CN115774935A - Weak-connection type wind-solar storage micro-grid operation optimization method and system - Google Patents
Weak-connection type wind-solar storage micro-grid operation optimization method and system Download PDFInfo
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Abstract
The invention relates to a weak-connection type wind-solar storage micro-grid operation optimization method and system, wherein the method comprises the following steps: acquiring data required by model building; establishing a wind-solar-storage micro-grid-connected operation optimization model by taking the minimum cost in an operation period as a target and considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and tie line transmission constraint; the method comprises the steps that a wind-solar-energy-storage microgrid off-grid operation optimization model is established by taking the minimum power supply loss in a failure guarantee period as a target, considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and load constraint and considering new energy prediction deviation; combining the two models to construct a wind-solar-storage micro-grid operation model considering fault guarantee; and calculating an operation decision in an operation period based on the constructed wind-solar-storage micro-grid operation model, and executing a first point decision result. The method and the system combine a grid-connected operation model and an off-grid operation model, and are favorable for considering both the operation cost and the reliability of the microgrid.
Description
Technical Field
The invention belongs to the technical field of micro-grid operation control, and particularly relates to a weak-connection type wind-solar storage micro-grid operation optimization method and system.
Background
The weak link type microgrid refers to a microgrid connected with a distribution network only through a single return tie line, and the structure of the microgrid is shown in fig. 2. When the tie line is disconnected due to faults, the power supply such as wind, light, storage and the like in the micro-grid is required. The power supply reliability is a difficult point of the operation and the dispatching of the weakly connected micro-grid under the influence of factors such as random fluctuation of new energy output and the like. In the grid-connected operation stage, how to arrange a wind-solar energy storage operation strategy in the microgrid to achieve optimal economy and reserve enough energy storage capacity to meet power supply requirements under the condition of possible line faults have important research significance. The traditional microgrid grid-connected operation method focuses more on researching how to control energy storage charging and discharging so as to obtain more economic benefits, and does not consider how to rely on wind-solar energy storage for reliable power supply after a fault; or the relatively rough method of reserving fixed energy storage capacity is used for meeting the power consumption requirement in a certain time in the future, and the flexibility is poor because the dynamic adjustment cannot be carried out according to the new energy prediction result.
Disclosure of Invention
The invention aims to provide a method and a system for optimizing the operation of a weak-connection type wind-solar storage micro-grid, which are favorable for considering both the operation cost and the reliability of the micro-grid.
In order to achieve the purpose, the invention adopts the technical scheme that: a weak connection type wind and light storage micro grid operation optimization method comprises the following steps:
acquiring data required by model construction, including predicted data, actually measured data, equipment parameters, electricity price data and predicted deviation data;
establishing a wind-solar-storage micro-grid-connected operation optimization model by taking the minimum cost in an operation period as a target and considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and tie line transmission constraint;
the method comprises the steps that a wind-solar-energy-storage microgrid off-grid operation optimization model is established by taking the minimum power supply loss in a failure guarantee period as a target, considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and load constraint and considering new energy prediction deviation;
constructing a wind-solar storage micro-grid operation model considering fault guarantee by combining a wind-solar storage micro-grid-connected operation optimization model and a wind-solar storage micro-grid off-grid operation optimization model;
and calculating an operation decision in an operation period based on the constructed wind-solar-storage micro-grid operation model, and executing a first point decision result.
Furthermore, the prediction data comprises short-term prediction results of the new energy output on the current day and the next day, ultra-short-term prediction results of the new energy output on the current day and the next day, important load prediction results on the current day and the next day and general load prediction results on the current day and the next day; the measured data comprises wind power generation power, photovoltaic power generation power, an important load value, a general load value and energy storage electric quantity at the current moment; the equipment parameters comprise the maximum transmission power of the tie line, the maximum energy storage charging and discharging power, the maximum energy storage and minimum energy storage quantity, the energy storage charging and discharging efficiency and the energy storage power self-loss coefficient; the electricity price data comprises the price of electricity sold in the microgrid, the price of electricity purchased in the large power grid, the price of electricity sold in the large power grid and the cost of the stored energy and electricity; the prediction deviation data comprise wind power prediction deviation and photovoltaic prediction deviation; the data required by calculation further comprise peak, flat and valley period information, fault supply time length and electric quantity required by black start after fault.
