A dual-layer power allocation method for AGC considering the participation of battery energy storage cluster

Abstract

The present invention discloses an AGC double-layer power allocation method considering the participation of a battery energy storage cluster, and belongs to the field of electric power resource regulation. The present invention will comprehensively consider the real-time instruction tracking requirements and energy storage operating status of various types of power generation equipment under AGC regulation. In the allocation process between energy storage clusters and non-energy storage clusters, the present invention determines the power allocation method based on the current adjustable capacity of each cluster to complete the allocation process between clusters; within the energy storage cluster, the real-time state of charge of the energy storage and the maximum adjustable power are coupled, and the charge-discharge coupling constraint power considering the influence of the energy storage SOC is calculated, and the power allocation process within the energy storage cluster is completed within the cluster with the charge-discharge coupling constraint power ratio. The present invention plays a significant role in improving the ability of power generation equipment to track AGC instructions and improving the operating status of energy storage equipment.

Description

Technical Field

[0001] The present invention relates to the field of power resource regulation, and in particular to an AGC double-layer power allocation method considering the participation of a battery energy storage cluster. Background Art

[0002] In order to reduce dependence on fossil energy and deal with environmental pollution and climate warming, the global energy structure is in a profound adjustment stage of clean, efficient and diversified development. The transition from fossil fuels to renewable energy generation is imperative, and new energy generation has become the main development trend of the power system. Among many new energy sources, wind energy and light energy have become one of the fastest-growing and most mature new energy generation methods due to their multiple advantages such as pollution-free, mature technology, huge storage capacity and relatively low development cost. The International Energy Agency predicts that China will still be the world's largest energy consumer in 2040, and is an indispensable force in promoting the development of global renewable energy and accelerating the world's energy transformation. China's installed capacity of renewable energy is continuously expanding, the level of energy utilization is constantly improving, and the role of clean energy substitution is becoming increasingly obvious, becoming the main force in promoting global energy transformation. In the foreseeable future, renewable energy, mainly wind power generation and solar power generation, will become the main power source in the field of energy and electricity, and a super-high proportion of new energy power grids will be an important feature of the future sustainable energy and power system.

[0003] However, as the penetration rate of new energy continues to increase, the characteristics of new energy, mainly wind and solar, such as weak inertia or even no inertia, make automatic generation control (AGC) more difficult and risky. It is difficult for the system to meet the frequency regulation needs of the current system by relying solely on conventional units to participate in AGC control. Energy storage technology has gradually developed due to its advantages such as fast response speed and high climbing rate. Among them, energy storage resources represented by electrochemistry have high energy density, fast reaction speed and good stability, and have gradually become an important resource to assist conventional units in participating in automatic generation control.

[0004] In the process of energy storage assisting in responding to AGC instructions, considering the particularity of the energy storage power generation process, how to give full play to the rapid adjustment ability of energy storage and effectively take into account the AGC instruction tracking and the capacity limitation of energy storage itself is a topic of widespread concern among scholars. At present, the relevant research on AGC systems with energy storage participation is mainly divided into the dispatching level and the control level. At the dispatching level, existing research mainly considers the collaborative participation of energy storage, proposes optimization schemes from the global perspective of power generation to power load, and considers the differences in characteristics of various power generation resources at the stage of issuing instructions. On this basis, many scholars have proposed new optimization algorithms and theories to improve the existing models in many aspects, so that the accuracy of dispatch optimization is further improved. At the control level, generally speaking, considering the differences in frequency regulation characteristics of traditional units and energy storage, it is accustomed to decompose the frequency regulation power into high and low frequencies, with the low frequency part borne by traditional units and the high frequency part borne by energy storage equipment. For energy storage clusters with multiple energy storage entities, internal allocation is often based on the SOC balance principle or the method of fixed ratio of remaining capacity. However, most of the existing strategies propose allocation methods based on some single aspects of energy storage characteristic constraints, and it is difficult to take all indicators into consideration, resulting in unreasonable problems in the allocation process and causing serious waste of resources. Therefore, proposing a reasonable power allocation strategy and effectively improving the AGC command tracking accuracy is a major issue that needs to be urgently addressed in the field of energy storage participating in AGC research. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an AGC double-layer power allocation method considering the participation of a battery energy storage cluster.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] An AGC two-layer power allocation method considering the participation of a battery energy storage cluster includes the following steps:

