Capacity configuration method of optical storage and charging and discharging station for emergency power supply

Abstract

The application discloses a light storage charging and discharging station capacity configuration method for emergency power supply, and specifically implements the following steps: determining the photovoltaic power generation installed capacity according to the roof area of important power users; determining the number of electric vehicle charging and discharging piles according to the power supply demand of important power users; calculating the energy storage capacity required by the self-provided emergency power supply of important power users during power supply interruption of a distribution network according to the load and photovoltaic power generation output characteristics of important power users; taking the maximization of the operating income of a light storage charging and discharging station operator as a target function, and taking the photovoltaic power generation installed capacity, the number of electric vehicle charging and discharging piles and the energy storage capacity of the self-provided emergency power supply as constraint conditions, establishing a light storage charging and discharging station energy storage capacity configuration model, solving the charging and discharging power of electric vehicles and the energy storage system and determining the energy storage capacity; and adjusting the energy storage capacity through checking. The method solves the problems of idle emergency power supply and poor economy during normal operation, improves energy utilization efficiency and realizes emergency resource sharing.

Description

Technical Field

[0001] This invention belongs to the field of emergency power supply configuration technology, specifically relating to a method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supplies. Background Technology

[0002] Emergency power systems are primarily designed for critical loads within the primary load category, and include self-provided power plants, diesel (gasoline, or natural gas) engine-driven generator sets, and static energy storage devices. Static energy storage devices include uninterruptible power supplies (UPS), emergency power supplies (EPS), and batteries. However, these systems suffer from issues such as idle emergency power supplies during normal operation and poor economic efficiency. Furthermore, using diesel generators can lead to carbon emissions and pollution problems. Summary of the Invention

[0003] The purpose of this invention is to provide a method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supplies, which solves the problem of emergency power shortage in scenarios of power supply interruption and ensures the power supply security and reliability of important power users.

[0004] The technical solution adopted in this invention is a method for configuring the capacity of a photovoltaic-storage charging and discharging station for emergency power supplies. The capacity of the photovoltaic-storage charging and discharging station includes the charging and discharging power of electric vehicles, the charging and discharging power of the energy storage system, and the photovoltaic power generation power. Specifically, it is implemented according to the following steps:

[0005] Step 1: Determine the photovoltaic power generation capacity based on the roof area of ​​major electricity users;

[0006] Step 2: Determine the number of electric vehicle charging and discharging stations based on the power supply needs of major electricity users;

[0007] Step 3: Calculate the required energy storage capacity of the backup emergency power supply for important power users in the event of a power outage in the distribution network, based on the load of important power users.

[0008] Step 4: Taking the maximization of revenue for the photovoltaic-storage charging and discharging station operator as the objective function, and the constraints of real-time system power balance, energy storage system operation, and photovoltaic output as conditions, establish a photovoltaic-storage charging and discharging station energy storage capacity configuration model. Input the photovoltaic power generation capacity, the number of electric vehicle charging and discharging piles, and the load data of important power users into the photovoltaic-storage charging and discharging station energy storage capacity configuration model, and solve for the charging and discharging power of electric vehicles and the charging and discharging power of the energy storage system.

[0009] Step 5: When the power supply of the distribution network is interrupted, the photovoltaic energy storage charging and discharging station serves as an emergency power source. It is determined whether the power supply of the photovoltaic energy storage charging and discharging station meets the 24-hour power demand of the important load. If it does, the capacity of the photovoltaic energy storage charging and discharging station is output. If it does not, the energy storage capacity is increased, and the process returns to step 4.

[0010] The invention is further characterized by:

[0011] Step 3 is as follows:

[0012] The backup time is determined based on the characteristics of important power users, and the typical daily load is selected from the load of important power users;

[0013] Starting from 0:00, calculate the electricity required by the typical daily load of important power users during the backup period, denoted as S0; then starting from 1:00, calculate the electricity required by the typical daily load of important power users during the backup period, denoted as S1; and so on, to obtain S2, S3...S23, the energy storage capacity required by the self-contained emergency power supply of important power users. .

