Energy storage system and operation method for optimal operation of demand response resources

Abstract

An energy storage system according to an embodiment of the present invention can be configured as a demand response resource connected to a virtual power plant system. Here, the energy storage system can include a power generation device that generates power, a battery that stores power, an energy management device that monitors a power production state and a power consumption state and creates an operation schedule for the battery, and a power conversion device that controls a charge / discharge operation of the battery according to the created operation schedule.

Description

[Technical field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2022-0022085, filed with the Korean Intellectual Property Office on February 21, 2022, and all of the contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an energy storage system and an operation method thereof, and more particularly to an energy storage system and an operation method thereof for optimal operation of demand response resources, and an energy management device for the energy storage system. [Background technology]

[0003] Distributed energy resources (DER) are power resources that are connected to the power grid to provide power or can provide support during peak power demand. Examples of distributed resources include distributed power sources, energy storage systems (ESS), and demand resources.

[0004] Distributed power sources and small-scale ESSs are becoming more popular, but they are scattered across various facilities such as homes and buildings, which limits their integrated operation. To solve this problem, a Virtual Power Plant (VPP) has been proposed that uses ICT technology to integrate and operate various distributed resources as if they were a single power plant. A virtual power plant can integrate and operate distributed resources that could only be managed individually, and can improve the accuracy of power generation forecasts through combined forecasts for each distributed resource, thereby improving the stability of the power system.

[0005] Virtual power plants can be classified into supply-type, demand-type, and integrated types depending on the form of resource collection. Among these, demand-type virtual power plants provide a service to stabilize the power grid by reducing power during power peaks using collected demand response resources. Small facilities such as homes, buildings, and factories mainly participate in virtual power plants as demand response resources. When demand response resources reduce power usage at the request of the virtual power plant or intermediary business (VPP Provider) system, compensation can be provided in the form of a settlement payment equivalent to the amount of power reduction.

[0006] Generally, energy storage systems (ESS) installed in small facilities control the charging and discharging of batteries depending on solar conditions and load conditions. Such conventional energy storage systems have difficulty in responding appropriately to demand response requests from virtual power plants, which can lead to operational problems when linked to virtual power plants. In addition, conventional energy storage systems operate with the goal of maximizing internal power generation or minimizing external power usage, but are not optimized in terms of power purchasing costs.

[0007] Therefore, there is a need for optimal operation technology for demand response resources that can maximize profits from demand response through optimal responses to demand response requests while at the same time minimizing electricity purchasing costs through the use of grid power. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE PRESENT EMBODIMENT In order to solve the above problems, an object of the present invention is to provide an energy storage system for optimal operation of demand response resources.

[0009] Another object of the present invention to solve the above problems is to provide a method for operating such an energy storage system.

[0010] Another object of the present invention to solve the above problems is to provide an energy management device for controlling the operation of such an energy storage system. [Means for solving the problem]

[0011] To achieve the above object, an energy storage system according to an embodiment of the present invention can be configured as a demand response resource connected to a Virtual Power Plant (VPP) system. Here, the energy storage system can include a power generation device that produces power, a battery that stores power, an energy management device that monitors a power production state and a power consumption state and creates an operation schedule for the battery, and a power conversion device that controls a charge / discharge operation of the battery according to the created operation schedule.

[0012] The energy management device collects basic information including information on power production status and power consumption status and grid power cost information, and uses the collected basic information to create an operation schedule for controlling the charging and discharging operation of the battery. If a demand response (DR) signal is received during the process of controlling the charging and discharging of the battery according to the operation schedule, the energy management device can adjust the operation schedule in response to the DR signal.

[0013] The energy management device can derive a charge / discharge amount of the battery for each unit time that minimizes the cost of purchasing grid power, and reflect the calculated charge / discharge amount in the operation schedule.

[0014] The energy management device can derive an operation schedule including the charge / discharge amount of the battery for each unit time by using an objective function defined by the purchasing cost of grid power.

[0015] The above objective function can be defined with constraints including at least one of a first condition regarding the balance between power supply and power consumption, a second condition regarding the state of charge (SOC) based on the charging and discharging efficiency of the battery, a third condition regarding the limit charge amount of the battery, a fourth condition regarding the limit output of the power conversion device, and a fifth condition regarding the binarization of the charging and discharging states.

[0016] The energy management device can collect basic information including battery-related parameters, grid power cost information, and information regarding power production states and power consumption states for a predefined first period, use the collected basic information to generate power production forecast information and power consumption forecast information for a predefined second period that is a period after the first period, and generate an operation schedule for the second period based on the generated forecast information.

[0017] When the demand response (DR) signal is received, the energy management device performs a demand response by controlling the charging and discharging operation of the battery to satisfy the DR duration and DR power amount included in the demand response (DR) signal regardless of the planned operation schedule, and can re-plan an operation schedule for the remaining period after the demand response is performed.

[0018] The energy management device can collect actual measurement information regarding power production status and power consumption status during the process of controlling the battery according to the operation schedule, derive an error between the information regarding the power production status and power consumption status included in the basic information and the collected actual measurement information, and adjust the operation schedule using the derived error.

