Multi-time scale operation method of wind-storage system for improving active power regulation capability

Abstract

The present invention provides a multi-time scale operation method of a wind storage system for improving the active power regulation capability, including: in order to reduce the number of energy storage charge and discharge state conversions, the energy storage units are divided into charging and discharging groups to bear the charging and discharging requirements respectively, and according to the charge state of the energy storage units, the energy storage units in the charging and discharging groups are updated by a dynamic grouping mechanism of the energy storage units; secondly, a multi-time scale operation model of the wind storage system is constructed based on the model predictive control method to improve the active power regulation capability of the wind farm at different time scales; a power allocation strategy for the energy storage unit is proposed, and the orderly operation of the energy storage unit is finely managed to optimize the power distribution of the energy storage output among the units. The multi-time scale operation method of a wind storage system for improving the active power regulation capability provided by the present invention can reduce the number of energy storage charge and discharge state conversions, can realize the strict implementation of the power generation plan by the wind storage system, and can also respond to the active power regulation demand of the system in real time on the basis of realizing its own stable grid connection.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage power stations, and in particular to a multi-time scale operation method of a wind energy storage system for improving active power regulation capability. Background Art

[0002] Nowadays, the active power regulation capability of wind power is poor, which aggravates the power regulation pressure of the system. The wind-storage system can effectively improve the active power regulation characteristics of the wind farm by adopting a reasonable regulation scheme, that is, the ability to track the power generation plan, smooth the grid-connected fluctuations and respond to the frequency regulation requirements of the system. Domestic and foreign scholars have conducted certain research on the operation strategy of improving the active power regulation capability of the wind-storage system. However, the operation strategies for improving the active power regulation capability proposed in the research are mostly aimed at the active power regulation capability of a single time scale, without considering the coordination problem between the active power regulation capabilities of different time scales; in addition, the service life of battery energy storage is affected by the number of charge and discharge conversions, and the configuration of two battery energy storages to meet the charge and discharge requirements respectively and the optimization control of the energy storage unit in a single battery energy storage can effectively reduce the number of energy storage charge and discharge state conversions. It is necessary to consider reducing the number of energy storage charge and discharge state conversions when determining the operation strategy of the wind-storage system to extend the operation life of the energy storage. Therefore, it is very necessary to design a multi-time scale operation method for wind-storage systems to improve the active power regulation capability. Summary of the invention

[0003] The purpose of the present invention is to provide a multi-time scale operation method of a wind-storage system for improving the active power regulation capability, which can realize the multi-time scale operation of the wind-storage system for improving the active power regulation capability.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A multi-time scale operation method of a wind power storage system for improving active power regulation capability comprises the following steps:

[0006] Step 1: Divide the active regulation capacity of the wind-storage system into two time scales of 15 minutes and 5 minutes. Configure a dual-battery energy storage group consisting of several energy storage units in the wind farm to compensate for the deviation every 15 minutes, smooth out the wind power output fluctuation every 5 minutes, and respond to the system frequency regulation requirements. Specifically:

[0007] According to the multi-time scale dispatching operation mode of conventional energy units participating in the system, combined with the wind power operation characteristics and regulation requirements, the active regulation capacity of the wind storage system is divided into two time scales of 15 minutes and 5 minutes. A dual battery energy storage group consisting of several energy storage units is configured in the wind farm, namely battery energy storage group A and battery energy storage group B. Battery energy storage group A is used to compensate for the deviation between wind power output and power generation plan every 15 minutes, and battery energy storage group B is used to smooth the fluctuation of wind power output every 5 minutes and implement the response system frequency regulation requirements;

[0008] Step 2: Divide the energy storage units of the dual-battery energy storage group into a charging group and a discharging group, and update the energy storage units in the charging group and the discharging group through the dynamic grouping mechanism of the energy storage unit, specifically:

[0009] The energy storage units of battery energy storage group A and battery energy storage group B are divided into a charging group and a discharging group, wherein the number of energy storage units in the charging group is m1, and the number of energy storage units in the discharging group is m2. If the energy storage units in the m1 charging group cannot meet the charging demand in this period, the discharging group selects n energy storage units from small to large according to SOC to assist in completing the charging shortage, wherein n is the minimum number to complete the shortage. When the charging of m1+n energy storage units is completed, the energy storage units in the n discharging groups that assist in charging are added to the charging group at the next moment, and n energy storage units in the energy storage units in the charging group are selected from large to small according to SOC to be added to the discharging group, so that the energy storage units of the charging and discharging groups become m1 and m2 again. If the charging and discharging groups complete the total charging and discharging demands separately in this period, the energy storage units in the charging and discharging groups remain unchanged in the next period. When grouping, if there are energy storage units in the charging group If there is an energy storage unit, then the energy storage unit is added to the discharge group, and the energy storage unit with the minimum SOC is selected from the discharge group to be added to the charging group. The state of charge and the maximum charge and discharge power of each energy storage unit are calculated. By summing up, the maximum charge and discharge power and state of charge of the battery energy storage groups A and B can be obtained as follows:

[0010]

[0011]

[0012]

[0013] In the formula, S b,j,t , are the SOC of energy storage unit j at time t and its upper and lower limits, which are 0.8 and 0.2 respectively. is the rated power and capacity of energy storage unit j, P b,j,t , are the operating power and the maximum allowable charging and discharging power of energy storage unit j at time t, η is the charging and discharging efficiency, η c , η d Both are 0.9, T c It is the energy storage control cycle;

[0014] Step 3: According to the MPC method, the output plan of the dual-battery energy storage group every 15 minutes and the wind storage system tracking planned power generation are rolled out, and the energy storage output is allocated to the energy storage units in the charging group and the discharging group, so that the wind storage system can track the power generation plan;

[0015] Step 4: According to the MPC method, the dual-battery energy storage group's output plan every 5 minutes and the wind storage system's fluctuating operating power are rolled out to optimize, and the energy storage output is allocated to the energy storage units in the charging group and the discharging group to achieve the smoothing of wind power grid-connected fluctuations. On the basis of smoothing wind power fluctuations, the wind storage system reserves frequency regulation standby to respond to the system's frequency regulation needs in real time, and the frequency regulation standby reserved and response power is allocated to the charging group and the discharging group energy storage units to achieve the wind storage system's real-time response to the system's frequency regulation needs;

[0016] Step 5: Construct evaluation indicators to evaluate the wind-storage system's ability to track power generation plans, smooth wind power grid-connected fluctuations, and respond to frequency regulation needs.