[0014] In step 4, the objective function is to maximize the revenue of the photovoltaic-storage charging and discharging station operator, and the expression is:

[0015]

[0016] In the formula: For the revenue of photovoltaic energy storage charging and discharging station operators;

[0017]

[0018] in, Revenue from selling electricity to electric vehicle owners, For peak-valley arbitrage profits of energy storage systems, For electricity purchase costs, For equipment operating costs, To meet the charging load demand of electric vehicles; The unit price for power supply to operators of photovoltaic energy storage charging and discharging stations; , These are the energy storage charging and discharging powers, respectively. For time-of-use pricing in the distribution network; For the amount of electricity purchased from the power distribution company; For the actual output of photovoltaic power generation; , These are the unit operating costs for photovoltaic and energy storage, respectively. This refers to the discharge period for energy storage; The charging period for energy storage; It is 24 hours.

[0019] Step 4, system power real-time balance constraints, includes:

[0020] 1) During normal operation, the following applies:

[0021]

[0022] In the formula: As an important power load; To meet the charging load demand of electric vehicles; , These are the energy storage charging and discharging powers, respectively. For the amount of electricity purchased from the power distribution company; For the actual output of photovoltaic power generation;

[0023] 2) When the power supply from the distribution network is interrupted, then:

[0024]

[0025] In the formula: This indicates the electric vehicle is in a discharged state.

[0026] Step 4: Energy storage system operating constraints include:

[0027] 1) Power constraint, expressed as:

[0028]

[0029] In the formula: This represents the real-time remaining percentage of the energy storage capacity. As the limit of the state of charge of energy storage, based on This is determined to meet the 2-hour electricity demand of critical loads of important power users at all times; This represents the upper limit of the energy storage state of charge. This refers to the actual energy storage capacity.

[0030] 2) Due to the energy conservation constraint, during the charge-discharge cycle of the energy storage system, we have:

[0031]

[0032] in, P ch ( t () indicates the energy storage charging power. P dis ( t () indicates the energy storage discharge power;

[0033] 3) Energy storage capacity constraints, expressed as:

[0034]

[0035] In the formula: E charge Indicates the actual energy storage capacity. The maximum energy storage capacity required for backup time for critical power users;

[0036] 4) Charge and discharge power limitation constraints, expressed as:

[0037]

[0038]

[0039] In the formula: , These are the maximum charging and discharging values ​​of the energy storage system, respectively. , Residual batteries The charging and discharging state variables for a given period are 0 for non-charging and 1 for discharging.

[0040] 5) Charge / discharge state transition constraint: The battery can only operate in one of two modes, charging or discharging, as expressed as:

[0041]

[0042] In the formula: , Residual batteries The charging and discharging state variables for each time period are either 1 or 0;

[0043] Step 4, photovoltaic output constraints, include:

[0044]

[0045] In the formula: Indicates the actual output of photovoltaic power generation. This indicates the installed capacity of photovoltaic power generation.

[0046] Step 4, solving for the charging and discharging power of the electric vehicle and the energy storage system, involves using MATLAB to call the external solver CPLEX to solve for the charging and discharging power of the electric vehicle and the energy storage system.

[0047] The beneficial effects of this invention are:

[0048] This invention provides a capacity configuration method for photovoltaic energy storage charging and discharging stations for emergency power supplies, which solves the problem of emergency power shortage in scenarios of power supply interruption and ensures the power supply security and reliability of important power users.