[0019] In order to achieve the above-mentioned another object, an energy management device according to an embodiment of the present invention can be configured as a demand response resource connected to a Virtual Power Plant (VPP) system, wherein the energy management device includes at least one processor; and a memory for storing at least one instruction executed by the at least one processor.

[0020] The at least one command may include an command to collect basic information including information on power production status and power consumption status and grid power cost information; an command to plan an operation schedule for controlling the charging and discharging operation of the battery using the collected basic information; an command to control the charging and discharging operation of the battery according to the planned operation schedule; and, if a demand response (DR) signal is received during the charging and discharging control process of the battery, an command to adjust the operation schedule in response to the DR signal.

[0021] The command to create the operation schedule may include a command to derive a charge / discharge amount of the battery for each unit time that minimizes the purchasing cost of grid power, and to reflect the charge / discharge amount in the operation schedule.

[0022] The command to create the operation schedule can include a command to derive an operation schedule including the charge / discharge amount of the battery per unit time using an objective function defined by the purchasing cost of grid power.

[0023] The above objective function can be defined with constraints including at least one of a first condition regarding the balance between power supply and power consumption, a second condition regarding the state of charge (SOC) based on the charging and discharging efficiency of the battery, a third condition regarding the limit charge amount of the battery, a fourth condition regarding the limit output of the power conversion device, and a fifth condition regarding the binarization of the charging and discharging states.

[0024] The instruction to collect the basic information may include an instruction to collect basic information including battery-related parameters, grid power cost information, and information on power production status and power consumption status for a predefined first period, wherein the instruction to develop an operation schedule may include an instruction to generate power production forecast information and power consumption forecast information for a predefined second period following the first period using the collected basic information; and an instruction to generate an operation schedule for the second period based on the generated forecast information.

[0025] When the demand response (DR) signal is received, the demand response may include an instruction to perform a demand response by controlling the charging / discharging operation of the battery to satisfy the DR duration and DR power amount included in the demand response (DR) signal, regardless of the planned operation schedule; and an instruction to re-plan an operation schedule for the remaining period after the demand response is performed.

[0026] After the instruction to control the charging and discharging operation of the battery according to the proposed operation schedule, the instruction may include an instruction to collect actual measurement information regarding the power production state and power consumption state; an instruction to derive an error between the information regarding the power production state and power consumption state contained in the basic information and the collected actual measurement information; and an instruction to adjust the operation schedule using the derived error.

[0027] In order to achieve the above-mentioned another object, an operating method according to one embodiment of the present invention is a method for operating an energy storage system configured as a demand response resource connected to a Virtual Power Plant (VPP) system, and includes a step of collecting basic information including information on a power production state and a power consumption state and grid power cost information; a step of planning an operating schedule for controlling a charging and discharging operation of a battery using the collected basic information; a step of controlling the charging and discharging operation of the battery according to the planned operating schedule; and a step of adjusting the operating schedule in response to the demand response (DR) signal if a demand response (DR) signal is received during the charging and discharging control process of the battery.

[0028] The step of creating the operation schedule may include a step of deriving a charge / discharge amount of the battery for each unit time that minimizes the purchasing cost of grid power, and reflecting the charge / discharge amount in the operation schedule.

[0029] The step of creating the operation schedule may include a step of deriving an operation schedule including the charge / discharge amount of the battery per unit time, using an objective function defined by the purchasing cost of grid power.

[0030] The above objective function can be defined with constraints including at least one of a first condition regarding the balance between power supply and power consumption, a second condition regarding the state of charge (SOC) based on the charging and discharging efficiency of the battery, a third condition regarding the limit charge amount of the battery, a fourth condition regarding the limit output of the power conversion device, and a fifth condition regarding the binarization of the charging and discharging states.

[0031] The step of collecting basic information may include a step of collecting basic information including battery-related parameters, grid power cost information, and information regarding a power production state and a power consumption state for a predefined first period, wherein the step of formulating an operation schedule may include a step of generating power production forecast information and power consumption forecast information for a predefined second period following the first period using the collected basic information; and a step of generating an operation schedule for the second period based on the generated forecast information.

[0032] The step of adjusting the operation schedule may include a step of performing a demand response by controlling a charging / discharging operation of a battery to satisfy a DR duration and a DR power amount included in the demand response (DR) signal, regardless of the planned operation schedule, when the demand response (DR) signal is received, regardless of the planned operation schedule; and a step of replanning an operation schedule for the remaining period after the demand response is performed.