[0017] Optionally, in step 3, the output plan of the dual-battery energy storage group every 15 minutes and the wind storage system tracking planned power generation are rolling optimized according to the MPC method, specifically:

[0018] Based on the current wind-storage system power generation plan, the actual wind power and the predicted power in the future period, the charging group and discharging group of the battery energy storage group A and the energy storage state, the optimization of the energy storage charge state and the minimum energy storage power are taken as the goal, and the constraints are considered. A 15-minute scale operation model of the wind-storage system based on MPC is established, where the control cycle and rolling step are 15 minutes, the prediction cycle is 1 hour, and the 15-minute scale power balance equation of the wind-storage system is:

[0019]

[0020] Based on the 15-minute scale power balance equation of the wind-storage system, the state space equation of the wind-storage system is established as the prediction model of MPC:

[0021]

[0022]

[0023]

[0024] D1=[1 0 0] T (8)

[0025] Where: P′ gz,t is the power generated by the wind energy storage system when the single energy storage group A of the battery energy storage group is in operation at time t, They are the single energy storage action power of battery energy storage group A at time t and the power increment compared with the previous moment, are the wind power every 15 minutes and the power increment compared with the previous moment, A1, B1, C1, and D1 are the model coefficient matrices. is the rated capacity of the battery energy storage group A, T c1 is the control period of battery energy storage group A, which is 15 minutes, and the state quantity is is the average SOC value of a single battery storage group A, and the control quantity Disturbance Output

[0026] The objective function of the rolling optimization of the wind-storage system with a time scale of 15 minutes is established as follows:

[0027]

[0028] Where M is the number of 5 time periods in the rolling optimization cycle;

[0029] The constraints of the wind-storage system on a 15-minute time scale are established, including the operation constraints of the energy storage system, the plan allowable deviation constraints, and the plan shortage power assistance constraints. The operation constraints of the energy storage system are:

[0030]

[0031] In the formula, They are the maximum charging power of the charging group and the maximum discharging power of the discharging group of the battery energy storage group A at time t respectively; They are the upper and lower limits of SOC of battery energy storage group A respectively;

[0032] The constraints for plan deviation are:

[0033]

[0034] Where: are the upper and lower limits of the allowable deviation of the power generation plan, is the power generation plan of the wind storage system at time t, δ pc Allowable deviation rate for power generation plan;

[0035] The planned power shortage assistance constraints are:

[0036]

[0037] In the formula, They are the maximum charging power of the discharge group and the maximum discharging power of the charging group of the battery energy storage group A at time t respectively;

[0038] According to the constraints and combined with the prediction model, we can solve the P at time t. gz,t and in, Scroll the time to the next moment, update the state input and repeat the above steps.

[0039] Optionally, in step 4, the output plan of the dual-battery energy storage group every 5 minutes and the wind storage system to smooth the fluctuating operating power are rolling optimized according to the MPC method, specifically:

[0040] Based on the planned power generation of the wind-storage system every 15 minutes, the actual power of wind power every 5 minutes\the predicted power of future time periods, the charging group and discharging group of the battery energy storage group B and the energy storage status, the 5-minute scale operation model of the wind-storage system based on MPC is established with the goal of optimizing the energy storage SOC and minimizing the energy storage power, and considering the constraints. The control cycle and rolling step are 5 minutes, the prediction cycle is 20 minutes, and the 5-minute scale wind-storage system fluctuation balance equation is:

[0041]

[0042] Based on the 5-min scale power balance equation of the wind-storage system, the state space equation of the wind-storage system is established as the prediction model of MPC:

[0043]

[0044]

[0045]

[0046] D2=[1 0 0] T (17)

[0047] Where: is the wind energy storage system operating power after the single group of battery energy storage group B smoothes the fluctuation at time t, They are the power fluctuation smoothing of the single energy storage of battery energy storage group B at time t and the power increment compared with the previous moment, are the wind power every 5 minutes and the power increment compared with the previous moment, A2, B2, C2, and D2 are the model coefficient matrices. is the rated capacity of battery energy storage group B, T c2 is the control period of battery energy storage group B, which is 5 minutes, and the state quantity is is the average SOC value of a single battery storage group B, and the control quantity Disturbance Output

[0048] The objective function of rolling optimization of wind-storage system with a time scale of 5 minutes is established as follows:

[0049]

[0050] The constraints of the wind-storage system with a time scale of 5 minutes are established, including the grid-connected power fluctuation constraint and the fluctuation over-limit power assistance constraint. The grid-connected power fluctuation constraint is:

[0051]

[0052] In the formula, The installed capacity of the wind farm, is the grid-connected power of the wind-storage system at the previous moment, δ bd Allowing fluctuations for grid connection;

[0053] The fluctuation over-limit power assistance constraint condition is:

[0054]

[0055] In the formula, They are the maximum charging power of the discharge group and the maximum discharging power of the charging group of the battery energy storage group B at time t respectively;

[0056] According to the constraints and combined with the prediction model, the wind-storage system is solved to smooth the fluctuating output And battery energy storage group B smoothes out fluctuating output in, Scroll the time to the next moment, update the state input and repeat the above steps, where the After that, the wind energy storage system reserves frequency regulation and responds to the system frequency regulation demand in real time. When the energy storage cannot provide backup, the wind turbine will reduce load and reserve backup P under the constraint of grid-connected power fluctuation. wJz,t When the reserve power has been used to respond to the system frequency regulation demand, if the wind turbine is in a load-reducing state, the wind turbine will be given priority to respond to the frequency regulation power, and the energy storage will bear the remaining frequency regulation demand.

[0057]

[0058] Determine whether the energy storage unit has the remaining regulation capacity to smooth fluctuations and retain the minimum reserve If yes, the SOC is within the primary limit, and the energy storage unit reserves additional backup power. Calculate the frequency regulation reserve power of the wind power storage system Down frequency regulation reserve power And grid-connected power for:

[0059]

[0060]

[0061]

[0062] In the formula, λ minis the minimum frequency regulation reserve rate, which is 0.1. The wind storage system actually responds to the frequency regulation demand power. Allocate power for energy storage units to smooth fluctuations, P wJcl,t Reduce wind power output in real time.

[0063] Optionally, in step 3, according to the output plan every 15 minutes and the wind storage system tracking the planned power generation, the energy storage output is allocated to the energy storage units in the charging group and the discharging group, so that the wind storage system tracks the power generation plan, which specifically includes the following steps:

[0064] S1: According to the power allocation priority of the energy storage unit, a set of energy storage unit action priorities is constructed according to the energy storage unit allocation priority;

[0065] S2: Construct an energy storage unit action priority set according to the energy storage unit allocation priority, and establish an energy storage unit power allocation strategy that takes the action priority into consideration.

[0066] Optionally, in step 4, according to the output plan every 5 minutes and the wind storage system's fluctuating operating power, the energy storage output is allocated to the energy storage units in the charging group and the discharging group, so as to realize the smoothing of wind power grid-connected fluctuations. On the basis of smoothing wind power fluctuations, the wind storage system reserves frequency regulation standby power to respond to the system frequency regulation requirements in real time, and allocates the frequency regulation standby reserved and response power to the energy storage units in the charging group and the discharging group, so as to realize the wind storage system's real-time response to the system frequency regulation requirements, which specifically includes the following steps:

[0067] D1: Based on the power allocation priority of the energy storage unit, a set of energy storage unit action priorities is constructed according to the energy storage unit allocation priority;

[0068] D2: Construct an energy storage unit action priority set based on the energy storage unit allocation priority, and establish an energy storage unit power allocation strategy that takes action priority into consideration;

[0069] D3: Construct a frequency modulation standby reserved response set and establish a power allocation strategy based on the set.

[0070] Optionally, in S1 or D1, according to the power allocation priority of the energy storage unit, an energy storage unit action priority set is constructed according to the energy storage unit allocation priority, specifically:

[0071] Determine the upper and lower limits of SOC And SOC secondary upper and lower limits for:

[0072]

[0073]

[0074] Determine the action priority of the energy storage unit according to the SOC limit. If the SOC of the energy storage unit is in the range and If the energy storage unit SOC is in the range of and If the energy storage unit is within the first, second, or third discharge priority level, a storage unit action priority set is constructed according to the energy storage unit allocation priority level, including set A, set B, set G1, set G2, set G3, set G4, set G5, set G6, set G7, set G8, set G9, and set G 10 , set G 11 , set G 12 and set G 13 ; Among them, set A is the energy storage unit of the charging group, set B is the energy storage unit of the discharging group, and set G1 is The set G2 is The set G3 is The set G4 is Set G5 is Set G6 is the same set A in sets G3 to G5 and the same set B in sets G1 and G2. Set G7 is the same set A in set G2 and the same set B in set G4. Set G8 is the same set A in set G1 and the same set B in set G5. Set G9 is the same set A in sets G1 to G4 and the same set B in sets G2 and G5. Set G 10 For the set A in G5 and the set B in G1, the set G 11 The energy storage unit assisting discharge in the charging group and the energy storage unit assisting discharge in the discharging group are grouped as G 12 For the set G 11 The same set G9, set G 13 For the set G 11 The same set G 10 .