Further, the objective function of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, t 0 、t d2 Respectively representing the starting time and the stopping time of the operation period; c. C load 、c out 、
c ES Respectively the price of electricity sold from the inside of the micro-grid to the large-grid, the price of electricity purchased from the large-grid by the micro-grid and the energy storage operation cost;
respectively predicting values of important load and general load; p t out 、P t in Respectively selling power to a large power grid and purchasing power to the large power grid; p t ES,c 、P t ES,d Respectively storing energy charging power and energy discharging power;
the power balance constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P t W 、P t S Wind power generation power and photovoltaic power generation power are respectively adopted;
the new energy operation constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P t W,fore 、P t S,fore Respectively predicting wind power output and photovoltaic output;
the energy storage operation constraint of the wind-solar-storage microgrid grid-connected operation optimization model comprises an energy storage charge-discharge power upper limit, an energy storage electric quantity constraint and an energy storage charge-discharge state constraint, and specifically comprises the following steps:
in the formula, P ES,max The upper limit of the energy storage power generation and discharge power is set; gamma ray t For the charge-discharge state constraint, 1 represents energy storage charging, and 0 represents energy storage discharging;
energy storage capacity is obtained; eta ES 、η c 、η d The self-loss coefficient, the charging efficiency and the discharging efficiency of the stored energy are respectively; Δ t is the temporal resolution; e t0 Storing energy for the initial moment; e ES,max The maximum energy storage capacity is obtained;
the tie line transmission constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P line The maximum transmittable power of the micro-grid and the distribution network connection line is achieved.
Further, the objective function of the wind-solar-storage microgrid off-grid operation optimization model is as follows:
in the formula, delta 1 、δ 2 Punishment for important load lossCoefficient, general load supply reward coefficient;
cutting a load value for the important load;
supplying a value for a general load; setting delta 1 Greater than delta 2 So that important loads are supplied preferentially in the off-grid operation stage;
the power balance constraint of the wind-solar-storage micro-grid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
respectively representing wind power generation power, photovoltaic power generation power, energy storage discharge power, energy storage charging power and important load supply values at the moment k after the fault of the tie line at the moment f;
the new energy operation constraint of the wind-solar storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
respectively predicting output conversion coefficients for wind power and photovoltaic;
the energy storage operation constraint of the wind-solar energy storage microgrid off-grid operation optimization model comprises an energy storage charge-discharge power upper limit, an energy storage electric quantity constraint, an energy storage charge-discharge state constraint and an energy storage electric quantity transition constraint, and specifically comprises the following steps:
in the formula, gamma f,k 、
Respectively representing an energy storage charging and discharging state and energy storage electric quantity in a fault scene; delta E ES The electric quantity required by the black start after the fault is completely provided by the stored energy after the connecting line is disconnected;
the energy storage electric quantity at the moment f before the fault is equal to the electric quantity at the same moment in the grid-connected operation model; energy storage after failure requires power consumption delta E ES For realizing black start of the system and the later stored energy capacity
Is reduced to
And entering off-grid operation;
the load constraint of the wind-solar storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
is a general load shedding value.
Further, the wind power and photovoltaic prediction output conversion coefficient
The method comprises the following steps:
according to the historical prediction and the operation data, calculating the historical prediction positive deviation according to the following formula:
in the formula, P i fore 、P i real Predicted values and actual values of historical output of new energy are obtained;
predicting the historical deviation Δ P i After the sequence of (1) is sorted from small to large, the value at 95% of the positions is denoted as Δ P 95％ Selecting a conversion coefficient
And
is 1- Δ P 95％ 。
Further, the objective function of the wind-solar-storage micro-grid operation model is as follows:
furthermore, a rolling optimization mode is adopted for operation decision, the wind-solar-storage micro-grid operation model is executed at each moment, but only the first point, namely the operation decision at the current moment, is executed, and the operation decision comprises new energy output, energy storage charging and discharging power and tie line transmission power; and after the next moment, reconstructing the wind-solar-storage micro-grid operation model to obtain a new decision scheme, and responding to the influence of the uncertainty factor in a mode of rolling and updating the operation decision.
