Distributed collaborative operation method for smart city energy hub

Abstract

The invention provides a smart city energy hub distributed collaborative operation method, and belongs to the technical field of energy management, and the method comprises the steps: building operation models of various energy devices in a building energy hub, calculating an electric energy gap and a heat energy gap of the energy hub based on the operation models of the energy devices, the transaction range is determined; within the transaction range, calculating the marginal cost of energy, and achieving point-to-point transaction with the purpose of minimizing the operation cost of an energy hub; calculating the transmission loss of the point-to-point energy transaction, and calculating the common income of the two parties of the point-to-point transaction based on the transmission loss of the point-to-point And after all point-to-point energy transactions are achieved in a single transaction period, constructing a constraint condition of transmission loss, recalculating the optimal power flow of the whole energy microgrid, and minimizing the transmission loss. And the total transaction income of the energy hub in the transaction period is optimal.

Description

Technical Field

[0001] This invention belongs to the field of energy management technology, and in particular relates to a distributed collaborative operation method for smart city energy hubs. Background Technology

[0002] Building energy hubs, as important nodes in urban energy networks, enable the coordinated supply of various energy forms such as electricity and heat. Existing technologies typically employ centralized energy management strategies, using a central controller to coordinate equipment operation to meet building energy demands.

[0003] In the energy trading sector, existing solutions primarily rely on the power grid and heating systems to compensate for energy gaps. Some advanced systems incorporate energy storage devices to mitigate supply and demand fluctuations and optimize local equipment operation through pre-defined scheduling strategies. For example, by predicting renewable energy output and combining it with the charging and discharging characteristics of energy storage, electricity can be stored during off-peak hours and discharged during peak hours, thereby reducing energy costs.

[0004] However, existing technologies have significant limitations: their energy trading mechanisms do not fully consider energy losses during point-to-point transmission, leading to deviations in transaction revenue calculations; furthermore, due to the lack of quantitative assessment and constraint optimization of transmission losses, it is difficult to maximize total revenue during cross-hub collaborative operations. This extensive trading model restricts the improvement of the economic efficiency of distributed energy hubs. Summary of the Invention

[0005] This invention provides a distributed collaborative operation method for smart city energy hubs, which at least solves the problem that the energy trading mechanism in the prior art does not fully consider the energy loss in the point-to-point transmission process, resulting in deviations in the calculation of trading revenue.

[0006] This application provides a distributed collaborative operation method for a smart city energy hub, the method comprising: Establish an operational model for various energy devices in a building energy hub, including photovoltaic modules, wind turbines, hydrogen fuel cells, gas generator sets, heat pumps, gas boilers, energy storage batteries, and thermal storage tanks; The electricity gap and heat gap of the energy hub are calculated based on the operation model of the energy equipment, thereby determining the scope of the transaction; Within the scope of the transaction, the marginal cost of energy is calculated, and the goal is to minimize the operating cost of the energy hub to achieve peer-to-peer transactions; Calculate the transmission loss of peer-to-peer energy transactions, and calculate the shared benefits of both parties in the peer-to-peer transaction based on the transmission loss of peer-to-peer energy transactions; After all point-to-point energy transactions are completed within a single trading cycle, constraints on transmission losses are constructed, the optimal power flow of the entire energy microgrid is recalculated, transmission losses are minimized, and the total trading revenue of the energy hub within this trading cycle is optimized.

[0007] Furthermore, the expression for the operating model of photovoltaic modules is as follows:

[0008] in, It is the power output of the photovoltaic module. It refers to the installed capacity of photovoltaic modules. It refers to solar radiation that reaches the photovoltaic module; The expression for the operating model of a wind turbine is:

[0009] in, It is the electrical energy output of the wind turbine. It refers to the installed capacity of the wind turbine. It is the wind speed through the plane of the wind turbine blades; The expression for the operating model of a hydrogen fuel cell is as follows:

[0010]

[0011]

[0012]

[0013]

[0014] in, It is the electrical energy output of the hydrogen fuel cell. It refers to the installed capacity of hydrogen fuel cells. It is the loading rate of hydrogen fuel cells. It is the hydrogen energy input of hydrogen fuel cells. It is the thermal energy output of the hydrogen fuel cell; The expression for the operating model of the gas generator set is:

[0015]

[0016]

[0017]

[0018]

