KR101827158B1 - Apparatus and method for operating energy storage system connected to microgrid - Google Patents

Abstract

The present invention relates to a device and a method to manage an energy storage system for a microgrid. To this end, the management device includes: a schedule writing part collecting real time management information and predicted data about energy price, power generation, and load by time section from a microgrid management system, defining a minimum charge amount of an energy storage device connected with a microgrid by time section, and writing charge and discharge schedules of the energy storage device by time section to minimize costs for the management of the microgrid; a command value deriving part determining an operational state of the energy storage device in accordance with the charge and discharge schedules and deriving an effective power command value outputted from the energy storage device; and a control part controlling the operation of the energy storage device in accordance with the operational state and the effective power command value. The schedule writing part writes the charge and discharge schedules to minimize the sum of energy costs, maximum power consumption costs, peak-load contribution costs, and lifespan reduction costs of the energy storage device.

Description

[0001] APPARATUS AND METHOD FOR OPERATING ENERGY STORAGE SYSTEM CONNECTED TO MICROGRID [0002]

The present invention relates to an apparatus and method for operating an energy storage device for a microgrid, and more particularly, to an operating apparatus and method for applying an energy storage device to a microgrid in a stable and economical manner.

Energy Storage System (ESS) is a device that can charge / discharge electric power as required, such as a pumped storage power plant. Recently, the power grid connection of energy storage system (ESS) is continuously increasing due to the rapid development of power electronics technology and energy storage technology. Power grid connected energy storage (ESS) can be used for various purposes such as frequency maintenance, reduction of intermittency of renewable energy source output, reduction of peak load, reduction of electricity bill, emergency power generation.

Due to these advantages, various operating techniques and control methods utilizing energy storage devices have been studied in the past. For example, in the prior art, a schedule-based driving method that maximizes the gain generated by charge / discharge of an energy storage device (ESS) using load and power generation prediction and electric energy price prediction data, energy generated by charging / discharging And consideration of cost reduction of equipment life of storage device (ESS). However, in the case of the prior art, the following problems exist.

First, the prior art has a problem in that it presents techniques that only consider a specific rate, for example, only energy charges. In general, the components of the electricity tariff defined in domestic and foreign electricity market rules can be classified as follows according to the factors of charges.

- Fixed rate: The charge that a certain amount is charged regardless of electricity usage and pattern of the customer

- Energy Fee: Based on the electric energy consumed by the customer and the charge determined by the usage time, the electricity consumption by time of day, the charge of TOU (Time Of Use), CPP (Critical Peak Pricing) and RTP (Real Time Pricing) Determined

- Maximum Power Consumption Charge: The rate determined by the maximum power consumed by the consumer over a period of time, including the base rate and overage use charge in the country and the charge for the transmission / distribution grid of the Canadian Ontario Electricity Market.

- Peak load contribution rate: This is the Global Adjustment charge for the Canadian Ontario power market at a rate determined by the percentage contribution to the peak load (peak load) of the upper grid.

The remaining rates, excluding the fixed rate, can affect different rates. If you operate an energy storage system (ESS) with a specific charge in a market where multiple charges are applied, the charge may be reduced, but other charges may increase and the overall electricity charge may increase. Therefore, it is necessary to consider the energy charge, the maximum power consumption charge, and the peak load contribution fee simultaneously to create charge / discharge schedule of the energy storage device (ESS) to reduce the electric charge of the customer. However, there is a problem in the prior patents in that a method for reducing only a specific charge (mostly energy charge) is proposed.

Second, the conventional technology has a problem in that there is no risk management method for prediction error. Since the capacity (kWh) of the energy storage device (ESS) is limited, the output control of the energy storage device (ESS) at the present time may affect the operation of the future energy storage device (ESS). Therefore, in order to reduce the electricity price of customers using energy storage device (ESS), the output control method of schedule based energy storage device (ESS) should be used. Since accurate values of future loads, power generation, and prices can not be known, the charge / discharge schedules of the energy storage device (ESS) are made using their predicted values. However, there may be an error in the predicted value and an unexpected damage may occur due to the error. However, in the prior art, there is a problem in that it can not propose a method for reducing the risk that may be caused by the error of the predicted value.

Third, the conventional art has a problem in that it manages the state of charge (SOC) manually. In order to use an energy storage device (ESS) as an emergency generator, the charge amount (SOC) must be maintained at a certain level (minimum charge amount) during normal operation. However, maintaining the charge level (SOC) above a certain level means that the capacity of the energy storage device (ESS) capable of charge / discharge during normal operation is reduced. As a result, the gain obtained by charging / discharging the energy storage device (ESS) can be reduced. Therefore, in order to maximize the gain obtained by charge / discharge of the energy storage device (ESS), it is necessary to actively define the minimum charge amount considering the load to be supplied as the emergency generator. However, in the prior art, there is a problem that the efficiency is lowered by keeping the minimum charge amount at a constant value regardless of the load.

Fourth, the conventional art has a problem that there is no state control technology of the energy storage device (ESS). Internal converters (IGBT switching losses, etc.) are generated even if the output is controlled to 0 in a converter that is often used as an energy storage system (ESS) linkage system. Therefore, if the charge / discharge schedule result output command value of the energy storage device (ESS) is 0, if the active power output of the energy storage device (ESS) is controlled to 0, the charge amount (SOC) do. In order to prevent such a phenomenon, on / off control is required based on the output command value of the energy storage device (ESS).

Accordingly, there is a need for a new operating device and method that can reliably and economically utilize an energy storage device (ESS) for microgrid operation while solving the problems of the prior art described above.

Korean Patent No. 1597993 (name: energy storage device)

It is an object of the present invention to provide an apparatus and method for operating an energy storage device for a microgrid which can stably and economically utilize an energy storage device (ESS) for micro grid operation.

In order to solve the above problems, an operating apparatus for an energy storage device for a micro grid of the present invention collects predicted data on load, power generation and energy price and real-time operating information from a micro grid operating system, A schedule creation unit for defining a minimum charge amount of the energy storage device connected to the micro grid by the liver and creating a charge and discharge schedule of the energy storage device by time period so as to minimize the operation cost of the micro grid; A command value derivation unit for determining an operation state of the energy storage device according to user setting information and the charge and discharge schedule and deriving an effective power command value to be output from the energy storage device; And a controller for controlling the operation of the energy storage device according to the operation state and the active power command value, wherein the schedule generator is configured to calculate an energy charge, a maximum power consumption cost, a peak load contribution fee, And the schedule creating unit creates a schedule data correction module for correcting the time-series forecast data based on real-time price information within the time period for each time period according to the setting of the user Wherein the prediction data correction module divides one time interval into a plurality of unit time intervals according to the setting of the user and stairizes the prediction data according to at least one stepping interval for each unit time period .

