figure 1 P4 in

[0097] (10), Adjustment precision duration T accu: The duration from the moment of entering the target dead zone to the moment of reaching the maximum calculation duration or receiving a new frequency modulation command, corresponding to Figure 1 T4 - T3 in

[0098] 2. Calculation of the frequency modulation performance index of the frequency modulation system

[0099] According to the frequency modulation rule, the comprehensive frequency modulation performance index k: used to measure the comprehensive performance of the power generation unit in responding to the AGC frequency modulation command, and the calculation formula is as follows

[0100] k = 0.25×(2×k1 + k2 + k3);

[0101] In the formula: k1 is the regulation rate index, which refers to the rate at which the power generation unit responds to the AGC frequency modulation command; k2 is the response time index, which refers to the time delay of the power generation unit in responding to the AGC frequency modulation command; k3 is the regulation accuracy index, which refers to the accuracy of the power generation unit's unit in responding to the AGC frequency modulation command;

[0102] Among them, the arithmetic mean of the comprehensive frequency modulation performance index k of the power generation unit within different time periods is the comprehensive frequency modulation performance index k within the corresponding statistical period.

[0103] The following will respectively introduce the calculations of the regulation rate index k1, the response time index k2, and the regulation accuracy index k3:

[0104] (2 - 1) Regulation rate index k1 Calculation

[0105] First of all, the calculation conditions for the regulation rate index k1 are:

[0106] 1. Calculate that the regulation amplitude of the output power during the calculation period reaches the regulation rate calculation threshold value P Ti ;

[0107] 2. Effectively capture the starting calculation moment and the ending calculation moment of the power generation unit during the calculation period, and the difference between the two is greater than L1 seconds (4 seconds).

[0108] The specific calculation formula for this regulation rate index k1 is:

[0109]

[0110] When it is judged that the frequency modulation command is evenly shared by the average of the units in the whole plant that are in operation:

[0111]

[0112] For a 600MW unit:

[0113]

[0114] To avoid over-regulation or overshoot when the unit's power generation unit responds to the AGC frequency modulation command, the maximum value of k1 does not exceed M (currently set to 3 in the system); the average standard regulation rate V of the AGC power generation units within the frequency modulation resource distribution area sv is currently set to 1.784 in the system.

[0115] Among them, the actual regulation rate V i is calculated as:

[0116] If |P i1 - P i0 | ≥ P Ti and t i1 - t i0 > L1, then

[0117] (unit: MW / s)

[0118] In the formula,

[0119] t i0 is the starting calculation moment of the calculation period i, which is the moment when the difference between the power output of the power generation unit and the power output at the starting moment is greater than the starting calculation set threshold P sd for the first time;

[0120] t i1 is the ending calculation moment of the calculation period i. To reasonably avoid the target dead zone and truly reflect the regulation rate, the moment when the power generation unit completes this frequency modulation command D% is selected;

[0121] P i0 is the starting value of the power output in the calculation period i, which is the power output of the power generation unit at the starting calculation moment t i0 ;

[0122] P i1 is the ending value of the power output in the calculation period i, which is the power output of the power generation unit at the ending calculation moment t i1 ;

[0123] P Ti is the regulation rate calculation threshold value, which is set to 6 MW for the 600 MW unit system.

[0124] (2 - 2) Calculation of the response time index k2

[0125] The calculation formula for the response time index k2 is:

[0126] k2 = 1 - (power generation unit response delay time / 5 min);

[0127] This calculation formula is transformed into:

[0128] k2 = 1 - T del / (Q × 60);

[0129] In the formula, Q is the reference time, taking 5 minutes; T del is the actual response delay time. If the response action time of the power generation unit is valid, that is, the difference between the output of the power generation unit and the starting output is greater than the action dead zone for the first time, then the actual response time is equal to the response action time T schg minus the starting time T start , that is

[0130] T del = T schg - T start .