[0008] S1. Aggregate the power generation equipment in the regional power grid into energy storage clusters and non-energy storage clusters according to the power allocation architecture;

[0009] S2, calculating the maximum adjustable power of the energy storage cluster and the non-energy storage cluster;

[0010] S3, based on the maximum adjustable power calculated in S2 and according to the cluster status information, coordinate and allocate power instructions to the non-energy storage cluster and the energy storage cluster;

[0011] S4. Considering the real-time state of charge, the real-time state of charge and rated power of the energy storage are coupled within the energy storage cluster, the charge-discharge coupling constraint power of each energy storage cell is calculated, and the total power of the energy storage cluster is distributed to each energy storage cell within the cluster in a ratio manner of the charge-discharge coupling constraint power.

[0012] Furthermore, the specific method of calculating the maximum adjustable power of the energy storage cluster and the non-energy storage cluster in S2 is:

[0013] S21. Calculate the power support capacity boundaries of the energy storage cluster and the non-energy storage cluster, and calculate the maximum adjustable power of a single unit in the non-energy storage cluster based on the power constraint and the ramp constraint;

[0014] S22. Based on the impact of capacity constraints on the maximum adjustable power, the maximum adjustable power of a single energy storage device in the energy storage cluster is calculated in combination with the upper and lower limits of the adjustable capacity of the energy storage device;

[0015] S23, based on the calculation results of S21 and S22, the non-energy storage cluster and the energy storage cluster are obtained. t The overall maximum adjustable power at all times.

[0016] Furthermore, the maximum adjustable power of a single unit in the non-energy storage cluster in S21 is calculated as follows:

[0017]

[0018] In the formula, for t Moment i Maximum adjustable power of conventional units, For the i Rated power of conventional units, for t -1 moment i Active output of conventional units, For the i Maximum ramp rate of conventional units, P RG,t Indicates the total active power command value of the conventional units at time t.

[0019] Furthermore, the maximum adjustable power of a single energy storage device in the energy storage cluster in S22 is calculated as follows:

[0020]

[0021] In the formula, for t Moment i The maximum adjustable power of each energy storage device, P rateb,i For the i Rated power of energy storage devices, R bi is the maximum ramp rate of the i-th energy storage device, P bi,t-1 for t -1 moment i The active output of each energy storage device, Ebi,t-1 The remaining t -1 moment i The capacity of energy storage equipment, η ic , η id The table shows the charging and discharging efficiency of energy storage, Δ t is the time interval of the control cycle, E bimax , E bimin The first i The adjustable minimum capacity and adjustable maximum capacity of each energy storage device, P Rb,t express t The total active power command value of the energy storage device at this moment.

[0022] Furthermore, the non-energy storage cluster and the energy storage cluster in S23 are t The specific calculation method of the overall maximum adjustable power at the moment is:

[0023]

[0024] In the formula, The non-energy storage cluster and the energy storage cluster are t The overall maximum adjustable power at all times, for t Moment i Maximum adjustable power of conventional units, for t Moment i The maximum adjustable power of each energy storage device, m and n Represent the total number of conventional units and energy storage equipment in non-energy storage clusters and energy storage clusters respectively.

[0025] Furthermore, the S3 power allocation process is specifically as follows:

[0026] S31. Settings t Moment state factor H R-SOC,t ;

[0027] S32, judging status factor H R-SOC,t ,like H R-SOC,t If it is negative, it means that the current AGC command is not conducive to the recovery of the energy storage SOC. At this time, the non-energy storage cluster is called first. If the maximum adjustable power of the non-energy storage cluster in the current control cycle is less than the total command issued by the AGC, the remaining commands are borne by the energy storage cluster and power is allocated accordingly.

[0028] S33, when HR-SOC,t If it is positive, it means that the current AGC instruction is beneficial to the energy storage SOC recovery. At this time, the energy storage cluster is called first. H R-SOC,t The sign is reversed, then quantization t The power required for the energy storage cluster's equivalent SOC to reach the benchmark value at that moment P arr,t And according to the power required by the benchmark value P arr,t value for power allocation.