[0033] After the step of controlling the charging and discharging operation of the battery according to the proposed operation schedule, the method may include the steps of collecting actual measurement information regarding power production status and power consumption status; deriving an error between the information regarding the power production status and power consumption status contained in the basic information and the collected actual measurement information; and adjusting the operation schedule using the derived error. Effect of the Invention

[0034] According to the above-described embodiment of the present invention, it is possible to maximize profits from demand response through optimal response to a demand response request, and at the same time, it is possible to minimize power purchasing costs due to the use of grid power. [Brief description of the drawings]

[0035] [Figure 1] FIG. 1 is a block diagram illustrating an energy storage system according to the present invention. [Diagram 2] FIG. 1 is a block diagram of an energy storage system according to an embodiment of the present invention. [Diagram 3] 1 is a block diagram showing an example of an energy storage system according to an embodiment of the present invention; [Figure 4] FIG. 4 is a flow chart showing a method for operating an energy storage system according to an embodiment of the present invention. [Diagram 5] FIG. 4 is a flow diagram showing a method for creating an operation schedule according to an embodiment of the present invention. [Figure 6] FIG. 1 is a flow diagram showing a method for adjusting an operation schedule for demand response according to an embodiment of the present invention. [Figure 7] FIG. 1 is a flow diagram showing a method for adjusting an operation schedule to respond to a real-time error according to an embodiment of the present invention. [Figure 8] 1 is a block diagram of an energy management device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, it is understood that this is not intended to limit the present invention to the specific embodiment, but includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Similar reference numerals are used for similar components while describing each drawing.

[0037] Terms such as first, second, A, B, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another. For example, a first component may be named a second component, and similarly, a second component may be named a first component, without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated listed items or any of multiple associated listed items.

[0038] When a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but there may also be other components in between. In contrast, when a component is referred to as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0039] The terms used in this application are merely used to describe certain embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and are not intended to preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0040] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as idealized or overly formal unless expressly defined in this application.

[0041] Some terms used in this specification are defined as follows:

[0042] Nominal capacity (Nominal Capa.) refers to the set capacity [Ah] of a battery that is set by the battery manufacturer at the time of development.

[0043] SOC (State of Charge) is the current charged state of the battery expressed as a percentage [%], and SOH (State of Health) is the current deterioration state of the battery expressed as a percentage [%].

[0044] A battery rack is a system with a minimum structure that can connect pack units set by the battery manufacturer in series / parallel and can be monitored and controlled through a BMS. It can consist of multiple battery modules and one BPU or protection device.

[0045] A battery bank can refer to a large-scale collection of battery rack systems consisting of multiple racks connected in parallel. The battery bank BMS can monitor and control the rack BMS (RBMS) for each battery rack.

[0046] A BSC (Battery System Controller) is a device that performs top-level control of a battery system including a bank-based battery system, and can also be used as a control device in a battery system having a multi-bank level structure.

[0047] Power limit refers to the output limit preset by the battery manufacturer according to the battery condition. Rack power limit refers to the output limit (in kW) set at the rack level, and can be set based on the battery's SOC and temperature.

[0048] The power limit can be divided into a charge power limit and a discharge power limit depending on whether it is charging or discharging. Also, a rack power limit for each rack and a bank power limit for each bank can be defined depending on the structure of the battery system.

[0049] Virtual Power Plant System means a collection of hardware and software for the operation of a Virtual Power Plant (VPP), which may be embodied in one physical device or distributed across multiple physical devices.

[0050] The demand response resource refers to a facility that is connected to a virtual power plant (VPP) system and controls power resources in response to a demand response request from the virtual power plant (VPP) or a VPP provider system. The demand response resource may correspond to various facilities such as a house, a building, a factory, etc., but the scope of the present invention is not limited to these.

[0051] Demand response (DR) refers to controlling power resources to change the amount of grid power usage so as to satisfy a demand response request.

[0052] The demand response request may include a request to control a power resource for a demand response resource or a request to change power usage. Here, the demand response request may include at least one of a demand response period and a demand response power amount (e.g., a reduced power amount).

[0053] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0054] FIG. 1 is a block diagram for explaining an energy storage system according to the present invention.

[0055] An energy storage system 100 according to the present invention can be configured within a demand response resource including a load 200, as shown in Fig. 1. Here, the energy storage system 100 is supplied with power from a power grid 300, and can supply the supplied grid power or power stored therein to the load 200.

[0056] The energy storage system 100 is connected to the VPP grid-connected device 400 via a network and configured to transmit and receive data to and from the VPP grid-connected device 400. The energy storage system 100 can receive a demand response (DR) signal, which is a signal related to a demand response request, from the VPP grid-connected device 400.

[0057] The VPP grid-connected device 400 may be included in a VPP system or may be configured to be included in a VPP provider system. The VPP grid-connected device 400 may be managed by a mediator that collects VPP service participants and demand response resources and provides a VPP service. The VPP grid-connected device 400 may generate a demand response (DR) signal when a power peak occurs in the power grid and transmit the DR signal to the energy storage system 100 configured as a demand response resource.

[0058] The energy storage system 100 can monitor the state of the internal power resource and operate the internal power resource according to a pre-planned operation schedule. If a demand response (DR) signal is received from the VPP grid-connection device 400 during the operation of the power resource, the operation schedule can be adjusted in response to the demand response signal. Meanwhile, a detailed description of the planning and adjustment of the operation schedule will be given later.

[0059] FIG. 2 is a block diagram of an energy storage system 100 according to an embodiment of the present invention.

[0060] Referring to FIG. 2, an energy storage system 100 according to one embodiment of the present invention may include a power generation device 110 that produces power; a battery 120 that stores power; an energy management device 140 that monitors a power production state and a power consumption state and creates an operation schedule for the battery 120; and a power conversion device 130 that controls the charging and discharging operation of the battery 120 according to the created operation schedule.

