A new energy power station power smoothing control method and system

Abstract

The application provides a new energy power station power smoothing control method and system. The method comprises the following steps: obtaining the dispatch active power and low-pass filtered power of the new energy power station; calculating the active power of the energy storage system according to the dispatch active power and the low-pass filtered power; obtaining the active power of the energy storage system at each time within a preset time period; calculating the fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time; selecting a target energy storage system according to the fluctuation value of the active power of the energy storage system and the energy storage type of each energy storage system, wherein the preset fluctuation interval corresponding to different types of energy storage systems is different; and controlling the target energy storage system to charge and discharge according to the active power of the energy storage system at the current time. Through the application, different types of energy storage system characteristics are combined, and corresponding energy storage systems are selected according to the fluctuation of the active power of the energy storage system, so as to realize the power smoothing of the new energy power station.

Description

TECHNICAL FIELD

[0001] The embodiment of the application relates to the technical field of electric power, in particular to a new energy power station power smoothing control method and system. BACKGROUND

[0002] With the vigorous development and popularization and application of renewable energy such as wind and light, the installed capacity and power generation capacity of wind farms and photovoltaic power stations in the power grid are increasing. The output of new energy has the characteristics of intermittency, volatility and randomness, which brings many problems and risks to the safe and stable operation of the power grid. Therefore, more and more attention is paid to improving the power quality of new energy power stations and improving the stability of the output power of new energy power stations.

[0003] The energy storage system has the advantages of suppressing new energy generation fluctuation, providing reliable capacity support, participating in system peak regulation and frequency regulation, and ensuring safe and stable operation. However, the existing energy storage system participating in the power smoothing control method of the new energy power station does not consider the power smoothing cost characteristics of different types of energy storage systems, and is not suitable for large-scale multi-type energy storage power station combined with new energy power station operation. SUMMARY

[0004] In order to combine the characteristics of different types of energy storage systems and realize power smoothing of new energy power stations, the application provides a new energy power station power smoothing control method and system.

[0005] In a first aspect, the application provides a new energy power station power smoothing control method, which comprises:

[0006] obtaining the dispatch active power and the low-pass filtered power of the new energy power station, the low-pass filtered power being obtained by filtering the actual active power of wind and light through a low-pass filter;

[0007] calculating the active power of the energy storage system according to the dispatch active power and the low-pass filtered power;

[0008] obtaining the active power of the energy storage system at each time within a preset time period;

[0009] calculating the fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time;

[0010] selecting a target energy storage system according to the fluctuation value of the active power of the energy storage system and the energy storage type of each energy storage system, the preset fluctuation interval of different types of energy storage systems being different, and the preset fluctuation interval being determined according to the installed capacity of the energy storage system with the smallest installed capacity in each energy storage system;

[0011] controlling the target energy storage system to charge and discharge according to the active power of the energy storage system at the current time.

[0012] Considering that different types of energy storage systems adapt to different ranges of power fluctuations, in the process of smoothing the new energy power station by using the energy storage system, according to the fluctuation value of the active power of the energy storage system and the preset fluctuation interval, the corresponding energy storage system is selected for charging and discharging, at the same time, the low-pass filter is used to filter the actual active power of wind and light, the high-frequency part in the actual active power of wind and light is filtered out, and the energy storage system only smoothes the low-frequency part in the actual active power of wind and light, so as to reduce the conversion times of charging and discharging of the energy storage system, realize the power smoothing of the new energy power station, and reduce the operation cost of the energy storage system.

[0013] With reference to the first aspect, in a first embodiment of the first aspect, the target energy storage system is selected according to the fluctuation value of the active power of the energy storage system and the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located, and the target energy storage system is selected according to the fluctuation value of the active power of the energy storage system and the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located.

[0014] The preset fluctuation interval in which the fluctuation value is located is determined according to the fluctuation value of the active power of the energy storage system.

[0015] The target energy storage system is selected according to the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located.