[0131] (2 - 3) Calculation of the regulation accuracy index k3

[0132] The calculation formula of the regulation accuracy index k3 is as follows:

[0133] k3 = 1 - (regulation error of the power generation unit / allowable regulation error of the power generation unit);

[0134] This calculation formula can be transformed into:

[0135] k3 = 1 - P accu / (S kj ×A%);

[0136] where S kj is the rated capacity of the power generation unit; and the allowable regulation error of the power generation unit is A% of its rated capacity, and A takes the value of 1.5; P accu is the actual regulation error;

[0137] where the calculation conditions for the actual regulation error P accu (calculate k3 when the conditions are met, otherwise do not calculate) are:

[0138] 1. The power generation unit enters the target dead zone and the continuous duration is greater than L2 seconds;

[0139] 2. The regulation accuracy calculation duration T accu is calculated starting from the moment when the power generation unit enters the target dead zone, and accumulates at most L3 seconds, that is, the number of valid data calculation points is (L3 + 1);

[0140] If the regulation accuracy duration T accu > the regulation accuracy calculation threshold time L2, then the calculation formula for the actual regulation error P accu is:

[0141] (unit: megawatt)

[0142] In the formula: P jd is from the moment T acut when entering the target dead zone to the end of the calculation moment (T acut + Taccu ) The actual output of the power generation unit between, with a sampling time interval of 1 second.

[0143] 3. Perform segmented control on different frequency modulation commands

[0144] For the response process of the k1 value of different frequency modulation commands, different control strategies should be adopted. Under the condition of conforming to the rules, make full use of the response ability of the energy storage system combined with the unit to improve the k1 value as much as possible; according to the regulation rate calculation conditions and rules, the output P of the energy storage combined unit can be optimized i In the response mode, while the unit load tracks the frequency modulation command value, the energy storage system relies on its own fast response ability and first outputs to the action dead zone P acut . After a stable time of L1 seconds, the combined output P of the energy storage combined unit i rises to the regulation rate calculation threshold value P Ti , and then enters the fuzzy control mode; for this reason, the steps of the specific segmented control strategy are as follows:

[0145] (3-1) Calculate the real-time output P of the energy storage system c :

[0146] P c =P i -P j

[0147] In the formula, P i is the output value that the energy storage combined unit should output; P j is the measured value of the real-time output of the unit.

[0148] Among them, the calculation formula for the output value P i that the energy storage combined unit should output is:

[0149]

[0150] After simplification according to the relevant fixed value parameters of a 600MW coal-fired unit, it is:

[0151]

[0152] In the formula:

[0153] P1 is the output value of the power generation unit at the start; P4 is the AGC frequency modulation command target value; t1 starts timing from the moment when the output value of the power generation unit reaches the regulation rate calculation threshold value P Ti moment, and t2 starts timing from the moment when the response process of the power generation unit increases or decreases with the unit load and reaches |ΔP i | = D% × |P4 - P1| - |P Ti | condition; β is a constant close to 1. In the fuzzy control mode of large commands, when the combined output ΔP of the power generation uniti ≤D% × |P i4 - P1| - P Ti In the case of, make it infinitely close to the regulation rate calculation threshold value P Ti to avoid reaching the regulation rate calculation threshold value P Ti When starting to calculate the value of k1, determine the value in combination with the actual regulation fluctuation range of the unit, and take 0.9 after actual measurement; ΔP i is the potential output value of the energy storage system combined with the unit after L1 seconds, reflecting the ability to reach the dead zone of the AGC frequency modulation command target command. Among them,

[0154] The described ΔP i is calculated as follows:

[0155]

[0156] In the formula, P ce is the rated power of the energy storage system, taking 20MW, P kj is the rated capacity of the unit, taking 600MW; V j is the real-time load change rate of the unit, equal to P L is the output of the energy storage combined unit, P j is the measured value of the real-time output of the unit.