[0061] The power generation device 110 is a device configured as a demand response resource to generate electric power, and may include at least one of a power generation device using sunlight, solar heat, wind power, and geothermal heat. However, the type of the power generation device 110 is not an essential component of the present invention, and the scope of the present invention is not limited to these individual devices.

[0062] The battery 120, which serves to store power, may be embodied in a form in which a number of battery modules form a battery rack, and a number of battery racks form a battery bank. Here, the battery rack may be called a battery pack depending on the device or system in which the battery is used. A battery management system (BMS) may be provided in each battery. The BMS may monitor the current, voltage, and temperature of each battery rack (or pack) under its management, calculate a status of charge (SOC) based on the monitoring results, and control charging and discharging.

[0063] The power conversion device 130 can control the power output from the power generation device 110, the charging and discharging power of the battery 120, and the power supplied to the load 200. Here, the power conversion device 130 can control the charging and discharging operation of the battery 120 according to an operation schedule established by the energy management device 140. The power conversion device 130 can include an AC / DC inverter that converts the DC output of the power generation device 110 and the battery 120 into an AC output and supplies it to the load 200.

[0064] The energy management device 140 can collect status information on the power generation device 110, the battery 120, the power conversion device 130, the load 200, and the power system 300, and monitor each of the components. Here, the status information can include at least one of a system power supply amount, a power production amount, a power consumption amount, an operation state of the battery 120, and a charging state of the battery 120. In order to collect status information on the power resources, the energy management device 140 can be connected to a sensor capable of sensing specific status information or a management device (e.g., a BMS) of a specific power resource.

[0065] The energy management device 140 creates an operation schedule for controlling the charging and discharging operation of the battery 120. Here, the operation schedule may include information regarding the amount of charging and discharging of the battery 120 per unit time.

[0066] When a specific event occurs during the process of controlling charging and discharging the battery 120 according to the operation schedule, the energy management device 140 can adjust the operation schedule already planned in response to the event. For example, the specific event can include reception of a demand response (DR) signal or occurrence of an error between basic information and actual measurement information of the operation schedule. Meanwhile, a detailed description of the adjustment of the operation schedule in response to the demand response signal and the error will be given later.

[0067] FIG. 3 is a block diagram illustrating an example of an energy storage system according to an embodiment of the present invention.

[0068] An energy storage system 100' according to an embodiment of the present invention may be configured in a house functioning as a demand response resource, as shown in Fig. 3. Here, the power generation device may correspond to a photovoltaic (PV) system 110', and the power conversion device may be embodied by being included in an inverter 130'. The energy management device may be embodied by being included in a Home Energy Management System (HEMS) 140', which is the highest level control system in the house. The VPP grid-connected device may be embodied by being included in a VPP Provider system 400' managed by an intermediary operator providing a VPP service.

[0069] As shown in FIG. 3, the energy storage system 100' may be realized as a DC Coupled energy storage system in which a solar power generation system 110' and a battery 120' are connected to a DC line. The DC-Coupled energy storage system includes a DC / DC converter capable of individually controlling DC voltage / current in each battery rack. Thus, a DC / AC converter used for linking with the solar power generation system 110' is no longer required, and efficiency is increased. In addition, even if differences in SOC, SOH, and capacity occur between the battery racks, it is possible to control the battery power amount taking into account the characteristics of each battery. In addition, PV modules with different output bands can be integrated into one system, which is advantageous in terms of stability of the solar power generation system 110'.

[0070] Meanwhile, the energy storage system 100' shown in Fig. 3 is an example for clarifying the present invention and is not intended to limit the scope of the present invention. Unlike that shown in Fig. 3, it can be configured in various demand response resources such as buildings and factories, and some components can be added or replaced, or the connection relationship between components can be changed as necessary.

[0071] FIG. 4 is a flow diagram showing a method for operating an energy storage system according to an embodiment of the present invention.

[0072] The method of operating the energy storage system 100 according to the embodiment of the present invention may be performed by the power conversion device 130 and the energy management device 140 configured in the energy storage system 100.

[0073] The energy management device 140 collects basic information for planning an operation schedule (S410). Here, the basic information may include information on the power production state and power consumption state, and grid power cost information.

[0074] The energy management device 140 uses the collected basic information to create an operation schedule for controlling the charging and discharging operation of the battery (S420). Here, the operation schedule may include the amount of charging and discharging of the battery 120 for each unit time that minimizes the purchasing cost of grid power. In the operation schedule, the unit time may be defined in various ways as necessary, for example, as 1 hour, 10 minutes, or 10 seconds. The operation schedule may include information regarding an operation period, for example, the operation start time may be defined as 0:00 on a specific day, and the operation end time may be defined as 24:00 on the corresponding day. The energy management device 140 may derive an operation schedule that minimizes the purchasing cost of grid power by using an optimization technique using an objective function.

[0075] The power conversion device 130 controls the charging and discharging operations of the battery 120 according to the operation schedule established by the energy management device 140 (S430).

[0076] The energy management device 140 checks whether or not a demand response (DR) signal has been received during the charge / discharge control process of the battery 120 (S440).