[0075] Optionally, in S2 or D3, an energy storage unit action priority set is constructed according to the energy storage unit allocation priority, and an energy storage unit power allocation strategy considering the action priority is established, specifically:

[0076] Get the total energy storage power allocated by the energy storage unit and maximum adjustable power like Then the power allocated to the energy storage unit in G6 is:

[0077]

[0078] In the formula, g6 is the number of energy storage units in the set G6;

[0079] like

[0080] Then the energy storage unit in G6 is Allocate power and calculate the power shortage at this time The energy storage unit in G7 is The ratio distribution

[0081]

[0082]

[0083]

[0084] In the formula, It is the difference power that does not enter the SOC primary limit after the energy storage unit is activated;

[0085] like

[0086] Then the energy storage units in G6 and G7 are The action cannot meet the demand, calculate the power shortage The energy storage unit in G7 can be adjusted according to the remaining power With G8 energy storage unit The ratio distribution for:

[0087]

[0088]

[0089] when Calculate the total power shortage when The auxiliary power allocation strategy is used to allocate the power shortage. G 12 The power distribution of the energy storage unit is:

[0090]

[0091] In the formula, g 12 For the set G 12 The number of energy storage units;

[0092] when G 12 The energy storage unit cannot complete the total power shortage and Allocate power and calculate the total power shortage at this time By G 13 The energy storage unit is allocated:

[0093]

[0094] like All energy storage units

[0095] Optionally, in step 5, an evaluation index is constructed to evaluate the wind-storage system's ability to track power generation plans, smooth wind power grid-connected fluctuations, and respond to frequency regulation needs, specifically:

[0096] The evaluation indicators are constructed as follows:

[0097]

[0098]

[0099]

[0100] In the formula, T is 24h, W is gz , W bd , W tp 、p gz , pbd, p tp They are the total power of tracking plan deviation, the total power of power fluctuation exceeding the limit, the total power of responding to frequency regulation demand shortage and the corresponding occurrence probability. The wind storage system is ready to respond to the frequency modulation demand, and the battery energy storage charge and discharge conversion times indicator CS b for:

[0101]

[0102]

[0103] Where P b,nz It is the action power of the last energy storage unit which is not 0.

[0104] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the multi-time scale operation method of the wind storage system for improving the active power regulation capability provided by the present invention can finely manage the orderly operation of the charging and discharging group energy storage units, reduce the number of energy storage charging and discharging state conversions, and the multi-time scale operation strategy of the wind storage system proposed by the method includes two time scales of 15min and 5min, which can realize the strict implementation of the power generation plan by the wind storage system, and can also respond to the system active power regulation needs in real time on the basis of achieving its own stable grid connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given to the drawings required for use in the embodiments. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0106] Figure 1 This is a schematic diagram of the wind storage system structure;

[0107] Figure 2 This is a schematic diagram of the multi-time scale operation concept of the wind storage system;

[0108] Figure 3 It is a schematic diagram of the action priority of the energy storage unit;

[0109] Figure 4 Construct a rule diagram for the collection;

[0110] Figure 5 It is a schematic diagram of power distribution of energy storage unit;

[0111] Figure 6 To track the power generation plan effect diagram;

[0112] Figure 7 It is a schematic diagram of the SOC of the battery energy storage group A;

[0113] Figure 8 This is a schematic diagram of the grouping and unit operation of the battery energy storage group A;

[0114] Fig. 9 This is the wind power fluctuation smoothing effect diagram;

[0115] Fig.10 This is the frequency modulation effect diagram of the wind storage system response;

[0116] Fig.11 This is a schematic diagram of the grouping and unit operation of the battery energy storage group B;

[0117] Fig.12 It is a schematic diagram of the SOC of the battery energy storage group B;

[0118] Fig.13 This is the actual grid-connected effect diagram of the wind storage system;

[0119] Fig.14 Schematic diagram of confidence in the regulation capacity of wind-storage system and thermal power units. DETAILED DESCRIPTION

[0120] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0121] The purpose of the present invention is to provide a multi-time scale operation method for a wind storage system for improving the active power regulation capability, which can finely manage the orderly operation of the charging and discharging group energy storage units, reduce the number of energy storage charging and discharging state conversions, enable the wind storage system to strictly implement the power generation plan, and respond to the system active power regulation needs in real time on the basis of achieving its own stable grid connection.

[0122] The multi-time scale operation method of a wind-storage system for improving active power regulation capability provided by an embodiment of the present invention comprises the following steps:

[0123] Step 1: Divide the active regulation capacity of the wind-storage system into two time scales of 15 minutes and 5 minutes. Configure a dual-battery energy storage group consisting of several energy storage units in the wind farm to compensate for the deviation every 15 minutes, smooth out the wind power output fluctuation every 5 minutes, and respond to the system frequency regulation requirements;

[0124] Step 2: Divide the energy storage units of the dual-battery energy storage group into a charging group and a discharging group, and update the energy storage units in the charging group and the discharging group through the energy storage unit dynamic grouping mechanism;

[0125] Step 3: According to the MPC method, the output plan of the dual-battery energy storage group every 15 minutes and the wind storage system tracking planned power generation are rolled out, and the energy storage output is allocated to the energy storage units in the charging group and the discharging group, so that the wind storage system can track the power generation plan;

[0126] Step 4: According to the MPC method, the dual-battery energy storage group's output plan every 5 minutes and the wind storage system's fluctuating operating power are rolled out to optimize, and the energy storage output is allocated to the energy storage units in the charging group and the discharging group to achieve the smoothing of wind power grid-connected fluctuations. On the basis of smoothing wind power fluctuations, the wind storage system reserves frequency regulation standby to respond to the system's frequency regulation needs in real time, and the frequency regulation standby reserved and response power is allocated to the charging group and the discharging group energy storage units to achieve the wind storage system's real-time response to the system's frequency regulation needs;

[0127] Step 5: Construct evaluation indicators to evaluate the wind-storage system's ability to track power generation plans, smooth wind power grid-connected fluctuations, and respond to frequency regulation needs.

[0128] The multi-time scale operation concept of the wind storage system of the present invention is as follows: Figure 2 As shown, the wind power output predicted a day before is used as the power generation plan for the next day, which will not be described here.