[0029] Furthermore, the power allocation formula in S32 is:

[0030]

[0031] In the formula, is the maximum adjustable power of the non-energy storage cluster at time t, P R,t express t Total active power command value at all times.

[0032] Furthermore, the quantification in S33 t The power required for the energy storage cluster's equivalent SOC to reach the benchmark value at that moment P arr,t And according to the power required by the benchmark value P arr,t The specific way to allocate power is as follows:

[0033] S331, if the current AGC instruction absolute value is not greater than P arr,t The absolute value of , the energy storage cluster power is called first, and the remaining part is allocated to the non-energy storage cluster, and power distribution is performed. The power distribution formula is:

[0034]

[0035]

[0036] In the formula, P R,t express t Total active power command value at all times, For energy storage clusters t The overall maximum adjustable power at all times; P Rb,t express t The total active power command value of the energy storage device at the moment,

[0037] S332, if the current AGC instruction absolute value is less than P arr,t The absolute value ofP arr,t The power value is then called by the non-energy storage cluster, and the remaining part is called by the energy storage cluster and power is allocated. The power allocation formula is:

[0038]

[0039]

[0040] In the formula, P R,t express t Total active power command value at all times, For non-storage clusters t There is always a power command at the moment, For non-storage clusters t The overall maximum adjustable power at all times, P Rb,t express t The total active power command value of the energy storage device at this moment.

[0041] Furthermore, the specific calculation method of the coupling constraint power in S4 is:

[0042]

[0043]

[0044]

[0045] In the formula, P ohci,t and P ohdi,t They are the real-time state of charge SOC and the coupling constraint power of the maximum adjustable power in the charging and discharging stages, P maxb,i For the i The maximum adjustable power of each energy storage device, β ic,t , β id,t They are the charge state deviation coefficients in the charge and discharge stages respectively; r is the adaptive factor; is the hyperbolic tangent function; SOC i,t express t Moment i The state of charge of the energy storage device SOC ref is the benchmark SOC value, SOC min , SOC max are the minimum and maximum values ​​of the state of charge, respectively.

[0046] Furthermore, in S4, the total power of the energy storage cluster is distributed to each energy storage unit in a manner of charging and discharging coupling constrained power ratio within the cluster, which is expressed as:

[0047]

[0048] In the formula, For the i Energy storage t The AGC command value at the moment, P ohci,t and P ohdi,t They are the real-time state of charge SOC and the coupling constraint power of the maximum adjustable power in the charging and discharging stages, for t The total active power command value of the energy storage device at this moment.

[0049] The present invention has the following beneficial effects:

[0050] The present invention changes the power allocation method from direct allocation to a three-level hierarchical allocation of region-cluster-device, which reduces the computational difficulty of the allocation process. Cluster aggregation is performed based on the power generation characteristics of different devices, so that a variety of differentiated power generation resources can be better managed in a coordinated manner. It plays a significant role in improving the ability of power generation equipment to track AGC instructions and improving the operating status of energy storage equipment. At the same time, the power allocation strategy between different clusters realizes the dynamic adjustment of the priority calling order of non-energy storage clusters and energy storage clusters by introducing state factors, taking into account the dual tasks of AGC instruction tracking and energy storage capacity recovery, which is more conducive to maintaining the power support of power generation resources on a long-term scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a flow chart of the AGC double-layer power allocation method considering the participation of a battery energy storage cluster in the present invention.

[0052] Figure 2 Schematic diagram of the overall AGC power allocation architecture according to an embodiment of the present invention.

[0053] Figure 3 The figure is a schematic diagram of the power allocation process between different clusters according to an embodiment of the present invention.

[0054] Figure 4 It is a comparison diagram of coupling constraint power curves of an embodiment of the present invention.