[0077] If a demand response (DR) signal is not received, the energy management device 140 checks whether the operation end time defined in the operation schedule has passed (S450). If the operation end time has not passed, the power conversion device 130 controls the charging and discharging operation of the battery 120 according to the operation schedule (S430). If the operation end time has passed, the power conversion device 130 ends the control operation according to the corresponding operation schedule.

[0078] If a demand response (DR) signal is received, the energy management apparatus 140 adjusts the operation schedule in response to the demand response (DR) signal (S460). Here, the energy management apparatus 140 may generate control information (e.g., a discharge amount and a discharge time of the battery) of the battery 120 that satisfies the DR condition included in the demand response (DR) signal. If the performance of the demand response is completed according to the derived control information, the energy management apparatus 140 may adjust the operation schedule for the remaining period after the performance of the demand response. In this case, if the operation end time defined in the operation schedule has not passed (S450), the power conversion apparatus 130 may control the charging and discharging operation of the battery 120 according to the adjusted operation schedule (S430).

[0079] Fig. 5 is a flow diagram showing a method for creating an operation schedule according to an embodiment of the present invention. In the following, a specific embodiment of steps S410 to S420 in Fig. 4 will be described in detail with reference to Fig. 5.

[0080] The energy management device 140 collects basic information (S510). Here, the collected basic information may include battery-related parameters, grid power cost information, and information regarding power production and consumption states for a predefined first period.

[0081] Battery-related parameters may include capacity, an upper limit of SOC, a lower limit of SOC, and a set lower limit of SOC (a value determined through discussion with the VPP provider, which may represent the minimum SOC that must be maintained when performing a demand response).

[0082] The grid power cost information may include a grid power supply amount per unit time and a grid power cost per unit time.

[0083] The information on the power production state and the power consumption state may include the amount of power generated by the power generation device 110 per unit time and the amount of power consumed by the load 200 per unit time.

[0084] The first period can be defined as various ranges taking into consideration the prediction accuracy of the prediction information, for example, from one year before a specific date (n days) to one day before the date (n-1 days) in question (n days).

[0085] The energy management device 140 generates prediction information for a second period predefined as a period following the first period using the collected basic information (S520).

[0086] The forecast information may include power production forecast information and power consumption forecast information, where the power production forecast information may include a forecast power generation amount of the power generating device 110 per unit time, and the power production forecast information may include a forecast consumption amount of the load 200 per unit time.

[0087] The second period is defined as an operation period of the operation schedule, and can be defined as, for example, from 0:00 to 24:00 on a specific day (day n).

[0088] The energy management device 140 may derive pattern information including a power production pattern and a power consumption pattern based on information on a power production state and a power consumption state included in the basic information, and generate power production forecast information and power consumption forecast information using the derived pattern information. For example, the energy management device 140 may calculate average values ​​of power generation and power consumption per unit time for a one-year period, and derive a forecasted power generation and power consumption per unit time for a specific day.

[0089] The energy management apparatus 140 generates an operation schedule for the second period based on the generated forecast information (S530). Here, the energy management apparatus 140 may derive the operation schedule using an objective function defined based on MILP (Mixed-integer Linear Programming). Hereinafter, a specific embodiment of a method for generating such an operation schedule will be described in detail.

[0090] The energy management device 140 may derive an operation schedule including the charge / discharge amount of the battery 120 for each unit time by using an objective function defined by the purchasing cost of grid power. Here, the objective function may be defined as in the following Equation 1.

[0091]

number

[0092] (where:

[0093]

number

[0094] is the grid power schedule,

number

[0095] is the grid electricity cost.)

[0096] Equation 1 is an objective function for deriving the charge or discharge amount of the battery 120 per unit time, which can minimize the grid power purchasing cost. Here, the objective function according to Equation 1 may define constraint conditions including at least one of a first condition regarding the balance between power supply and power consumption, a second condition regarding the state of charge (SOC) according to the charge and discharge efficiency of the battery, a third condition regarding the limit charge amount of the battery, a fourth condition regarding the limit output of the power conversion device, and a fifth condition regarding the binarization of the charge state and the discharge state.

[0097]

number

[0098] (where:

[0099]

number

[0100] is the battery charge amount,

[0101]

number

[0102] is the amount of discharged power of the battery,

[0103]

number

[0104] is the predicted power generation,

number

[0105] is the predicted power consumption.)

[0106]

number

[0107] (Here, SOC(t) is the SOC of the battery, E cap is the battery capacity,

[0108]

number

[0109] is the charging efficiency of the power converter,

[0110]

number

[0111] is the discharge efficiency of the power converter.)

[0112]

number

[0113] (where SOC DR_Min is the lower limit of the SOC setting, SOC Max is the upper limit of SOC.)

[0114]

number

[0115] (where:

[0116]

number

[0117] is a battery state for charging value having a value of 0 or 1, P Inv_max is the maximum output of the power converter.)

[0118]

number

[0119] (where:

[0120]

number

[0121] is the battery state for discharging, which has a value of 0 or 1.

[0122]

number

[0123] The first condition can be embodied in Equation 4, where the decision variable is

[0124]

number

[0125] and

[0126]

number

[0127] It works by determining the balance between electricity supply and demand.