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The schedule creation unit includes a minimum charge amount setting module for setting a minimum charge amount of the energy storage device connected to the micro grid on a time axis basis. The minimum charge amount setting module includes a minimum charge amount of the energy storage device for emergency power generation, Based on the minimum charge of the device, the minimum time for the energy storage to operate as an emergency generator, the predicted data for the load, the predicted data for the power generation and the rated energy capacity of the energy storage device, Can be set.

The schedule generator may also create a temporary charge and discharge schedule for the energy storage device by converting the charge and discharge control problem to an optimization problem and finding an optimal solution to the optimization problem.

In addition, the objective function of the optimization problem can be made to minimize the sum of the energy charge, the maximum power consumption cost, the peak load contribution charge, and the life saving cost of the energy storage device.

Also, the schedule creating unit may analyze the temporary charging charge and discharge schedule and the schedule for generating the final charging and discharging schedule by distributing the temporary charging and discharging schedules so that the charging and discharging schedules are dispersed to the maximum, And may further include a correction module.

The schedule creating unit defines the charge price and the maximum charge amount between the individual time periods, defines time periods that are continuously the same state as the charge state or the discharge state as a set of target time frames to be corrected, And the final charging and discharging schedules can be generated by performing the correction through comparison of the time interval and the average output belonging to each set of correction target time points.

In addition, the operating device for the energy storage device for microgrid according to an embodiment of the present invention may further include a user interface part used for generating user setting information, wherein the user interface part detects a power generation occurrence signal, When the operation command of the energy storage device is inputted from the user when the switch is closed, the operation signal of the energy storage device according to the operation command is blocked and a warning message can be generated.

In addition, the user interface unit can interrupt the operation of the microgrid's associated switch and generate a warning message when the voltages of the upper power grid and the customer power grid are not synchronized during the independent operation of the energy storage device.

According to another aspect of the present invention, there is provided a method of operating an energy storage device for a microgrid, the method including: generating schedule data from the microgrid operating system based on predicted data on load, Collecting information; Defining a minimum charge amount of an energy storage device connected to a micro grid by a time interval by the schedule creating unit; Creating a charge and discharge schedule of the energy storage device by time period so that the operating cost of the microgrid is minimized by the schedule creating unit; Determining an operating state of the energy storage device according to the user setting information and the charging and discharging schedule by the command value deriving part and deriving an effective power command value to be output from the energy storage device; And controlling the operation of the energy storage device according to the operation state and the active power command value by the control unit, wherein the step of generating the charge and discharge schedule of the energy storage device includes the steps of: , The peak load contribution rate, and the life reduction cost of the energy storage device are minimized, and the schedule creating unit creates the schedule information based on the real time price information within the time period, Wherein the step of correcting the predictive data includes: dividing one time interval into a plurality of unit time intervals according to the setting of the user; And stairing the prediction data according to at least one stepping interval for each unit time period.

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Further, the step of defining the minimum charge amount of the energy storage device includes a step of calculating a minimum charge amount of the energy storage device for emergency power generation, a minimum charge amount of the physical energy storage device, a minimum time required for the energy storage device to operate as an emergency generator, Prediction data, prediction data for power generation, and rated energy capacity of the energy storage device.

The step of creating the charging and discharging schedule of the energy storage device may further include the steps of converting the charging and discharging control problem into an optimization problem and creating a temporary charging and discharging schedule for the energy storage device by finding an optimal solution of the optimization problem . ≪ / RTI >

In addition, the objective function of the optimization problem can be made to minimize the sum of the energy charge, the maximum power consumption cost, the peak load contribution charge, and the life saving cost of the energy storage device.

In addition, the step of creating the charging and discharging schedule of the energy storage device may include analyzing the charging charge and discharging schedule at the time of day and distributing the temporary charging and discharging schedule so that the charging and discharging plans are distributed at maximum And generating a final charge and discharge schedule.

In addition, the step of generating the final charge and discharge schedule defines the charge price and the maximum charge amount between the individual pointers, defines the time periods continuously the same as the charge state or the discharge state as a set of correction target time intervals, By calculating the average output of the time periods belonging to the temporal aggregation and performing the correction by comparing the temporal and average outputs belonging to each correction target temporal aggregation group.

The method of operating an energy storage device for a microgrid according to an embodiment of the present invention includes the steps of: when a power failure signal is sensed by a user interface unit and a high power grid link switch is closed, When the operation command is input, it may further include a step of blocking an operation signal of the energy storage device according to the operation command and generating a warning message.

According to another aspect of the present invention, there is provided a method of operating an energy storage device for a microgrid, the method comprising the steps of: when a voltage of an upper grid and a customer grid is not synchronized during independent operation of the energy storage device, And stopping the operation of the linkage switch and generating a warning message.

According to an apparatus and method for operating an energy storage device for a microgrid according to an embodiment of the present invention, electric charge of a micro grid can be reduced by performing charging / discharging at normal times, and electric power can be supplied to an micro grid There is an advantage.

1 and 2 are conceptual diagrams of a micro operating system to which an operating apparatus and method according to an embodiment of the present invention can be applied.
3 is a block diagram of an apparatus for operating an energy storage device for a microgrid according to an embodiment of the present invention.
4 is a block diagram of a schedule creating unit according to an embodiment of the present invention.
FIG. 5 is a conceptual diagram for explaining a method of correcting predicted data through a predictive data correction module according to an embodiment of the present invention.
FIG. 6 is a conceptual diagram for explaining a method of setting a minimum charge amount through a minimum charge amount setting module according to an embodiment of the present invention.
7 is a conceptual diagram illustrating a schedule correction method performed by the schedule correction module according to an embodiment of the present invention.
8 is a flowchart illustrating a method of operating an energy storage device for a microgrid according to an embodiment of the present invention.
FIG. 9 is a flowchart of a charging and discharging schedule creation step according to an embodiment of the present invention.
FIG. 10 is a flowchart of a correction step of a temporary schedule according to an embodiment of the present invention.
11 is a flowchart of a step of deriving a command value according to an embodiment of the present invention.
12 is a conceptual diagram of a control method performed through a control step according to an embodiment of the present invention.