[0049] In response to the limited, uneconomical, and polluting issues associated with existing emergency technologies during power outages in distribution networks, this invention fully utilizes the energy storage characteristics of electric vehicles, improving the utilization rate of energy storage systems for emergency use, reducing investment in emergency power equipment, decreasing carbon emissions, and enabling emergency resource sharing and complementary advantages. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the electrical structure of the photovoltaic energy storage charging and discharging station provided in an embodiment of the present invention;

[0051] Figure 2 This is a flowchart of the capacity planning strategy for photovoltaic energy storage charging and discharging stations provided in an embodiment of the present invention;

[0052] Figure 3 This is a schematic diagram of a typical daily load curve for an important power user provided in an embodiment of the present invention;

[0053] Figure 4 This is a schematic diagram of the required reserve capacity under the critical power user scenario 1 provided in the embodiments of the present invention;

[0054] Figure 5 This is a schematic diagram of the required reserve capacity under the critical power user scenario 2 provided in this embodiment of the invention;

[0055] Figure 6 This is a schematic diagram of a typical daily photovoltaic power generation curve for a rooftop building of an important power user, provided in an embodiment of the present invention.

[0056] Figure 7 This is a schematic diagram of the summer operation status of the photovoltaic energy storage charging and discharging station provided in an embodiment of the present invention;

[0057] Figure 8 This is a schematic diagram of the winter operation status of the photovoltaic energy storage charging and discharging station provided in an embodiment of the present invention;

[0058] Figure 9 This is a schematic diagram of the emergency operation status of the photovoltaic energy storage charging and discharging station in summer, provided in an embodiment of the present invention.

[0059] Figure 10 This is a schematic diagram of the emergency operation status of the photovoltaic energy storage charging and discharging station in winter, provided in an embodiment of the present invention. Detailed Implementation

[0060] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0061] Vehicle-to-grid (V2G) electric vehicles, as an important demand-side flexibility resource, possess energy storage and controllability, and can provide ancillary services such as peak shaving, frequency regulation, system backup, and automatic generation control (AGC) for the system. A photovoltaic-storage charging station, consisting of electric vehicle charging facilities, photovoltaic power generation, and energy storage, can utilize energy storage to improve the absorption rate of photovoltaic power generation during normal operation. It can also serve as an emergency power source when the power grid is interrupted, improving energy utilization efficiency, offering good economic benefits, and reducing carbon emissions.

[0062] In this invention, important power users refer to power-consuming units or places with special requirements for power supply reliability that occupy an important position in the social, political, and economic life of a country or a region (city), and whose power outages may cause personal injury or death, significant environmental pollution, significant political impact, significant economic losses, or serious disruption to public order. The classification and scope of important power users are detailed in GB / T29328—2018 Technical Specification for Configuration of Power Supply and Backup Emergency Power Supply for Important Power Users.

[0063] In the event of a power outage in the distribution network, the photovoltaic-storage charging and discharging station serves as an emergency power source to verify its ability to meet the power load demands of important electricity users (considering photovoltaic power generation output and electric vehicle discharge).

[0064] If the required capacity is insufficient in an emergency, the energy storage capacity needs to be re-evaluated under normal power supply conditions of the distribution network; otherwise, it is not necessary.

[0065] This invention provides a capacity configuration method for photovoltaic-storage charging and discharging stations for emergency power supplies. It verifies the emergency power supply capacity under power outage scenarios, ensuring the power supply security and reliability for critical power users. This solution fully utilizes the energy storage characteristics of electric vehicles, improves the utilization rate of energy storage systems used for emergencies, reduces investment in emergency power equipment, reduces carbon emissions, and enables emergency resource sharing and complementary advantages. The capacity of the photovoltaic-storage charging and discharging station includes the charging and discharging power of electric vehicles, the charging and discharging power of the energy storage system, and the photovoltaic power generation power. The specific implementation steps are as follows:

[0066] Step 1: Determine the photovoltaic power generation capacity based on the roof area of ​​major electricity users;

[0067] Step 2: Determine the number of electric vehicle charging and discharging stations based on the power supply needs of major electricity users;

[0068] Step 3: Based on the load characteristics of key power users and the output characteristics of photovoltaic power generation, calculate the energy storage capacity required for the backup emergency power supply of key power users when the power distribution network is interrupted; the specific process is as follows:

[0069] The backup time is determined based on the characteristics of important power users, and the typical daily load is selected from the load of important power users;

[0070] Starting from 0:00, calculate the electricity required by the typical daily load of important power users during the backup period, denoted as S0; then starting from 1:00, calculate the electricity required by the typical daily load of important power users during the backup period, denoted as S1; and so on, to obtain S2, S3...S23, the energy storage capacity required by the self-contained emergency power supply of important power users. .