[0128] The second condition can be embodied in Equation 9, and functions such that the SOC in the next unit time is determined based on the battery capacity and the charge / discharge efficiency.

[0129] The third condition can be embodied in Equation 12, which functions to determine whether the SOC is within the set upper and lower limits.

[0130] The fourth and fifth conditions can be embodied in Equations 13 to 17, and the decision variables are

[0131]

number

[0132] and

[0133]

number

[0134] does not exceed the output capacity of the power conversion device 130, and at the same time, the amount of charging power and the amount of discharging power cannot be determined at the same time.

[0135] The energy management device 140 satisfies the above objective function and constraint conditions.

[0136]

number

[0137] and

[0138]

number

[0139] and generate an operation schedule including the derived formula. The objective function and constraint conditions for planning the operation schedule may have various modifications, and the scope of the present invention is not limited to the above-mentioned formula.

[0140] Fig. 6 is a flow diagram showing a method for adjusting an operation schedule for demand response (DR) according to an embodiment of the present invention. In the following, a specific embodiment of step S460 in Fig. 4 will be described in detail with reference to Fig. 6.

[0141] The energy management device 140 receives a demand response (DR) signal from the VPP grid-connected device 400 (S610). The demand response (DR) signal may include a DR condition consisting of at least one of a DR duration and a DR power amount. Here, the DR duration may indicate a power reduction operation time due to a power peak, and the DR power amount may indicate a grid power usage amount to be reduced.

[0142] The energy management device 140 performs a demand response by controlling the charging and discharging operation of the battery to satisfy the DR condition included in the DR signal regardless of the operation schedule already planned (S620). The energy management device 140 can derive control information for the battery 120 to satisfy the DR condition included in the DR signal, and can cause the battery 120 to discharge the battery by the DR power amount for the DR duration according to the derived control information.

[0143] After performing the demand response (S620), the energy management apparatus 140 re-creates the operation schedule for the remaining operation period of the operation schedule (S630). The energy management apparatus 140 may re-create the operation schedule by using the corrected objective function according to the following Equation 24. Here, the objective function according to Equation 24 may be set with the constraint conditions according to the above Equations 4 to 17.

[0144]

number

[0145] (where t DRend is the time required to complete the demand response.)

[0146] The energy management device 140 can transmit the re-planned operation schedule to the power conversion device 130 so that the charging and discharging operations of the battery 120 are controlled according to the adjusted operation schedule.

[0147] FIG. 7 is a flow diagram showing a method for adjusting an operation schedule to handle real-time errors according to an embodiment of the present invention.

[0148] Hereinafter, with reference to FIG. 7, a method for real-time adjustment of an operation schedule that can be performed after step S430 of FIG. 4 regardless of whether a DR signal is received (S440) will be described in detail.

[0149] The energy management device 140 collects actual measurement information on the power production state and power consumption state during the charge / discharge control process of the battery 120 according to the operation schedule (S710). Here, the collected actual measurement information may include actual power generation amount and actual power consumption amount per unit time.

[0150] The energy management apparatus 140 derives an error between the information on the power production state and the power consumption state included in the basic information and the collected actual measurement information (S720). Here, the energy management apparatus 140 may derive the error by calculating a difference between the predicted power generation amount and predicted power consumption amount per unit time applied to derive the operation schedule and the actual power generation amount and actual power consumption amount per unit time, as shown in the following Equation 25.

[0151]

number

[0152] The energy management device 140 adjusts the already planned operation schedule using the derived error (S730). The energy management device 140 derives an actual grid power value by the following Equation 26, and can regenerate the operation schedule by reflecting the derived actual grid power value in the objective function according to Equation 1 and the constraint conditions according to Equations 4 to 17.

[0153]

number

[0154]

number

[0155] is the actual grid power.)

[0156] The energy management device 140 can either regenerate the operation schedule for the remaining operation period after the adjustment point, or derive the charge / discharge amount of the battery 120 only for the specific unit time where the error occurred and modify only the operation schedule for that unit time.

[0157] FIG. 8 is a block diagram of an energy management device according to an embodiment of the present invention.

[0158] Hereinafter, with reference to FIG. 8, a main configuration of an energy management device 140 that performs an operation method according to an embodiment of the present invention will be described.

[0159] The energy management device 140 according to an embodiment of the present invention is a control device for the energy storage system 100 configured as a demand response resource, and may include at least one processor 141, a memory 142 for storing at least one instruction to be executed through the processor, and a transceiver 143 for communicating with other components in the energy storage system 100.

[0160] The energy management device 140 according to an embodiment of the present invention may be a power management system (PMS) or an energy management system (EMS), but the scope of the present invention is not limited to these.

[0161] The at least one instruction executed by the at least one processor may include an instruction to collect basic information including information on power production status and power consumption status and grid power cost information; an instruction to plan an operation schedule for controlling the charging and discharging operation of the battery using the collected basic information; an instruction to control the charging and discharging operation of the battery according to the planned operation schedule; and, if a demand response (DR) signal is received during the charging and discharging control process of the battery, an instruction to adjust the operation schedule in response to the DR signal.