The present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, a repeated description, a known function that may obscure the gist of the present invention, and a detailed description of the configuration will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity.

First, a description will be given of a micro operating system to which an apparatus and method for operating an energy storage device for a micro grid according to an embodiment of the present invention (hereinafter, an operating apparatus and method) can be applied.

1 and 2 are conceptual diagrams of a micro operating system 10 to which an operating apparatus and method according to an embodiment of the present invention can be applied. The microgrid 20 managed by the micro operating system 10 includes a settling meter 22 used for electricity bill settlement and a micro grid connection switch 21 capable of physically separating the micro grid 20 from the high power grid, Scale power system connected to the power system 30 through the power system 30. [ The microgrid 20 is normally operated in conjunction with the upper grid 30 and the microgrid operating system 10 provides status information of the microgrid 20 and the energy storage system ESS, Real-time control of the active power of the energy storage device (ESS) using market price and load information provided by the meteorological data providing system 50, weather information provided by the meteorological data providing system 50, and user operation information. On the other hand, if a problem occurs in the upper power system, the micro grid connection switch 21 is used to disconnect the upper power system and perform independent operation. The micro grid 20 may be a single customer such as a home, a factory, a building, or the like, and may be largely a distribution system of a main transformer unit.

In addition, an operating apparatus and method according to an embodiment of the present invention may be connected to and perform operations of the micro grid operating system 10 shown in FIG. That is, the operating apparatus and method according to an embodiment of the present invention can derive the status and output command value of the energy storage device (ESS) using data acquired from various data sources such as terminal data, external data, database, have. The derived command value is transmitted to the energy storage device (ESS) of the field via the communication device and the real time output and state control of the energy storage device (ESS) can be performed based on the command value at the energy storage device (ESS) have. Various information (status, output, alarms and events, charging / discharging schedules, etc.) related to the operation of the energy storage unit (ESS) are displayed through the HMI. In addition, the microgrid operator can change the operating strategy (operation mode, output value, etc.) of the energy storage device (ESS) based on the displayed information and control the devices constituting the microgrid. Finally, all history related to the operation of the Energy Storage System (ESS) is stored in the database and can be periodically generated in the report management to provide the user with a historical report. Also, through the operation apparatus and the method according to an embodiment of the present invention, the energy storage device (ESS) can be largely controlled in the stop state, the ready state, and the operation state.

First, the suspended state indicates that the mechanical switch (VCB, MCCB, etc.) connecting the energy storage device (ESS) and the microgrid is opened. At this time, the energy storage device (ESS) . The ready state indicates that all preparations for output control (mechanical switch closing, DC stage initial charge completion, etc.) have been completed, and all semiconductor switches (eg IGBT) are open and the output current is zero.

The operation state indicates a state in which the on / off state of the semiconductor switch is controlled to control the output of the energy storage device (ESS). This operation state can be divided into a manual operation mode used during a grid-connected operation, a schedule operation mode, and a constant voltage / frequency operation mode and a synchronous operation mode used during an islanded operation. Here, the manual operation mode represents a state in which the active power output of the energy storage device (ESS) is controlled by a value set by the user, and the schedule operation mode is a mode for reducing the electric charge in the operation process for the energy storage device (ESS) (ESS) is automatically controlled according to the charge / discharge schedule of the energy storage device (ESS) that is periodically created. The constant voltage / frequency operation mode controls the size and frequency of the output voltage of the energy storage device (ESS) to a value set by the user to maintain the balance of the micro / grid reactive power during independent operation. In synchronous operation mode, the output voltage of the energy storage device (ESS) is controlled to control the phase angle and size of the primary side (upper system) and the secondary side (micro grid) voltage of the microgrid- The phase angle and size are controlled. This function enables re-linking of the micro grid to the uninterruptible upper system.

3 is a block diagram of an operating system 100 for an energy storage device for a microgrid according to an embodiment of the present invention. As described above, an operating device (hereinafter, an operating device) for an energy storage device for a micro grid according to an embodiment of the present invention is divided into six features for solving the problems of the prior art.

First, the operating device 100 according to an embodiment of the present invention is characterized in that charge / discharge schedules are created by considering various electric charges. Specifically, the operating device 100 according to an embodiment of the present invention not only considers only a specific fee (e.g., an energy fee) of the prior art, but also an energy charge, as well as a maximum power consumption charge, , And the charge / discharge schedule of the energy storage device (ESS) is created by solving the optimization problem considering the life reduction cost of the energy storage device.

Second, the operating system 100 according to an exemplary embodiment of the present invention performs risk management on a prediction error. That is, the operating apparatus and method according to an embodiment of the present invention corrects the predicted value of the current time point by using the past history of the current time point together with the predicted value and the real time measured value, and uses it to create the charge / discharge schedule, The error can be reduced. In addition, the operating apparatus 100 according to the embodiment of the present invention may predict the data at predetermined intervals, and distribute the charging / discharging schedules as much as possible for the charging / discharging costs of the energy charging apparatus (ESS) By creating schedules, the risk of errors can be dispersed. In addition, the operating device 100 according to an embodiment of the present invention can provide an environment in which the interval for stairing can be set according to a user strategy (here, if the interval is increased, the expected value of the risk and the gain is decreased, There is an expected increase in risk and gain. In addition, the operating device 100 according to the embodiment of the present invention is characterized by adding a condition for maintaining the charge amount (SOC) at an upper limit at a user set time when creating a charge and discharge schedule. This makes it possible to secure a discharge reserve for coping with a prediction error.

Thirdly, the operating device 100 according to an embodiment of the present invention is characterized by actively managing a charge amount (SOC) of an energy storage device (ESS) using predictive data. That is, the operating device 100 according to an embodiment of the present invention actively determines the minimum charge amount for emergency power generation using the load and power generation prediction results, and uses it to create a schedule to calculate a charge amount SOC) area can be enlarged. Accordingly, there is an advantage that the economical operation of the energy storage device (ESS) can be increased.

Fourth, the operating device 100 according to an embodiment of the present invention is characterized by automatically controlling the state of the energy storage device (ESS). If the energy storage device (ESS) is automatically operated according to a schedule in the microgrid operating system, by performing the on / off control of the energy storage device (ESS) together with the active power output, It is possible to reduce the loss caused by the operation of the semiconductor switch for controlling the voltage to be zero.