[0157] (3 - 2) Calculate the corresponding k1 values under different sizes of frequency modulation commands

[0158]

[0159] Among them, the output rate V of the energy storage combined unit i is calculated by the formula:

[0160]

[0161] Then the calculation formula of the regulation rate index k1 is:

[0162]

[0163] In the formula, t i0 is the starting calculation moment of the calculation period i, that is, the moment when the difference between the output of the power generation unit and the output at the starting moment is greater than the starting calculation set threshold P sd for the first time; t i1 is the ending calculation moment of the calculation period i, that is, to reasonably avoid the target dead zone and truly reflect the regulation rate, select the moment when the power generation unit completes the current frequency modulation command D%; D is the ratio from the calculation period to the ending calculation moment, and the system standard fixed value is 70; P i0 is the starting value of the output of the calculation period i, that is, the output of the power generation unit at the starting calculation moment t i0 ; Pi1 is the output termination value for calculation period i, i.e., the output of the power generation unit at the termination calculation moment t i1 ; P Ti is the threshold value for regulating rate calculation. To avoid over-regulation or super-regulation when the power generation unit responds to the AGC frequency modulation command, the maximum value of k1 is set not to exceed 3 in the current frequency modulation market system.

[0164] According to the frequency modulation trading rules, taking the positive-direction frequency modulation command as an example, V sv takes 1.784, D% takes 70%, P Ti takes 6MW, L1 takes 4 seconds, then calculate k1 and P z The corresponding relationship table is as follows:

[0165] Pz (MW) 5 6 7 8 9 10 11 12 13 14 15 16 17 18 k1 0 0 0 0 0.09 0.14 0.24 0.34 0.43 0.53 0.63 0.73 0.82 0.92 Pz (MW) 19 20 21 22 23 24 25 26 27 28 29 30 31 32 k1 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 Pz (MW) 33 34 35 36 37 38 39 40 41 42 43 44 45 46 k1 2.4 2.5 2.6 2.7 2.8 2.9 3 3 3 3 3 3 3 3

[0166] P in the table Z is the difference between the output P L of the energy storage combined unit and the target value P4 of the system frequency modulation command, which is expressed by the formula: P z = |P4 - P L |.

[0167] When P z is lower than 19MW, the value of k1 is less than 1. According to the response rate of the energy storage, the measured rate of the power generation unit is within the range of the response output ability. Relying on the fast charge and discharge speed of the energy storage system, it can reach infinity, which is much greater than the average standard regulation rate (V sv ) of the AGC power generation unit within the market range. When the measured rate of the power generation unit is outside the range of the response output ability, relying solely on the fast response ability of the energy storage system, it is impossible to reach the dead zone of the AGC frequency modulation command P4 or around 70% within L1 (4 seconds). As the value of P z increases, the time for the maximum output of the energy storage system plus the combined output of the unit to reach the target dead zone of the AGC frequency modulation command P4 or around 70% will become longer and longer. Subsequently, it is necessary to rely on the unit to increase or decrease the load to complete it, and the time of the calculation interval of k1 will continue to increase, resulting in a decrease in the overall frequency modulation rate, and thus the actually calculated value of k1 will decrease significantly. This is the reason why the energy storage system combined with the unit will also obtain a lower k value. In addition, if the energy storage system blindly tracks the AGC frequency modulation target with the maximum capacity and ignores the calculation rules of the k value, it cannot obtain a higher k value either. When the battery is in the maximum charge and discharge state for a long time, the SOE curve is prone to enter the deviation state of full charge and full discharge, and the output ability of the subsequent energy storage system will be greatly reduced, affecting the overall energy storage frequency modulation effect. Therefore, according to the requirements of the frequency modulation trading rules, the response of the frequency modulation command needs to be optimized.

[0168] Observed from the frequency modulation market information of a 600MW coal-fired power unit, recent statistics show that the comprehensive performance index k value of the power generation unit of the energy storage system combined with the unit is between 0.46 and 1.9 in each time period, and the average value is about 1.2. The response time index k2 and the regulation accuracy index k3 have a relatively low weight in the calculation of the comprehensive performance index K value, and there is little room for optimization. Therefore, the key is to optimize the regulation rate index k1. Therefore, it is necessary to control the AGC frequency modulation command in a segmented strategy according to its size. Classify Pz into two types: small commands and large commands. Set adjustable parameters for the segmented frequency modulation commands to facilitate adjustment and optimization according to the output capacity of the power generation unit. Among them,