[0162] The command to create the operation schedule may include a command to derive a charge / discharge amount of the battery for each unit time that minimizes the purchasing cost of grid power, and to reflect the charge / discharge amount in the operation schedule.

[0163] The command to create the operation schedule can include a command to derive an operation schedule including the charge / discharge amount of the battery per unit time using an objective function defined by the purchasing cost of grid power.

[0164] The above objective function can be defined with constraints including at least one of a first condition regarding the balance between power supply and power consumption, a second condition regarding the state of charge (SOC) based on the charging and discharging efficiency of the battery, a third condition regarding the limit charge amount of the battery, a fourth condition regarding the limit output of the power conversion device, and a fifth condition regarding the binarization of the charging and discharging states.

[0165] The instruction to collect the basic information may include an instruction to collect basic information including battery-related parameters, grid power cost information, and information on power production status and power consumption status for a predefined first period, wherein the instruction to develop an operation schedule may include an instruction to generate power production forecast information and power consumption forecast information for a predefined second period following the first period using the collected basic information; and an instruction to generate an operation schedule for the second period based on the generated forecast information.

[0166] When the demand response (DR) signal is received, the demand response may include an instruction to perform a demand response by controlling the charging / discharging operation of the battery to satisfy the DR duration and DR power amount included in the demand response (DR) signal, regardless of the planned operation schedule; and an instruction to re-plan an operation schedule for the remaining period after the demand response is performed.

[0167] After the instruction to control the charging and discharging operation of the battery according to the proposed operation schedule, the instruction may include an instruction to collect actual measurement information regarding the power production state and power consumption state; an instruction to derive an error between the information regarding the power production state and power consumption state contained in the basic information and the collected actual measurement information; and an instruction to adjust the operation schedule using the derived error.

[0168] The energy management device 140 may further include an input interface device 144, an output interface device 145, a storage device 146, etc. The components included in the energy management device 140 are connected to each other by a bus 147 and can communicate with each other.

[0169] Here, the processor 141 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the embodiment of the present invention is performed. The memory (or storage device) may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be composed of at least one of a read only memory (ROM) and a random access memory (RAM).

[0170] The operation of the method according to the embodiment of the present invention can be embodied as a computer readable program or code in a computer readable recording medium. The computer readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. In addition, the computer readable recording medium can be distributed to computer systems connected via a network, and the computer readable program or code can be stored and executed in a distributed manner.

[0171] Some aspects of the invention have been described in the context of an apparatus, but it may also be presented in terms of a corresponding method, where a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may be presented in terms of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0172] Although the present invention has been described with reference to preferred embodiments thereof, those skilled in the art will understand that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as set forth in the following claims. [Explanation of symbols]

[0173] 100 Energy Storage System 100' Energy Storage System 110 Power generation equipment 110' Solar Power System 120 batteries 120' battery 130 Power conversion device 130' Inverter 140 Energy Management Device 141 processors 142 Memory 143 Transmitting and Receiving Equipment 144 Input Interface Device 145 Output Interface Device 146 Storage device 147 Bus 200 Load 300 Power system 400 VPP interconnection device 400' Provider System

Claims

1. An energy storage system configured as a demand response resource connected to a virtual power plant (VPP) system, Generating equipment to produce electricity; Batteries to store electricity; An energy management device that monitors the power production and consumption states and creates an operation schedule for the battery; and A power conversion device that controls the charging and discharging operation of the battery according to the proposed operation schedule; The energy management device includes: Collect basic information including information on a power production state and a power consumption state and grid power cost information, and create an operation schedule for controlling a charge / discharge operation of a battery using the collected basic information. If a demand response (DR) signal is received during the battery charge / discharge control process according to the operation schedule, adjust the operation schedule in response to the DR signal; The energy management device includes: When the demand response (DR) signal is received, the demand response is performed by controlling the charging and discharging operation of the battery so as to satisfy the DR duration and the DR power amount included in the demand response (DR) signal regardless of the proposed operation schedule; An energy storage system that re-plans its operation schedule for the remaining period after performing a demand response.

2. The energy management device includes: The energy storage system according to claim 1 , wherein a charge / discharge amount of the battery per unit time that minimizes a purchase cost of grid power is calculated and reflected in the operation schedule.

3. The energy management device includes: The energy storage system according to claim 1 , wherein an operation schedule including the charge / discharge amount of the battery per unit time is derived using an objective function defined by the purchasing cost of grid power.

4. The objective function is:

4. The energy storage system according to claim 3, wherein the constraint conditions include at least one of a first condition related to a balance between power supply and power consumption, a second condition related to a state of charge (SOC) based on the charging and discharging efficiency of the battery, a third condition related to a limit charge amount of the battery, a fourth condition related to a limit output of a power conversion device, and a fifth condition related to binarization of the charging state and the discharging state.

5. The energy management device includes: Collect basic information including battery-related parameters, grid power cost information, and information regarding power production and consumption states for a predefined first time period; Using the collected basic information, generate power production forecast information and power consumption forecast information for a second period predefined as a period following the first period; The energy storage system of claim 1 , further comprising: generating an operation schedule for the second time period based on the generated forecast information.

