An active power control optimization method for energy storage system

Abstract

The present application relates to a kind of active power control optimization methods of energy storage system, this method is mainly in different operating conditions under the control parameter setting of new energy energy storage system and active power coordinated control, to limit active regulation rate when the normal charge-discharge operation of energy storage system is guaranteed to run the stable operation of power grid, while, in primary frequency modulation, emergency power control etc. Operating condition is quickly adjusted to the purpose of providing support for power grid.The present application solves the problem that the active power regulation rate of current new energy energy storage system cannot adapt to automatic adjustment of operating condition and power coordinated control between different operating conditions is imperfect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy storage system access and control technology, and particularly relates to an active power control optimization method for a storage system. BACKGROUND

[0002] Due to the fast regulation rate of the storage, in order to ensure the safe operation of the power grid, the power grid institution requires that the regulation rate of the active power of the storage power station needs to be limited under normal operation conditions. For example, during the process of a power control capability test of a storage power station in a certain province of the South Grid, the active power of the storage power station rapidly changes in the range of 200 MW, which causes the active power of the AC outlet of a certain province in the South to instantaneously jump too much, triggers the AGC (Automatic Generation Control) anti-misoperation strategy, and causes the AGC to be temporarily suspended for a short time, which causes great disturbance to the safe operation of the system. At the same time, under special conditions such as primary frequency modulation and emergency power control, the storage system needs to respond quickly to provide support for the power grid. At present, the storage system applied to new energy basically only sets a set of active power regulation parameters in the PCS master control program, and can only respond to a unique operating condition under the same time scale. In addition, the PMS lacks a judgment strategy and a coordinated control strategy for different operating conditions. The innovation of the present application is to set active power control parameters for different operating conditions in the PCS, and to add a judgment and coordinated control strategy for different operating conditions in the PMS. Through the cooperation of the PMS and the PCS, the problem that the current new energy storage system only has a set of active power control parameters in the PCS and cannot automatically adjust the control parameters for different operating conditions such as normal operation, primary frequency modulation and emergency power support, and cannot perform coordinated control between power instructions for different operating conditions, is solved. SUMMARY

[0003] In order to solve the above problems, the present application provides an active power control optimization method for a storage system. The method uses active power control parameters for different operating conditions set in the PCS, and adds a judgment and coordinated control strategy for different operating conditions in the PMS. Through the cooperation of the PMS and the PCS, the new energy storage system can automatically adjust the control parameters for different operating conditions such as normal operation, primary frequency modulation and emergency power support, and can perform coordinated control between different operating conditions.

[0004] The present application is implemented as follows: while maintaining the active regulation rate limit during normal charging and discharging operation of the storage power station, the active regulation rate is not limited under conditions such as primary frequency modulation and emergency power control. The power control strategy optimization and adaptation need to be performed on the storage coordinated control system (PMS) and the storage converter (PCS) control system.

[0005] The specific method is as follows:

[0006] Step 1: distinguish the working conditions of the energy storage device of the energy storage power station: ① normal operation, meeting the condition that the charge and discharge rate is less than 50Pn% / min, Pn is the rated power of the energy storage; ② primary frequency control, meeting the conditions that the primary frequency lag time of the energy storage system is not greater than 1s, the primary frequency rise time is not greater than 3s, and the primary frequency regulation time is not greater than 4s; ③ emergency power support of the electrochemical energy storage, reaching the maximum dischargeable or chargeable power within 200ms;

[0007] Step 2: the state signal of PMS normal operation power regulation is recorded as N, first, two state signal points are added in PMS, a primary frequency action signal, that is, whether the frequency change of the grid connection point sampled by PMS exceeds the frequency modulation dead zone is triggered, and the state signal thereof is recorded as F; and an emergency power support signal, that is, an external signal received, which is composed of signals such as grid failure and excessive load, and the state signal thereof is recorded as S; the two state signal points realize reliable transmission of real-time information between PMS and PCS through the GOOSE (General Object Oriented Substation Event) communication protocol in the IEC 61850 communication protocol;