[0169] For the frequency modulation response process of small commands, a fixed control mode is adopted: First, it is necessary to ensure that the small command is within the comprehensive output capacity of the energy storage combined unit, and then it can directly respond and track the target value of the frequency modulation command according to a fixed standard mode, and complete a fixed standard mode to obtain higher K2 and K3 values. Since the k1 value obtained in this frequency modulation command segment is relatively low, from the correspondence table between k1 and P z it can be seen that when P z is below 19MW, the k1 values are all below 1.0. The k1 values generated by these frequency modulation commands will lower the arithmetic mean value of the k1 value in each time period. Therefore, these lower k1 values can be not taken, that is, according to the fixed control mode of the response of the power generation unit, so that the response process does not meet the calculation conditions of the regulation rate, so the k1 value of this AGC frequency modulation command is not counted.

[0170] The specific strategy of the fixed mode is: After the power generation unit receives the AGC frequency modulation command, the energy storage system first responds and outputs directly to reach the action dead zone P acut When it reaches, after L1 seconds, the output function according to the fixed control mode reaches the regulation rate calculation threshold value P Ti and then directly outputs to reach the target value of the AGC frequency modulation command, and cooperates with the unit output to stabilize at the target value P4 of the frequency modulation command, quickly responding to obtain a higher k2 value; using the fast regulation ability of the energy storage system can compensate for the small fluctuations of the unit and track the target value P4 of the frequency modulation command to obtain a higher k3 value; this fixed control mode is mainly to optimize the frequency modulation accuracy k3, try to improve the regulation accuracy k3, and avoid obtaining a lower k1 value. The response process requires that after the output power of the power generation unit enters the target dead zone of the AGC frequency modulation command, it needs to continue to track the target value of the frequency modulation command for at least L3 (40 seconds) or more to meet the calculation conditions of the k3 value. The output of the energy storage system can choose to return to zero, and whether to return immediately is determined according to the battery charge and discharge strategy.

[0171] Let P x be the output function of the fixed control mode for small commands, then

[0172]

[0173] Under the increasing AGC frequency modulation command, let P xz be the positive output function of the fixed control mode for small commands, then:

[0174]

[0175] Under the decreasing AGC frequency modulation command, let P xf be the negative output function of the fixed control mode for small commands, then

[0176]

[0177] In the formula, P j is the measured value of the real-time output of the unit;

[0178] Among them, Figure 3 is the positive output function diagram of the fixed control mode of P xz (19 MW).

[0179] For the frequency modulation response process of large commands, a fuzzy control mode is adopted. This frequency modulation command segment is the key to obtaining a high value of k1. From the correspondence table between k1 and P z it can be obtained that when P z is above 19 MW, the value of k1 is above 1.0. After calculation, the value of k1 can be obtained in the range of 1 - 3 (3 is the maximum value restricted by the rules). After the power generation unit receives the AGC frequency modulation command, the energy storage system first responds and outputs directly to reach the action dead zone P acut . After maintaining for L1 seconds (4 seconds), the combined output P i of the energy storage combined unit rises to near the regulation rate calculation threshold value P Ti , and then responds according to the fuzzy control calculation, rising to more than D% of the frequency modulation command target value P4. Subsequently, it cooperates with the unit to track the AGC frequency modulation command target value P4 until it enters the target dead zone of the frequency modulation command. It can return within 10 seconds after entering the target dead zone and wait for the next frequency modulation command without participating in the calculation of the K3 value. When the AGC frequency modulation target command value P4 is 39 MW, the theoretically calculated k1 can reach the highest limit value of 3.

[0180] Let P d be the output function of the fuzzy control mode for large commands, then

[0181]

[0182] Among them, Figure 4 is the mode response process diagram of the large command -25 MW.

[0183] (3 - 3) Automatically and manually optimize and improve the k1 value under the fuzzy control mode

[0184] Output P of the energy storage system c = P i - P j , where P i is the output value that the energy storage combined unit should output; P j is the measured value of the real-time output of the unit.