Fifth, the operating device 100 according to an embodiment of the present invention has an advantage of being able to perform control according to a user's judgment, and to prevent user erroneous operation. That is, the operating device 100 according to an embodiment of the present invention displays various acquisition information together with the charge / discharge schedule information in the user interface, and can control the energy storage device (ESS) Environment can be provided. In addition, it is possible to provide a protection function for preventing user's erroneous operation in the user interface.

Sixth, the operating device 100 according to an embodiment of the present invention can provide an uninterruptible independent operation function. The local control system of the energy storage system (ESS) can monitor the state of the power system for stable uninterruptible operation and grid linkage and automatically change the output control mode of the energy storage device (ESS) based on this.

In order to perform the above functions, the operating apparatus 100 according to an embodiment of the present invention includes a schedule creating unit 110, a command value deriving unit 120, a user interface unit 130, and a control unit 140 Lt; / RTI > In order to facilitate understanding of the present invention, the above-described configurations are classified according to function, and it is also possible to implement them through a single processing device.

The schedule creating unit 110 has a function of creating a charging and discharging schedule of the energy storage device (ESS). Specifically, the schedule creating unit 110 creates a charging and discharging schedule of the energy storage device (ESS) by time period so as to minimize the operating cost of the microgrid. As described above, if the components of the electricity tariff defined in the domestic and foreign power market rules are classified according to the factors of the tariff, they can be largely classified into the fixed tariff, the energy tariff, the maximum power tariff, and the peak load contribution tariff. All of these charges, other than the flat rate, may affect different rates. If you operate an energy storage system (ESS) with a specific charge in a market where multiple charges are applied, the charge may be reduced, but other charges may increase and the overall electricity charge may increase. Therefore, it is necessary to consider the energy charge, the maximum power consumption charge, and the peak load contribution fee simultaneously to create charge / discharge schedule of the energy storage device (ESS) to reduce the electric charge of the customer. Accordingly, the schedule creating unit 110 creates a charge and discharge schedule so that the operating cost representing the sum of the energy charge, the maximum power consumption charge, the peak load contribution charge, and the life reduction cost of the energy storage device is minimized do.

4, the schedule creating unit 110 includes a prediction data correction module 111, a minimum charge amount setting module 112, an initial schedule creation module 113, And a schedule correction module 114. [0033]

The prediction data correction module 111 has a function of correcting an error that may exist in the prediction data used for creating the charging and discharging schedules. Specifically, the prediction data correction module 111 can correct the prediction data by time period according to the setting information set by the user, and can perform the function of stairing the prediction data. First, a method of correcting the temporal prediction data through the prediction data correction module 111 will be described.

Typically, the settlement price in a Real-Time Pricing (RTP) plan is calculated and known after operating the actual power market. Therefore, since the actual settlement price can not be known at the time of operation, it is inevitable to perform charge / discharge using the predicted price. That is, if the predicted price is low, the charge is performed, and if it is expensive, the discharge is performed. Therefore, the difference between the predicted price and the actual settlement price can lead to damages. For example, if the actual charge is lower than the actual charge, the charge is charged at an expensive price and the charge is discharged at a low price, resulting in damage due to charging / discharging operation . In addition, similar problems can occur with maximum power consumption and peak load contribution cost. That is, the maximum power consumption or the system maximum load did not appear in the prediction, but it occurred in the actual operation result. In this case, when the charge / discharge operation is performed using only the predicted value, the maximum power consumption cost and the peak power consumption which can be reduced due to the non-discharge at the time of occurrence of the corresponding event even though the SOC reserving power for discharging is secured It does not reduce the load contribution cost.

Accordingly, the prediction data correction module 111 corrects the prediction data of the set price (or load) by using the real-time price information (or the real-time load information) in order to reduce the risk of the error described above according to the setting of the user can do. For example, as shown in the upper part of FIG. 5, if there is no corresponding real-time price information (or real-time load information) between the current time periods, the prediction data correction module 111 uses the prediction data as it is to create the charge / discharge schedule. However, if there is real-time price information or real-time load information as shown in FIG. 5, the predictive data correction module 111 can correct the predictive data with a real-time price or a real-time load and a weighted average of these predictive data. The corrected prediction data can then be used for the charging and discharging schedules recited below. The error between the predicted data and the value used in the actual settlement can be reduced in accordance with the correction of the predicted data.

In addition, the prediction data correction module 111 can stair the prediction data to reduce the risk that may occur due to the difference of the small prediction values that may occur in the optimization-based charge / discharge scheduling technique according to the user's setting . For example, if the current market price prediction value at the point in time of charging is much larger than the next time interval estimate, a schedule is made to perform the charging in the next time period, and therefore the charging is not performed in the current time period. However, if the market price rises during the following time period, the charge will be made at an expensive cost different from the plan. In order to disperse the risk, the prediction data correction module 111 divides the time interval into a plurality of unit time periods as shown in the lower part of FIG. 5, and outputs the prediction data for the real time price or real time load to at least one step It can be stepped by unit interval according to interval. That is, if the stair-stepping is performed in this example, the price between the current time period and the next time period is corrected to the same value, and the current time period and the next time period are charged in the same manner. Therefore, even if the market price rises during the next period, the damage due to the price increase can be reduced compared to the case of using the predicted value immediately.

In this way, the prediction data correction module 111 can perform two functions as described above. In other words, the prediction data can be corrected in consideration of the characteristics of the micro grid and the power market, or the stairing interval can be set appropriately. This can be selectively performed depending on the setting of the user, that is, Everyone can be used.

The minimum charge amount setting module 112 has a function of setting a minimum charge amount so that the load of the micro grid during independent operation can be supplied for a predetermined time (for example, the time required for starting the emergency diesel generator) in order to use the energy storage device as an emergency generator . That is, the energy charging device (ESS) must be maintained at least the minimum charging amount when preparing the charging and discharging schedule of the energy charging device (ESS). The minimum charging amount setting module 112 functions to set the minimum charging amount.

If the minimum charge amount is set high, the charge / discharge capacity of the energy storage device (ESS) may decrease, and the gain obtained by charging or discharging the energy storage device (ESS) may be reduced. Therefore, in order to improve the utilization of the energy storage device (ESS), it is necessary to set the minimum charge amount as low as possible.