[0008] Step 3: active power control of grid voltage orientation is adopted, first, current instructions are obtained by preprocessing power instructions, then PI regulators are adopted for closed-loop control of the current, and at the same time, the d-axis current and q-axis current obtained by Clark coordinate transformation of the three-phase current in the feedforward link are decoupled and controlled, the current control loop can be simplified as a second-order system, K i / K p is removed to optimize the dynamic performance of the system, and the closed-loop output of the current control loop is:

[0009]

[0010] Among them:

[0011]

[0012] K p is the proportional coefficient, K i is the integral coefficient, R is the system resistance, L is the system inductance, ζ is the damping ratio of the second-order system, ω n is the undamped natural angular frequency, and the PI parameters (i.e. K p and K i ) of the PCS are designed according to the relationship between the time domain response of the second-order system and ω n , ζ, and the PI parameters (i.e. K Ni / K NP and K Fi / KFP , K Si / K SP ), each group of PI parameter control effect meets the requirements of step 1 corresponding state condition;

[0013] Step 4: PCS receives and stores the power instructions of three working conditions respectively, and comprehensively judges different energy storage operation conditions according to the remote power instructions and remote signal issued by PMS, so as to call different PI parameters to control the charging and discharging power. When F=S=0, the first kind of working condition in step 1 adopts the mode that PMS decomposes the power instruction and issues it to PCS to adjust gradually to the position, or PMS directly issues the power instruction which is executed gradually to the position by the PCS decomposed instruction, according to the different adjustment rate of the required energy storage system. After formula (1) is substituted, the power instruction executed by PCS in normal operation power adjustment is as follows:

[0014]

[0015] Formula (3) represents the floor function; I0 is the initial value of current; ΔI is the adjustment step, which is automatically calculated by the system according to the modified adjustment rate parameter configuration in the system; m is the round order number of multiple instructions, P ref represents the power instruction, I ref represents the current instruction;

[0016] Step 5: When F=1, S=0, the power instruction increment of the second kind of working condition in step 1 is calculated by PMS according to formula (5), and the power instruction executed by PCS in one frequency modulation is as formula (6):

[0017]

[0018] In the formula: ΔP t is the active power change of the energy storage system; K t is the active frequency modulation coefficient; Δf is the frequency deviation of the power system; f N is the rated frequency of the power system, unit: Hz; P t is the active power of the energy storage system.

[0019]

[0020] Step 6: When F=0, S=1, the power instruction of the third kind of working condition in step 1 is issued by PMS according to the direction of the required support power, and the full power charging / discharging instruction is executed by PCS to the position, and the power instruction executed by PCS is as follows:

[0021]

[0022] Step 7: When two or more of the three working conditions in step 1 are triggered at the same time, PMS increases the power instruction coordination logic strategy.

[0023] Further, the primary frequency modulation lag time in step 1 is the time required from the system frequency exceeding the frequency modulation dead zone to the actual output active power variation of the electrochemical energy storage system reaching 10% of the difference between the active target value and the initial value.

[0024] Further, the primary frequency modulation rise time in step 1 is the time required from the system frequency exceeding the frequency modulation dead zone to the actual output active power variation of the electrochemical energy storage power station reaching 90% of the difference between the active target value and the initial value.

[0025] Further, the primary frequency modulation adjustment time in step 1 is the shortest time from the system frequency exceeding the frequency modulation dead zone to the absolute value of the difference between the actual output active power of the electrochemical energy storage power station and the active target value always being no more than 2% of the difference between the active target value and the initial value.

[0026] Further, when two or more of the three working conditions in step 1 are triggered at the same time, the PMS increases the power instruction coordination logic strategy is as follows:

[0027] When S=1, only the emergency power support instruction of formula (7) is executed, and the PMS blocks the primary frequency modulation and normal regulation power instructions;