The invention also provides a weak-connection type wind-solar storage micro-grid operation optimization system for realizing the method, which comprises the following steps:
the data acquisition module is used for acquiring data required by model construction;
the grid-connected model building module is used for building a wind-solar-storage micro-grid-connected operation optimization model;
the off-grid model building module is used for building an off-grid operation optimization model of the wind-solar storage micro-grid;
the comprehensive model building module is used for building a wind-solar energy storage micro-grid operation model considering fault guarantee by combining a wind-solar energy storage micro-grid-connected operation optimization model and a wind-solar energy storage micro-grid off-grid operation optimization model; and
and the operation optimization module is used for calculating an operation decision in an operation period based on the constructed wind-solar-storage micro-grid operation model and executing a head decision result.
The present invention also provides a computer readable storage medium having stored thereon computer program instructions executable by a processor, the computer program instructions when executed by the processor being capable of performing the above-described method steps.
The invention also provides a weak-connection type wind-solar storage micro-grid operation optimization device which comprises a memory, a processor and computer program instructions stored on the memory and capable of being operated by the processor, wherein when the processor operates the computer program instructions, the steps of the method can be realized.
Compared with the prior art, the invention has the following beneficial effects: according to the method and the system, an off-grid operation model is introduced on the basis of a traditional grid-connected operation model with optimal economy, and a wind-light storage micro-grid operation model considering fault guarantee is constructed, so that the economic target of grid-connected operation and the power supply protection requirement of off-grid operation after fault can be considered in the obtained operation decision, and the economy and the reliability of micro-grid operation are improved.
Drawings
Fig. 1 is a flowchart of an implementation of a weak-link type wind-solar storage micro grid operation optimization method according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a wind-solar energy storage micro grid in an embodiment of the invention;
FIG. 3 is a schematic diagram of a microgrid operation decision in an embodiment of the present invention;
FIG. 4 is a schematic diagram of a new energy output prediction curve according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a fault period in an embodiment of the present invention;
FIG. 6 is a load/wind/photovoltaic graph in an embodiment of the present invention;
FIG. 7 shows the operation results of the grid-connected operation optimization model in the embodiment of the present invention;
FIG. 8 illustrates the operation of the microgrid according to an embodiment of the present invention.
Detailed Description
The invention is further explained below with reference to the drawings and the embodiments.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure herein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The invention provides a weak-connection type wind-solar-storage micro-grid operation strategy optimization method considering fault supply aiming at the difficult problem of grid-connected operation decision of a weak-connection type wind-solar-storage micro-grid, which considers the operation target with the maximum economic benefit during grid connection and the important load power supply requirement during fault, optimizes the micro-grid operation decision, and updates the operation scheme according to the new energy power prediction result in a rolling manner, thereby ensuring the accuracy and reasonability of the operation scheme.
As shown in fig. 1, the operation optimization method for the weak-link type wind-photovoltaic-storage microgrid provided by the embodiment includes the following steps:
1) Prediction data: the current and next day new energy output short-term prediction results, the new energy output ultra-short-term prediction results, the current and next day important load prediction results and the current and next day common load prediction results;
2) Actually measured data: wind power generation power, photovoltaic power generation power, important load value, general load value and energy storage electric quantity at the current moment;
3) Equipment parameters: the maximum transmission power of the tie line, the maximum charging/discharging power of the stored energy, the maximum/minimum stored energy quantity of the stored energy, the charging/discharging efficiency of the stored energy and the self-loss coefficient of the stored energy power;
4) Electricity price data: the price of electricity sold in the microgrid, the price of electricity purchased in the large power grid (distinguishing peak, flat and valley period prices), the price of electricity sold in the large power grid and the cost of electricity stored in the energy storage degree;
5) Predicted deviation data: wind power and photovoltaic prediction deviation, the prediction deviation under 95% confidence coefficient can be calculated according to historical operation data, and typical values can be selected when the historical data is insufficient;
6) Other data: peak/flat/valley period information, a fault reserve time length, electric quantity required for black start after a fault, and the like.
And 2, establishing a wind-solar-energy-storage micro-grid-connected operation optimization model by taking the minimum cost in the operation period as a target and considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and tie line transmission constraint.