[0019] In the formula, For the electrical energy output of the gas generator set, For the installed capacity of natural gas generator sets, For the load factor of the gas-fired power generation unit, For natural gas energy input to the gas generator set, For the thermal energy output of the gas generator set; The expression for the operating model of a heat pump is:

[0020]

[0021]

[0022] In the formula, For the heat energy output of the heat pump, For the installed capacity of the heat pump, For heat pump load rate, For heat pump electrical energy input; The expression for the operating model of a gas-fired boiler is as follows:

[0023]

[0024]

[0025] In the formula, For the heat energy output of the gas-fired boiler, For the installed capacity of the gas-fired boiler, For gas-fired boiler load rate, Natural gas energy input for the gas cooker; The expression for the operating model of energy storage batteries is:

[0026]

[0027]

[0028] in, It refers to the state of charge of the energy storage battery. It refers to the load rate of the energy storage battery. It refers to the electrical energy input or output of an energy storage battery. It refers to the installed capacity of energy storage batteries; The expression for the operating model of the thermal storage tank is:

[0029]

[0030]

[0031] in, It refers to the state of charge of the thermal storage tank. For the load rate of the thermal storage tank, For the thermal energy input or output of the thermal storage box. This refers to the installed capacity of the thermal storage tank.

[0032] Furthermore, the expression for the electrical energy gap of the energy hub is:

[0033] in, It is the power shortage in the energy hub. It is the building's electrical energy consumption; The expression for the thermal energy gap of the energy hub is:

[0034] in, It is a thermal energy gap in the energy hub. It refers to the building's heat energy consumption.

[0035] Furthermore, based on the operating model of the energy equipment, the electricity gap and heat gap of the energy hub are calculated to determine the scope of the transaction, specifically including: An energy consumption cost model for an energy hub is constructed based on the operating model of energy equipment, the electricity gap of the energy hub, and the heat gap of the energy hub. A carbon emission model for an energy hub is constructed based on the operating model of energy equipment, the electricity gap of the energy hub, and the heat gap of the energy hub. The scope of transactions is determined based on the electricity gap and thermal gap of the energy hub.

[0036] Furthermore, the energy consumption cost model for the energy hub is expressed as follows:

[0037] in, It is the energy consumption cost of the energy hub. It's the energy price of hydrogen. It refers to the energy price of natural gas. It is the energy price of electricity. It is the energy price of thermal energy; The expression for the carbon emission model of the energy hub is:

[0038] in, It is the carbon emission cost of the energy hub. It is the carbon emission coefficient of natural gas. It is the carbon emission coefficient of electricity. It is the carbon emission coefficient of thermal energy; The operating cost of an energy hub is calculated based on its energy consumption cost model and carbon emission model. The expression for the operating cost of an energy hub is as follows:

[0039] in, It is the operating cost of the energy hub. It is the operating cost of the energy hub; The expression for the marginal cost of electricity is:

[0040] The expression for the marginal cost of thermal energy is:

[0041] The expressions for the marginal cost of the package are as follows: .

[0042] Furthermore, the scope of the transaction is determined based on the electricity gap and heat gap of the energy hub, specifically including: The upper limit of the power deficit of the energy hub is determined by the following expression:

[0043] in, It is the upper limit of the power shortage of the energy hub. That is the maximum power generation capacity of hydrogen fuel cells. This is the maximum power generation capacity of the gas generator set. This is the maximum power generation capacity of the energy storage battery. This is the minimum power consumption capacity of a heat pump; The lower limit of the energy gap of the energy hub is determined by the following expression:

[0044] in, It is the lower limit of the power shortage in the energy hub. This is the minimum power generation capacity of a hydrogen fuel cell. This is the minimum power generation capacity of a gas generator set. This is the minimum power generation capacity of an energy storage battery. This is the maximum power consumption capacity of the heat pump; Based on the upper limit and lower limit of the energy gap of the energy hub, the trading scope of the energy hub's electricity is determined as follows: .

[0045] Furthermore, determining the trading scope based on the electricity gap and heat gap of the energy hub also includes: The upper limit of the thermal energy gap of the energy hub is determined by the following expression:

[0046] in, It is the upper limit of the thermal energy gap of the energy hub. This is the maximum heating capacity of the heat pump. This is the maximum heating capacity of the gas-fired boiler. This is the maximum heating capacity of the thermal storage tank; The lower limit of the thermal energy gap of the energy hub is determined by the following expression:

[0047] in, It is the lower limit of the thermal energy gap of the energy hub. This is the minimum heat output of the heat pump. This is the minimum calorific value of a gas-fired boiler. It is the minimum heat output of the thermal storage tank; Based on the upper limit and lower limit of the thermal energy gap of the energy hub, the trading range of thermal energy of the energy hub is determined as follows: .