[0071] Step 4: Taking the maximization of revenue for the photovoltaic-storage charging and discharging station operator as the objective function, and using real-time system power balance constraints, energy storage system operation constraints, and photovoltaic output constraints as constraints, establish a photovoltaic-storage charging and discharging station energy storage capacity configuration model. Input photovoltaic power generation capacity, number of electric vehicle charging and discharging piles, and load data of important power users into the photovoltaic-storage charging and discharging station energy storage capacity configuration model, and use MATLAB to call the external solver CPLEX to solve the charging and discharging power of electric vehicles and energy storage systems to achieve energy storage capacity optimization.

[0072] Taking the maximization of revenue for photovoltaic-storage-charging-discharging station operators as the objective function, the expression is:

[0073]

[0074] In the formula: For the revenue of photovoltaic energy storage charging and discharging station operators;

[0075]

[0076] in, Revenue from selling electricity to electric vehicle owners, For peak-valley arbitrage profits of energy storage systems, For electricity purchase costs, For equipment operating costs, To meet the charging load demand of electric vehicles; The unit price for power supply to operators of photovoltaic energy storage charging and discharging stations; , These are the energy storage charging and discharging powers, respectively. For time-of-use pricing in the distribution network; For the amount of electricity purchased from the power distribution company; For the actual output of photovoltaic power generation; , These are the unit operating costs for photovoltaic and energy storage, respectively. This refers to the discharge period for energy storage; The charging period for energy storage; It is 24 hours.

[0077] The specific constraints are as follows:

[0078] (1) Real-time power balance constraints of the system:

[0079] 1) During normal operation, the following applies:

[0080]

[0081] In the formula: As an important power load; To meet the charging load demand of electric vehicles; , These are the energy storage charging and discharging powers, respectively. For the amount of electricity purchased from the power distribution company; For the actual output of photovoltaic power generation;

[0082] 2) When the power supply from the distribution network is interrupted, then:

[0083]

[0084] In the formula: The electric vehicle is in a discharged state;

[0085] (2) Energy storage system operation constraints:

[0086] 1) Power constraint, expressed as:

[0087]

[0088] In the formula: This represents the real-time remaining percentage of the energy storage capacity. This is the upper limit of the state of charge of energy storage, and its value is based on... This is determined to meet the 2-hour electricity demand of critical loads of important power users at all times; This represents the upper limit of the energy storage state of charge. This represents the actual energy storage capacity.

[0089] 2) The energy conservation constraint is expressed as:

[0090]

[0091] During the charge and discharge cycle, the energy storage charging power of the energy storage system is equal to the energy storage discharging power.

[0092] 3) Capacity constraint, expressed as:

[0093]

[0094] In the formula: The maximum energy storage capacity required for backup time for critical power users;

[0095] 4) Charge and discharge power limitation constraints, expressed as:

[0096]

[0097]

[0098] In the formula: , These are the maximum charging and discharging values ​​of the energy storage system, respectively. , Residual batteries The charging and discharging state variables for a given period are 0 for non-charging and 1 for discharging.

[0099] 5) Charge / discharge state transition constraints, expressed as:

[0100]

[0101] In the formula: , Residual batteries The charging and discharging state variables for each time period are either 1 or 0;

[0102] (3) Photovoltaic output constraint, expressed as:

[0103]

[0104] In the formula: This indicates the installed capacity of photovoltaic power generation.

[0105] Step 5: When the power supply of the distribution network is interrupted, the photovoltaic-storage charging and discharging station is used as an emergency power source. The system checks whether the power supply of the photovoltaic-storage charging and discharging station meets the 24-hour power demand of important loads (considering photovoltaic power generation output and electric vehicle discharge). If it meets the requirements, the capacity of the photovoltaic-storage charging and discharging station is output. If it does not meet the requirements, the energy storage capacity in the constraints is increased (e.g., 100kWh of energy storage capacity is increased) and the calculation is repeated.