6. The energy management device includes: Collecting actual measurement information regarding power production and power consumption during the battery control process according to the operation schedule; Deriving an error between information on the power production state and the power consumption state included in the basic information and the collected actual measurement information; The energy storage system of claim 1 , further comprising: adjusting the operational schedule using the derived error.

7. An energy management device configured as a demand response resource connected to a virtual power plant (VPP) system, at least one processor; a memory for storing at least one instruction to be executed by said at least one processor; The at least one instruction: An instruction to collect basic information including information on the status of electricity production and consumption and grid electricity cost information; A command to develop an operational schedule for controlling the charging and discharging operation of the battery using the collected baseline information; instructions for controlling the charging and discharging operations of the battery according to a proposed operating schedule; and When a demand response (DR) signal is received during a charge / discharge control process of the battery, a command to adjust the operation schedule in response to the demand response (DR) signal is received, the command comprising: When the demand response (DR) signal is received, a command to perform a demand response by controlling a charging / discharging operation of a battery so as to satisfy a DR duration and a DR power amount included in the demand response (DR) signal regardless of the planned operation schedule; and An order to re-plan the operation schedule for the remaining period after demand response is implemented 23. An energy management device comprising:

8. The order to formulate the operational schedule is: The energy management device according to claim 7 , further comprising a command to derive a charge / discharge amount of the battery for each unit time that minimizes a purchasing cost of grid power, and to reflect the charge / discharge amount in the operation schedule.

9. The order to formulate the operational schedule is: The energy management device according to claim 7 , further comprising a command to derive an operation schedule including a charge / discharge amount of the battery per unit time using an objective function defined by a purchasing cost of grid power.

10. The objective function is: The energy management device of claim 9, wherein constraint conditions are defined that include at least one of a first condition regarding the balance between power supply and power consumption, a second condition regarding the state of charge (SOC) based on the charging and discharging efficiency of the battery, a third condition regarding the limit charge amount of the battery, a fourth condition regarding the limit output of the power conversion device, and a fifth condition regarding the binarization of the charging state and the discharging state.

11. The command to collect the basic information is instructions for collecting baseline information including battery-related parameters, grid power cost information, and information regarding power production and consumption states for a predefined first time period; The order to formulate the operational schedule is: instructions for generating power production forecast information and power consumption forecast information for a predefined second time period using the collected baseline information, the second time period being a time period subsequent to the first time period; and The energy management apparatus of claim 7 , further comprising: instructions for generating an operational schedule for the second time period based on the generated forecast information.

12. After the instruction to control the charging and discharging operation of the battery according to the proposed operation schedule, An order to collect actual information on the state of electricity production and consumption; An instruction to derive an error between the information on the power production state and the power consumption state included in the basic information and the collected actual measurement information; and The energy management apparatus of claim 7 , further comprising: instructions for adjusting the operational schedule using a derived error.

13. A method for operating an energy storage system configured as a demand response resource connected to a virtual power plant (VPP) system, comprising: Collecting basic information including information on power production status and power consumption status and grid power cost information; A step of creating an operation schedule for controlling the charging and discharging operation of the battery using the collected basic information; Controlling the charging and discharging operations of the battery according to the proposed operation schedule; and If a demand response (DR) signal is received during a charge / discharge control process of the battery, adjusting the operation schedule in response to the demand response (DR) signal, When the demand response (DR) signal is received, performing a demand response by controlling a charging / discharging operation of a battery so as to satisfy a DR duration and a DR power amount included in the demand response (DR) signal regardless of the planned operation schedule; and re-planning an operation schedule for a remaining period after performing the demand response; A method for operating an energy storage system, comprising:

14. The step of formulating an operation schedule includes: The method for operating an energy storage system according to claim 13, further comprising the step of: deriving a charge / discharge amount of the battery for each unit time that minimizes a purchasing cost of grid power, and reflecting the charge / discharge amount in the operation schedule.

15. The step of formulating an operation schedule includes: The method for operating an energy storage system according to claim 13, comprising the step of deriving an operation schedule including a charge / discharge amount of the battery per unit time by using an objective function defined by a purchasing cost of grid power.

16. The objective function is:

16. The method of operating an energy storage system according to claim 15, wherein constraint conditions are defined including at least one of a first condition related to a balance between power supply and power consumption, a second condition related to a state of charge (SOC) based on the charging and discharging efficiency of the battery, a third condition related to a limit charge amount of the battery, a fourth condition related to a limit output of a power conversion device, and a fifth condition related to binarization of the charging state and the discharging state.

17. The step of collecting basic information includes: collecting basic information including battery-related parameters, grid power cost information, and information regarding power production and consumption states for a predefined first time period; The step of formulating an operation schedule includes: generating power production forecast information and power consumption forecast information for a second time period predefined as a time period subsequent to the first time period using the collected basic information; and The method of claim 13, further comprising: generating an operation schedule for the second time period based on the generated forecast information.

18. After the step of controlling the charging and discharging operation of the battery according to the proposed operation schedule, collecting actual measurement information regarding power production and consumption status; Deriving an error between the information on the power production state and the power consumption state included in the basic information and the collected actual measurement information; and 14. The method of claim 13, comprising: adjusting the operating schedule using the derived error.

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