[0028] When S=0, F=1, and N=1, according to the coordination relationship between the primary frequency modulation and the normal regulation power, the following five kinds are divided, each of which is realized by the function on-off of the PMS program, and only one coordination mode can be put into operation at the same time, ① same direction superposition, reverse blocking normal regulation: when the directions of the primary frequency modulation and the normal regulation instructions are the same, the PCS executes the power instruction as the algebraic sum of the normal regulation amount and the primary frequency modulation response adjustment amount, and formula (6) is executed first and formula (4) is executed later; when the directions of the primary frequency modulation and the normal regulation instructions are opposite, the PMS blocks the normal regulation instruction, and the PCS executes the power instruction of formula (6); ② same direction superposition, reverse blocking primary frequency modulation: when the directions of the primary frequency modulation and the normal regulation instructions are the same, the PCS executes the power instruction as the algebraic sum of the normal regulation amount and the primary frequency modulation response adjustment amount, and formula (6) is executed first and formula (4) is executed later; when the directions of the primary frequency modulation and the normal regulation instructions are opposite, the PMS blocks the primary frequency modulation instruction, and the PCS executes the power instruction of formula (4); ③ instruction superposition: the PCS executes the power instruction as the algebraic sum of the normal regulation amount and the primary frequency modulation response adjustment amount, and formula (6) is executed first and formula (4) is executed later; ④ normal regulation priority: the PMS blocks the primary frequency modulation instruction, and the PCS executes the power instruction of formula (4); ⑤ primary frequency modulation priority, the PMS blocks the normal regulation instruction, and the PCS executes the power instruction of formula (6).

[0029] Compared with the prior art, the beneficial effects of the present application are:

[0030] The current energy storage system applied in new energy basically only sets a set of active power regulation parameters in the PCS master program, and can only respond to a unique operating condition under the same time scale. A set of parameters with faster regulation rate is generally used to preferentially meet the primary frequency modulation demand, and the power command is decomposed and issued by the PMS to meet the rate limit demand during normal regulation. Due to communication delay and other reasons, the command decomposed by the PMS cannot be very small, resulting in that the regulation effect of this method is actually step type and not smooth enough. At the same time, the PMS also lacks different operating condition judgment strategies and active power coordination control strategies for different operating conditions, and some additional primary frequency modulation devices are added to realize coordination control, which increases the cost. The present application adjusts the active power control parameters for different operating conditions in the PCS master control to adapt to different regulation rates, avoids the communication delay problem, and the regulation effect is close to ramp type during normal regulation, which is smooth and effective control rate. At the same time, through the cooperation of PMS and PCS, the problems that the current new energy storage system cannot automatically adjust the control parameters for different operating conditions such as normal operation, primary frequency modulation and emergency power support, and cannot perform power command coordination control between different operating conditions are solved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the vector control block diagram of the three-phase three-wire energy storage PCS of the present application oriented to grid voltage;

[0032] Figure 2 is the simplified control block diagram of the current loop of the present application;

[0033] Figure 3 is the implementation flowchart of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below in combination with embodiments. Those skilled in the art can understand that all the terms (including technical terms and scientific terms) used herein have the same meaning as that generally understood by those skilled in the art to which the present application belongs, unless otherwise defined. Those skilled in the art will understand that the following embodiments are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the embodiments, it is carried out according to the technology or condition described in the literature in the art or according to the product instruction. If the reagent or instrument used is not specified by the manufacturer, it is a conventional product that can be obtained by purchase.

[0035] EMBODIMENT:

[0036] An active power control optimization method of an energy storage system, which utilizes the active power control parameters of the PCS under different operating conditions, adds the judgment and coordinated control strategy of different operating conditions in the PMS, and realizes the automatic adjustment of the control parameters of the new energy storage system under different operating conditions such as normal operation, primary frequency modulation, and emergency power support through the cooperation of the PMS and the PCS, while coordinating the different operating conditions.

[0037] While maintaining the active regulation rate limit during the normal charging and discharging operation of the energy storage power station, the active regulation rate is not limited under the conditions of primary frequency modulation and emergency power control. The power control strategy optimization and adaptation of the energy storage cooperative control system PMS and the energy storage converter PCS control system are required. The specific method is as follows:

[0038] Step 1: The working conditions of the energy storage device are divided into: ① normal operation, which satisfies the charging and discharging rate less than 50Pn% / min (Pn is the rated power of the energy storage, the value can be set); ② primary frequency modulation control, which needs to satisfy the primary frequency modulation hysteresis time (from the system frequency exceeding the frequency modulation dead zone to the actual output active power change of the electrochemical energy storage system reaching 10% of the difference between the active target value and the initial value) not more than 1s, the primary frequency modulation rise time (from the system frequency exceeding the frequency modulation dead zone to the actual output active power change of the electrochemical energy storage station reaching 90% of the difference between the active target value and the initial value) not more than 3s, and the primary frequency modulation adjustment time (from the system frequency exceeding the frequency modulation dead zone to the absolute value of the difference between the actual output active power of the electrochemical energy storage station and the active target value always not more than 2% of the difference between the active target value and the initial value) not more than 4s; ③ electrochemical energy storage emergency power support, which reaches the maximum dischargeable or chargeable power within 200ms.