[0185] Calculate the output P of the energy storage system according to the following formula i :

[0186]

[0187] In the formula, P ce is the rated power of the energy storage system, P kj is the rated capacity of the unit, V j is the real-time change rate of the unit load, P L is the output of the energy storage combined unit, P j is the measured value of the real-time output of the unit.

[0188] After simplification according to the relevant fixed value parameters of a 600MW coal-fired unit, it is:

[0189]

[0190] Then the output P of the energy storage system i is:

[0191]

[0192] According to the relevant parameter settings of the energy storage system, assuming that the unit remains stationary after the frequency regulation command is issued, then the entire response process is borne entirely by the energy storage system. Let ΔP = P4 - P1. At this time

[0193]

[0194] For the moment when the system issues the target value of the frequency regulation command, when the difference ΔP between the target value of the frequency regulation command and the unit load P1 reaches more than 28.57MW, the output capacity of the energy storage system reaches the critical point under the condition that the unit load does not change. Considering the increase and decrease factors of the unit load, this critical point will shift up and down. This shift amount should consider extreme cases, that is, when the power generation unit receives the target value of the frequency regulation command, if the unit is increasing or decreasing the load in the opposite direction, there will be a delay from the issuance of the frequency regulation command to the increase or decrease of the load in the same direction. Calculate the maximum deviation of the unit:

[0195]

[0196] In the formula:

[0197] is the maximum deviation of the power generation unit's response to the target value of the frequency regulation command when reaching the output capacity critical point;

[0198] P kj is 600 MW;

[0199] V j is the standard regulation rate of the coal-fired unit (unit: % / minute), taking 15% / minute;

[0200] t is the response time of the power generation unit (unit: second), and the time to reach the output critical point is 8 seconds;

[0201] Substituting the above parameters, we can get:

[0202]

[0203] For the moment when the system issues the target value of the frequency modulation command, considering the load change of the unit's load increase and decrease, at the critical point where the combined response output ability of the energy storage system and the unit reaches 28.57 ± 1.2 MW, that is, when ΔP = 27.37 MW, the 70% target value of the frequency modulation command can be reached in 8 seconds. When 0 ≤ ΔP ≤ 27.37, the combined response output process of the energy storage system and the unit can rely on the fast response ability of the energy storage system to obtain a fixed k1, and obtain the corresponding k1 according to the correspondence table of k1 and P z correspondence table to obtain the corresponding k1, Figure 6 When the output of the energy storage system returns to the zero position, that is, P j = P i At this time, for the simulation response process at the critical point of ΔP = 27 MW, after reaching P1, it is necessary to rely on the unit to increase or decrease the load to continue climbing. The time to reach the target value of the frequency modulation command depends on the unit's load change rate. The subsequent response process affects the size of the frequency modulation mileage in this frequency modulation command period. However, after reaching the target dead zone of the frequency modulation command, the output of the energy storage system should return to the zero position within 10 seconds, avoiding reaching the frequency modulation accuracy calculation condition and not participating in the calculation of the frequency modulation accuracy k3 for entering the target dead zone.

[0204] To sum up, after the target value of the frequency modulation command is issued, the power generation unit should respond as soon as possible. From the long-term frequency modulation information statistics of the system, the interval time between the issuance of the frequency modulation command and the issuance of the next frequency modulation command generally exceeds 30 seconds. Therefore, after completing the response process within 30 seconds as soon as possible, the output of the energy storage system returns to the zero position. At this time, at the moment when the AGC frequency modulation command is issued, there is P1 = P L , so:

[0205] ΔP = |P4 - P L | = P z

[0206] The energy storage system can be based on k1 and P zObtain the corresponding k1 from the correspondence table. Set the automatic filtering function from 0:00 to 59:59 in a time period. Starting from the first frequency modulation command that generates a k1 value, superimpose parameters so that the subsequent k1 values are only higher and not lower. In addition to filtering out small k1 values using the response fixed control mode of small commands, perform fuzzy control on the response fuzzy control mode of large commands, thereby improving the arithmetic average comprehensive k value of all AGC frequency modulation commands in the entire time period. For the response process below the frequency modulation command target value of 27 MW, the influence of the unit can be ignored. In P c Add a variable integer a to the function, with an initial value of zero, a = ΔP - 19 + 1. After calculating a k1 value, reassign the value. The corresponding list of a value, k1, and ΔP is as follows:

[0207] ΔP 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 <![CDATA[k1]]> 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3

[0208]

[0209] In the formula, t1 starts timing from the adjustment rate calculation threshold value P Ti moment. t2 starts timing from the moment when the response process of the power generation unit gradually approaches the frequency modulation command target D% × |P i4 - P1| - P Ti moment as the unit load increases or decreases.