The microgrid operation decision in this embodiment is shown in fig. 3. In order to exert the energy storage time-span adjusting function and dynamically adjust the electric quantity by combining the new energy prediction result, the embodiment selects the time from the current moment to the next day of 24 days as an operation cycle, records the cycle as T and the time resolution as 15 minutes, and constructs a grid-connected operation optimization model.
The wind-solar-storage micro-grid-connected operation optimization model has the objective functions as follows:
in the formula, t 0 、t d2 Respectively representing the starting time and the stopping time of the operation cycle, and in the embodiment, representing the current time and the next day 24; c. C load 、c out 、
c ES The price of electricity sold from the inside of the micro-grid to the large grid, the price of electricity sold from the large grid to the micro-grid, and the energy storage operation cost are respectively set;
respectively predicting values of important load and general load; p is t out 、P t in Respectively selling power to a large power grid and purchasing power to the large power grid; p t ES,c 、P t ES,d Respectively storing energy charging power and energy discharging power;
the power balance constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P t W 、P t S Respectively wind power generation power and photovoltaic power generation power.
The new energy operation constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P t W,fore 、P t S,fore And respectively predicting wind power output and photovoltaic output. Taking the predicted output of wind power as an example, as shown in fig. 4, the predicted output of new energy consists of 3 parts: 1) The current time output value is the actual power which can be generated; 2) The output is predicted for the ultra-short period within 15 minutes to 4 hours from the current moment; the ultra-short term predicted capacity is updated before each execution of the operational optimization; 3) Short term predicted output was obtained after 4 hours to 24 times. Through superposition of actual/predicted outputs of new energy at different stages, the predicted output adopted by calculation is closer to a true value, and the feasibility of decision making is improved.
The energy storage operation constraint of the wind-solar energy storage micro-grid-connected operation optimization model comprises an energy storage charge-discharge power upper limit, an energy storage electric quantity constraint and an energy storage charge-discharge state constraint, and specifically comprises the following steps:
in the formula, P ES,max The upper limit of the energy storage power generation and discharge power is set; gamma ray t For the charge-discharge state constraint, 1 represents energy storage charging, and 0 represents energy storage discharging;
the energy is stored; eta ES 、η c 、η d The self-loss coefficient, the charging efficiency and the discharging efficiency of the stored energy are respectively; Δ t is the time resolution, in this example 15 minutes; e t0 Storing energy for the initial moment; e ES,max The maximum energy storage capacity is obtained.
The tie line transmission constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P line The maximum transmissible power of the line connecting the micro-grid and the distribution network is achieved.
And 3, establishing an off-grid operation optimization model of the wind-solar energy storage micro-grid by taking the minimum power supply loss in a failure guarantee period as a target, considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and load constraint and considering the prediction deviation of new energy.
Because the time of the fault occurrence is uncertain, the embodiment adopts an exhaustion method to check the energy-saving capacity after the fault occurs at all times in the operation cycle.
In this embodiment, a schematic diagram of a fault period in the off-grid operation optimization model is shown in fig. 5. After the failure of the outgoing call tie line occurs at each moment, the micro-grid needs to maintain reliable power supply for a certain time (recorded as H) by virtue of internal wind and light storage equipment, and if the failure moment is recorded as f, the power supply interval is ensured to be T f ＝[f,f+H]. For example, considering that a fault occurs at the 5 th moment in the grid-connected operation cycle, the time interval of power supply needs to be ensured to be T 5 ＝[5,5+H]. In the power supply guarantee period, stable power supply of important loads in the microgrid needs to be guaranteed, and if wind and light resources are good, common loads can be supplied as much as possible.
The wind-solar-storage microgrid off-grid operation optimization model aims at minimizing important load loss in all fault intervals and maximizing general load supply, and the objective function is as follows:
in the formula, delta 1 、δ 2 Respectively supplying an important load loss penalty coefficient and a general load supply reward coefficient;
cutting a load value for the important load;
supplying a value for a general load; setting delta 1 Greater than delta 2 So that important loads are supplied preferentially in the off-grid operation phase.
The power balance constraint of the wind-solar storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
and respectively the wind power generation power, the photovoltaic power generation power, the energy storage discharge power, the energy storage charging power and the important load supply value at the moment k after the fault of the tie line at the moment f.