[0055] Figure 5 This is a diagram of the AGC power allocation model according to an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0057] An AGC two-layer power allocation method considering the participation of battery energy storage clusters, such as Figure 1 As shown, the following steps are included:

[0058] S1. Aggregate the power generation equipment in the regional power grid into energy storage clusters and non-energy storage clusters according to the power allocation architecture;

[0059] In order to give full play to the characteristic advantages of different power generation resources and complete the reasonable allocation of AGC power among different power generation resources, this embodiment divides the regional power grid into several levels of "region-cluster-device", and the basic concepts and components of each level are described as follows.

[0060] 1) Regional level: generally refers to the unified control entity participating in AGC frequency regulation, which includes multiple types of power generation resources. From a geographical perspective, it generally refers to the jurisdiction of a city or provincial power grid.

[0061] 2) Cluster level: generally refers to a whole composed of similar power generation resources. Most of the power generation equipment in the cluster has the same or similar power generation characteristics. In modern power systems, clusters generally include thermal power clusters, energy storage clusters, etc. Clusters participate in regional regulation and allocation on the one hand, and complete the coordinated management of internal equipment on the other.

[0062] 3) Equipment level: The bottom-level units involved in AGC control are the power generation equipment that specifically participates in command execution and outputs active power. They receive commands from the upper layer and follow the commands to complete power output based on their actual power generation capacity.

[0063] This embodiment is based on the fact that multiple types of power generation resources cooperate to bear the AGC power generation instructions, and constructs a power allocation architecture between different control levels. Figure 2 shown.

[0064] First, within the regional power grid, the power distribution architecture aggregates numerous power generation equipment into two parts: non-energy storage clusters and energy storage clusters. The AGC control master station generates a total power command based on the current power grid demand, and coordinates the allocation of power commands to non-energy storage clusters and energy storage clusters based on cluster status information.

[0065] Secondly, the allocation within the non-energy storage cluster is based on the "three public principles", and within the energy storage cluster, the rated power, capacity and other indicators of the energy storage are considered to calculate the maximum adjustable charging and discharging power, and complete the further allocation of power instructions.

[0066] Finally, each power generation equipment responds to power generation instructions according to its current power generation capacity, outputs active power, and "bundles" it out of the power grid in the form of a cluster to smooth out real-time regional control errors.

[0067] The design of this architecture changes the power allocation method from direct allocation to a three-level hierarchical allocation of region-cluster-device, which reduces the computational difficulty of the allocation process. Cluster aggregation is performed based on the power generation characteristics of different devices, so that multiple differentiated power generation resources can be better managed in a coordinated manner.

[0068] S2, calculating the maximum adjustable power of the energy storage cluster and the non-energy storage cluster;

[0069] In this embodiment, the following steps are specifically included:

[0070] S21. Calculate the power support capacity boundaries of the energy storage cluster and the non-energy storage cluster, and calculate the maximum adjustable power of a single unit in the non-energy storage cluster based on the power constraint and the ramp constraint;

[0071] First, calculate the power support capacity boundaries of the energy storage cluster and the non-energy storage cluster. The maximum power output of the non-energy storage cluster should be affected by factors such as rated power and maximum ramp rate. The non-energy storage cluster represents the combination of all conventional units. t Moment i Maximum adjustable power of conventional units P maxGi,t It can be expressed as shown in formula (1):

[0072] (1)

[0073] In the formula, P rateG,i , R Gi Respectively represent i Rated power and maximum ramp rate of conventional units; P Gi,t-1 express t -1 moment i The maximum adjustable power in the forward frequency regulation stage takes the larger value of the power constraint and the ramp constraint, and the smaller value of the two in the reverse frequency regulation stage. P RG,t Indicates the total active power command value of the conventional units at time t.