[0106] Example

[0107] like Figure 1 The diagram shown illustrates the electrical structure of a typical photovoltaic-storage charging and discharging station according to the method of this invention. It includes a power distribution system, photovoltaic power generation, energy storage, an electric vehicle charging and discharging station, and local loads within the service area (taking a hospital as an example). The photovoltaic-storage charging and discharging station of this invention operates in two states: normal operation and emergency operation when the power distribution network is interrupted. The specific operation is implemented according to the following process:

[0108] During normal operation:

[0109] The hospital is primarily powered by the power distribution network. Photovoltaic power generation supplies power to the photovoltaic-storage charging and discharging station, with any shortfall obtained from the distribution network. Backfeeding from photovoltaic power generation to the distribution network is not considered. When the actual output of photovoltaic power generation exceeds the charging demand of electric vehicles, it charges the energy storage batteries. When the actual output of photovoltaic power generation is lower than the charging demand of electric vehicles, and the state of charge of the energy storage batteries meets the discharge conditions, the energy storage system, in conjunction with the distribution network, provides the necessary power to the electric vehicle charging load.

[0110] Emergency operating status during power outage in the distribution network:

[0111] Energy storage can meet the hospital's backup power needs for 2 hours, while photovoltaic power generation and electric vehicle discharge can serve as emergency power sources to meet the hospital's 24-hour power needs.

[0112] like Figure 2 As shown, the specific implementation steps are as follows:

[0113] First, based on the hospital's roof area, the installed capacity of photovoltaic power generation was determined to be 600 kWh, and the maximum output curve of its photovoltaic array is shown below. Figure 3 As shown.

[0114] Secondly, consider two extreme scenarios: Scenario 1, a power outage occurs at night when there is no photovoltaic power generation; Scenario 2, extreme weather occurs during the day (rain or snow, photovoltaic output is only 0.38 times that of a sunny day) and the power outage occurs. The energy storage capacity required for the hospital's backup time is obtained using a piecewise integral method.

[0115] Calculate the required energy storage capacity for hospital backup time under the following scenarios: power outage at night with no photovoltaic output, and low photovoltaic output during the day due to extreme weather. Simulation results are as follows: Figure 4 , Figure 5 What I saw.

[0116] Figure 4 , Figure 5 These are schematic diagrams illustrating the required backup capacity for hospital scenarios 1 and 2, respectively. Figure 4 , Figure 5 As can be seen, Scenario 2 is the most unfavorable operating condition, and the maximum backup capacity of 3600kWh in Scenario 2 is taken as the constraint condition for energy storage capacity.

[0117] Secondly, the number of electric vehicle charging stations will be determined based on the hospital's power supply needs. For scenario 2, ensuring power supply to the hospital's critical loads (70% of daily load) will be provided by... Figure 6 The maximum power requirement of the hospital can be determined. Taking a 4:1 ratio of slow charging to fast charging in the photovoltaic-storage charging and discharging station as an example, the fast charging power is 30kW, the slow charging power is 7.2kW, and the discharge efficiency is 0.9. Based on the hospital's building area and parking space allocation regulations, and considering that the charging facilities need to reserve a 10% margin, the number of electric vehicle charging and discharging piles is determined to be 130.

[0118] Finally, the simulation model parameters are substituted into the method of this invention, and the constraint conditions are considered. The solution is then obtained using the CPLEX solver. The simulation results are as follows: Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown.

[0119] The objective function is:

[0120]

[0121] In the formula: For the revenue of photovoltaic energy storage charging and discharging station operators;

[0122]

[0123] in, Revenue from electricity sales to electric vehicle owners, For peak-valley arbitrage profits of energy storage systems, For electricity purchase costs, For equipment operating costs. To meet the charging load demand of electric vehicles; The unit price for power supply to operators of photovoltaic energy storage charging and discharging stations; , These are the energy storage charging and discharging powers, respectively. For time-of-use pricing in the distribution network; For the amount of electricity purchased from the power distribution company; For the actual output of photovoltaic power generation; , These are the unit operating costs for photovoltaic and energy storage, respectively. This refers to the discharge period for energy storage; The charging period for energy storage; It is 24 hours.

