A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination

Abstract

The present invention belongs to the technical field of electric power system, and specifically relates to a method for comprehensive consumption and dispatching of new energy based on source-grid-load-storage coordination, comprising the following steps: obtaining grid operation data at the current moment; predicting the grid load power at the next moment based on the obtained operation data; judging the grid power imbalance for the obtained grid load power; when there is grid power imbalance, judging whether the energy storage system meets the grid power difference on the premise of ensuring that wind power and photovoltaic power are both in the maximum output state, and if so, adjusting the charging and discharging power of the energy storage system; otherwise, calculating the grid power secondary difference on the basis of adjusting the charging and discharging power of the energy storage system, satisfying the grid power secondary difference through load adjustment of controllable power users, and realizing comprehensive consumption and dispatching of new energy.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power systems, and specifically relates to a new energy comprehensive consumption and dispatching method based on source-grid-load-storage coordination. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] The power system is gradually developing towards a new power system with new energy as the main body, and it is necessary to actively promote the integration of power source, grid, load and storage and multi-energy complementarity. In order to implement the renewable energy consumption capacity, the source, grid, load and storage integration project should give full play to the load-side regulation response capability, carry out the effect analysis of the regulation support demand of the large power grid, coordinate and balance the development of power sources at all levels in the region, and promote the coordinated development and operation of the grid, source, load and storage. Distributed photovoltaic, energy storage and controllable loads will be widely connected to the distribution network. Due to the lack of coordination with grid dispatching, distribution network planning and distribution network upgrading and transformation, this will have a negative impact on the high-quality power supply to users, the safe and reliable operation of distribution facilities and the peak load regulation of the grid. At the same time, considering the high cost of energy storage system and the limited means of distribution network regulation, how to ensure the safe and economic operation of the distribution network and reduce the operating costs of energy storage, controllable loads, comprehensive energy, etc. is an urgent problem that current power grid companies and new energy development companies need to solve.

[0004] Different from the centralized large power grid, after the source, grid, load and storage are connected to the distribution network, the autonomous and coordinated operation capabilities of the distribution network in the substation, multiple distribution networks and regional distribution networks are mainly considered, and the various distributed dispatchable resources in the regional source, grid, load and storage system are coordinated to achieve multi-objective power optimization strategies to meet the flexible optimization operation of various energy situations. Traditional control is designed with the lowest power supply cost and the best new energy consumption as the optimization goals, which is not conducive to the balanced optimization of the interests of multiple parties of the source, grid, load and storage, and does not maximize the economic and social benefits of the entire source, grid, load and storage.

[0005] Considering the continuous access of integrated energy and adjustable loads, existing studies have relatively single considerations on flexibility measures, which makes it difficult to meet the flexibility needs of absorbing a high proportion of new energy connected to the grid. In addition, the flexibility modeling of traditional grids is complex, and the absorption model is difficult to solve efficiently. Since a single control strategy is often accompanied by its inherent limitations, such as the large amount of computation in centralized control resulting in limited response speed, and the lack of information interaction in decentralized control resulting in the inability to effectively reduce its regulation cost, it is difficult for a single control strategy to take into account both the rapidity and economy of regulation. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a new energy comprehensive consumption and dispatching method based on source-grid-load-storage coordination. According to the fixed load demand of power users, the full consumption of the maximum output of wind power and photovoltaic power is guaranteed. According to the system power balance, the regulation capacity of the controllable power user load is adjusted in real time, and the charging and discharging state of the energy storage system is adjusted to achieve power balance of the entire power system and effectively reduce load fluctuations and operating costs.

[0007] According to some embodiments, the solution of the present disclosure provides a new energy comprehensive consumption scheduling method based on source-grid-load-storage coordination, which adopts the following technical solutions:

[0008] A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination comprises the following steps:

[0009] Obtain the current power grid operation data;

[0010] Predicting the power grid load power at the next moment based on the acquired operation data;

[0011] Determine the power imbalance of the power grid based on the obtained power grid load power;

[0012] When there is a power imbalance in the power grid, under the premise of ensuring that wind power and photovoltaic power are both in the maximum output state, it is determined whether the energy storage system can meet the power difference of the power grid. If it does, the charging and discharging power of the energy storage system is adjusted; otherwise, the secondary power difference of the power grid is calculated based on the adjustment of the charging and discharging power of the energy storage system, and the secondary power difference of the power grid is met through load adjustment of controllable power users, thereby realizing the comprehensive consumption and dispatch of new energy.