[0048] Furthermore, the calculation of transmission losses in peer-to-peer energy transactions specifically includes: Calculating the energy loss in peer-to-peer energy trading specifically includes: The energy loss of the cable is calculated, and the energy loss in point-to-point energy trading is calculated based on the cable's energy loss. The expression is as follows:

[0049] in, It is the energy loss in peer-to-peer energy trading. It is the collection of all cables along the shortest power supply path; This is the energy loss of a single cable, expressed as:

[0050] in, It is the branch resistance. It is a branch reactor. It is the branch voltage. It is the active power of the branch circuit. It is the reactive power of the branch circuit; The expression for calculating heat transfer losses in point-to-point energy trading based on heat loss in thermal pipelines is as follows:

[0051] in, It refers to the heat transfer loss in point-to-point energy trading. and It is the collection of all heat pipes along the shortest heating path and the shortest heat return path, respectively; This is the heat loss of a single cable, expressed as:

[0052] in, It is the branch circuit thermal resistance. It is the branch temperature. It is the branch circuit thermal power.

[0053] Furthermore, the shared benefit between the two parties in a peer-to-peer energy transaction is calculated based on the transmission loss of the transaction, and its expression is as follows:

[0054] in, It is a shared benefit for both parties in a peer-to-peer transaction. It is the electricity price sold by the power grid. It is the price of heat sold by the heating system.

[0055] Furthermore, after all peer-to-peer energy transactions are completed within a single trading cycle, constraints on transmission losses are constructed, and the optimal power flow of the entire energy microgrid is recalculated to minimize transmission losses, including: The constraints for the electrical energy flow are expressed as follows:

[0056]

[0057] in, This represents the square of the branch current. It is the square of the voltage; The constraints for the thermal energy flow are expressed as follows:

[0058]

[0059] in, This indicates the volumetric flow rate of hot water. It is the specific heat capacity of water; The energy loss of a smart city microgrid is calculated as the sum of the energy losses from all cables and pipes after all energy transactions have been offset. Its expression is:

[0060] in, It is the energy loss of smart city micro-energy grids. It is a collection of all cables and pipes; The operating cost of a smart city microgrid is calculated as the sum of energy losses from all cables and conduits after all electricity transactions have been offset. The expression for this cost is:

[0061] in, It is the operating cost of a smart city microgrid. It refers to the number of energy hubs. It is the electricity price sold by the power grid. It is the price of heat sold by the heating system; The expression for calculating the point-to-point transaction cost of imported energy at the energy hub is as follows:

[0062] in, This indicates the cost of point-to-point transactions for imported energy at the energy hub. It's the cost of importing electricity. It is the cost of importing thermal energy; The total transaction revenue and transaction fees of the energy hub are the sum of all peer-to-peer transaction orders, expressed as:

[0063] in, This represents the total transaction revenue and transaction fees of the energy hub. It is the collection of all transaction orders in the energy center; The total transaction revenue of an energy hub during this trading cycle is calculated based on its total transaction revenue and transaction fees. The expression for this calculation is as follows:

[0064] in, This represents the total trading revenue of the energy hub during this trading cycle.

[0065] As can be seen from the above technical solutions, the present invention has the following advantages: The distributed collaborative operation method for smart city energy hubs provided in this application solves the problem of neglecting transmission loss in existing technologies by calculating the electrical and thermal losses in point-to-point energy transactions. Based on cable resistance, reactance parameters, and pipeline thermal resistance characteristics, it accurately quantifies the energy loss in the transaction process, providing a true basis for calculating shared benefits.

[0066] This application solves the problem of inaccurate definition of the trading scope in the prior art by establishing precise operation models of energy equipment such as photovoltaics, wind turbines, and hydrogen fuel cells, and constructing power and heat gaps. By quantifying the maximum / minimum power generation and energy consumption capacity of the equipment, the trading boundary is dynamically determined, providing a precise energy supply and demand matching basis for point-to-point transactions.