[0210] It can be deduced from the above-listed function that after a k1 value greater than 1.0 is generated in a time period, the subsequent k1 values can only be higher than the previous k1 value. Otherwise, complete the response process according to the fixed control mode and no k1 value is generated. Assuming that the distribution of the frequency modulation command is balanced, then the average value of k1 between 1.0 and 3 is k1 = 2, and the k1 value generated according to the listed function will be greater than 2. In addition, the manual control mode can be switched to increase the k1 value. From the correspondence table of K1 and P z correspondence, the expected value can be proposed based on human experience judgment. By manual operation, a more ideal k1 value can be achieved. Just assign a value to a manually. As long as a frequency modulation command target value greater than the expected value appears once in a time period, the requirement can be met and the expected k1 value can be obtained. Without changing the k2 and k3 values, the frequency modulation comprehensive performance index k is improved.

[0211] The following is the calculation specification fixed value list of the power generation unit frequency modulation index adopted in this embodiment (taking a 600 MW coal-fired unit as an example)

[0212]

[0213]

[0214] The above is a preferred embodiment of the present invention. However, the embodiments of the present invention are not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for optimizing comprehensive frequency modulation performance indicators, wherein, The comprehensive frequency modulation performance index k is used to measure the comprehensive performance of the power generation unit in responding to the AGC frequency modulation command, and the calculation formula is as follows: k = 0.25×(2×k1 + k2 + k3); In the formula: k1 is the regulation rate index, which refers to the rate at which the power generation unit responds to the AGC frequency modulation command; k2 is the response time index, which refers to the time delay of the power generation unit in responding to the AGC frequency modulation command; k3 is the regulation accuracy index, which refers to the accuracy of the power generation unit's unit in responding to the AGC frequency modulation command; Among them, the arithmetic mean of the comprehensive frequency modulation performance index k of the power generation unit within different time periods is the comprehensive frequency modulation performance index k within the corresponding statistical period; The comprehensive frequency modulation performance index optimization method realizes the optimization of the regulation rate index k1, the response time index k2, and the regulation accuracy index k3 by performing segmented strategy control and fuzzy control strategy on the AGC frequency modulation command, and is characterized by including the following steps: S1. Calculate the P value according to the frequency modulation target instruction issued by the system, where P is the difference between the output P of the energy storage combined unit and the target value P4 of the system frequency modulation instruction, and is expressed by the formula: P = |P4 - P|; Z Z L Z L ​​​​​ Substitute the obtained P Z value into the following formula: k1 = measured rate of the power generation unit / average standard regulation rate of AGC power generation units within the market range Where: V sv is the average standard regulation rate of AGC power generation units within the market scope; When the power generation unit reaches the moment of completing D% of the current AGC frequency modulation command according to the adjustment rate calculation threshold time L1, L1 = t i1 -t i0 ; where the output rate V i of the energy storage combined unit is calculated by the formula: Then the calculation formula for the regulation rate index k1 is: where t i0 is the starting calculation moment of the calculation period i, that is, the moment when the difference between the output of the power generation unit and the output at the starting moment is greater than the starting calculation set threshold P sd for the first time; t i1 is the ending calculation moment of the calculation period i, that is, to reasonably avoid the target dead zone and truly reflect the regulation rate, the moment when the power generation unit completes the current frequency modulation command D%; D is 70; P i0 is the starting value of the output of the calculation period i, that is, the output of the power generation unit at the starting calculation moment t i0 ; P i1 is the ending value of the output of the calculation period i, that is, the output of the power generation unit at the ending calculation moment t i1 ; P Ti is the threshold value for the regulation rate calculation. To avoid over-regulation or overshoot when the power generation unit responds to the AGC frequency modulation command, the maximum value of k1 set by the frequency modulation market system does not exceed 3; S2. According to the calculated value of k1, divide P Z into small instructions and large instructions, based on: when the value of k1 is greater than or equal to 1.0, it is a large instruction; when the value of k1 is less than 1.0, it is a small instruction. After classification, the following strategies are used to control small instructions and large instructions respectively: For the frequency modulation command of small commands, a fixed control mode is adopted; the strategy of the fixed control mode is that after the power generation unit receives the AGC frequency modulation command, the energy storage system immediately responds and outputs to the action dead zone value P acut , and reaches the adjustment rate calculation threshold value P after L1 seconds according to the fixed control mode output function Ti , and then directly outputs to reach the frequency modulation command target value P4, and cooperates with the unit to output and stabilize at the frequency modulation command target value P4; Let P x be the fixed control mode output function of the small instruction, then where P j is the measured value of the real-time output of the unit; For the frequency modulation response process of large commands, a fuzzy control mode is adopted; the strategy of the fuzzy control mode is as follows: after the power generation unit receives the AGC frequency modulation command, the energy storage system first responds and outputs directly to reach the action dead zone P acut When it reaches, after maintaining for L1 seconds, the combined output P of the energy storage combined unit i Approaches the adjustment rate calculation threshold value P Ti , and then responds according to the calculation of the output function of the fuzzy control mode, rising to more than D% of the frequency modulation command target value P4. Subsequently, it cooperates with the unit to track the frequency modulation command target value P4 until it enters the target dead zone of the frequency modulation command and returns within 10 seconds after entering the target dead zone, waiting for the next AGC frequency modulation command; Let P d be the fuzzy control mode output function of the large instruction, then Where: P c is the real-time output of the energy storage system.