[0074] S22. Based on the impact of capacity constraints on the maximum adjustable power, the maximum adjustable power of a single energy storage device in the energy storage cluster is calculated in combination with the upper and lower limits of the adjustable capacity of the energy storage device;

[0075] Maximum adjustable power of energy storage equipment Pmaxbi,t In addition to considering power constraints and ramp constraints, it is also necessary to consider the impact of capacity constraints on its maximum adjustable power, as shown in formula (2):

[0076] (2)

[0077] In the formula, P rateb,i , R bi Respectively represent i The rated power and maximum ramp rate of each energy storage device; P bi,t-1 , E bi,t-1 express t -1 moment i Active output and remaining capacity of each energy storage device; η ic , η id Indicates the charging and discharging efficiency of energy storage, Δ t Indicates the time interval of the control cycle; P Rb,t express t Total active power command value of energy storage equipment at every moment; E bimax , E bimin Indicates i The adjustable minimum capacity and the adjustable maximum capacity of each energy storage device are expressed as shown in formula (3):

[0078] (3)

[0079] In the formula, i The rated capacity of the energy storage device, SOC min , SOC max They are the minimum and maximum values ​​of the state of charge, respectively, and are generally taken as 0.1 and 0.9.

[0080] S23, based on the calculation results of S21 and S22, the non-energy storage cluster and the energy storage cluster are obtained. t The overall maximum adjustable power at all times.

[0081] Furthermore, we can get the non-energy storage cluster and the energy storage cluster in t Overall maximum adjustable power at all times P maxG,t and P maxb,t As shown in formula (4).

[0082] (4)

[0083] In the formula, m and n Represent the total number of conventional units and energy storage equipment in non-energy storage clusters and energy storage clusters respectively.

[0084] S3, based on the maximum adjustable power calculated in S2 and according to the cluster status information, coordinate and allocate power instructions to the non-energy storage cluster and the energy storage cluster;

[0085] In this embodiment, if Figure 3 As shown in the figure, the power allocation process is as follows:

[0086] S31. Settings t Moment state factor H R-SOC,t ;

[0087] Considering the particularity of the energy storage power generation process, it is necessary to determine the correspondence between the instructions issued by each round of AGC and the current state of charge of the energy storage cluster. Generally, a SOC benchmark value is established as a standard. The closer the current SOC value of a certain energy storage is to this benchmark value, the better the state of charge of the energy storage is at this time. Based on this, in the actual power allocation process, set t Moment state factor H R-SOC,t , defined as shown in formula (5):

[0088] (5)

[0089] In the formula, SOC ref It is the benchmark SOC value, generally taken as 0.5.

[0090] S32, judging status factor H R-SOC,t ,like H R-SOC,t If it is negative, it means that the current AGC command is not conducive to the recovery of the energy storage SOC. At this time, the non-energy storage cluster is called first. If the maximum adjustable power of the non-energy storage cluster in the current control cycle is less than the total command issued by the AGC, the remaining commands are borne by the energy storage cluster and power is allocated accordingly.

[0091] when H R-SOC,t If it is negative, it means that the current AGC instruction is not conducive to the recovery of the energy storage SOC. At this time, the non-energy storage cluster is called first. If the maximum adjustable power of the non-energy storage cluster in the current control cycle is less than the total instruction issued by the AGC, the remaining instructions are borne by the energy storage cluster. The power allocation calculation formula of the non-energy storage cluster is shown in (11), and the power allocation calculation formula of the energy storage cluster is shown in (6).

[0092] (6)

[0093] S33, when H R-SOC,t If it is positive, it means that the current AGC instruction is beneficial to the energy storage SOC recovery. At this time, the energy storage cluster is called first. H R-SOC,t The sign is reversed, then quantization t The power required for the energy storage cluster's equivalent SOC to reach the benchmark value at that moment P arr,t And according to the power required by the benchmark value P arr,t value for power allocation.

[0094] when H R-SOC,t If it is positive, it means that the current AGC instruction is beneficial to the energy storage SOC recovery, and the energy storage cluster is called first. However, in the process of calling the energy storage cluster, it may cause H R-SOC The sign of is reversed, so it needs to be quantized t The power required for the energy storage cluster's equivalent SOC to reach the benchmark value at that moment P arr,t , as shown in formula (7).

[0095] (7)

[0096] If the current AGC instruction absolute value is not greater than P arr,t The absolute value of | P R,t |≤| P arr,t |, the energy storage cluster power is used first, and the remaining part is allocated to the non-energy storage cluster. The power allocation formula is shown in (8) and (9).

[0097] (8)

[0098] (9)

[0099] On the contrary, if | P R,t |>| P arr,t |, then energy storage is called first P arr,t The power value is then called by the non-energy storage cluster, and finally the remaining part is called by the energy storage cluster. The power allocation formulas are shown in (10) and (11).