[0129] In step 1, the active regulation capacity of the wind-storage system is divided into two time scales of 15 minutes and 5 minutes. A dual-battery energy storage group consisting of several energy storage units is configured in the wind farm to compensate for the deviation every 15 minutes, smooth the wind power output fluctuation every 5 minutes, and respond to the system frequency regulation requirements. Specifically:

[0130] Referring to the multi-time scale dispatching operation mode of conventional energy units participating in the system, combined with the operation characteristics and regulation requirements of wind power, the active regulation capacity of the wind storage system is divided into two time scales of 15min and 5min. A dual-battery energy storage composed of several energy storage units is configured in the wind farm, such as Figure 1 As shown in the figure, according to the multi-time scale dispatching operation mode of the conventional energy units participating in the system, combined with the wind power operation characteristics and regulation requirements, the active regulation capacity of the wind storage system is divided into two time scales of 15 minutes and 5 minutes. A dual battery energy storage group composed of several energy storage units is configured in the wind farm, namely, battery energy storage group A and battery energy storage group B. Among them, battery energy storage group A is used to compensate for the deviation between the wind power output and the power generation plan every 15 minutes, and battery energy storage group B is used to smooth the fluctuation of wind power output every 5 minutes. In order to reduce the number of energy storage charge and discharge state conversions and extend the service life of energy storage, the energy storage units are divided into charging and discharging groups to participate in the formulation of the call plan. When the charging and discharging groups cannot undertake the charging and discharging tasks alone, the energy storage unit power allocation strategy is adopted to select another group of all (or part) energy storage units to assist in completing them.

[0131] In step 2, the energy storage units of the dual-battery energy storage group are divided into a charging group and a discharging group, and the energy storage units in the charging group and the discharging group are updated through the energy storage unit dynamic grouping mechanism, specifically:

[0132] The energy storage units of battery energy storage group A and battery energy storage group B are divided into a charging group and a discharging group, wherein the number of energy storage units in the charging group is m1, and the number of energy storage units in the discharging group is m2. If the energy storage units in the m1 charging group cannot meet the charging demand in this period, the discharging group selects n energy storage units from small to large according to SOC to assist in completing the charging shortage, wherein n is the minimum number to complete the shortage. When the charging of m1+n energy storage units is completed, the energy storage units in the n discharging groups that assist in charging are added to the charging group at the next moment, and n energy storage units in the energy storage units in the charging group are selected from large to small according to SOC to be added to the discharging group, so that the energy storage units of the charging and discharging groups become m1 and m2 again. If the charging and discharging groups complete the total charging and discharging demands separately in this period, the energy storage units in the charging and discharging groups remain unchanged in the next period. When grouping, if there are energy storage units in the charging group If there is an energy storage unit, then the energy storage unit is added to the discharge group, and the energy storage unit with the minimum SOC is selected from the discharge group to be added to the charging group. The state of charge and the maximum charge and discharge power of each energy storage unit are calculated. By summing up, the maximum charge and discharge power and state of charge of the battery energy storage groups A and B can be obtained as follows:

[0133]

[0134]

[0135]

[0136] In the formula, S b,j,t , are the SOC of energy storage unit j at time t and its upper and lower limits, which are 0.8 and 0.2 respectively. is the rated power and capacity of energy storage unit j, P b,j,t , are the operating power and the maximum allowable charging and discharging power of energy storage unit j at time t, η is the charging and discharging efficiency, η c , η d Both are 0.9, T c It is the energy storage control cycle.

[0137] In step 3, the output plan of the dual-battery energy storage group every 15 minutes and the wind storage system tracking planned power generation are rolled out according to the MPC method, specifically:

[0138] The present invention takes into account the impact of wind power changes in the future when implementing the rolling optimization operation plan according to the MPC method. The general steps are as follows: first, establish a prediction model based on the state space equation of the wind-storage system; second, establish the rolling optimization target and constraint conditions of the wind-storage system, solve the rolling optimization model to obtain the optimization results within a period of time, and execute the first optimization result as the wind-storage system operation plan; finally, roll the time to the next moment, update the state input and repeat the above steps;

[0139] Based on the current wind-storage system power generation plan, the actual wind power and the predicted power in the future period, the charging group and discharging group of the battery energy storage group A and the energy storage state, the optimization of the energy storage charge state and the minimum energy storage power are taken as the goal, and the constraints are considered. A 15-minute scale operation model of the wind-storage system based on MPC is established, where the control cycle and rolling step are 15 minutes, the prediction cycle is 1 hour, and the 15-minute scale power balance equation of the wind-storage system is:

[0140]

[0141] Based on the 15-minute scale power balance equation of the wind-storage system, the state space equation of the wind-storage system is established as the prediction model of MPC:

[0142]

[0143]

[0144]

[0145] D1=[1 0 0] T (8)

[0146] Where: P′ gz,t is the power generated by the wind energy storage system when the single energy storage group A of the battery energy storage group is in operation at time t, They are the single energy storage action power of battery energy storage group A at time t and the power increment compared with the previous moment, are the wind power every 15 minutes and the power increment compared with the previous moment, A1, B1, C1, and D1 are the model coefficient matrices. is the rated capacity of the battery energy storage group A, T c1 is the control period of battery energy storage group A, which is 15 minutes, and the state quantity is is the average SOC value of a single battery storage group A, and the control quantity Disturbance Output

[0147] The objective function of the rolling optimization of the wind-storage system with a time scale of 15 minutes is established as follows:

[0148]

[0149] Where M is the number of 5 time periods in the rolling optimization cycle;

[0150] The constraints of the wind-storage system on a 15-minute time scale are established, including the operation constraints of the energy storage system, the plan allowable deviation constraints, and the plan shortage power assistance constraints. The operation constraints of the energy storage system are:

[0151]

[0152] In the formula, They are the maximum charging power of the charging group and the maximum discharging power of the discharging group of the battery energy storage group A at time t respectively; They are the upper and lower limits of SOC of battery energy storage group A respectively;

[0153] The constraints for plan deviation are:

[0154]

[0155] Where: are the upper and lower limits of the allowable deviation of the power generation plan, is the power generation plan of the wind storage system at time t, δ pc Allowable deviation rate for power generation plan;

[0156] The planned power shortage assistance constraints are:

[0157]

[0158] In the formula, They are the maximum charging power of the discharge group and the maximum discharging power of the charging group of the battery energy storage group A at time t respectively;

[0159] According to the constraints and combined with the prediction model, we can solve the P at time t. gz,t and in, Scroll the time to the next moment, update the state input and repeat the above steps.

[0160] In step 4, the MPC method is used to roll out the optimization of the 5-minute output plan of the dual-battery energy storage group and the wind storage system to smooth the fluctuating operating power, specifically:

[0161] Based on the planned power generation of the wind-storage system every 15 minutes, the actual power of wind power every 5 minutes, the predicted power in the future period, the charging group and discharging group of the battery energy storage group B and the energy storage status, the 5-minute scale operation model of the wind-storage system based on MPC is established with the goal of optimizing the energy storage SOC and minimizing the energy storage power, and considering the constraints. The control cycle and rolling step are 5 minutes, the prediction cycle is 20 minutes, and the 5-minute scale wind-storage system fluctuation power balance equation is:

[0162]

[0163] Based on the 5-min scale power balance equation of the wind-storage system, the state space equation of the wind-storage system is established as the prediction model of MPC:

[0164]

[0165]

[0166]

[0167] D2=[1 0 0] T (17)

[0168] Where: is the wind energy storage system operating power after the single group of battery energy storage group B smoothes the fluctuation at time t, They are the power fluctuation smoothing of the single energy storage of battery energy storage group B at time t and the power increment compared with the previous moment, are the wind power every 5 minutes and the power increment compared with the previous moment, A2, B2, C2, and D2 are the model coefficient matrices. is the rated capacity of battery energy storage group B, T c2 is the control period of battery energy storage group B, which is 5 minutes, and the state quantity is is the average SOC value of a single battery storage group B, and the control quantity Disturbance Output

[0169] The objective function of rolling optimization of wind-storage system with a time scale of 5 minutes is established as follows:

[0170]