Accordingly, the minimum charge setting module 112 may set the minimum SOC criterion between the individual pointers differently from the load and power generation predicted values and the minimum time for the energy storage device (ESS) to operate as the emergency generator, unlike the existing patents. As shown in FIG. 6, when the predicted value of (load-generation) after the time period is large, the energy storage device (ESS) needs to supply a large amount of electric power in case of emergency. In the opposite case, set the minimum charge amount to a low value. As a result, the charging amount corresponding to the shaded area in FIG. 6 can be utilized for normal operation in comparison with the method used in the prior art. The minimum charge amount is calculated as shown in Equation (1) below.

In Equation 1, SOC _opr ^min (t) represents the minimum charge amount of the energy storage device (ESS) for emergency power generation, SOC _mech ^min (t) represents the minimum charge amount of the physical energy storage device _{min, back} indicates the minimum amount of time that the energy storage system (ESS) to operate as an emergency generator, P _LD (x) denotes a load prediction value, P _DG (x) denotes a power generation prediction value _(kw), E _{ESS, rated} is the rated energy capacity of the energy storage device.

The temporary schedule creation module 113 functions to create a temporary charge and discharge schedule for the energy storage device (ESS) by converting the charge and discharge control problem into an optimization problem and finding an optimal solution to the optimization problem. Specifically, the temporary schedule creation module 113 functions to create a temporary charging and discharging schedule for optimally controlling the energy storage device (ESS) for individual time periods. As described above, the operating device 100 according to an embodiment of the present invention generates a schedule such that the sum of the energy charge, the maximum power consumption cost, and the peak load attribution charge and the sum of the life reduction cost of the energy storage device is minimized In the optimization process, the objective function and the constraint condition can be expressed by Equations (2) and (3), respectively.

In Equation (2), PESS (i) represents the output of the energy storage device (ESS) at the time interval (i), C _energy represents the energy charge, C _{MG, peak} represents the maximum power consumption charge _{, Peak} represents the peak load contribution rate, C _{wear, tear} represents the lifetime reduction cost of the energy storage device (ESS), and the specific equation can be defined by the electricity rate settlement rule of the electricity market to which the microgrid belongs.

As the constraint conditions, the upper and lower limit conditions of the active power and the upper and lower limit conditions of the charged amount can be used. In addition, the temporary schedule creation module 113 may use the charge amount (SOC) constraint condition as shown in Equation (3) in order to secure the discharge reserve for the error of the predicted value.

In Equation (3), T _{SOC, max} represents the time interval during which the charged amount should be maximized, SOC (T _{SOC, max} ) represents the charging amount at the time interval T _{SOC, max} , and SOC _max represents the maximum charging amount.

The constraint referred to in Equation (3) can perform the following functions. For example, assume that there is no discharge gain in the afternoon. In this situation, the prior art does not perform charging at the early morning and early morning hours, even if the SOC is low. Therefore, even if the actual price rises in the afternoon and a gain can be obtained by the discharge, the discharge can not be performed due to the shortage of the SOC. However, if the above constraint is applied to the schedule and the maximum time of charge (SOC) is set at 8:00 am, the operation process of the energy storage device (ESS) Charge / discharge can be performed in the liver. Therefore, even if an unexpected event occurs after 8:00, the discharge can be performed.

The schedule correction module 114 functions to generate a final schedule by correcting the temporary schedule created through the temporary schedule creation module 113. [ If the objective function is a linear form (defined by the most linear form of the electric charge) and the coefficients have the same time interval, then the optimal solution combination that minimizes the objective function can be infinite. That is, there are infinite charge / discharge schedules that minimize the objective function. For example, if the price of city 1 and city 2 is the same at 100 won / kWh, it is necessary to charge 10 kWh from city area 1, to charge 5 kWh from city area 2, from 1 to 5 kWh from city area 2, All costs equal to 1,500 won. Among various charge / discharge schedules that minimize the objective function, in the present invention, in order to reduce the risk of the prediction error, as shown in FIG. 7, among the schedules derived from the optimization problem, the charging price (discharge price is opposite in sign) The schedule for dispersing the charge / discharge as much as possible can be selected as the final charge / discharge schedule.

The schedule correction method through the schedule correction module 114 can be roughly divided into three processes.

First, the schedule correction module 114 may define the charging price and the maximum charge amount between the individual time periods. The temporary schedule created through the temporary schedule creation module 113 can be substituted into the objective function of the optimization problem to find the activated price coefficient in the individual time zone and calculate the charging price of the individual districts. Next, the maximum charge amount that does not change the charge price is calculated for each interval. For example, the charging of an energy storage device (ESS) increases the maximum power consumption rate when a new maximum power consumption of the microgrid occurs. Therefore, in this case, the maximum amount of charge between the individual time zones is the maximum charge amount that can keep the power consumption between the respective time zones below the maximum power consumption predicted value (the largest value among the maximum power consumption and the maximum power consumption when the schedule is applied) Be determined

Also, the schedule correction module 114 may derive a set of time periods for performing a correction operation on the basis of the time interval T in which the present operation is being performed. That is, the schedule correction module 114 calculates a set of time periods (i.e., a set of correction target time periods) that are maintained in the same state in consideration of the charged state or the discharged state of the time period T currently undergoing the calculation . For example, if the schedule result of the time interval (T) during which the current operation is performed is a charge, then the set of the correction target time periods is the current time interval between the current calculation time period and the immediately preceding time period, It is a collection of identical time periods. On the contrary, if the schedule result of the time period (T) during which the current operation is performed is discharge, the correction target time period set is the time period between the current calculation time period and the charging time point . If the current scheduling result is 0, then the set of correction target time intervals is defined on the basis of the scheduling result of the first time after the current scheduling interval is not 0.

When the derivation of the correction target time interval set for performing the correction operation described above is completed, the schedule correction module 114 performs the schedule correction work for the time periods belonging to the correction target time interval set. First, the schedule correction module 114 calculates the average output of the time periods belonging to the set of target time points to be corrected, and performs the schedule correction for the time periods in the order of the smallest maximum charge amount among the time points belonging to the target time- You can proceed. If the maximum amount of charge between the corresponding points is smaller than the average power, the schedule of the corresponding period may be set as the maximum charge amount, the average power of the remaining time points may be recalculated, and calculations for the following time periods may be performed. On the contrary, if the maximum charge amount is larger than the average charge amount, the charge amount in the corresponding section is set as the average charge amount, and the calculation for the next section is performed.