The new energy operation constraint of the wind-solar-storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
and predicting output conversion coefficients for wind power and photovoltaic respectively.
Because the future output of the new energy cannot be accurately predicted, the predicted output and the actual output usually have deviation, and if the operation plan during the fault period is directly considered according to the predicted output, the situation that the actual output is smaller than the predicted value and the total output of the power supply is smaller than the load may occur. Therefore, from a conservative point of view, the predicted output should be converted, and the operation decision should be taken according to smaller data, such as the decision taken according to 90% predicted output.
The conversion factor may be calculated from historical predictions and operating data, for example, by taking the value of the 95% quantile of the reference historical prediction bias. The specific method comprises the following steps:
the historical predicted positive bias is first calculated:
in the formula, P i fore 、P i real And the predicted value and the actual value of the historical output of the new energy are obtained.
The 95% quantile of the prediction deviation is: predicting the historical deviation Δ P i After the sequence of (1) is sorted from small to large, the value at 95% of the positions is denoted as Δ P 95％ Selecting a conversion coefficient
And
is 1-delta P 95％ 。
If historical prediction and operating data are less, typical values may be selected with reference to a standard or operating experience. The conversion coefficients of wind power and photovoltaic power are selected respectively, and the conversion coefficients of short-term and ultra-short-term prediction are selected respectively.
The energy storage operation constraint of the wind-solar energy storage microgrid off-grid operation optimization model comprises an energy storage charge-discharge power upper limit, an energy storage electric quantity constraint, an energy storage charge-discharge state constraint and an energy storage electric quantity transition constraint, and specifically comprises the following steps:
in the formula, gamma f,k 、
The energy storage charging and discharging states and the energy storage electric quantity under the fault scene are respectively; delta E ES The electric quantity required by the black start after the fault is completely provided by the stored energy after the connecting line is disconnected;
the energy storage electric quantity at the moment f before the fault is equal to the electric quantity at the same moment in the grid-connected operation model; energy storage after failure requires power consumption delta E ES Is used for realizing the black start of the system, and the post energy storage capacity is
Is reduced to
And entering off-grid operation.
The load constraint of the wind-solar storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
is a general load shedding value.
And 4, constructing a wind-solar-storage micro-grid operation model considering fault guarantee by combining the wind-solar-storage micro-grid-connected operation optimization model and the wind-solar-storage micro-grid off-grid operation optimization model.
The wind-solar-storage micro-grid operation model has the objective functions as follows:
and 5, calculating an operation decision in an operation period based on the constructed wind-solar-storage micro-grid operation model, and executing a first point decision result.
In this embodiment, a rolling optimization manner is adopted for operation decision, and for each time, the wind-photovoltaic-energy-storage microgrid operation model is executed, but only the operation decision of the first point (i.e., the current time) is executed, including new energy output, energy storage charge-discharge power and tie line transmission power. And (4) after entering the next moment, re-executing the steps 1-4, constructing a wind-solar-storage micro-grid operation model to obtain a new decision scheme, and responding to the influence of uncertain factors such as new energy prediction deviation by a rolling updating operation decision mode.
The embodiment also provides a weak-connection type wind and light storage micro-grid operation optimization system for implementing the method, which comprises the following steps:
the data acquisition module is used for acquiring data required by model construction;
the grid-connected model building module is used for building a wind-solar-storage micro-grid-connected operation optimization model;
the off-grid model building module is used for building an off-grid operation optimization model of the wind-solar-storage micro-grid;
the comprehensive model building module is used for building a wind-solar energy storage micro-grid operation model considering fault guarantee by combining a wind-solar energy storage micro-grid-connected operation optimization model and a wind-solar energy storage micro-grid off-grid operation optimization model; and
and the operation optimization module is used for calculating an operation decision in an operation period based on the constructed wind-solar-storage micro-grid operation model and executing a first point decision result.
The present embodiments also provide a computer-readable storage medium having stored thereon computer program instructions executable by a processor, the computer program instructions, when executed by the processor, being capable of performing the above-described method steps.
The embodiment also provides an operation optimization device of the weak-connection type wind-solar storage micro-grid, which is characterized by comprising a memory, a processor and computer program instructions which are stored on the memory and can be executed by the processor, wherein when the processor executes the computer program instructions, the method steps can be realized.