[0013] As a further technical limitation, when there is no power imbalance in the power grid, the existing operating status of wind power, photovoltaic power, energy storage systems and power controllable users in the power grid is maintained.

[0014] As a further technical limitation, in the process of predicting the grid load power at the next moment based on the acquired operating data, iterative optimization is performed according to different time scales. Based on the operating laws of wind power, photovoltaics, electrically controllable users and energy storage systems, and considering the differences in inertia response time of power electronic equipment, within the preset sampling calculation time period, the operating power of wind power, photovoltaics, electrically controllable users and energy storage systems at the next moment is predicted simultaneously to realize the prediction of the grid load power at the next moment.

[0015] Furthermore, in the process of wind power prediction, based on the historical data information of wind power output and considering the influence of wind power uncertainty factors, the probability interval information of wind power output at the next moment is predicted by using a probability prediction method, and the wind power prediction value at the next moment is provided by the maximum probability; when the next moment occurs, the actual wind power value at the next moment is compared with the wind power prediction value to optimize the wind power prediction;

[0016] In the process of photovoltaic power prediction, based on the historical data information of photovoltaic output and considering the influence of photovoltaic uncertainty factors, the probability interval information of photovoltaic output at the next moment is predicted by probabilistic prediction, and the photovoltaic power prediction value at the next moment is provided with the maximum probability; when the next moment occurs, the actual photovoltaic power value at the next moment is compared with the photovoltaic power prediction value to optimize the photovoltaic power prediction.

[0017] Specifically, on the basis of wind power forecast and photovoltaic power forecast, according to the spatiotemporal complementary characteristics of wind power and photovoltaic, and based on the historical law of new energy superposition power, a secondary correction is made to the wind power and photovoltaic power on the same time scale to improve the accuracy of new energy output superposition.

[0018] Furthermore, in the process of energy storage system power prediction, the battery charge state of the energy storage system is used to predict the power of the energy storage system. Based on the maximum rated available capacity of the energy storage system battery and the charge and discharge operating power of the energy storage system at the current moment, the remaining charge and discharge power of the energy storage system is calculated, that is, the predicted value of the available charge and discharge power of the energy storage system at the next moment.

[0019] Furthermore, in the process of predicting the power of controllable power users, the load prediction of fixed power users is superimposed with the prediction of the controllable load range, and statistical analysis is performed according to the spatiotemporal characteristics to obtain the predicted value of the power of controllable power users.

[0020] As a further technical limitation, in the process of judging whether the power of the power grid is unbalanced, the power generation power and the power consumption power within the power grid are calculated based on the predicted value of the power load power of the power grid at the next moment, and the power imbalance of the power grid is judged by comparing the balance between the power generation power and the power consumption power; the power generation power includes wind power, photovoltaic power and the discharge power of the energy storage system, and the power consumption power includes the charging power of the energy storage system and the power of controllable users of the power.

[0021] As a further technical limitation, the objective function of the comprehensive consumption and dispatch of new energy is: Among them, α is the penalty factor, are the optimized dispatch plan values ​​for the day and the day before at the current moment, respectively, and f2 is the controllable load power value that needs to be adjusted in the power grid.

[0022] Furthermore, the constraints of the objective function include node voltage constraints, energy storage system charging and discharging constraints, and controllable load constraints.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention fully explores and coordinates the temporal and spatial complementary characteristics of controllable loads, new energy output and loads through effective modeling of various flexible resources, reduces the peak-to-valley difference of the power grid and ensures the maximum output of new energy; through the scheduling of various resources, there are obvious differences between peaks and valleys, and after optimization, the changes in peak shaving and valley filling are obvious, the new energy consumption situation is improved, the peak-to-valley difference of load is significantly reduced, and the load fluctuation and operating costs are effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure.

[0026] Figure 1 It is a flow chart of a new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination in an embodiment of the present disclosure;

[0027] Figure 2 It is a schematic diagram of the structure of wind power-photovoltaic-energy storage connected to the power grid in the embodiment of the present disclosure;

[0028] Figure 3 is a schematic diagram of the prediction results of a typical daily load in an embodiment of the present disclosure;

[0029] Figure 4 It is a schematic diagram of the optimized scheduling result in the embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] In the absence of conflict, the embodiments in the present disclosure and the features in the embodiments may be combined with each other.