[0171] The constraints of the wind-storage system with a time scale of 5 minutes are established, including the grid-connected power fluctuation constraint and the fluctuation over-limit power assistance constraint. The grid-connected power fluctuation constraint is:

[0172]

[0173] In the formula, The installed capacity of the wind farm, is the grid-connected power of the wind-storage system at the previous moment, δ bd Allowing fluctuations for grid connection;

[0174] The fluctuation over-limit power assistance constraint condition is:

[0175]

[0176] In the formula, They are the maximum charging power of the discharge group and the maximum discharging power of the charging group of the battery energy storage group B at time t respectively;

[0177] According to the constraints and combined with the prediction model, the wind-storage system is solved to smooth the fluctuating output And battery energy storage group B smoothes out fluctuating output in, Scroll the time to the next moment, update the state input and repeat the above steps, where the After that, the wind energy storage system reserves frequency regulation and responds to the system frequency regulation demand in real time. When the energy storage cannot provide backup, the wind turbine will reduce load and reserve backup P under the constraint of grid-connected power fluctuation. wJz,tWhen the reserve power has been used to respond to the system frequency regulation demand, if the wind turbine is in a load-reducing state, the wind turbine will be given priority to respond to the frequency regulation power, and the energy storage will bear the remaining frequency regulation demand.

[0178]

[0179] Determine whether the energy storage unit has the remaining regulation capacity to smooth fluctuations and retain the minimum reserve If yes, the SOC is within the primary limit, and the energy storage unit reserves additional backup power. Calculate the frequency regulation reserve power of the wind power storage system Down frequency regulation reserve power And grid-connected power for:

[0180]

[0181]

[0182]

[0183] In the formula, λ min is the minimum frequency regulation reserve rate, which is 0.1. The wind storage system actually responds to the frequency regulation demand power. Allocate power for energy storage units to smooth fluctuations, P wJcl,t Reduce wind power output in real time.

[0184] In step 3, according to the output plan every 15 minutes and the planned power generation of the wind storage system, the energy storage output is allocated to the energy storage units in the charging group and the discharging group, so that the wind storage system can track the power generation plan, which specifically includes the following steps:

[0185] S1: According to the power allocation priority of the energy storage unit, a set of energy storage unit action priorities is constructed according to the energy storage unit allocation priority;

[0186] S2: Construct an energy storage unit action priority set according to the energy storage unit allocation priority, and establish an energy storage unit power allocation strategy that takes the action priority into consideration.

[0187] In step 4, according to the output plan every 5 minutes and the wind storage system's fluctuating operating power, the energy storage output is allocated to the energy storage units in the charging group and the discharging group to achieve the smoothing of wind power grid-connected fluctuations. On the basis of smoothing wind power fluctuations, the wind storage system reserves frequency regulation standby to respond to the system frequency regulation requirements in real time, and allocates the frequency regulation standby reserved and response power to the energy storage units in the charging group and the discharging group to achieve the wind storage system's real-time response to the system frequency regulation requirements. Specifically, the following steps are included:

[0188] D1: Based on the power allocation priority of the energy storage unit, a set of energy storage unit action priorities is constructed according to the energy storage unit allocation priority;

[0189] D2: Construct an energy storage unit action priority set based on the energy storage unit allocation priority, and establish an energy storage unit power allocation strategy that takes action priority into consideration;

[0190] D3: Construct a frequency modulation standby reserved response set and establish a power allocation strategy based on the set.

[0191] In S1 or D1, according to the power allocation priority of the energy storage unit, the energy storage unit action priority set is constructed according to the energy storage unit allocation priority, specifically:

[0192] Determine the upper and lower limits of SOC And SOC secondary upper and lower limits for:

[0193]

[0194]

[0195] The action priority of the energy storage unit is determined according to the SOC limit, where the division rule is as follows: Figure 3 As shown, it is not described in detail here. According to the energy storage unit allocation priority, the energy storage unit action priority set is constructed. The set structure is as follows Figure 4 As shown, no detailed description is given here.

[0196] Take the selection of assisting discharge energy storage unit in the charging group as an example to illustrate the set G 11 Construction method: In order to alleviate the loss of "bidirectional regulation" capability due to the extreme SOC of the energy storage unit, the SOC in the discharge group is about to be in an extreme state (i.e. ) The number of energy storage units is y, and the charging group selects x (the minimum number to complete the shortfall) energy storage units from large to small SOC to assist in discharge. If x is less than y, yx energy storage units are selected from the charging group to assist in discharge.

[0197] In S2 or D2, an energy storage unit action priority set is constructed according to the energy storage unit allocation priority, and an energy storage unit power allocation strategy considering the action priority is established, specifically:

[0198] A power allocation strategy for energy storage units consisting of basic power and auxiliary power allocation is proposed to ensure that each energy storage unit allocates the total power of energy storage. When the remaining available capacity requirement is met, the energy storage units determine the allocated power in turn according to the action priority. At maximum adjustable power The total power of energy storage units is obtained within the range of and maximum adjustable power

[0199] like Then the power allocated to the energy storage unit in G6 is:

[0200]

[0201] In the formula, g6 is the number of energy storage units in the set G6;

[0202] like The energy storage unit in G6 is Allocate power and calculate the power shortage at this time The energy storage unit in G7 is The ratio distribution

[0203]

[0204]

[0205]

[0206] In the formula, It is the difference power that does not enter the SOC primary limit after the energy storage unit is activated;

[0207] like The energy storage units in G6 and G7 are The action cannot meet the demand, calculate the power shortage The energy storage unit in G7 can be adjusted according to the remaining power With G8 energy storage unit The ratio distribution for:

[0208]

[0209]

[0210] when Calculate the total power shortage when The auxiliary power allocation strategy is used to allocate the power shortage. G 12 The power distribution of the energy storage unit is:

[0211]

[0212] In the formula, g 12 For the set G 12 The number of energy storage units;

[0213] when G 12The energy storage unit cannot complete the total power shortage and Allocate power and calculate the total power shortage at this time By G 13 The energy storage unit is allocated:

[0214]

[0215] like All energy storage units

[0216] In D3, a frequency modulation standby reserved response set is constructed, and a power allocation strategy is established based on the set, specifically:

[0217] Construct the corresponding collection, as follows Figure 5 As shown, before calling the energy storage unit power allocation strategy, the set G needs to be determined 14 ~G 20 Internal energy storage unit belongs to G6~G8 and G 12 ~G 13 In the case of allocating the response frequency modulation power, if The allocation strategy can be called according to the action priority set of the energy storage unit in the charging and discharging group; When the set G 19 , G 20 The power distribution of each energy storage unit is in:

[0218]

[0219] In the formula, Response allocation for additional reserved FM power.

[0220] In step 5, evaluation indicators are constructed to evaluate the wind storage system's ability to track power generation plans, smooth wind power grid-connected fluctuations, and respond to frequency regulation needs. Specifically,

[0221] The evaluation indicators are constructed as follows:

[0222]

[0223]

[0224]

[0225] In the formula, T is 24h, W is gz , W bd , W tp 、p gz 、p bd 、p tpThey are the total power of tracking plan deviation, the total power of power fluctuation exceeding the limit, the total power of responding to frequency regulation demand shortage and the corresponding occurrence probability. The wind storage system is ready to respond to the frequency modulation demand, and the battery energy storage charge and discharge conversion times indicator CS b for:

[0226]

[0227]

[0228] Where P b,nz It is the action power of the last energy storage unit which is not 0.