[0100] (10)

[0101] (11)

[0102] S4. Considering the real-time state of charge, the real-time state of charge and rated power of the energy storage are coupled within the energy storage cluster, the charge-discharge coupling constraint power of each energy storage cell is calculated, and the total power of the energy storage cluster is distributed to each energy storage cell within the cluster in a fixed ratio of the charge-discharge coupling constraint power;

[0103] In order to better maintain the operating state of energy storage and improve the overall life of the energy storage cluster, while effectively exerting the power support capacity of energy storage, the present invention takes into account the SOC index value in the power distribution process to complete the AGC instruction distribution process within the energy storage cluster. By coupling the maximum adjustable power of energy storage and the real-time SOC state index, the coupling constraint power of SOC and maximum adjustable power in the charging and discharging stage is defined. P ohci,t and P ohdi,t , the functional relationship between the coupling constraint power and SOC should conform to the S-type function. This paper adopts the hyperbolic tangent function as shown in equations (12), (13), and (14).

[0104] (12)

[0105] (13)

[0106] (14)

[0107] In the formula, P maxb,i For the i The maximum adjustable power of each energy storage device can be calculated by formula (2); SOC i,t express t Moment i The state of charge of each energy storage device; β ic,t , β id,t They represent the charge state deviation coefficients in the charge and discharge stages respectively; r is the adaptive factor; Figure 4 The adaptive factor r Comparison of coupling constraint power curves under different values. The coupling constraint power takes the per-unit value, and the reference value is set as the maximum adjustable power of the energy storage. Through comparison, it can be seen that r If the value is too large, the curve will converge to 0 or the maximum value too quickly. If the value is too small, the curve will lose continuity due to slow convergence. Therefore, considering the rationality of the charge and discharge constraints, this embodiment will r The value is set to 3.

[0108] The power allocation within the energy storage cluster is measured by the energy storage coupling constraint power, and the power instructions are allocated proportionally.i Energy storage t AGC command value at the moment P Rbi,t As shown in formula (15):

[0109] (15)

[0110] In the formula, P ohci,t and P ohdi,t about i Sum representation t The overall coupling power value of the energy storage cluster at each moment.

[0111] The power allocation mechanism within the energy storage cluster takes into account the differences in adjustable power and real-time state of charge of different energy storages. During periods when the energy storage state of charge is sufficient, the power value is allocated according to the maximum adjustable power without being restricted by the SOC constraint; during periods when the energy storage state of charge is insufficient, the power value borne by the energy storage decreases accordingly as the SOC state deteriorates according to the coupling constraint. Allocating AGC power instructions based on the coupling characteristics of energy storage power capacity can prevent overcharging and over-discharging problems in a single energy storage SOC, and at the same time improve the overall power support capacity of the energy storage cluster.

[0112] The AGC power distribution model constructed by the present invention simulates the distribution process of AGC power instructions between non-energy storage clusters and energy storage clusters and within each cluster in the context of the AGC system participating in frequency control, and is used to measure the execution effect of AGC instructions under different distribution modes. In terms of the construction of power generation equipment, the present invention adopts a simplified model of water, fire, wind and light, and uses transfer functions to simulate the response characteristics of the unit. No detailed modeling is performed. The energy storage monomer model only considers the first-order delay link of the converter unit, and uses the integral calculation method to obtain the real-time value of capacity loss and state of charge. The AGC power distribution model under the collaborative participation of multiple types of power generation resources is as follows: Figure 5 shown.

[0113] In the case of AGC system frequency control, the system frequency deviation Δ is generally collected by the control master station. f , tie line power deviation Δ P tie , the total power command is generated by the controller P R , and then sent to each power generation equipment through the power allocation mechanism. The power generation equipment of non-energy storage clusters includes thermal power units, hydropower units, wind and solar farms and other types of power generation equipment. Different equipment has different response models. The equivalent modeling of each power generation equipment is shown below.