[0016] With reference to the first aspect, in a second embodiment of the first aspect, the fluctuation value of the active power of the energy storage system is calculated according to the active power of the energy storage system at each time point, and the fluctuation value of the active power of the energy storage system is calculated according to the active power of the energy storage system at each time point.

[0017] The difference value of the active power of the energy storage system at each adjacent time point is calculated according to the active power of the energy storage system at each time point.

[0018] The fluctuation value of the active power of the energy storage system is obtained by summing the difference value of the active power of the energy storage system at each adjacent time point.

[0019] With reference to the first embodiment of the first aspect, in a third embodiment of the first aspect, the target energy storage system is selected according to the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located.

[0020] When the fluctuation value is in the first preset fluctuation interval, the first energy storage system is selected as the target energy storage system.

[0021] When the fluctuation value is in the second preset fluctuation interval, the second energy storage system is selected as the target energy storage system.

[0022] With reference to the first aspect or the third embodiment of the first aspect, in a fourth embodiment of the first aspect, the transfer relationship of the low-pass filter comprises:

[0023]

[0024] Wherein, P filter is the low-pass filtered power; s is the differential operator; T1 is the filtering time constant; P windP is the actual active power of the wind power station before the low-pass filter; pv P is the actual active power of the photovoltaic station before the low-pass filter; all P is the sum of the actual active power of the wind power station and the actual active power of the photovoltaic station before the low-pass filter.

[0025] In a second aspect, the present application also provides a new energy power station power smoothing control system, which comprises a signal acquisition unit, an energy storage internal energy distribution calculation unit and an energy storage control unit.

[0026] The signal acquisition unit is configured to acquire the dispatch active power and the low-pass filter power of the new energy power station, wherein the low-pass filter power is obtained by filtering the actual active power of the wind and light through a low-pass filter.

[0027] The energy storage internal energy distribution calculation unit is configured to calculate the active power of the energy storage system according to the dispatch active power and the low-pass filter power, acquire the active power of the energy storage system at each time within a preset time length, calculate the fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time, and select a target energy storage system according to the fluctuation value of the active power of the energy storage system and the energy storage type of each energy storage system, wherein the preset fluctuation interval corresponding to different types of energy storage systems is different, and the preset fluctuation interval is determined according to the installed capacity of the energy storage system with the smallest installed capacity among the energy storage systems.

[0028] The energy storage control unit is configured to control the target energy storage system to charge and discharge according to the active power of the energy storage system at the current time.

[0029] Considering that different types of energy storage systems adapt to different power fluctuation ranges, in the process of smoothing the new energy power station by using the energy storage system, the corresponding energy storage system is selected for charging and discharging according to the matching of the fluctuation value of the active power of the energy storage system and the preset fluctuation interval, and at the same time, the low-pass filter is used to filter the actual active power of the wind and light, so as to filter out the high-frequency part of the actual active power of the wind and light, and the energy storage system only smoothes the low-frequency part of the actual active power of the wind and light, so as to reduce the charging and discharging conversion times of the energy storage system, realize the power smoothing of the new energy power station, and reduce the operation cost of the energy storage system.

[0030] In combination with the second aspect, in a first embodiment of the second aspect, the energy storage internal energy distribution calculation unit selects the target energy storage system through the following sub-units:

[0031] The first determination sub-unit is configured to determine the preset fluctuation interval in which the fluctuation value is located according to the fluctuation value of the active power of the energy storage system.

[0032] The first selection sub-unit is configured to select the target energy storage system according to the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located.

[0033] In combination with the first embodiment of the second aspect, in a second embodiment of the second aspect, the system further comprises:

[0034] a dispatching instruction receiving unit configured to receive a dispatching active power issued by a dispatching system;

[0035] a power station control unit configured to control the wind power station and the photovoltaic power station according to the dispatching active power.

[0036] In combination with the second embodiment of the second aspect, in a third embodiment of the second aspect, the system further comprises:

[0037] a super-short-term wind-solar power prediction unit configured to predict wind-solar active power of the new energy power station at a next time and report the dispatching system to correct the dispatching active power.