[0229] A real-time example of the present invention is: a calculation example is constructed based on the relevant data of a wind farm in Xinjiang and the connected areas, including the predicted power and measured power of the wind farm for 15 minutes and 5 minutes, the predicted power and actual power of the system's 5-minute frequency regulation demand, and the relevant parameters of the wind storage system are shown in Table 1. The battery energy storage groups A and B are both composed of 8 energy storage units, and δ pc , δ bd Both are 0.02;

[0230] Table 1 Wind energy storage system related parameters

[0231]

[0232] In order to reflect the operation effect of the strategy of the present invention and the degree of reduction in the number of energy storage charge and discharge state conversions, the following comparative strategies are designed: Strategy 1: overall energy storage control strategy with the minimum power action to complete the demand; Strategy 2: overall energy storage control with MPC to determine the energy storage action amount; Strategy 3: the method recorded in the present invention.

[0233] A comparative analysis was conducted on four typical days, and the results are as follows:

[0234] The wind storage system tracks the power generation plan every 15 minutes, and the battery energy storage A tracks the power generation plan SOC (strategy 3 is the average value of the energy storage unit) as follows: Figure 6 and Figure 7 The specific performance indicators are shown in Table 2;

[0235] Table 2 Tracking plan performance indicators

[0236]

[0237] Depend on Figure 6 , Figure 7 It can be seen that compared with other strategies, the wind energy storage system power of strategy 3 deviates the least from the power generation plan, and the SOC of battery energy storage group A in each strategy will not exceed the limit. Taking typical day 1 as an example, the charging and discharging grouping and energy storage unit operation of battery energy storage group A in some periods are as follows: Figure 8 As shown; further comparison with Table 2 shows that: W gz Strategy 1 is the largest, strategy 2 is the second, and strategy 3 is the smallest; and p gz Strategy 3 is the smallest, strategies 1 and 2 are basically the same, and except for typical day 4, strategy 3 completely tracks the power generation plan. This further proves that strategy 3 can more effectively achieve the wind storage system tracking the power generation plan every 15 minutes. b It has the same characteristics as strategies 1 and 2 and is much higher than strategy 3, which means that strategy 3 reduces the number of energy storage charge and discharge state transitions by about 50% while tracking the power generation plan. In summary, the method of the present invention can not only improve the wind storage system's ability to track the plan every 15 minutes, but also effectively reduce the number of energy storage charge and discharge state transitions.

[0238] After the wind storage system completes the tracking of the power generation plan every 15 minutes, it can smooth out the wind power fluctuation every 5 minutes. Fig. 9 The specific performance indicators are shown in Table 3;

[0239] Table 3 Fluctuation Smoothing Performance Indicators

[0240]

[0241] Depend on Fig. 9 It can be seen that compared with other strategies, the wind power fluctuation exceeding the limit every 5 minutes in the wind storage system of strategy 3 is the smallest; further comparison with Table 3 shows that except for typical day 2, W bd 、p bd All of them have the characteristics of strategy 1 being the largest, strategy 2 being the second, and strategy 3 being the smallest, and strategy 3’s W bd Compared with Strategy 1 and Strategy 2, it is reduced by about 80% and 65% respectively; although Strategy 2 improves the ability to smooth fluctuations compared with Strategy 1, it greatly increases CS b , while strategy 3 improves the ability to smooth fluctuations while significantly reducing CS b , which is reduced by 50% and 66% respectively compared with strategies 1 and 2. In summary, the strategy of the present invention can not only improve the ability of the wind storage system to smooth the wind power fluctuation every 5 minutes, but also effectively reduce the number of energy storage charging and discharging state conversions; the wind storage system responds to the system frequency regulation demand in real time. Fig.10 The specific performance indicators are shown in Table 4;

[0242] Table 4 Response frequency modulation performance indicators

[0243]

[0244] Further comparison with Table 4 shows that: on each typical day, Wtp and ptp have the characteristics that strategy 1 is the largest, strategy 2 is the second, and strategy 3 is the smallest; in terms of CSb, strategies 1 and 2 are basically the same, while strategy 3 is reduced by about 35% compared with the other strategies. In summary, the present invention not only improves the ability of the wind energy storage system to respond to the system frequency regulation requirements in real time, but also effectively reduces the number of energy storage charge and discharge state conversions. Taking typical day 1 as an example, the charging and discharging grouping of battery energy storage B and the operation of energy storage units in some time periods are as follows Fig.11 As shown. Fig.11 The charging and discharging grouping and the energy storage unit action are explained as follows: at time point 98, the energy storage units of the charging and discharging group are numbered 2, 3, 5, 6 and 1, 4, 7, 8 respectively. At this time, the charging group can meet the charging demand for smoothing fluctuations, so energy storage units 2, 3, 5, 6 are in charging state, and 1, 4, 7, 8 are in standby state. Then the system sends a frequency modulation signal to be responded to (i.e., the wind storage system increases power), and the power to be responded to requires all energy storage units to complete together. At this time, the charging power of energy storage units 2, 3, 5, 6 is reduced from smoothing fluctuations to 0, that is, from charging state to standby state, and energy storage units 1, 4, 7, 8 are changed from standby state to discharging state to meet the frequency modulation demand. Since there is no phenomenon of charging group discharging and discharging group charging when smoothing fluctuations and responding to frequency modulation in time period 98 are completed, and there is no energy storage unit with SOC in extreme state, so at time point 99, the energy storage unit grouping is consistent with time point 98. Since the discharge group is charged when responding to the frequency modulation demand in time period 99, the charged energy storage units in the discharge group are added to the charging group at time point 100, and the same number of energy storage units are selected from the charging group to join the discharge group. However, at this time, the SOC of the energy storage units in the discharge group is in an extreme state, so the grouping at time point 100 remains unchanged from the previous moment. Fig.12 It can be seen that the SOC of battery energy storage B will not exceed the limit under each strategy, and the fluctuation smoothing effect and response frequency regulation effect of each strategy are positively correlated with the degree of change of energy storage charge state, that is, the strategy in this paper improves the wind storage system's ability to smooth fluctuations and respond to frequency regulation while increasing the amount of energy storage action to a certain extent. The final grid-connected effect of the wind storage system is as follows Fig.13 As shown in the figure, the wind-storage system realizes the wind-storage joint upper frequency regulation reserve and energy storage lower frequency regulation reserve on the basis of smoothing fluctuations. The grid-connected power that responds to the system frequency regulation demand in real time is basically within the frequency regulation reserve reserve range. Outside this range, the wind turbine reduces its output in real time to respond to the frequency regulation demand. The battery energy storage B smoothes the wind power fluctuation and responds to the frequency regulation. The SOC is as follows Fig.12Assuming that conventional energy units can fully meet the requirements of tracking plan allowable deviation, grid-connected fluctuation rate and response system frequency regulation demand in the whole period, under four typical days with a total of 384 power generation plan assessment points, 1152 grid-connected fluctuation assessment points and 299 frequency regulation time points to be responded, the wind storage system and conventional energy units can complete the following Fig.14 As shown in the figure. mzgz 、p mzbd 、p mztp The confidence levels for tracking plan, smoothing fluctuations and real-time response to frequency regulation are 99.740%, 97.656% and 83.541% respectively for the wind-storage system under the proposed strategy, indicating that the proposed strategy can enable the wind-storage system to have the same multi-time-scale active power regulation capability as conventional energy units to a certain extent.

[0245] The present invention provides a multi-time scale operation method for a wind storage system for improving the active power regulation capability. The method can finely manage the orderly operation of the charging and discharging group energy storage units and reduce the number of energy storage charging and discharging state conversions. The multi-time scale operation strategy of the wind storage system proposed by the method includes two time scales of 15 minutes and 5 minutes. The wind storage system can strictly execute the power generation plan and can also respond to the system active power regulation needs in real time on the basis of achieving its own stable grid connection.