[0114] For thermal power units, the response process is affected by the speed governor and the steam turbine. Its function is to control the opening of the steam turbine valve, thereby controlling the steam flow to achieve the purpose of effective output of mechanical power. The transfer function G g1 (s) is shown in formula (16):

[0115] (16)

[0116] In the formula, T g They represent the time constant of the speed regulator respectively; F H is the reheater gain; T R is the reheater time constant; T c Represents the time constant of the prime mover.

[0117] For hydropower units, the power output principle is similar to that of thermal power units. By controlling the opening of the turbine guide vanes, the water flow is controlled to determine the mechanical power output value of the turbine. G g2 (s) is expressed as shown in formula (17):

[0118] (17)

[0119] In the formula, T w is the inertia time constant of the water flow.

[0120] The response process of wind and solar power generation units depends on the response time of the inverter. G g3 (s), G g4 (s) is defined as shown in equations (18) and (19):

[0121] (18)

[0122] (19)

[0123] In the formula, T wind , T pv are the inertia time constants of wind power and photovoltaic power respectively.

[0124] For the energy storage monomer model for grid frequency regulation, this patent uses the first-order inertia link processing and the transfer function model G b (s) is expressed as shown in formula (20):

[0125] (20)

[0126] In the formula, T b Indicates the response time constant of the energy storage output.

[0127] After the AGC instructions are distributed to each power generation equipment between and within the group, the power generation equipment executes the instructions to output power, and is "bundled" in the form of a cluster to obtain the non-energy storage cluster power output. P G and energy storage cluster power output P b , sum to get the total power output of the power generation equipment P .Compare P and P R The size of can measure the execution effect of the AGC instruction in the current allocation mode.

[0128] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0129] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0130] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0131] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. 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 a limitation on the present invention.

[0132] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. An AGC two-layer power allocation method considering the participation of battery energy storage clusters, characterized in that: The steps include: S1. Aggregate the power generation equipment in the regional power grid into energy storage clusters and non-energy storage clusters according to the power allocation architecture; S2, calculating the maximum adjustable power of the energy storage cluster and the non-energy storage cluster; S3: Based on the maximum adjustable power calculated in S2 and according to the cluster status information, coordinate and allocate power instructions to the non-energy storage cluster and the energy storage cluster. The power allocation process is specifically as follows: S31. Settings t Moment state factor H R-SOC,t ; S32, judging status factor H R-SOC,t ,like H R-SOC,t If it is negative, it means that the current AGC instruction is not conducive to the recovery of the energy storage SOC. At this time, the non-energy storage cluster is called first. If the maximum adjustable power of the non-energy storage cluster in the current control cycle is less than the total instruction issued by the AGC, the remaining instructions are borne by the energy storage cluster and power is allocated accordingly. The power allocation formula is: In the formula, is the maximum adjustable power of the non-energy storage cluster at time t, P R,t express t Total active power command value at all times; S33, when H R-SOC,t If it is positive, it means that the current AGC instruction is beneficial to the energy storage SOC recovery. At this time, the energy storage cluster is called first. H R-SOC,t If the sign is reversed, then quantization t The power required for the energy storage cluster's equivalent SOC to reach the benchmark value at that moment P arr,t And according to the power required by the benchmark value P arr,t The power is allocated according to the value, and the specific method is as follows: S331, if the current AGC instruction absolute value is not greater than P arr,t The absolute value of , the energy storage cluster power is called first, and the remaining part is allocated to the non-energy storage cluster, and power distribution is performed. The power distribution formula is: In the formula, P R,t express t Total active power command value at all times, For energy storage clusters t The overall maximum adjustable power at all times; P Rb,t express t The total active power command value of the energy storage device at the moment, S332, if the current AGC instruction absolute value is less than P arr,t The absolute value of P arr,t The power value is then called by the non-energy storage cluster, and the remaining part is called by the energy storage cluster and power is allocated. The power allocation formula is: In the formula, P R,t express t Total active power command value at all times, For non-storage clusters t There is always a power command at the moment, For non-storage clusters t The overall maximum adjustable power at all times, P Rb,t express t Total active power command value of energy storage equipment at every moment; S4. Considering the real-time state of charge, the real-time state of charge and rated power of the energy storage are coupled within the energy storage cluster, the charge-discharge coupling constraint power of each energy storage cell is calculated, and the total power of the energy storage cluster is distributed to each energy storage cell within the cluster in a ratio manner of the charge-discharge coupling constraint power.