2. The comprehensive frequency modulation performance index optimization method according to claim 1, wherein In step S2, the real-time output P of the energy storage system c : P c = P i -P j Where, P i is the output value that the energy storage combined unit should output; P j is the measured value of the real-time output of the unit.

3. The comprehensive frequency modulation performance index optimization method according to claim 2, wherein The energy storage combined unit in the fuzzy control mode of the large instruction should output the output value P i The calculation formula is as follows: In the formula: P1 is the output value of the power generation unit at the start; P4 is the AGC frequency modulation command target value; t1 starts timing from the moment when the output value of the power generation unit reaches the adjustment rate calculation threshold value P Ti ; t2 starts timing from the moment when the response process of the power generation unit increases or decreases with the unit load and reaches |ΔP i | = D% × |P4 - P1| - |P Ti |; β is a constant and takes 0.9; ΔP i is the potential output value of the energy storage system combined with the unit after L1 seconds, reflecting the ability to reach the dead zone of the AGC frequency modulation command target command. Among them, The described ΔP i is calculated as follows: Wherein, P ce is the rated power of the energy storage system, P kj is the rated capacity of the unit, V j is the real-time change rate of the unit load, P L is the output of the energy storage combined unit, P j is the measured value of the real-time output of the unit.

4. The comprehensive frequency modulation performance index optimization method according to claim 1, wherein In step S1, calculate the k1 value of the regulation rate index of each AGC frequency modulation command in real time. Among them, if the unit is a 600MW coal-fired unit, then Among them, the average standard regulation rate V of the AGC power generation unit sv is set to 1.

784.

5. The comprehensive frequency modulation performance index optimization method according to claim 4, characterized in that The power generation unit preferentially uses the fast response output of the energy storage system in response to the AGC frequency modulation command. At the moment when the AGC frequency modulation command is issued, it immediately outputs to reach the action dead zone value P acut , making the response time close to zero. Since the frequency modulation response speed of the energy storage system is much greater than that of the unit, the optimization effect reaches the best; Among them, the calculation formula for the time delay index k2 of the power generation unit in responding to the AGC frequency modulation command is: k2 = 1 - (response delay time of the power generation unit / 5min); Among them, the response delay time of the power generation unit refers to the delay time between the AGC action of the power generation unit and the power generation unit receiving the AGC frequency modulation command; When the response is output by the unit, it takes more than 30 seconds to reach the action dead zone. When encountering reverse regulation of the unit, the actual response time will be extended to more than 2 minutes, while the response of the energy storage system is approximately zero seconds, and the k2 value is close to 1.