[0124] The constraints are as follows:

[0125] (1) Real-time power balance constraints of the system

[0126] 1) Normal operation

[0127]

[0128] In the formula: As an important power load; To meet the charging load demand of electric vehicles; , These are the energy storage charging and discharging powers, respectively. For the amount of electricity purchased from the power distribution company; This contributes to the actual output of photovoltaic power generation.

[0129] 2) When the power supply from the distribution network is interrupted

[0130]

[0131] In the formula: This indicates the electric vehicle is in a discharged state.

[0132] (2) Operational constraints of energy storage systems

[0133] 1) Power constraint, expressed as:

[0134]

[0135] In the formula: This represents the real-time remaining percentage of the energy storage capacity. This is the upper limit of the state of charge of energy storage, and its value is based on... This is determined to meet the 2-hour electricity demand of critical loads of important power users at all times; This represents the upper limit of the energy storage state of charge. This represents the actual energy storage capacity.

[0136] 2) The energy conservation constraint is expressed as:

[0137]

[0138] The amount of charge a storage system generates is equal to the amount of discharge during a charge-discharge cycle.

[0139] 3) Capacity constraint, expressed as:

[0140]

[0141] In the formula: The maximum energy storage capacity required for backup time for critical power users;

[0142] 4) Charge and discharge power limitation constraints, expressed as:

[0143]

[0144]

[0145] In the formula: , These are the maximum charging and discharging values ​​of the energy storage system, respectively. , Residual batteries The charging and discharging state variables for a given period are 0 for non-charging and 1 for discharging.

[0146] 5) Charge / discharge state transition constraints, expressed as:

[0147]

[0148] In the formula: , Residual batteries The charging and discharging state variables for each time period are either 1 or 0;

[0149] (3) Photovoltaic output constraints

[0150]

[0151] In the formula: This indicates the installed capacity of photovoltaic power generation.

[0152] like Figure 7 , Figure 8 The figure shows the energy exchange between different photovoltaic outputs and power distribution networks, energy storage, and electric vehicle charging loads in summer and winter. The vertical axis represents positive power generation and negative power absorption. The figure also shows the sources of electricity supply and the power balance at various times.

[0153] contrast Figure 7 and Figure 8 It is evident that due to the long hours of sunshine and high radiation intensity in summer, the actual output of photovoltaic power generation is sufficient. However, the duration and intensity of sunshine are significantly reduced in winter, resulting in an increase in the amount of electricity purchased from the distribution network compared to summer, and a decrease in the revenue of photovoltaic-storage-charging-discharging stations.

[0154] The operating indicators of the photovoltaic-storage charging and discharging station in summer and winter are shown in Table 1:

[0155] Table 1

[0156]

[0157] As shown in Table 1, the energy storage capacity constraint must meet the condition that the hospital requires a backup capacity of 3600kWh. Therefore, the energy storage system configuration capacity of the photovoltaic-storage-charging-discharging station belonging to the hospital is 3700kWh.

[0158] like Figure 9 , Figure 10 The diagrams shown illustrate the operational status of a hospital's photovoltaic-storage charging and discharging station under emergency conditions. Taking a power outage starting at midnight as an example, the power distribution network is interrupted, and extreme weather (such as rain or snow) occurs during the day. At this time, electric vehicles and energy storage units within the photovoltaic-storage charging and discharging station provide backup capacity. In this state, electric vehicles, acting as load-reducing and energy storage components, provide power balance support through V2G discharge when the energy storage units cannot meet the hospital's power supply balance; the energy storage capacity can meet the hospital's backup power demand (2 hours). During this period, information on the hospital's power demand and incentive measures can be disseminated through media and other channels to meet the hospital's power demand in subsequent periods. During the transition period of charging pile construction or when there are insufficient electric vehicles participating in the discharge, some charging and discharging piles in the photovoltaic-storage charging and discharging station may discharge; therefore, the scenario is set as follows:

[0159] 1) Scenario 3: All charging and discharging piles participate in the discharge.