The effectiveness of the invention is illustrated by the following examples.
A certain microgrid has wind power of 6MW, photovoltaic of 2MW and energy storage of 2MW/4MWh, key technical and economic parameters are shown in a table 1, and the load, wind power and photovoltaic conditions of the current day and the next day of optimized operation are shown in a figure 6.
TABLE 1 Key technical economic parameters
By adopting the grid-connected operation optimization model constructed in the step 2 of the method, the microgrid operation strategy is optimized moment by moment, and the operation decision of the first day is shown in fig. 7. It can be seen that, before time 67 (i.e., 16) the wind and photovoltaic power generation capacity in the microgrid is higher than the load power, and after the internal power demand of the microgrid is met, the excess power is sent out to the large power grid through the interconnection lines; 16: and after 30, the wind power and photovoltaic power generation is smaller than the load, and the power is purchased from a large power grid or stored for discharging so as to supplement the power shortage of the load. Because the electricity purchasing cost of the large power grid is reduced from peak time, normal time and valley time in sequence, and the stored energy is limited, the operation cost is reduced by preferentially using the stored energy to generate electricity at the peak time. Therefore, the energy is discharged in the peak period, the electricity is purchased from the large power grid in the valley period, and the energy is partially stored and supplied for the normal period and partially purchased and supplied for the large power grid in the normal period.
The energy storage capacity at the last moment is 1.12MWh, and is not reduced to the lower limit of the energy storage capacity. This is because when making a decision at each moment, the operating period from the current moment to the next day 24 is considered, so that the stored energy capacity is preferentially reserved to meet the operating requirement of the next day. This avoids making a more "short-look" decision from the current moment's condition considerations only.
Therefore, the model grid-connected operation part provided by the method can select a strategy with better economical efficiency according to the real-time state and the prediction result, and obtain the operation result with the highest benefit. The yield of the whole day operation of the example is 23284 yuan.
On the basis, off-grid fault supply factors are considered, the model provided by the method optimizes the micro-grid operation strategy moment by moment, and the operation decision is shown in fig. 8. After the off-grid part model is introduced, because the power generation power of the new energy is predicted to be lower the next day (see fig. 6), the available power of the stored energy on the current day is further reduced in order to ensure that the stored energy has enough power and the microgrid is started up in black and is matched with wind and light to supply power stably for 2 hours. Therefore, in the operation result, when the output of the new energy in the microgrid is lower than the load, the stored energy is discharged only in the peak time period, and the rest of the flat time period and the valley time period are charged by the external electricity to supplement the shortage of the electricity.
The all-day income of the operation strategy is 23055 yuan, which is slightly lower than the income when the off-network operation is not considered. The capacity of the energy storage at the last moment is 1.57MWh, which is higher than 1.12MWh when the off-grid operation is not considered. The method reserves more energy storage electric quantity to deal with possible faults and has higher reliability. Therefore, the method can give consideration to the goals of grid-connected operation economy and off-grid operation reliability, and obtains a comprehensive and better operation strategy.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and so forth) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.
Claims (10)
1. A weak-connection type wind-solar storage micro-grid operation optimization method is characterized by comprising the following steps:
acquiring data required by model building, including prediction data, measured data, equipment parameters, electricity price data and prediction deviation data;
establishing a wind-solar-storage micro-grid-connected operation optimization model by taking the minimum cost in an operation period as a target and considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and tie line transmission constraint;
the method comprises the steps that a wind-solar-energy-storage microgrid off-grid operation optimization model is established by taking the minimum power supply loss in a failure guarantee period as a target, considering constraint conditions including power balance constraint, new energy operation constraint, energy storage operation constraint and load constraint and considering new energy prediction deviation;
constructing a wind-solar storage micro-grid operation model considering fault guarantee by combining a wind-solar storage micro-grid-connected operation optimization model and a wind-solar storage micro-grid off-grid operation optimization model;
and calculating an operation decision in an operation period based on the constructed wind-solar-storage micro-grid operation model, and executing a first point decision result.