6. The integrated frequency modulation performance index optimization method according to claim 1, wherein The optimization strategy for the accuracy k3 of the power generation unit's response to AGC frequency modulation commands is P Z When it is a small command, the power generation unit actively responds to reach the target value of the frequency modulation command. Within the output capacity range of the energy storage system's rated capacity, the time to track the target value of the frequency modulation command is until the calculated frequency modulation accuracy condition is met; while in P Z When it is a large command, it is necessary to make the time to track the target value of the frequency modulation command not meet the requirements of the calculated frequency modulation accuracy condition and not participate in the k3 calculation, so as to avoid the reduction of the accuracy of tracking the target value of the frequency modulation command due to the insufficient output capacity of the energy storage system. Among them, The calculation formula for the accuracy k3 of the power generation unit in responding to the AGC frequency modulation command is as follows: k3 = 1 - (regulation error of the power generation unit / allowable regulation error of the power generation unit); Among them, the regulation error of the power generation unit refers to the deviation between the actual output value and the command value of the power generation unit after responding to the AGC frequency modulation command; the allowable regulation error of the power generation unit is 1.5% of the rated output of the power generation unit.

7. The comprehensive frequency modulation performance index optimization method according to claim 6, characterized in that In the fixed control mode, during the response process, it is required that after the output power of the power generation unit enters the frequency modulation command target dead zone, it needs to continue to track the frequency modulation command target value for at least 40s. When the time to enter the target dead zone meets the calculation conditions of the k3 value, the output of the energy storage system should return to zero to prepare for responding to the next AGC frequency modulation command.

8. The comprehensive frequency modulation performance index optimization method according to claim 7, characterized in that The calculation conditions of the said k3 value, that is, the requirements for calculating the frequency modulation accuracy conditions, are: (1), The power generation unit enters the target dead zone and the continuous duration is greater than 20 seconds; (2) Calculation duration T of adjustment accuracy accu It is calculated starting from the moment when the power generation unit enters the target dead zone, with a maximum cumulative time of 40 seconds, that is, the number of valid data calculation points is 41.

9. The comprehensive frequency modulation performance index optimization method according to claim 2, characterized in that Set the automatic optimization mode in the fuzzy control mode, and find the best control strategy among the randomly issued frequency modulation command target values, so as to increase the k1 value and thus increase the comprehensive frequency modulation performance index k value; the steps are: After a k1 value greater than 1.0 is generated in a time period, the k1 values in subsequent time periods can only be higher than the previous k1 value. Otherwise, the response process is completed according to the fixed control mode without generating a k1 value. At the same time, in P c Add a variable integer a to the function, with an initial value of zero, and a = ΔP - 19 + 1. After calculating a k1 value, reassign the value immediately. Then In the formula: P xz Positive output function for the fixed control mode of small instructions; P xf Negative output function for the fixed control mode of small instructions; ΔP is the difference between the AGC frequency modulation command target value P4 and the output value P1 of the power generation unit at the start; That is, ΔP = P4 - P1, where P1 is the output value of the power generation unit at the start of the change of the AGC frequency modulation command; P4 is the AGC frequency modulation command target value; t1 is the timing value starting from the moment when the output value of the power generation unit reaches the regulation rate calculation threshold value P Ti moment, t2 is the timing value starting from the moment when the power generation unit response process reaches the condition of |ΔP i | = D% × |P4 - P1| - |P Ti |; It can be seen that after a k1 value greater than 1.0 is generated in a period, the subsequent k1 values can only be higher than the previous k1 value. Otherwise, the response process is completed according to the fixed control mode without generating a k1 value. Assuming that the distribution of the frequency modulation command is uniform, then the average value of k1 between 1.0 and 3 is k1 = 2. According to the above P c The k1 value generated by the function will be greater than 2.

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