The command value derivation unit 120 sets the operation mode (manual / schedule) of the energy storage device (ESS) according to the charging and discharging schedule created through the scheduling unit 110, that is, the final charging and discharging schedule, And derives the state of the energy storage device (ESS) to be transferred to the controller 130 of the energy storage device (ESS) and the effective power command value according to the power output command value. If the operation mode of the energy storage device (ESS) is the manual mode, there is no change of the state command value of the energy storage device (ESS), and only the active power command value is changed to the user input value. However, if the energy storage unit (ESS) is operating in schedule mode, the state of the energy storage unit (ESS) and the output command value can be determined. In addition, the command value derivation unit 120 changes the state of the energy storage device (ESS) to ready (turn off the semiconductor switch) when the schedule result command value is zero. With this operation, it is possible to reduce the loss caused by an unnecessary standby operation (switching of the semiconductor switch for controlling the output to 0).

The control unit 140 controls the operation state and output control of the energy storage device (ESS) based on the command value derived through the command value deriving unit 120 and transmitted to the micro grid operating system, . As described above, the operation state of the energy storage device (ESS) can be divided into a manual operation mode and a schedule operation mode used during grid-connected operation, and a constant voltage / frequency operation mode and a synchronous operation mode used during independent operation .

Here, the schedule operation mode, that is, the active power and reactive power control mode, indicates a mode for controlling the active power and the reactive power according to the command value, and the constant voltage / frequency operation mode is a mode for controlling the voltage and frequency with the command value . The synchronous operation mode is a mode for synchronizing the magnitude and phase angle of the voltage on the secondary side (microgrid) of the microgrid coupled switch with the voltage on the primary side by controlling the magnitude and phase angle of the output voltage.

In addition, the control unit 140 provides protection functions such as an AC / DC voltage, a current, and a charged amount in order to protect the system of the energy storage device (ESS). A feature of the control unit 140 is that uninterrupted operation is possible. That is, if the anti-island function is turned off, it automatically performs independent operation (voltage / frequency control mode) when it detects an accident in the power grid. When the upper power grid is restored, it is detected and automatically synchronized. When the micro grid connection switch is closed, the operation mode is automatically switched to the power / reactive power operation mode. Such an operation minimizes the problems (ESS overcurrent protection, excessive inrush current, etc.) that can occur in the measurement error and in the case where the energy storage device (ESS) maintains the synchronous mode after being linked with the upper power network.

The user interface unit 130 provides an environment in which a user can express various information for controlling various matters related to the operation of the energy storage device (ESS) and can control related devices. The data displayed in the user interface unit 130 is as follows.

- Energy storage device (ESS): status (stop / ready / operation), operation mode (independent operation / synchronization / auto / manual), warning and alarm, SOC, Status, upper power grid synchronization result, etc.

- Micro grid connection switch: status (open / close), reactive / reactive power, communication status, etc.

- Charge / discharge schedule of energy storage device (ESS): Schedule result and operation history, market price history and forecast value, micro grid power history and forecast value, upper grid load history and forecast value, operation gain of energy storage device

The user can perform the following operations through the user interface unit 130 based on the above-described data.

- Energy storage device (ESS): Control of state (stop / preparation / operation), setting of anti-island function, selection of automatic / manual mode, control of reactive power output in manual mode, Output voltage control light

- Micro grid connection switch: state (open / close) control light

- Charging / discharging schedule of energy storage device (ESS): Change of schedule creation cycle, change of variables related to scheduling, etc.

In addition, the user interface unit 130 may further provide two functions to prevent a problem that may be caused by erroneous operation by the user. Here, first, the user interface unit 130 may provide a black start prevention function connected to an upper power grid. Here, when the anti-island mode is activated and a power failure occurs due to a failure of the upper power grid, the energy storage device (ESS) stops operating. In order to use the energy storage unit (ESS) as an emergency generator to power the microgrid, the user must open the microgrid connection switch and start the energy storage unit (ESS). If the energy storage device (ESS) is started without opening the microgrid connection switch, in the worst case, an overcurrent occurs in the energy storage device (ESS) and the semiconductor switch may be burned out. In order to prevent such a problem, when a power failure occurs (that is, when a power failure occurrence signal is detected), the user interface unit 130 inputs an operation command of the energy storage device (ESS) It is possible to prevent the operation signal of the energy storage device (ESS) and display a warning message.

Also, the user interface unit 130 may provide an asynchronous re-association prevention function. If the upper power grid is restored during independent operation, it should be re-connected to the higher power grid of the micro grid. In this case, when the micro grid connection switch is closed in the state where the voltage of the upper power system and the micro grid are not synchronized (size and phase angle), an excessive inrush current may cause a power failure of the upper power system protection device or the ESS protection device have. In order to prevent this problem, the asynchronous re-connection prevention function prevents the operation of the micro grid connection switch and displays the related warning message if the voltages of the upper power grid and the customer power grid are not synchronized during the independent operation

The operating result of the operating device 100 according to an embodiment of the present invention can be used to minimize the energy cost, the maximum power consumption charge, the peak load contribution fee, and the life span reduction cost of the energy storage device (ESS) The point was confirmed.

FIG. 8 is a flowchart of an operation method (hereinafter referred to as an operation method) for an energy storage device for a microgrid according to an embodiment of the present invention. Now, an operation method according to an embodiment of the present invention will be described with reference to FIGS. 8 to 12. FIG. Further, in the following description, the redundant description is omitted.

In step S110, the schedule creating unit creates a schedule for charging and discharging the energy charging apparatus (ESS) using the micro grid operating system. Specifically, step S110 may include collecting forecast data and real-time operating information on load, power generation, and energy price by time period from the micro grid operating system, and step S110 may include steps shown in FIG. 9 .

In step S111, the schedule creating unit corrects the time-series forecast data on the basis of real-time price information within the time period for each time period according to the user's setting. The step S111 may include dividing one time interval into a plurality of unit time intervals according to a user's setting and stepping the prediction data according to at least one stepping interval for each unit time interval . However, the correction process and the stair-step process of the prediction data are not necessarily performed in the two processes, but may be performed selectively or both according to the setting of the user.

In step S112, the schedule generator sets the minimum charge amount so that the load of the micro grid during the independent operation can be supplied for a predetermined time (for example, the time required for starting the emergency diesel generator) to use the energy storage device as the emergency generator . That is, if the minimum charge amount is set high, the charge / discharge capacity of the energy storage device (ESS) may decrease, and the gain obtained by charging or discharging the energy storage device (ESS) may decrease. Therefore, in order to improve the utilization of the energy storage device (ESS), it is necessary to set the minimum charge amount as low as possible.