2. The operation optimization method for the weak connection type wind, light and storage microgrid according to claim 1, characterized in that the prediction data comprises a current day and next day new energy output short-term prediction result, a current day and next day new energy output ultra-short-term prediction result, a current day and next day important load prediction result and a current day and next day common load prediction result; the measured data comprise wind power generation power, photovoltaic power generation power, an important load value, a general load value and energy storage electric quantity at the current moment; the equipment parameters comprise the maximum transmission power of the tie line, the maximum energy storage charging and discharging power, the maximum energy storage and minimum energy storage quantity, the energy storage charging and discharging efficiency and the energy storage power self-loss coefficient; the electricity price data comprises the price of electricity sold in the microgrid, the price of electricity purchased in the large power grid, the price of electricity sold in the large power grid and the cost of the stored energy and electricity; the prediction deviation data comprise wind power prediction deviation and photovoltaic prediction deviation; the data required by calculation further comprise peak, flat and valley period information, fault supply time length and electric quantity required by black start after fault.
3. The operation optimization method of the weak-connection type wind-solar-storage micro-grid according to claim 1, wherein an objective function of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, t 0 、t d2 Respectively representing the starting time and the stopping time of the operation period; c. C load 、c out 、
c ES Respectively the price of electricity sold from the inside of the micro-grid to the large-grid, the price of electricity purchased from the large-grid by the micro-grid and the energy storage operation cost;
respectively predicting values of important load and general load; p t out 、P t in Respectively selling power to a large power grid and purchasing power to the large power grid; p t ES,c 、P t ES,d Respectively storing energy charging power and energy discharging power;
the power balance constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P t W 、P t S Wind power generation power and photovoltaic power generation power are respectively adopted;
the new energy operation constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P t W,fore 、P t S,fore Respectively predicting wind power output and photovoltaic output;
the energy storage operation constraint of the wind-solar-storage microgrid grid-connected operation optimization model comprises an energy storage charge-discharge power upper limit, an energy storage electric quantity constraint and an energy storage charge-discharge state constraint, and specifically comprises the following steps:
in the formula, P ES,max The upper limit of the energy storage power generation and discharge power is set; gamma ray t For the charge-discharge state constraint, 1 represents energy storage charging, and 0 represents energy storage discharging;
the energy is stored; eta ES 、η c 、η d The self-loss coefficient, the charging efficiency and the discharging efficiency of the stored energy are respectively; Δ t is the temporal resolution; e t0 Storing energy for the initial moment; e ES,max The maximum energy storage capacity;
the tie line transmission constraint of the wind-solar-storage micro-grid-connected operation optimization model is as follows:
in the formula, P line The maximum transmittable power of the micro-grid and the distribution network connection line is achieved.
4. The operation optimization method of the weak-connection type wind-solar-storage micro-grid according to claim 3, wherein an objective function of the wind-solar-storage micro-grid off-grid operation optimization model is as follows:
in the formula, delta 1 、δ 2 Respectively supplying an important load loss penalty coefficient and a general load supply reward coefficient;
cutting a load value for the important load;
supplying a value for a general load; set delta 1 Greater than delta 2 So that important loads are supplied preferentially in the off-grid operation stage;
the power balance constraint of the wind-solar storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
respectively representing wind power generation power, photovoltaic power generation power, energy storage discharge power, energy storage charging power and important load supply values at the moment k after the fault of the tie line at the moment f;
the new energy operation constraint of the wind-solar storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
forecasting output for wind power and photovoltaic power respectivelyA conversion coefficient;
the energy storage operation constraint of the wind-solar energy storage microgrid off-grid operation optimization model comprises an energy storage charge-discharge power upper limit, an energy storage electric quantity constraint, an energy storage charge-discharge state constraint and an energy storage electric quantity transition constraint, and specifically comprises the following steps:
in the formula, gamma f,k 、
Respectively representing an energy storage charging and discharging state and energy storage electric quantity in a fault scene; delta E ES The electric quantity required by the black start after the fault is completely provided by the stored energy after the connecting line is disconnected;
to failThe energy storage electric quantity at the front f moment is equal to the electric quantity at the same moment in the grid-connected operation model; energy storage after failure requires consumption of electric quantity delta E ES Is used for realizing the black start of the system, and the post energy storage capacity is
Is reduced to
And entering off-grid operation;
the load constraint of the wind-solar storage microgrid off-grid operation optimization model is as follows:
in the formula (I), the compound is shown in the specification,
is a general load shedding value.