2. The AGC double-layer power allocation method considering the participation of battery energy storage cluster according to claim 1 is characterized in that: The specific method of calculating the maximum adjustable power of the energy storage cluster and the non-energy storage cluster in S2 is: S21. Calculate the power support capacity boundaries of the energy storage cluster and the non-energy storage cluster, and calculate the maximum adjustable power of a single unit in the non-energy storage cluster based on the power constraint and the ramp constraint; S22. Based on the impact of capacity constraints on the maximum adjustable power, the maximum adjustable power of a single energy storage device in the energy storage cluster is calculated in combination with the upper and lower limits of the adjustable capacity of the energy storage device; S23, based on the calculation results of S21 and S22, the non-energy storage cluster and the energy storage cluster are obtained. t The overall maximum adjustable power at all times.

3. The AGC double-layer power allocation method considering the participation of battery energy storage cluster according to claim 2 is characterized in that: The maximum adjustable power calculation method of a single unit in the non-energy storage cluster in S21 is: In the formula, for t Moment i Maximum adjustable power of conventional units, For the i Rated power of conventional units, for t -1 moment i Active output of conventional units, For the i Maximum ramp rate of conventional units, P RG,t Indicates the total active power command value of the conventional units at time t.

4. The AGC double-layer power allocation method considering the participation of battery energy storage cluster according to claim 2 is characterized in that: The maximum adjustable power of a single energy storage device in the energy storage cluster in S22 is calculated as follows: In the formula, for t Moment i The maximum adjustable power of each energy storage device, P rateb,i For the i Rated power of energy storage devices, R bi is the maximum ramp rate of the i-th energy storage device, P bi,t-1 for t -1 moment i The active output of each energy storage device, E bi,t-1 The remaining t -1 moment i The capacity of energy storage equipment, η ic , η id The table shows the charging and discharging efficiency of energy storage, Δ t is the time interval of the control cycle, E bimax , E bimin The first i The adjustable minimum capacity and adjustable maximum capacity of each energy storage device, P Rb,t express t The total active power command value of the energy storage device at this moment.

5. The AGC double-layer power allocation method considering the participation of battery energy storage cluster according to claim 2 is characterized in that: The non-energy storage cluster and energy storage cluster in S23 are t The specific calculation method of the overall maximum adjustable power at the moment is: In the formula, The non-energy storage cluster and the energy storage cluster are t The overall maximum adjustable power at all times, for t Moment i Maximum adjustable power of conventional units, for t Moment i The maximum adjustable power of each energy storage device, m and n Represent the total number of conventional units and energy storage equipment in non-energy storage clusters and energy storage clusters respectively.

6. The AGC double-layer power allocation method considering the participation of battery energy storage cluster according to claim 1 is characterized in that: The specific calculation method of the coupling constraint power in S4 is: In the formula, P ohci,t and P ohdi,t They are the real-time state of charge SOC and the coupling constraint power of the maximum adjustable power in the charging and discharging stages, P maxb,i For the i The maximum adjustable power of each energy storage device, β ic,t , β id,t They are the charge state deviation coefficients in the charge and discharge stages respectively; r is the adaptive factor; is the hyperbolic tangent function; SOC i,t express t Moment i The state of charge of the energy storage device SOC ref is the benchmark SOC value, SOC min , SOC max are the minimum and maximum values ​​of the state of charge, respectively.

7. The AGC double-layer power allocation method considering the participation of battery energy storage cluster according to claim 1 is characterized in that: In S4, the total power of the energy storage cluster is distributed to each energy storage unit in the manner of charging and discharging coupling constrained power ratio within the cluster, which is expressed as: In the formula, For the i Energy storage t The AGC command value at the moment, P ohci,t and P ohdi,t They are the real-time state of charge SOC and the coupling constraint power of the maximum adjustable power in the charging and discharging stages, for t The total active power command value of the energy storage device at this moment.

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