Also, the step S112 may be performed by setting the minimum SOC criterion between the individual cities using the predicted value of the load and generation amount and the minimum time for the energy storage device (ESS) to operate as the emergency generator. As described with reference to FIG. 6, if the predicted value of (load-generation) after the time interval is large, the energy storage device (ESS) must supply a large amount of electric power in case of emergency. In the opposite case, it is preferable to set the minimum charge amount to a low value.

In addition, as described with reference to Equation (1), step S112 is a step of calculating the minimum charge amount of the energy storage device for emergency power generation, the minimum charge amount of the physical energy storage device, the minimum time required for the energy storage device to operate as an emergency generator, The prediction data for the power generation, the predicted data for the power generation, and the rated energy capacity of the energy storage device.

Step S113 is a step of converting the charging and discharging control problem into an optimization problem and creating a temporary charging and discharging schedule for the energy storage device by finding an optimum solution to the optimization problem. Here, the objective function of the optimization problem can be made to minimize the sum of the energy charge, the maximum power consumption cost, the peak load contribution charge and the life saving cost of the energy storage device. Here, the objective function and the constraint condition in the optimization process performed in step S113 have been described with reference to equations (2) and (3), and thus redundant description will be omitted.

In step S114, the final charging and discharging schedules are generated by analyzing the charging price of the time slot and the temporary charging and discharging schedules, and distributing the temporary charging and discharging schedules so that the charging and discharging schedules are dispersed to the maximum . Here, the step of generating the final charge and discharge schedule through step S114 is shown in Fig.

Step S114a is a step of defining the charging price and the maximum charging amount between the individual time periods. Here, the charging price can be calculated by charging the temporary schedule created in step S113 to the objective function of the optimization problem, searching for the activated price coefficient in the individual time zone, and the charging price between the individual cities.

Also, the step S114a may define a maximum charge amount that does not cause the charge price to fluctuate with respect to each interval. For example, charging the energy storage unit (ESS) causes a new maximum power consumption of the microgrid, which increases the maximum power consumption charge. Therefore, in this case, the maximum charge amount between the individual pointers is determined by the maximum charge amount that can keep the power consumption between the respective pointers below the maximum power consumption predicted value (the largest value among the maximum power consumption and the maximum power consumption when the schedule is applied) do

Step S114b is a step of initializing the variables used for the correction to be described below, and setting the correction target to the current time period.

Step S114c is a step of determining whether the correction of the current time interval, i.e., the time interval T, is completed. As a result of the determination, if it is determined that the correction for the time period T has been completed, control is passed to step S114f. Otherwise, control is passed to step S114d.

Step S114d is a step of deriving a set of time periods for performing the correction work on the basis of the time interval T in which the present calculation is in progress. That is, the step S114d derives a set of time periods, i.e., a set of correction target time periods, which are maintained in the same state, in consideration of the charged state or the discharged state of the time period T in which the current operation is being performed. In step S114d, if the schedule result of the current calculation period is 0, the correction target time period aggregation can be defined based on the schedule result of the first time after the current calculation time interval after the current calculation time period.

In step S114e, when the derivation of the correction target time period aggregation is completed, the schedule correction operation is performed on the time periods belonging to the correction target time period aggregate. Here, in step S114e, the average output of the time periods belonging to the correction target time period set is calculated, and the schedule correction for the time periods can be performed in the order of the smallest maximum charge amount among the time periods belonging to the correction target time period set. If the maximum amount of charge between the corresponding points is smaller than the average power, the schedule of the corresponding period may be set as the maximum charge amount, the average power of the remaining time points may be recalculated, and calculations for the following time periods may be performed. On the contrary, if the maximum charge amount is larger than the average charge amount, the charge amount in the corresponding section is set as the average charge amount, and the calculation for the next section is performed.

Step S114f is a step for determining whether the current time interval is the last time interval, that is, whether there is a subsequent time interval for which correction is required. If there is a time period required for the correction, the control is transferred to the step S114g, and a selection process for the next time period is performed. Otherwise, control is passed to step S120.

Thus, the charging and discharging schedules of the energy storage device can be made by time period so that the operation cost of the micro grid can be minimized through step S110. In addition, since the sum of the energy charge, the maximum power consumption cost, the peak load contribution charge, and the life reduction cost of the energy storage device is minimized, it is possible to lower the electricity price of the customer and to operate more efficiently There are advantages. In addition, since the error correction is performed on the prediction data considering the real-time price in step S110, the damage due to the error can be minimized.

In operation S120, the command value derivation unit determines the operation state of the energy storage device according to the user setting information and the charge and discharge schedule, and derives an effective power command value to be output from the energy storage device. Here, step S120 may be performed by performing the steps shown in FIG. As mentioned earlier. If the operation mode of the energy storage device (ESS) is the manual mode, there is no change in the state command value of the energy storage device (ESS), and only the active power command value can be changed to the user input value. As shown in step S122, if the schedule result command value is 0, the control is transferred to step S123, and the state of the energy storage device is changed to the ready state (i.e., the semiconductor switch is turned off). This operation can reduce the loss caused by unnecessary standby operation.

In operation S130, the control unit controls the operation of the energy storage device according to the operation state and the effective power command value. Specifically, step S130 is a step of performing an operation state and an output control of the energy storage device (ESS) based on the command value derived through step S120 and transmitted to the micro grid operating system and the operation state setting value. Here, the control step performed in step S130 may provide protection functions such as AC / DC voltage, current, and SOC for protecting the energy storage system (ESS) itself as shown in FIG. 12, Mode switching can be performed. When the ESS maintains the synchronous mode after it is connected to the upper power grid by this operation, problems (ESS overcurrent protection operation, excessive inrush current, etc.) that may occur in the measurement error and in the sensing period can be minimized.