5. The operation optimization method of the weak-connection type wind-solar-storage micro-grid according to claim 4, wherein the wind power and photovoltaic predicted output conversion coefficient
The method comprises the following steps:
and according to the historical prediction and the operation data, calculating the historical prediction positive deviation according to the following formula:
in the formula, P i fore 、P i real Predicted values and actual values of historical output of new energy are obtained;
predicting the historical deviation Δ P i After the sequence of (1) is sorted from small to large, the value at 95% of the positions is denoted as Δ P 95％ Selecting a conversion coefficient
And
is 1- Δ P 95％ 。
6. The operation optimization method of the weak-connection type wind-solar-storage micro-grid according to claim 4, wherein an objective function of the wind-solar-storage micro-grid operation model is as follows:
7. the operation optimization method of the weak-link type wind-solar-storage micro-grid according to claim 4, characterized in that an operation decision is made in a rolling optimization mode, and for each moment, the wind-solar-storage micro-grid operation model is executed, but only the operation decision of the first point, namely the current moment, is executed, wherein the operation decision comprises new energy output, energy storage charging and discharging power and tie line transmission power; and after the next moment, reconstructing the wind-solar-storage micro-grid operation model to obtain a new decision scheme, and responding to the influence of the uncertainty factor in a mode of rolling and updating the operation decision.
8. A weakly connected wind-solar-storage microgrid operation optimization system for implementing the method according to any one of claims 1 to 7, characterized by comprising:
the data acquisition module is used for acquiring data required by model construction;
the grid-connected model building module is used for building a wind-solar-storage micro-grid-connected operation optimization model;
the off-grid model building module is used for building an off-grid operation optimization model of the wind-solar storage micro-grid;
the comprehensive model building module is used for building a wind-solar energy storage micro-grid operation model considering fault guarantee by combining a wind-solar energy storage micro-grid-connected operation optimization model and a wind-solar energy storage micro-grid off-grid operation optimization model; and
and the operation optimization module is used for calculating an operation decision in an operation period based on the constructed wind-solar-storage micro-grid operation model and executing a first point decision result.
9. A computer readable storage medium having stored thereon computer program instructions executable by a processor, the computer program instructions when executed by the processor being capable of implementing the method steps of any of claims 1-7.
10. A weakly-connected wind-solar-storage microgrid operation optimization device, characterized by comprising a memory, a processor and computer program instructions stored on the memory and executable by the processor, the computer program instructions, when executed by the processor, being capable of implementing the method steps of any one of claims 1 to 7.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116562575A (en) * | 2023-05-16 | 2023-08-08 | 中国电力工程顾问集团有限公司 | Optimized scheduling method of comprehensive energy system |
| CN117022010A (en) * | 2023-07-03 | 2023-11-10 | 福建时代星云科技有限公司 | Method, terminal and system for energy scheduling of minimized cost of optical storage filling inspection |
| CN117638996A (en) * | 2024-01-25 | 2024-03-01 | 深圳市智赋新能源有限公司 | Layered control photovoltaic micro-grid energy management system and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116562575A (en) * | 2023-05-16 | 2023-08-08 | 中国电力工程顾问集团有限公司 | Optimized scheduling method of comprehensive energy system |
| CN116562575B (en) * | 2023-05-16 | 2023-10-31 | 中国电力工程顾问集团有限公司 | Optimized scheduling method of comprehensive energy system |
| CN117022010A (en) * | 2023-07-03 | 2023-11-10 | 福建时代星云科技有限公司 | Method, terminal and system for energy scheduling of minimized cost of optical storage filling inspection |
| CN117022010B (en) * | 2023-07-03 | 2024-09-13 | 福建时代星云科技有限公司 | Method, terminal and system for energy scheduling of minimized cost of optical storage filling inspection |
| CN117638996A (en) * | 2024-01-25 | 2024-03-01 | 深圳市智赋新能源有限公司 | Layered control photovoltaic micro-grid energy management system and method |
| CN117638996B (en) * | 2024-01-25 | 2024-05-03 | 深圳市智赋新能源有限公司 | Layered control photovoltaic micro-grid energy management system and method |
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