[0039] Step 2: The PMS normal operation power regulation state signal is recorded as N. First, two state signal points are added in the PMS, namely the primary frequency modulation action signal (triggered by the PMS sampling grid point frequency change whether exceeding the frequency modulation dead zone), the state signal is recorded as F, and the emergency power support signal (received external signal, synthesized by signals such as grid fault and heavy load), the state signal is recorded as S; the two state signal points realize the reliable transmission of real-time information between PMS and PCS through the Generic Object Oriented Substation Event (GOOSE) communication protocol in IEC 61850.

[0040] Step 3: The active power control simplified block diagram of grid voltage orientation is as follows Figure 1The current command is obtained by pre-processing the power command, and then the PI regulator is used for closed-loop control of the current, while the feedforward link decouples the control of the d-axis current and the q-axis current. The current control loop can be simplified as a second-order system as shown in the figure, and K Figure 2 i p The low-frequency pole introduced by the resistance is eliminated, and the system dynamic performance is optimized, and the closed-loop output of the current control loop is:

[0041]

[0042] where:

[0043]

[0044] ζ is the damping ratio of the second-order system, ω n is the undamped natural angular frequency, and the PI parameters of the PCS are designed according to the relationship between the time-domain response of the second-order system and ω n , ζ, which adjusts between the speed and stability of the system response. Three sets of PI parameters for the active power control current loop need to be stored in the PCS main program, and the control effect of each set of PI parameters meets the requirements of step 1;

[0045] Step 4: The PCS receives and stores the power commands of three kinds of working conditions, and calls different PI parameters for charge and discharge power control according to the remote power command and remote signal issued by the PMS. When F=S=0, the first kind of working condition in step 1 can adopt the method of gradually adjusting to the required storage system adjustment rate or directly issuing the power command by the PMS, and the PCS executes the power command as follows:

[0046]

[0047] where formula (3) represents the floor function; I0 is the initial current value; ΔI is the adjustment step, which is automatically calculated by the system according to the modified adjustment rate parameter configuration; and m is the round number of the multi-round command.

[0048] Step 5: When F=1 and S=0, the power command increment of the second kind of working condition in step 1 is calculated by the PMS according to formula (5), and the PCS executes the power command as formula (6):

[0049]

[0050] where: ΔP t is the active power change of the storage system; K t is the active frequency modulation coefficient; and Δf is the frequency deviation of the power system.​​N is the rated frequency of the power system, unit: Hz; f is the grid-connected point frequency; P t is the active power of the energy storage system.

[0051]

[0052] Step 6: When F = 0 and S = 1, the power command of the third condition in step 1 is issued by the PMS according to the direction of the power to be supported, and the full power charge / discharge command is executed by the PCS to the position, and the power command executed by the PCS is as follows:

[0053]

[0054] Step 7: When two or more of the three conditions in step 1 are triggered at the same time, the PMS increases the power command coordination logic strategy as follows:

[0055] When S = 1, only the emergency power support command of formula (7) is executed, and the PMS is locked for primary frequency modulation and normal regulation power command;