[0038] In combination with the third embodiment of the second aspect, in a fourth embodiment of the second aspect, the system further comprises:

[0039] a recording unit configured to record the dispatching active power, the actual wind-solar active power, the low-pass filtered power and the active power of the energy storage system. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0041] Figure 1 is a flow chart of a new energy power station power smoothing control method according to an exemplary embodiment;

[0042] Figure 2 is a design flow chart of a low-pass filter in an example;

[0043] Figure 3 is a structural schematic diagram of a new energy power station power smoothing control system according to an exemplary embodiment. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0045] In addition, the technical features involved in the different embodiments of the application described below can be combined with each other as long as there is no conflict.

[0046] To combine the characteristics of different types of energy storage systems and realize power smoothing of new energy power stations, the application provides a new energy power station power smoothing control method and system.

[0047] Figure 1 A flowchart of a new energy power station power smoothing control method according to an exemplary embodiment is shown in FIG. 1. As shown in FIG. 1, the method comprises the following steps. Figure 1

[0048] Step S101: Obtain the dispatch active power of the new energy power station and the low-pass filtered power, which is obtained by filtering the wind-solar actual active power through a low-pass filter.

[0049] In an optional embodiment, the new energy power station comprises a wind power station, a photovoltaic power station and an energy storage system.

[0050] In an optional embodiment, the dispatch active power is the active power in the dispatch instruction issued by the upper dispatch system to the new energy power station.

[0051] In an optional embodiment, the wind-solar actual active power is the sum of the actual active power of the wind power station and the actual active power of the photovoltaic power station.

[0052] In an optional embodiment, the low-pass filtered power is obtained by removing the high-frequency components from the wind-solar actual active power of the new energy power station.

[0053] Step S102: Calculate the active power of the energy storage system according to the dispatch active power and the low-pass filtered power.

[0054] In an optional embodiment, the active power of the energy storage system at the current time is equal to the difference between the dispatch active power at the current time and the low-pass filtered power at the current time.

[0055] Step S103: Obtain the active power of the energy storage system at each time within a preset time period. In an optional embodiment, the active power of the energy storage system at each time refers to the active power at the historical time. Exemplarily, the active power of the energy storage system at each time can be obtained through a recording system.

[0056] In an optional embodiment, the preset time period can be set according to actual needs.

[0057] Step S104: Calculate the fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time.

[0058] ​Step S105: According to the fluctuation value of the active power of the energy storage system and the energy storage type of each energy storage system, a target energy storage system is selected. The preset fluctuation interval corresponding to different types of energy storage systems is different, and the preset fluctuation interval is determined according to the installed capacity of the energy storage system with the smallest installed capacity.

[0059] In an optional embodiment, the energy storage type is obtained by classifying the energy storage system according to the adaptive power fluctuation interval. Different fluctuation intervals correspond to different power fluctuation values. The energy storage systems suitable for larger power fluctuation values include but are not limited to battery energy storage systems such as lithium batteries, lead-acid batteries and flow batteries. Energy storage systems suitable for smaller power fluctuation values include but are not limited to supercapacitor energy storage, flywheel energy storage and superconducting magnetic energy storage. Such energy storage systems have short response time and high cycle number.

[0060] Step S106: According to the active power of the energy storage system at the current time, the target energy storage system is controlled to charge and discharge.

[0061] In an optional embodiment, when the active power of the energy storage system is positive, the energy storage system discharges; when the active power of the energy storage system is negative, the energy storage system charges; and when the active power of the energy storage system is 0, the energy storage system does not act.

[0062] Considering that different types of energy storage systems adapt to different power fluctuation ranges, in the process of smoothing the new energy power station by using the energy storage system, the energy storage system is selected for charging and discharging according to the matching between the fluctuation value of the active power of the energy storage system and the preset fluctuation interval. At the same time, the low-pass filter is used to filter the actual active power of wind and light, and the high-frequency part of the actual active power of wind and light is filtered out. The energy storage system only smoothes the low-frequency part of the actual active power of wind and light to reduce the charging and discharging conversion times of the energy storage system and reduce the impact of frequent charging and discharging on the energy storage system. In addition, the power smoothing of the new energy power station is realized, and the operation cost of the energy storage system is reduced.