[0034] Example

[0035] Embodiment 1 of the present disclosure introduces a new energy comprehensive consumption scheduling method based on source-grid-load-storage coordination.

[0036] Day-ahead dispatch is to predict the output and load of new energy sources on the dispatch day through historical data and the weather forecast on the dispatch day, and then formulate a dispatch day plan based on historical data. To maintain the balance of the entire power system, wind power, photovoltaic power, thermal power and other power sources are required, and then the losses of power grid lines and transformers are added. At the same time, according to the fixed load demand of power users, the full absorption of the maximum output of wind power and photovoltaic power is guaranteed first. According to the power balance of the system, the regulation capacity of the controllable user load is adjusted in real time, and the charging and discharging state of the energy storage system is adjusted, so as to finally achieve the power balance of the entire power system.

[0037] like Figure 1 A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination is shown, comprising the following steps:

[0038] Step S01: Obtain the current grid operation data, and perform power forecasts for wind power, photovoltaic power, power load and energy storage system at the next moment;

[0039] Step S02: Based on the power forecast, the power load of the power grid is obtained, the power generation and power consumption balance in the power grid is calculated, and it is determined whether there is a power imbalance problem in the power grid at the next moment.

[0040] Step S03: If there is no power balance problem, wind power, photovoltaic power, energy storage, power users, etc. maintain the original operating status; if there is a power balance problem, the power deviation value that needs to be adjusted is calculated, and on the premise of maintaining the maximum output state of wind power and photovoltaic power, it is determined whether the energy storage charging and discharging capacity meets the current power deviation demand;

[0041] Step S04: If the energy storage charging and discharging capacity can meet the current power deviation requirement, the energy storage system is preferentially selected for charging and discharging power adjustment;

[0042] Step S05: If the energy storage charging and discharging capacity cannot meet the current power deviation demand, the power difference that has not been made up is calculated on the basis of giving priority to the energy storage system for charging and discharging power adjustment, and the controllable load makes another adjustment;

[0043] Step S06: After the controllable load adjustment is completed, determine whether the power grid power at the current moment has reached power balance. If power balance is achieved, the system reaches a balanced state. If not, continue to return to step S01 for iterative adjustment and optimization.

[0044] In step S01, all power forecasts are iteratively optimized and calculated according to different time scales. According to the operating law characteristics of wind power, photovoltaic power, electric load, and energy storage, and taking into account the difference in inertia response time of power electronic equipment (photovoltaic power generation is a device with no inertia or very weak inertia, wind power has a certain buffering capacity, and electric load is a fixed conventional ordinary load with a controllable load with a certain time scale; energy storage is controlled according to the charge and discharge rate of the battery), 1 minute is used as the sampling calculation cycle of the entire system. By simultaneously calculating the balance of wind power, photovoltaic power, electric load and energy storage operating status at the current moment, the power situation in the next minute is predicted. The specific prediction process is as follows:

[0045] (1) Wind power forecast: Based on the historical data of wind power output and taking into account the influence of uncertainty factors in weather forecasts, a probability forecasting method is used to predict the probability interval information of wind power output at the next moment, and the wind power forecast value at the next moment is provided according to the maximum probability. At the same time, when the next moment occurs, the actual wind power output information is compared with the predicted power output, which in turn optimizes the wind power model and improves the accuracy of model prediction.

[0046] (2) Photovoltaic power prediction: Based on the historical data of photovoltaic output and the influence of uncertainty factors in weather forecasts, a probability prediction method is used to predict the probability interval information of photovoltaic output at the next moment, and the photovoltaic power prediction value at the next moment is provided according to the maximum probability. At the same time, when the next moment occurs, the actual photovoltaic output information is compared with the predicted power output, which in turn optimizes the photovoltaic power model and improves the accuracy of model prediction.

[0047] On the basis of wind power forecast and photovoltaic power forecast, according to the characteristics of spatiotemporal complementarity between wind power and photovoltaic power, and based on the historical law of new energy superposition power, a secondary correction is made to the wind power and photovoltaic power on the same time scale to improve the accuracy of the new energy output superposition.

[0048] (3) Electric load power forecasting uses a superposition method of fixed power user load forecasting and controllable load range forecasting, and performs statistical analysis based on temporal and spatial characteristics.