[0056] When S = 0, F = 1, and N = 1, according to the coordination relationship between primary frequency modulation and normal regulation power, it is divided into the following five kinds, each of which is realized by PMS program function on-off, and only one coordination mode can be put into operation at the same time. ① Same direction superposition, reverse lock normal regulation: when the direction of primary frequency modulation and normal regulation command is the same, the PCS executes the power command as the algebraic sum of normal regulation and primary frequency modulation response regulation, and formula (6) is executed first, and then formula (4) is executed. When the direction of primary frequency modulation and normal regulation command is opposite, the PMS locks the normal regulation command, and the PCS executes the power command of formula (6); ② Same direction superposition, reverse lock primary frequency modulation: when the direction of primary frequency modulation and normal regulation command is the same, the PCS executes the power command as the algebraic sum of normal regulation and primary frequency modulation response regulation, and formula (6) is executed first, and then formula (4) is executed. When the direction of primary frequency modulation and normal regulation command is opposite, the PMS locks the primary frequency modulation command, and the PCS executes the power command of formula (4); ③ Command superposition: the PCS executes the power command as the algebraic sum of normal regulation and primary frequency modulation response regulation, and formula (6) is executed first, and then formula (4) is executed. ④ Normal regulation priority: the PMS locks the primary frequency modulation command, and the PCS executes the power command of formula (4); ⑤ Primary frequency modulation priority, the PMS locks the normal regulation command, and the PCS executes the power command of formula (6).

[0057] As shown in Figure 1 , three-phase voltage U abc and current i abcThe system phase angle is input into the PCS main controller (such as a DSP digital signal processing chip). The sampling signal is first transformed by Clark to obtain the d-axis and q-axis components, and then subtracted from the current command calculated by the execution power command of the PCS in the embodiment. The deviation is subjected to feedforward decoupling and PI control algorithm to obtain a voltage reference value. The voltage reference value is subjected to coordinate inverse transformation to generate a modulation signal, and then a modulation algorithm (such as SPWM sinusoidal pulse width modulation, SVPMW voltage space vector modulation, etc.) is used to generate the driving waveform required for the operation of the switching device IGBT (insulated gate bipolar transistor) in the PCS, and finally the command power is output to complete the closed-loop control.

[0058] Application examples:

[0059] A new energy storage station is equipped with a 10MW / 20MWh energy storage system. The power control PI parameters for emergency power support, primary frequency regulation, and normal regulation are set for each. The energy storage power symbol "-" is defined as charging, and "+" is defined as discharging. The command P is also defined. The numbers in the table below represent the command round, and the letters represent the adjustment parameters for the execution of the command round. The initial current value I0 is set to 0; the ΔI adjustment step is 5% I n ;K t The active frequency modulation coefficient is 100, and Δf is the power system frequency deviation of +0.15 Hz. The power increment calculated after frequency modulation is -3 MW. The normal regulation power command is set to +1 MW. Table 1 shows typical results for this example.

[0060] Table 1

[0061]

[0062] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for active power control optimization of an energy storage system, characterized by: The following steps are taken: Step 1: distinguish the working conditions of the energy storage device of the energy storage power station: ① normal operation, meet the charge and discharge rate less than 50Pn% / min, Pn is the rated power of the energy storage; ② primary frequency control, need to meet the primary frequency control hysteresis time of the energy storage system is not more than 1s, the primary frequency control rising time is not more than 3s, the primary frequency control adjustment time is not more than 4s, ③ emergency power support of electrochemical energy storage, reach the maximum dischargeable or chargeable power within 200ms; Step 2: the state signal of PMS normal operation power regulation is recorded as N, first add two state signal points in PMS, one is primary frequency control action signal, which is triggered by whether the frequency change of grid-connected point sampled by PMS exceeds the frequency dead zone, and its state signal is recorded as F; the other is emergency power support signal, which is composed of external signals received from grid failure and heavy load signals, and its state signal is recorded as S; the reliable transmission of real-time information between PMS and PCS is realized through the generic object-oriented substation event (GOOSE) communication protocol in IEC 61850 communication protocol; Step 3: Active power control with grid voltage orientation vector, first get the current command by preprocessing the power command, then use PI regulator for closed-loop control of the current, while the feedforward link decouples the d-axis current and q-axis current obtained by Clark coordinate transformation of the three-phase current, the current control loop can be simplified as a second-order system, let K i / K p = R / L to eliminate the low-frequency pole introduced by the resistance and inductance, optimize the dynamic performance of the system, and the closed-loop output of the current control loop is: Wherein: K p is the proportional coefficient, K i is the integral coefficient, R is the system resistance, L is the system inductance, ζ is the damping ratio of the second-order system, ω n is the undamped natural angular frequency, and ω n is adjusted between the rapidity and stability of the system response according to the relationship between the time-domain response of the second-order system and ω p , and the PI parameters K i and K Ni of the PCS are designed. NP , K Fi , K FP , K Si , and K SP , and the control effects of each group of PI parameters meet the requirements of the corresponding state conditions in step 1. Step 4: PCS receives and stores the power commands of the three working conditions respectively, comprehensively judges different energy storage operating conditions according to the remote power command and remote signal issued by PMS, and calls different PI parameters to control the charge and discharge power; when F=S=0, step 1, the first kind of working condition, according to the different adjustment rate of the required energy storage system, adopts the method of PMS decomposing power command to adjust step by step to the right, or directly issuing power command by PMS and executing the decomposed command by PCS step by step to the right, and then formula (1) is substituted to get the power command executed by PCS in normal operation power regulation as follows: Formula (3) represents a down-rounding function; I0 is an initial value of the current; ΔI is an adjustment step, which is automatically calculated by the system after the modification of the adjustment rate parameter configuration in the system; m is the round order number of the multi-round instruction, P ref represents a power instruction, I ref represents a current instruction; Step 5: when F=1, S=0, step 1, the second kind of working condition, the power command increment is calculated by PMS according to formula (5), and the power command executed by PCS in primary frequency control is as formula (6): wherein: ΔP t is the active power variation of the energy storage system; K t is the active frequency regulation coefficient; Δf is the power system frequency deviation; f N is the power system rated frequency, in Hz; P t is the active power of the energy storage system Step 6: when F=0, S=1, step 1, the third kind of working condition, the power command is issued by PMS according to the direction of the required support power, and the full power charge / discharge command is executed by PCS to the right, and the power command executed by PCS is as follows: Step 7: when two or more of the three working conditions in step 1 are triggered at the same time, PMS increases the logic strategy of issuing power command coordination.