[0160] 2) Scenario 4: Only 70 charging and discharging piles participate in the discharge.

[0161] Depend on Figures 9-10 It can be seen that when the power distribution network is unable to supply power, and in rainy or snowy weather, electric vehicles combined with energy storage can provide continuous power to the hospital's critical loads.

[0162] The benefits obtained by electric vehicle owners mainly include load reduction compensation and power battery discharge compensation. The discharge benefits of a single charging and discharging pile for 24 hours and the backup time (2 hours) in emergency situations, as well as the maximum discharge capacity of the energy storage system, are shown in Table 2.

[0163] Table 2

[0164]

[0165] As shown in Table 2, the energy storage system with a capacity of 3700 kWh meets the emergency power supply requirements. It should be noted that the photovoltaic output on sunny days is greater than that during extreme weather (such as rain and snow), therefore, the capacity also meets the requirements on sunny days.

[0166] Under scenario 4, taking winter as an example, what is the hospital's longest operating time? The energy storage capacity configured under Scenario 4 is insufficient to meet the hospital's 24-hour power demand, which is 9 hours. The energy storage capacity is increased, and the capacity is recalculated to meet the hospital's 24-hour power demand, resulting in a capacity of 9200 kWh.

[0167] Furthermore, the configuration results of traditional emergency power supplies such as EPS mobile generators, diesel generators, and UPS uninterruptible power supplies are compared with the method of the present invention.

[0168] Taking the hospital as an application scenario of the method of this invention, the capacity and cost of traditional emergency power supply equipment are shown in Table 3:

[0169] Table 3

[0170]

[0171] Table 3 shows that diesel generators have the highest cost, at 59.2046 million yuan, due to the additional fuel and environmental costs associated with them. Since the maximum emergency energy storage capacity is 1893.56 kWh, while the hospital's maximum backup capacity is 3600 kWh, the economic analysis only needs to consider the initial investment and operation and maintenance costs of the additional 1900 kWh of energy storage and 600 kW of photovoltaic power. Electric vehicles are primarily used for transportation and only generate revenue through V2G technology in emergency situations; therefore, their purchase cost is not considered. The results indicate that the configuration method of this invention has the lowest cost and brings more significant economic benefits.

[0172] Through the above examples, this invention provides a method for configuring the capacity of photovoltaic energy storage charging and discharging stations for emergency power supplies. This method has the lowest cost and can bring considerable economic benefits. It avoids problems such as idle emergency power supplies, poor economic efficiency, and pollution and carbon emissions. This invention makes full use of the energy storage characteristics of electric vehicles, improves the utilization rate of energy storage systems used for emergency response, reduces investment in emergency power supply equipment, reduces carbon emissions, and enables emergency resource sharing and complementary advantages.