[0049] (4) Energy storage charging and discharging power prediction uses the battery charge state of the energy storage system for prediction, which is consistent with the energy storage battery management system. The rated maximum available capacity of the energy storage battery is deducted from the charging and discharging operating power of the energy storage battery at the current moment. The remaining charging and discharging power is the available charging and discharging power predicted at the next moment.

[0050] In step S02, after determining the power deviation, the safe operating capacity range of each device is considered, and then a control strategy is issued for each device. The specific calculation process is: based on the power forecast of wind power, photovoltaics, energy storage, load, etc., the difference between the power generation power in the system and the power required by the user is calculated. If the power generation power is inconsistent with the power required by the user after deducting the network loss, it indicates that the power generation and power consumption are unbalanced, and there is a power imbalance problem in the power grid. According to the power difference, it is necessary to adjust the controllable load, energy storage charging and discharging power, etc. in time, while giving priority to satisfying the maximum power output of new energy and the continuous supply of conventional fixed power users' loads, so as to ensure the power balance between power generation and power consumption and achieve safe and stable operation of the entire system.

[0051] In step S05, when the charging and discharging power of the energy storage system cannot achieve the regulation of the power imbalance of the power grid, it is necessary to introduce the secondary difference of the power grid, that is, to obtain the secondary difference of the power grid through the difference between the power value of the power imbalance of the power grid and the charging and discharging power of the energy storage system. The secondary difference of the power grid is satisfied through the load adjustment of the controllable power users, so as to realize the comprehensive consumption and scheduling of new energy.

[0052] The goal of intraday dispatch is to maximize and prioritize the use of renewable energy generation, while keeping the controllable units in the grid and the adjustment of day-ahead dispatch at a minimum. The objective function is:

[0053]

[0054] Among them, α is the penalty factor, are the optimized dispatch plan values ​​for the day and the day before at the current time t, respectively, and f2 is the controllable load power value that needs to be adjusted in the power grid. f2 represents the deviation between the power generation power and the power consumption power in the power grid, and is also the controllable load power that needs to be adjusted. The minimum f2 represents the minimum coordinated dispatch of multiple flexible resources.

[0055] The constraints of the objective function of intraday scheduling are mainly subject to the technical indicators of the active distribution network, including node voltage, power balance, energy storage charging and discharging, controllable load, etc.

[0056] The node voltage constraints are:

[0057] in, The node voltages U i The lower and upper limits of .

[0058] The power balance constraints are:

[0059] in, is the wind power output at the current time t, is the wind power output at the current time t, is the charging / discharging output of the energy storage at the current time t, is the thermal power output at the current time t, is the power grid loss at the current moment t, is the power load of ordinary users at the current time t, is the controllable user power load at the current moment t.

[0060] The energy storage charging and discharging constraints are:

[0061] in, is the minimum charging / discharging capacity of the energy storage system at the current time t, is the maximum charging / discharging capacity of the energy storage system at the current time t, is the state of charge of the energy storage system at the current time t, is the minimum state of charge of the energy storage system at the current time t, is the maximum state of charge of the energy storage system at the current time t.

[0062] The controllable load constraints are:

[0063] in, is the minimum regulating capacity of the controllable load at the current moment t, It is the maximum regulating capacity of the controllable load at the current moment t.

[0064] In order to verify the feasibility of the proposed scheduling method, the IEEE 33-node system is taken as an example. Figure 2 As shown, photovoltaic power, energy storage, and controllable loads are all connected to node 6, and wind power, energy storage, and controllable loads are all connected to node 31. The thermal power units and power user loads in the power grid maintain normal operation, and there is no power exchange between the upper-level power grid, maintaining the power balance of power generation and power consumption in the power grid.

[0065] Carry out load forecasting for wind power, photovoltaic power, and conventional power loads, calculate according to typical load days, and predict the results. Figure 3 As shown. Figure 3 It can be seen that the distribution network load has obvious peak-valley variation characteristics over time, with the peak value mainly concentrated around 12:00 to 14:00, and the load trough time mainly concentrated in midnight and early morning.

[0066] The long time scale is 1 hour as a unit, 24 hours a day, to formulate an optimized scheduling plan, and the optimized scheduling results are as follows Figure 4 shown.