[0063] In an example, the specific steps of calculating the fluctuation value of the active power of the energy storage system in step S104 above include:

[0064] First, the difference between the active power of each adjacent time of the energy storage system is calculated according to the active power of the energy storage system at each time.

[0065] Then, the sum of the difference between the active power of each adjacent time of the energy storage system is calculated to obtain the fluctuation value of the active power of the energy storage system.

[0066] In an optional embodiment, the fluctuation value of the active power of the energy storage system is calculated by the following formula:

[0067]

[0068] wherein, is the fluctuation value of the active power of the energy storage system; Δt is the time interval at each time; T1 is a preset time length, is the active power of the energy storage system at t+kΔt, is the active power of the energy storage system at t+(k-1)Δt. Exemplarily, the preset time length can be 1 minute.

[0069] In an example, in the step S105, the selection of the target energy storage system is achieved by the following steps:

[0070] Firstly, according to the fluctuation value of the active power of the energy storage system, a preset fluctuation interval in which the fluctuation value is located is determined.

[0071] Then, according to the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located, the target energy storage system is selected.

[0072] In an optional embodiment, the specific steps of selecting the target energy storage system according to the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located are as follows:

[0073] Firstly, when the fluctuation value is in a first preset fluctuation interval, a first energy storage system is selected as the target energy storage system.

[0074] Then, when the fluctuation value is in a second preset fluctuation interval, a second energy storage system is selected as the target energy storage system.

[0075] The installed capacity of different types of energy storage systems is different, so the preset fluctuation interval can be determined according to the installed capacity of the energy storage system. In an optional embodiment, according to the size of the fluctuation value, the energy storage system is divided into two types of energy storage systems, one type is suitable for the energy storage system with large fluctuation value, and the other type is suitable for the energy storage system with small fluctuation value. The preset fluctuation interval is determined according to the installed capacity of the energy storage system with the smallest installed capacity. Exemplarily, in order to maintain the health state of the energy storage system, the boundary value of the fluctuation interval is determined according to 10% of the installed capacity of the energy storage system with the smallest installed capacity. When the fluctuation interval is in a first preset fluctuation interval [0, boundary value], a first energy storage system is selected, for example, super capacitor energy storage, flywheel energy storage and superconducting magnetic energy storage, which are suitable for energy storage systems with small fluctuation value; when the fluctuation interval is in a second preset fluctuation interval [boundary value, maximum installed capacity of the energy storage system], a second energy storage system is selected, for example, lithium battery, lead-acid battery and flow battery, which are suitable for battery energy storage systems with large fluctuation value.

[0076] In an example, the transfer relationship of the low-pass filter includes:

[0077]

[0078] wherein, P filteris the low-pass filtered power; s is the differential operator; T1 is the filter time constant; P wind is the actual active power of the wind power station before the low-pass filter; P pv is the actual active power of the photovoltaic power station before the low-pass filter; P all is the actual active power of the wind-photovoltaic power station before the low-pass filter. Figure 2 is a design flowchart of the low-pass filter. P * grid is the dispatch active power; P * sto is the active power of the energy storage system, and the large-scale energy storage system selects a corresponding energy storage system according to the fluctuation value of the active power of the energy storage system, P sto is the actual active power of the energy storage system; P grid is the actual active power of the grid-connected point, that is, the sum of the actual active power of the wind-photovoltaic power station and the actual active power of the energy storage system.

[0079] Figure 3 is a structural schematic diagram of a new energy power station power smoothing control system according to an example embodiment, and the system comprises a signal acquisition unit 301, an energy storage internal energy distribution calculation unit 302, and an energy storage control unit 303.

[0080] The signal acquisition unit 301 is configured to acquire the dispatch active power and the low-pass filtered power of the new energy power station, and the low-pass filtered power is obtained by filtering the actual active power of the wind-photovoltaic power station through a low-pass filter. For details, refer to the description of step S101 in the above embodiment, which will not be repeated here.