[0067] This application solves the problem of minimizing transmission loss by constructing electrical / thermal energy flow constraints, and generates low-loss energy transmission paths through optimization algorithms, thereby improving the total transaction revenue of energy hubs. Attached Figure Description

[0068] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0069] Figure 1 This is a schematic diagram of the energy hub structure for a smart city.

[0070] Figure 2 A schematic diagram of a blockchain for energy trading in a smart city microgrid.

[0071] Figure 3 This is a typical case study of a smart city microgrid and energy hub.

[0072] Figure 4 For each building, the hourly energy demand data and daily fluctuations are provided, among which, Figure 4 (a) For peak office electricity demand, Figure 4 (b) To meet the peak electricity demand of the shopping mall, Figure 4 (c) For peak electricity demand of the hotel, Figure 4 (d) represents the peak daily electricity consumption of each building. Detailed Implementation

[0073] To make the purpose, features, and advantages of this application more apparent and understandable, specific embodiments and accompanying drawings will be used to clearly and completely describe the technical solution protected by this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this patent, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this patent.

[0074] This application provides a distributed collaborative operation method for smart city energy hubs, addressing the urgent technical problem of improving the total transaction revenue of energy hubs.

[0075] The technical solutions proposed in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0076] This application provides a distributed collaborative operation method for a smart city energy hub, the method comprising: Establish an operational model for various energy devices in a building energy hub, including photovoltaic modules, wind turbines, hydrogen fuel cells, gas generator sets, heat pumps, gas boilers, energy storage batteries, and thermal storage tanks; The electricity gap and heat gap of the energy hub are calculated based on the operation model of the energy equipment, thereby determining the scope of the transaction; Within the scope of the transaction, the marginal cost of energy is calculated, and the goal is to minimize the operating cost of the energy hub to achieve peer-to-peer transactions; Calculate the transmission loss of peer-to-peer energy transactions, and calculate the shared benefits of both parties in the peer-to-peer transaction based on the transmission loss of peer-to-peer energy transactions; After all point-to-point energy transactions are completed within a single trading cycle, constraints on transmission losses are constructed, the optimal power flow of the entire energy microgrid is recalculated, transmission losses are minimized, and the total trading revenue of the energy hub within this trading cycle is optimized.

[0077] A. Operating Model of Energy Equipment Energy equipment in building energy hubs can be divided into two main categories: energy conversion equipment and energy storage equipment. Energy conversion equipment includes devices that handle different forms of energy input and output, such as wind turbines, generator sets, and hydrogen fuel cells. On the other hand, energy storage equipment has the same input and output energy forms, including batteries and thermal storage tanks.

[0078] Photovoltaic modules are devices that can be installed on the roofs and exterior walls of buildings to convert solar energy into electrical energy. Their output primarily depends on the intensity of solar radiation. The operating model of a photovoltaic module is expressed as follows:

[0079] in, It refers to the electrical energy output (kW) of the photovoltaic module. It refers to the installed capacity (kW) of photovoltaic modules. It is the solar radiation (kW) radiated to the photovoltaic module; Wind turbines are devices that can be installed in building yards or suburbs to convert wind energy into electricity. Their output depends primarily on wind speed and intensity. The operating model of a wind turbine is expressed as follows:

[0080] in, It is the electrical energy output (kW) of a wind turbine. It is the installed capacity (kW) of the wind turbine. It is the wind speed (m / s) through the plane of the wind turbine blades; A hydrogen fuel cell is a device that can be installed in a building's machine room or auxiliary room to convert hydrogen energy into electrical and thermal energy. Its input and output mainly vary with the load rate. The operating model of a hydrogen fuel cell is expressed as follows:

[0081]

[0082]

[0083]

[0084]

[0085] in, It refers to the electrical energy output (kW) of the hydrogen fuel cell. It refers to the installed capacity (kW) of hydrogen fuel cells. It is the loading rate of hydrogen fuel cells. It is the hydrogen energy input (kW) of the hydrogen fuel cell. It is the thermal energy output (kW) of the hydrogen fuel cell. Similarly, gas generator sets can also be installed in building machine rooms or auxiliary rooms to convert natural gas energy into electrical and thermal energy. Their input and output mainly vary with the load rate; the operating model of a gas generator set is expressed as follows:

[0086]

[0087]

[0088]

[0089]