In addition, according to the operating method of the present invention, when an operation command of the energy storage device is inputted from the user when the power failure signal is detected by the user interface unit and the upper power network link switch is closed, And blocking the operation signal of the energy storage device according to the operation command and generating a warning message. The method further includes the step of, when the voltage of the upper power grid and the customer power grid are not synchronized with each other during the independent operation of the energy storage device by the user interface unit, interrupting the operation of the microgrid association switch and generating a warning message can do.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: Operating device for energy storage device for Micro Grid
110: schedule generating unit 120: command value deriving unit
130: user interface unit 140:

Claims (20)

The microgrid operating system collects forecast data and real-time operating information on load, power generation and energy price by time period, defines the minimum charge amount of energy storage device connected to the micro grid per time period, minimizes the operation cost of the micro grid A schedule creating unit for creating a charge and discharge schedule of the energy storage device by time intervals;
A command value derivation unit for determining an operation state of the energy storage device according to user setting information and the charge and discharge schedule and deriving an effective power command value to be output from the energy storage device; And
And a controller for controlling the operation of the energy storage device according to the operation state and the effective power command value,
The schedule creating unit creates a charge and discharge schedule so that the sum of the energy charge, the maximum power consumption cost, the peak load contribution charge, and the life reduction cost of the energy storage device is minimized,
The schedule generating unit may further include a prediction data correcting module for correcting the time-series prediction data based on real-time price information within a time period,
Wherein the prediction data correction module divides one time interval into a plurality of unit time intervals according to the setting of the user and stairs the prediction data according to at least one stepwise interval for each unit time period Operating device for an energy storage device for microgrid characterized. delete delete The method according to claim 1,
Wherein the schedule creation unit includes a minimum charge amount setting module for setting a minimum charge amount of the energy storage device connected to the micro grid on a time axis basis and the minimum charge amount setting module sets a minimum charge amount of the energy storage device for emergency power generation, Based on the minimum charge of the device, the minimum time for the energy storage to operate as an emergency generator, the predicted data for the load, the predicted data for the power generation and the rated energy capacity of the energy storage device, Wherein the energy storage device comprises a plurality of energy storage devices. The method according to claim 1,
Wherein the scheduler creates a temporary charge and discharge schedule for the energy storage device by converting a charge and discharge control problem into an optimization problem and finding an optimal solution to the optimization problem, Device. 6. The method of claim 5,
Wherein the objective function of the optimization problem is configured to minimize the sum of the energy charge, the maximum power consumption cost, the peak load contribution charge, and the life reduction cost of the energy storage device. The method according to claim 6,
The schedule creating unit
A schedule correction module for analyzing the temporal charging price and the temporary charging and discharging schedule and distributing the temporary charging and discharging schedules so that the charging and discharging schedules for the time periods are dispersed to a maximum, Wherein the energy storage device comprises an energy storage device. 8. The method of claim 7,
The schedule creating unit defines a charging price and a maximum charge amount between individual pointers, defines time periods that are continuously the same state as a charged state or a discharged state as a set of correction target time intervals, Calculating an average output and performing a correction by comparing the time-series and the average power belonging to each set of correction target time points to generate a final charging and discharging schedule. The method according to claim 1,
Wherein when the operation command of the energy storage device is input from the user when the power generation signal is detected and the upper power network link switch is closed, the user interface unit The operation signal of the energy storage device according to the operation command is blocked and a warning message is generated. 10. The method of claim 9,
Wherein the user interface unit interrupts the operation of the microgrid's associated switch and generates a warning message when the voltages of the upper grid and the customer grid are not synchronized during independent operation of the energy storage device Operating device for storage device. Collecting prediction data and real-time operating information on load, power generation, and energy price by time period from the micro grid operating system by a schedule creating unit;
Defining a minimum charge amount of an energy storage device connected to a micro grid by a time interval by the schedule creating unit;
Creating a charge and discharge schedule of the energy storage device by time period so that the operating cost of the microgrid is minimized by the schedule creating unit;
Determining an operating state of the energy storage device according to the user setting information and the charging and discharging schedule by the command value deriving part and deriving an effective power command value to be output from the energy storage device; And
Controlling the operation of the energy storage device by the control unit according to the operation state and the effective power command value,
Wherein the step of creating the charging and discharging schedule of the energy storage device is performed so as to minimize the sum of the energy charge, the maximum power consumption cost, the peak load contribution fee, and the life saving cost of the energy storage device,
Further comprising the step of correcting the time-series forecast data based on real-time price information within the time period by the time period according to the setting of the user by the schedule creating unit,
The step of correcting the predictive data may include: dividing one time interval into a plurality of unit time intervals according to the setting of the user; And
And stairing the prediction data according to at least one stepping interval for each unit time period. delete delete 12. The method of claim 11,
Wherein defining the minimum charge amount of the energy storage device comprises:
The minimum charge of the energy storage device for emergency power generation, the minimum charge of the physical energy storage device, the minimum time the energy storage device must operate as an emergency generator, the predicted data of the load, Characterized in that the energy storage device is based on the rated energy capacity. 12. The method of claim 11,
Wherein the step of creating a charge and discharge schedule of the energy storage device comprises the steps of converting a charge and discharge control problem to an optimization problem and creating a temporary charge and discharge schedule for the energy storage device by finding an optimal solution to the optimization problem Wherein the method further comprises the steps of: 16. The method of claim 15,
Wherein the objective function of the optimization problem is such that the sum of the energy charge, the maximum power consumption cost, the peak load contribution charge, and the life reduction cost of the energy storage device is minimized. 17. The method of claim 16,
The charging and discharging schedule of the energy storage device may include:
Further comprising analyzing the temporal charging price and the temporary charging and discharging schedule and generating a final charging and discharging schedule by distributing the temporary charging and discharging schedules such that the temporal charging and discharging schedules are maximally distributed Wherein the energy storage device is a micro grid. 18. The method of claim 17,
The step of generating the final charge and discharge schedule defines a charge price and a maximum charge amount between individual pointers and defines a time period that is continuously the same state as a charge state or a discharge state as a set of correction target time points, Calculating the average power of the time periods belonging to the inter-set, and performing the correction by comparing the average power and the time-interval belonging to each set of the correction target time periods. 12. The method of claim 11,
When the operation instruction of the energy storage device is input by the user when the power generation signal is detected by the user interface unit and the upper power network link switch is closed, the operation signal of the energy storage device according to the operation instruction is blocked, Further comprising generating a warning message for the microgrid. ≪ RTI ID = 0.0 >< / RTI > 20. The method of claim 19,
Further comprising the step of, when the voltages of the upper power grid and the customer power grid are not synchronized by the user interface unit during the independent operation of the energy storage device, interrupting the operation of the micro grid switch and generating a warning message Wherein the energy storage device is a micro grid.

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