[0081] The energy storage internal energy distribution calculation unit 302 is configured to calculate the active power of the energy storage system according to the dispatch active power and the low-pass filtered power, acquire the active power of the energy storage system at each time within a preset time length, calculate the fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time, select a target energy storage system according to the fluctuation value of the active power of the energy storage system and the energy storage types of each energy storage system, and the preset fluctuation interval corresponding to different types of energy storage systems is different, and the preset fluctuation interval is determined according to the installed capacity of the energy storage system with the smallest installed capacity in each energy storage system. For details, refer to the descriptions of steps S102 to S104 in the above embodiment, which will not be repeated here.

[0082] The energy storage control unit 303 is configured to control the target energy storage system to charge and discharge according to the active power of the energy storage system at the current time. For details, refer to the description of step S105 in the above embodiment, which will not be repeated here.

[0083] Considering that different types of energy storage systems adapt to different ranges of power fluctuations, in the process of smoothing the new energy power station by using the energy storage system, according to the fluctuation value of the active power of the energy storage system and the preset fluctuation interval, the corresponding energy storage system is selected for charging and discharging, and at the same time, the low-pass filter is used to filter the actual active power of wind and light, and the high-frequency part of the actual active power of wind and light is filtered out. The energy storage system only smoothes the low-frequency part of the actual active power of wind and light, so as to reduce the number of charging and discharging conversion of the energy storage system, realize the power smoothing of the new energy power station, and reduce the operation cost of the energy storage system.

[0084] In an example, the energy storage internal energy distribution calculation unit 302 selects the target energy storage system by the following subunit:

[0085] The first determination subunit is used for determining the preset fluctuation interval where the fluctuation value is located according to the fluctuation value of the active power of the energy storage system. For details, refer to the description in the above embodiment, which will not be repeated here.

[0086] The first selection subunit is used for selecting the target energy storage system according to the energy storage type corresponding to the preset fluctuation interval where the fluctuation value is located. For details, refer to the description in the above embodiment, which will not be repeated here.

[0087] In an example, the system further comprises:

[0088] The dispatching instruction receiving unit is used for receiving the dispatching active power issued by the dispatching system. For details, refer to the description in the above embodiment, which will not be repeated here.

[0089] The power station control unit is used for controlling the wind power station and the photovoltaic power station according to the dispatching active power. Illustratively, the power station control unit distributes the dispatching active power, and then controls the wind power station and the photovoltaic power station. For details, refer to the description in the above embodiment, which will not be repeated here.

[0090] In an example, the system further comprises:

[0091] The ultra-short-term wind and light power prediction unit is used for predicting the wind and light active power of the new energy power station at the next time, and reporting to the dispatching system to correct the dispatching active power. Illustratively, the prediction time of the ultra-short-term wind and light power prediction unit is 4 hours, and the resolution is 15 minutes. For details, refer to the description in the above embodiment, which will not be repeated here.

[0092] In an example, the system further comprises:

[0093] The recording unit is configured to record the dispatch active power, the actual active power of the wind and solar power, the low-pass filtered power, and the active power of the energy storage system. By way of example, the recording unit uses an event-triggering mechanism. When the energy storage system charges and discharges to smooth the power, the recording unit is started. For details, refer to the description in the above embodiments, which will not be repeated here.