2. The method of claim 1, wherein: The primary frequency control hysteresis time in step 1 is the time required from the system frequency exceeding the frequency dead zone to the actual output active power of the electrochemical energy storage system changing by 10% of the difference between the active target value and the initial value.

3. The method of claim 1, wherein: The primary frequency control rising time in step 1 is the time required from the system frequency exceeding the frequency dead zone to the actual output active power of the electrochemical energy storage power station changing by 90% of the difference between the active target value and the initial value.

4. The method of claim 1, wherein: The primary frequency control adjustment time in step 1 is the shortest time from the system frequency exceeding the frequency dead zone to the absolute value of the difference between the actual output active power of the electrochemical energy storage power station and the active target value always being not more than 2% of the difference between the active target value and the initial value.

5. The method of claim 1, wherein: The PMS increases the power command coordination logic strategy as follows when two or more of the three working conditions in step 1 are triggered simultaneously: When S = 1, only the emergency power support command of formula (7) is executed, and the PMS blocks the primary frequency modulation and normal regulation power commands; When S = 0, F = 1, and N = 1, the coordination relationship between the primary frequency modulation and normal regulation power is divided into the following five categories, each of which is realized by the PMS program function being turned on or off. Only one coordination mode can be turned on at the same time, ① same direction superposition, reverse lock normal regulation: when the directions of the primary frequency modulation and normal regulation commands are the same, the PCS executes the power command as the algebraic sum of the normal regulation amount and the primary frequency modulation response regulation amount, and formula (6) is executed first, followed by formula (4). When the directions of the primary frequency modulation and normal regulation commands are opposite, the PMS blocks the normal regulation command, and the PCS executes the power command of formula (6); ② same direction superposition, reverse lock primary frequency modulation: when the directions of the primary frequency modulation and normal regulation commands are the same, the PCS executes the power command as the algebraic sum of the normal regulation amount and the primary frequency modulation response regulation amount, and formula (6) is executed first, followed by formula (4). When the directions of the primary frequency modulation and normal regulation commands are opposite, the PMS blocks the primary frequency modulation command, and the PCS executes the power command of formula (4); ③ command superposition: the PCS executes the power command as the algebraic sum of the normal regulation amount and the primary frequency modulation response regulation amount, and formula (6) is executed first, followed by formula (4); ④ normal regulation priority: the PMS blocks the primary frequency modulation command, and the PCS executes the power command of formula (4); ⑤ primary frequency modulation priority, the PMS blocks the normal regulation command, and the PCS executes the power command of formula (6).

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