Claims

1. A method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supplies, characterized in that, The capacity of the photovoltaic-storage charging and discharging station includes the charging and discharging power of electric vehicles, the charging and discharging power of the energy storage system, and the photovoltaic power generation power, which will be implemented according to the following steps: Step 1: Determine the photovoltaic power generation capacity based on the roof area of ​​major electricity users; Step 2: Determine the number of electric vehicle charging and discharging stations based on the power supply needs of major electricity users; Step 3: Calculate the required energy storage capacity of the backup emergency power supply for important power users in the event of a power outage in the distribution network, based on the load of important power users. Step 4: Taking the maximization of revenue for the photovoltaic-storage charging and discharging station operator as the objective function, and the constraints of real-time system power balance, energy storage system operation, and photovoltaic output as conditions, establish a photovoltaic-storage charging and discharging station energy storage capacity configuration model. Input the photovoltaic power generation capacity, the number of electric vehicle charging and discharging piles, and the load data of important power users into the photovoltaic-storage charging and discharging station energy storage capacity configuration model, and solve for the charging and discharging power of electric vehicles and the charging and discharging power of the energy storage system. The objective function described in step 4, which is to maximize the revenue of the photovoltaic-storage charging and discharging station operator, is expressed as: In the formula: For the revenue of photovoltaic energy storage charging and discharging station operators; in, Revenue from selling electricity to electric vehicle owners, For peak-valley arbitrage profits of energy storage systems, For electricity purchase costs, For equipment operating costs, To meet the charging load demand of electric vehicles; The unit price for power supply to operators of photovoltaic energy storage charging and discharging stations; , These are the energy storage charging and discharging powers, respectively. For time-of-use pricing in the distribution network; For the amount of electricity purchased from the power distribution company; For the actual output of photovoltaic power generation; , These are the unit operating costs for photovoltaic and energy storage, respectively. This refers to the discharge period of energy storage; The charging period for energy storage; For 24 hours; Step 5: When the power supply of the distribution network is interrupted, the photovoltaic energy storage charging and discharging station serves as an emergency power source. It is determined whether the power supply of the photovoltaic energy storage charging and discharging station meets the 24-hour power demand of the important load. If it does, the capacity of the photovoltaic energy storage charging and discharging station is output. If it does not, the energy storage capacity is increased, and the process returns to step 4.

2. The method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supply according to claim 1, characterized in that, Step 3 is as follows: The backup time is determined based on the characteristics of important power users, and the typical daily load is selected from the load of important power users; Starting from 0:00, calculate the electricity required by the typical daily load of important power users during the backup period, denoted as S0; then starting from 1:00, calculate the electricity required by the typical daily load of important power users during the backup period, denoted as S1; and so on, to obtain S2, S3...S23, the energy storage capacity required by the self-contained emergency power supply of important power users. .

3. The method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supply according to claim 1, characterized in that, The real-time power balance constraints of the system mentioned in step 4 include: 1) During normal operation, the following applies: In the formula: As an important power load; To meet the charging load demand of electric vehicles; , These are the energy storage charging and discharging powers, respectively. For the amount of electricity purchased from the power distribution company; For the actual output of photovoltaic power generation; 2) When the power supply from the distribution network is interrupted, then: In the formula: This indicates the electric vehicle is in a discharged state.

4. The method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supply according to claim 1, characterized in that, The operational constraints of the energy storage system mentioned in step 4 include: 1) Power constraint, expressed as: In the formula: This represents the real-time remaining percentage of the energy storage capacity. As the limit of the state of charge of energy storage, based on This is determined to meet the 2-hour electricity demand of critical loads of important power users at all times; This represents the upper limit of the energy storage state of charge. This refers to the actual energy storage capacity. 2) Due to the energy conservation constraint, during the charge-discharge cycle of the energy storage system, we have: in, P ch ( t () indicates the energy storage charging power. P dis ( t () indicates the energy storage discharge power; 3) Energy storage capacity constraints, expressed as: In the formula: E charge Indicates the actual energy storage capacity. The maximum energy storage capacity required for backup time for critical power users; 4) Charge and discharge power limitation constraints, expressed as: In the formula: , These are the maximum charging and discharging values ​​of the energy storage system, respectively. , Residual batteries The charging and discharging state variables for a given period are 0 for non-charging and 1 for discharging. 5) Charge / discharge state transition constraint: The battery can only operate in one of two modes, charging or discharging, as expressed as: In the formula: , Residual batteries The charging and discharging state variables for each time period are either 1 or 0.

5. The method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supply according to claim 1, characterized in that, The photovoltaic output constraints mentioned in step 4 include: In the formula: Indicates the actual output of photovoltaic power generation. This indicates the installed capacity of photovoltaic power generation.

6. The method for configuring the capacity of a photovoltaic energy storage charging and discharging station for emergency power supply according to claim 1, characterized in that, Step 4, which involves solving for the charging and discharging power of the electric vehicle and the energy storage system, specifically involves using MATLAB to call the external solver CPLEX to solve for the charging and discharging power of the electric vehicle and the energy storage system.

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