[0094] It should be noted that, in this document, the terms "first", "second", and so on are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or device. Without further limitation, the element defined by the statement "includes a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0095] The above is only a specific embodiment of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A new energy power station power smoothing control method, characterized in that, The method comprises: acquiring a dispatch active power and a low-pass filtered power of a new energy power station, the low-pass filtered power being obtained by filtering an actual wind-solar active power through a low-pass filter; calculating an active power of an energy storage system according to the dispatch active power and the low-pass filtered power; acquiring the active power of the energy storage system at each time within a preset time length; calculating a fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time; selecting a target energy storage system according to the fluctuation value of the active power of the energy storage system and the energy storage types of each energy storage system, the preset fluctuation intervals corresponding to different types of energy storage systems being different, the preset fluctuation intervals being determined according to the installed capacity of the energy storage system with the smallest installed capacity among the energy storage systems; controlling the target energy storage system to charge and discharge according to the active power of the energy storage system at a current time; selecting a target energy storage system according to the fluctuation value of the active power of the energy storage system and the energy storage types of each energy storage system, comprising: determining a preset fluctuation interval in which the fluctuation value is located according to the fluctuation value of the active power of the energy storage system; selecting a target energy storage system according to the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located; selecting a target energy storage system according to the energy storage type corresponding to the preset fluctuation interval in which the fluctuation value is located, comprising: when the fluctuation value is in a first preset fluctuation interval, selecting a first energy storage system as the target energy storage system; when the fluctuation value is in a second preset fluctuation interval, selecting a second energy storage system as the target energy storage system.

2. The method of claim 1, wherein, calculating a fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time, comprising: calculating a difference value of the active power of each adjacent time of the energy storage system according to the active power of the energy storage system at each time; summing the difference values of the active power of each adjacent time of the energy storage system to obtain the fluctuation value of the active power of the energy storage system.

3. The method of claim 1, wherein, The transfer relationship of the low-pass filter comprises: wherein P filter is the low pass filtered power; s is a differential operator; T 1 is a filter time constant; P wind is the actual active power of the wind power plant before the low pass filter; P pv is the actual active power of the photovoltaic power plant before the low pass filter; P all is the sum of the actual active power of the wind power plant and the actual active power of the photovoltaic power plant before the low pass filter.

4. A new energy power station power smoothing control system, characterized in that, The system comprises a signal acquisition unit, an energy storage internal energy distribution calculation unit and an energy storage control unit; The signal acquisition unit is configured to acquire a dispatch active power and a low-pass filtered power of a new energy power station, the low-pass filtered power being obtained by filtering an actual wind-solar active power through a low-pass filter; The energy storage internal energy distribution calculation unit is configured to calculate an active power of an energy storage system according to the dispatch active power and the low-pass filtered power, acquire the active power of the energy storage system at each time within a preset time length, calculate a fluctuation value of the active power of the energy storage system according to the active power of the energy storage system at each time, and select a target energy storage system according to the fluctuation value of the active power of the energy storage system and the energy storage types of each energy storage system, the preset fluctuation intervals corresponding to different types of energy storage systems being different, the preset fluctuation intervals being determined according to the installed capacity of the energy storage system with the smallest installed capacity among the energy storage systems; The energy storage control unit is configured to control the target energy storage system to charge and discharge according to the active power of the energy storage system at a current time; The energy storage internal energy distribution calculation unit selects a target energy storage system through the following subunit: A first determination subunit is configured to determine a preset fluctuation interval in which a fluctuation value of an active power of an energy storage system is located according to the fluctuation value of the active power of the energy storage system. The first selection subunit is configured to select a target energy storage system according to an energy storage type corresponding to a preset fluctuation interval in which the fluctuation value is located. The selecting a target energy storage system according to an energy storage type corresponding to a preset fluctuation interval in which the fluctuation value is located includes: When the fluctuation value is located in a first preset fluctuation interval, a first energy storage system is selected as the target energy storage system. When the fluctuation value is located in a second preset fluctuation interval, a second energy storage system is selected as the target energy storage system.

5. The system of claim 4, wherein, The system further includes: A dispatch instruction receiving unit configured to receive a dispatch active power issued by a dispatch system. A power plant control unit configured to control a wind power plant and a photovoltaic power plant according to the dispatch active power.

6. The system of claim 5, wherein, The system further includes: An ultra-short-term wind-solar power prediction unit configured to predict wind-solar active power of a new energy power plant at a next time point and report the dispatch system to correct the dispatch active power.

7. The system of claim 6, wherein, The system further includes: A recording unit configured to record the dispatch active power, the wind-solar actual active power and the energy storage system active power.

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