[0246] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A multi-time scale operation method of a wind-storage system for improving active power regulation capability, characterized in that: The steps include: Step 1: Divide the active regulation capacity of the wind-storage system into two time scales of 15 minutes and 5 minutes. Configure a dual-battery energy storage group consisting of several energy storage units in the wind farm to compensate for the deviation every 15 minutes, smooth out the wind power output fluctuation every 5 minutes, and respond to the system frequency regulation requirements; Step 2: Divide the energy storage units of the dual-battery energy storage group into a charging group and a discharging group, and update the energy storage units in the charging group and the discharging group through the energy storage unit dynamic grouping mechanism; Step 3: According to the MPC method, the output plan of the dual-battery energy storage group every 15 minutes and the wind storage system tracking planned power generation are rolled out, and the energy storage output is allocated to the energy storage units in the charging group and the discharging group, so that the wind storage system can track the power generation plan; Step 4: According to the MPC method, the dual-battery energy storage group's output plan every 5 minutes and the wind storage system's fluctuating operating power are rolled out to optimize, and the energy storage output is allocated to the energy storage units in the charging group and the discharging group to achieve the smoothing of wind power grid-connected fluctuations. On the basis of smoothing wind power fluctuations, the wind storage system reserves frequency regulation standby to respond to the system's frequency regulation needs in real time, and the frequency regulation standby reserved and response power is allocated to the charging group and the discharging group energy storage units to achieve the wind storage system's real-time response to the system's frequency regulation needs; Step 5: Construct evaluation indicators to evaluate the wind-storage system's ability to track power generation plans, smooth wind power grid-connected fluctuations, and respond to frequency regulation needs.

2. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 1, characterized in that: In step 1, the active regulation capacity of the wind-storage system is divided into two time scales of 15 minutes and 5 minutes. A dual-battery energy storage group consisting of several energy storage units is configured in the wind farm to compensate for the deviation every 15 minutes, smooth the wind power output fluctuation every 5 minutes, and respond to the system frequency regulation requirements. Specifically: According to the multi-time scale dispatching operation mode of conventional energy units participating in the system, combined with the operation characteristics and regulation requirements of wind power, the active regulation capability of the wind storage system is divided into two time scales of 15 minutes and 5 minutes. A dual battery energy storage group consisting of several energy storage units is configured in the wind farm, namely battery energy storage group A and battery energy storage group B. Battery energy storage group A is used to compensate for the deviation between wind power output and power generation plan every 15 minutes, and battery energy storage group B is used to smooth the fluctuation of wind power output every 5 minutes and implement the response system frequency regulation requirements.

3. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 2, characterized in that: In step 2, the energy storage units of the dual-battery energy storage group are divided into a charging group and a discharging group, and the energy storage units in the charging group and the discharging group are updated through the energy storage unit dynamic grouping mechanism, specifically: The energy storage units of battery energy storage group A and battery energy storage group B are divided into a charging group and a discharging group, wherein the number of energy storage units in the charging group is m1, and the number of energy storage units in the discharging group is m2. If the energy storage units in the m1 charging group cannot meet the charging demand in this period, the discharging group selects n energy storage units from small to large according to SOC to assist in completing the charging shortage, wherein n is the minimum number to complete the shortage. When the charging of m1+n energy storage units is completed, the energy storage units in the n discharging groups that assist in charging are added to the charging group at the next moment, and n energy storage units in the energy storage units in the charging group are selected from large to small according to SOC to be added to the discharging group, so that the energy storage units of the charging and discharging groups become m1 and m2 again. If the charging and discharging groups complete the total charging and discharging demands separately in this period, the energy storage units in the charging and discharging groups remain unchanged in the next period. When grouping, if there are energy storage units in the charging group If there is an energy storage unit, then the energy storage unit is added to the discharge group, and the energy storage unit with the minimum SOC is selected from the discharge group to be added to the charging group. The state of charge and the maximum charge and discharge power of each energy storage unit are calculated. By summing up, the maximum charge and discharge power and state of charge of the battery energy storage groups A and B can be obtained as follows: In the formula, S b,j,t , are the SOC of energy storage unit j at time t and its upper and lower limits, which are 0.8 and 0.2 respectively. is the rated power and capacity of energy storage unit j, P b,j,t , are the operating power and the maximum allowable charging and discharging power of energy storage unit j at time t, η is the charging and discharging efficiency, η c , η d Both are 0.9, T c It is the energy storage control cycle.

4. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 3 is characterized in that: In step 3, the output plan of the dual-battery energy storage group every 15 minutes and the wind storage system tracking planned power generation are rolled out according to the MPC method, specifically: Based on the current wind-storage system power generation plan, the actual wind power and the predicted power in the future period, the charging group and discharging group of the battery energy storage group A and the energy storage state, the optimization of the energy storage charge state and the minimum energy storage power are taken as the goal, and the constraints are considered. A 15-minute scale operation model of the wind-storage system based on MPC is established, where the control cycle and rolling step are 15 minutes, the prediction cycle is 1 hour, and the 15-minute scale power balance equation of the wind-storage system is: Based on the 15-minute scale power balance equation of the wind-storage system, the state space equation of the wind-storage system is established as the prediction model of MPC: D1=[1 0 0] T (8) Where: P′ gz,t is the power generated by the wind energy storage system when the single energy storage group A of the battery energy storage group is in operation at time t, They are the single energy storage action power of battery energy storage group A at time t and the power increment compared with the previous moment, are the wind power every 15 minutes and the power increment compared with the previous moment, A1, B1, C1, and D1 are the model coefficient matrices. is the rated capacity of the battery energy storage group A, T c1 is the control period of battery energy storage group A, which is 15 minutes, and the state quantity is is the average SOC value of a single battery storage group A, and the control quantity Disturbance Output The objective function of the rolling optimization of the wind-storage system with a time scale of 15 minutes is established as follows: Where M is the number of 5 time periods in the rolling optimization cycle; The constraints of the wind-storage system on a 15-minute time scale are established, including the operation constraints of the energy storage system, the plan allowable deviation constraints, and the plan shortage power assistance constraints. The operation constraints of the energy storage system are: In the formula, They are the maximum charging power of the charging group and the maximum discharging power of the discharging group of the battery energy storage group A at time t respectively; They are the upper and lower limits of SOC of battery energy storage group A respectively; The constraints for plan deviation are: Where: are the upper and lower limits of the allowable deviation of the power generation plan, is the power generation plan of the wind storage system at time t, δ pc Allowable deviation rate for power generation plan; The planned power shortage assistance constraints are: In the formula, They are the maximum charging power of the discharge group and the maximum discharging power of the charging group of the battery energy storage group A at time t respectively; According to the constraints and combined with the prediction model, we can solve P at time t. gz,t and in, Scroll the time to the next moment, update the state input and repeat the above steps.

5. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 4, characterized in that: In step 4, the MPC method is used to roll out the optimization of the 5-minute output plan of the dual-battery energy storage group and the wind storage system to smooth the fluctuating operating power, specifically: Based on the planned power generation of the wind-storage system every 15 minutes, the actual power of wind power every 5 minutes, the predicted power in the future period, the charging group and discharging group of the battery energy storage group B and the energy storage status, the 5-minute scale operation model of the wind-storage system based on MPC is established with the goal of optimizing the energy storage SOC and minimizing the energy storage power, and considering the constraints. The control cycle and rolling step are 5 minutes, the prediction cycle is 20 minutes, and the 5-minute scale wind-storage system fluctuation power balance equation is: Based on the 5-min scale power balance equation of the wind-storage system, the state space equation of the wind-storage system is established as the prediction model of MPC: D2＝[1 0 0] T (17) Where: is the wind energy storage system operating power after the single group of battery energy storage group B smoothes the fluctuation at time t, They are the power fluctuation smoothing of the single energy storage of battery energy storage group B at time t and the power increment compared with the previous moment, are the wind power every 5 minutes and the power increment compared with the previous moment, A2, B2, C2, and D2 are the model coefficient matrices. is the rated capacity of battery energy storage group B, T c2 is the control period of battery energy storage group B, which is 5 minutes, and the state quantity is is the average SOC value of a single battery storage group B, and the control quantity Disturbance Output The objective function of rolling optimization of wind-storage system with a time scale of 5 minutes is established as follows: The constraints of the wind-storage system with a time scale of 5 minutes are established, including the grid-connected power fluctuation constraint and the fluctuation over-limit power assistance constraint. The grid-connected power fluctuation constraint is: In the formula, The installed capacity of the wind farm, is the grid-connected power of the wind-storage system at the previous moment, δ bd Allowing fluctuations for grid connection; The fluctuation over-limit power assistance constraint condition is: In the formula, They are the maximum charging power of the discharge group and the maximum discharging power of the charging group of the battery energy storage group B at time t respectively; According to the constraints and combined with the prediction model, the wind-storage system is solved to smooth the fluctuating output And battery energy storage group B smoothes out fluctuating output in, Scroll the time to the next moment, update the state input and repeat the above steps, where the After that, the wind energy storage system reserves frequency regulation and responds to the system frequency regulation demand in real time. When the energy storage cannot provide backup, the wind turbine will reduce load and reserve backup P under the constraint of grid-connected power fluctuation. wJz,t When the reserve power has been used to respond to the system frequency regulation demand, if the wind turbine is in a load-reducing state, the wind turbine will be given priority to respond to the frequency regulation power, and the energy storage will bear the remaining frequency regulation demand. Determine whether the energy storage unit has the remaining regulation capacity to smooth fluctuations and retain the minimum reserve If yes, the SOC is within the primary limit, and the energy storage unit reserves additional backup power. Calculate the frequency regulation reserve power of the wind power storage system Down frequency regulation standby power And grid-connected power for: In the formula, λ min is the minimum frequency regulation reserve rate, which is 0.

1. The wind storage system actually responds to the frequency regulation demand power. Allocate power for energy storage units to smooth fluctuations, P wJcl,t Reduce wind power output in real time.

6. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 5, characterized in that: According to the output plan every 15 minutes and the planned power generation of the wind storage system, the energy storage output is allocated to the energy storage units in the charging group and the discharging group, so that the wind storage system can track the power generation plan. Specifically, the steps include: S1: According to the power allocation priority of the energy storage unit, a set of energy storage unit action priorities is constructed according to the energy storage unit allocation priority; S2: Construct an energy storage unit action priority set according to the energy storage unit allocation priority, and establish an energy storage unit power allocation strategy that takes the action priority into consideration.

7. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 6, characterized in that: According to the 5-minute output plan and the wind storage system's fluctuating operating power, the energy storage output is allocated to the energy storage units in the charging group and the discharging group to achieve the smoothing of wind power grid-connected fluctuations. On the basis of smoothing wind power fluctuations, the wind storage system reserves frequency regulation standby to respond to the system frequency regulation needs in real time, and allocates the frequency regulation standby reserved and response power to the energy storage units in the charging group and the discharging group to achieve the wind storage system's real-time response to the system frequency regulation needs. The specific steps include: D1: Based on the power allocation priority of the energy storage unit, a set of energy storage unit action priorities is constructed according to the energy storage unit allocation priority; D2: Construct an energy storage unit action priority set based on the energy storage unit allocation priority, and establish an energy storage unit power allocation strategy that takes action priority into consideration; D3: Construct a frequency modulation standby reserved response set and establish a power allocation strategy based on the set.

8. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 7, characterized in that: In S1 or D1, according to the power allocation priority of the energy storage unit, the energy storage unit action priority set is constructed according to the energy storage unit allocation priority, specifically: Determine the upper and lower limits of SOC And SOC secondary upper and lower limits for: Determine the action priority of the energy storage unit according to the SOC limit. If the SOC of the energy storage unit is in the range and If the energy storage unit SOC is in the range of and If the energy storage unit is within the first, second, or third discharge priority level, a storage unit action priority set is constructed according to the energy storage unit allocation priority level, including set A, set B, set G1, set G2, set G3, set G4, set G5, set G6, set G7, set G8, set G9, and set G 10 , set G 11 , set G 12 and set G 13 ; Among them, set A is the energy storage unit of the charging group, set B is the energy storage unit of the discharging group, and set G1 is The set G2 is The set G3 is The set G4 is Set G5 is Set G6 is the same set A in sets G3 to G5 and the same set B in sets G1 and G2. Set G7 is the same set A in set G2 and the same set B in set G4. Set G8 is the same set A in set G1 and the same set B in set G5. Set G9 is the same set A in sets G1 to G4 and the same set B in sets G2 and G5. Set G 10 For the set A in G5 and the set B in G1, the set G 11 The energy storage unit assisting discharge in the charging group and the energy storage unit assisting discharge in the discharging group are grouped as G 12 For the set G 11 The same set G9, set G 13 For the set G 11 The same set G 10 .

9. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 8, characterized in that: In step S2 or step D3, an energy storage unit action priority set is constructed according to the energy storage unit allocation priority, and an energy storage unit power allocation strategy considering the action priority is established, specifically: Get the total energy storage power allocated by the energy storage unit and maximum adjustable power like Then the power allocated to the energy storage unit in G6 is: In the formula, g6 is the number of energy storage units in the set G6; like The energy storage unit in G6 is Allocate power and calculate the power shortage at this time The energy storage unit in G7 is The ratio distribution In the formula, It is the difference power that does not enter the SOC primary limit after the energy storage unit is activated; like The energy storage units in G6 and G7 are The action cannot meet the demand, calculate the power shortage The energy storage unit in G7 can be adjusted according to the remaining power With G8 energy storage unit The ratio distribution for: when Calculate the total power shortage when The auxiliary power allocation strategy is used to allocate the power shortage. G 12 The power distribution of the energy storage unit is: In the formula, g 12 For the set G 12 The number of energy storage units; when G 12 The energy storage unit cannot complete the total power shortage and Allocate power and calculate the total power shortage at this time By G 13 The energy storage unit is allocated: like All energy storage units 10. The multi-time scale operation method of a wind-storage system for improving active power regulation capability according to claim 9, characterized in that: In step 5, evaluation indicators are constructed to evaluate the wind storage system's ability to track power generation plans, smooth wind power grid-connected fluctuations, and respond to frequency regulation needs. Specifically, The evaluation indicators are constructed as follows: In the formula, T is 24h, W is gz , W bd , W tp 、p gz , pbd, p tp They are the total power of tracking plan deviation, the total power of power fluctuation exceeding the limit, the total power of responding to frequency regulation demand shortage and the corresponding occurrence probability. The wind storage system is ready to respond to the frequency modulation demand, and the battery energy storage charge and discharge conversion times indicator CS b for: Where P b,nz It is the action power of the last energy storage unit which is not 0.

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