[0067] According to the premise of ensuring the maximum absorption of wind power and photovoltaic power, ensuring the continuous power supply of conventional power loads, and adjusting the capacity of controllable loads to the minimum reasonable, the charging and discharging capacity of controllable loads and energy storage is determined under the day-ahead dispatch. Figure 3 and Figure 4 In the load curves before and after optimization, there are obvious differences between peaks and valleys through the scheduling of multiple resources. After optimization, the peak shaving and valley filling changes are obvious, the consumption of new energy is improved, and the load peak-valley difference is significantly reduced, which verifies the accuracy and reliability of the optimization model.

[0068] Through the scheduling of multiple resources in this embodiment, there are obvious differences between peaks and valleys. After optimization, the changes in peak shaving and valley filling are obvious, the consumption of new energy is improved, the peak-to-valley difference of load is significantly reduced, and the load fluctuation and operating costs are effectively reduced.

[0069] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination, characterized in that: The following steps are involved: Obtain the current power grid operation data; Predicting the power grid load power at the next moment based on the acquired operation data; Determine the power imbalance of the power grid based on the obtained power grid load power; When there is a power imbalance in the power grid, under the premise of ensuring that wind power and photovoltaic power are both at their maximum output, determine whether the energy storage system can meet the power difference of the power grid. If so, adjust the charging and discharging power of the energy storage system; otherwise, calculate the secondary power difference of the power grid on the basis of adjusting the charging and discharging power of the energy storage system, and meet the secondary power difference of the power grid through load adjustment of controllable power users, so as to realize the comprehensive consumption and dispatch of new energy; In the process of predicting the grid load power at the next moment based on the acquired operating data, iterative optimization is performed according to different time scales. Based on the operating rules of wind power, photovoltaic power, power controllable users and energy storage systems, and considering the differences in the inertia response time of power electronic equipment, the operating power of wind power, photovoltaic power, power controllable users and energy storage systems at the next moment is predicted simultaneously within the preset sampling calculation time period to realize the prediction of the grid load power at the next moment. In the process of judging the imbalance of power in the power grid, based on the predicted value of the power load power of the power grid at the next moment, the power generation power and the power consumption power in the power grid are calculated, and the power imbalance of the power grid is judged by comparing the balance between the power generation power and the power consumption power; the power generation power includes wind power, photovoltaic power and the discharge power of the energy storage system, and the power consumption power includes the charging power of the energy storage system and the power of the controllable power user; The objective function of the comprehensive consumption and dispatch of new energy is: Among them, α is the penalty factor, are the optimized dispatch plan values ​​for the day and the day before at the current moment, respectively, and f2 is the controllable load power value that needs to be adjusted in the power grid.

2. A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination as described in claim 1, characterized in that: When there is no power imbalance in the power grid, the existing operating status of wind power, photovoltaic power, energy storage systems and power controllable users in the power grid is maintained.

3. A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination as described in claim 1, characterized in that: In the process of wind power prediction, based on the historical data information of wind power output and considering the influence of wind power uncertainty factors, the probability interval information of wind power output at the next moment is predicted by probabilistic prediction, and the wind power prediction value at the next moment is provided with the maximum probability; when the next moment occurs, the actual wind power value at the next moment is compared with the wind power prediction value to optimize the wind power prediction.

4. A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination as described in claim 1, characterized in that: In the process of photovoltaic power prediction, based on the historical data information of photovoltaic output and considering the influence of photovoltaic uncertainty factors, the probability interval information of photovoltaic output at the next moment is predicted by probabilistic prediction, and the photovoltaic power prediction value at the next moment is provided with the maximum probability; when the next moment occurs, the actual photovoltaic power value at the next moment is compared with the photovoltaic power prediction value to optimize the photovoltaic power prediction.

5. A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination as described in claim 1, characterized in that: In the process of energy storage system power prediction, the battery charge state of the energy storage system is used to predict the power of the energy storage system. Based on the maximum rated available capacity of the energy storage system battery and the charging and discharging operating power of the energy storage system at the current moment, the remaining charging and discharging power of the energy storage system is calculated, that is, the predicted value of the available charging and discharging power of the energy storage system at the next moment.

6. A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination as described in claim 1, characterized in that: In the process of power prediction for controllable power users, the load prediction for fixed power users is superimposed with the prediction for the controllable load range, and statistical analysis is performed according to the spatiotemporal characteristics to obtain the predicted value of the power for controllable power users.

7. A new energy comprehensive consumption dispatching method based on source-grid-load-storage coordination as described in claim 1, characterized in that: The constraints of the objective function include node voltage constraints, energy storage system charging and discharging constraints, and controllable load constraints.

Images