[0090] In the formula, The electrical energy output (kW) of the gas generator set. The installed capacity (kW) of the natural gas generator set. For the load factor of the gas-fired power generation unit, Natural gas energy input (kW) for gas generator sets. The thermal energy output (kW) of the gas generator set; Heat pumps, including ground source heat pumps and air source heat pumps, are devices that can be installed in building machine rooms or auxiliary rooms, consuming electrical energy to extract heat energy. Their input and output mainly vary with the load rate. The expression for the operating model of a heat pump is:

[0091]

[0092]

[0093] In the formula, The heat energy output (kW) of the heat pump. The installed capacity of the heat pump is (kW). For heat pump load rate, For heat pump electrical energy input (kW); A gas-fired boiler is a device that can be installed in a building's machine room or auxiliary room to convert natural gas energy into heat energy. Its input and output mainly vary with the load rate. The operating model expression for a gas-fired boiler is as follows:

[0094]

[0095]

[0096] In the formula, The heat output (kW) of the gas-fired boiler. The installed capacity (kW) of the gas-fired boiler. For gas-fired boiler load rate, Natural gas energy input (kW) for gas cookers; Energy storage batteries are devices that can be installed in building equipment rooms or auxiliary rooms to supply or consume electrical energy according to a scheduling plan. Their input or output is primarily based on load rate and shrinks to state of charge (SOC). The operating model of an energy storage battery is expressed as follows:

[0097]

[0098]

[0099] in, It refers to the state of charge of the energy storage battery. It refers to the load rate of the energy storage battery. It is the electrical energy input of the energy storage battery ( )) or output ( (kW), It is the installed capacity (kWh) of energy storage batteries. Similarly, thermal storage tanks are devices that can be installed in building machine rooms or auxiliary rooms to supply or consume thermal energy according to a scheduling plan. Their inputs or outputs are primarily based on load factor and reduced to state of charge (SOC). The operating model of a thermal storage tank is expressed as follows:

[0100]

[0101]

[0102] in, It refers to the state of charge of the thermal storage tank. For the load rate of the thermal storage tank, For the heat input of the thermal storage box ( ) or output ( (kW), It is the installed capacity of the thermal storage tank (kWh).

[0103] B. Energy Hub Model Energy hubs consume local energy to meet the energy needs of buildings. When local energy supply is insufficient, energy can be purchased from other energy hubs. Conversely, when local energy supply is excessive, the surplus energy can be sold to other energy hubs. The energy hub model is a collection of models of all equipment within the hub, incorporating their cooperative strategies.

[0104] The internal electrical balance of an energy hub is represented by its power generation attempt to keep pace with the electricity consumption of its energy equipment and buildings. The expression for the electrical deficit of an energy hub is:

[0105] in, It is the power shortage in the energy hub. It is the building's electrical energy consumption; Similarly, the internal thermal balance of an energy hub is represented by the heat generated attempting to match the heat consumption of its energy equipment and buildings. The expression for the thermal deficit of an energy hub is:

[0106] in, It is a thermal energy gap in the energy hub. It refers to the building's heat energy consumption.

[0107] Based on the operating model of energy equipment, the electricity gap and heat gap of the energy hub are calculated to determine the scope of the transaction, specifically including: An energy consumption cost model for an energy hub is constructed based on the operating model of energy equipment, the electricity gap of the energy hub, and the heat gap of the energy hub. A carbon emission model for an energy hub is constructed based on the operating model of energy equipment, the electricity gap of the energy hub, and the heat gap of the energy hub. The scope of transactions is determined based on the electricity gap and thermal gap of the energy hub.

[0108] The energy cost of an energy hub primarily stems from the energy consumption of its equipment and the electrical and thermal energy exchanged with other hubs or energy systems. The energy cost model for an energy hub is expressed as follows:

[0109] in, It is the energy consumption cost of the energy hub. It's the energy price of hydrogen. It refers to the energy price of natural gas. It is the energy price of electricity. It is the energy price of thermal energy; The carbon emissions of an energy hub are expressed as the energy consumption of energy equipment minus the electricity and heat purchased from other hubs or energy systems. The expression for the carbon emissions model of an energy hub is:

[0110] in, It is the carbon emission cost of the energy hub. It is the carbon emission coefficient of natural gas. It is the carbon emission coefficient of electricity. It is the carbon emission coefficient of thermal energy; The operating cost of an energy hub is the sum of energy consumption cost and carbon emission cost. Based on the energy consumption cost model and carbon emission model of the energy hub, the operating cost is calculated as follows:

[0111] in, This refers to the operating cost of the energy hub, representing the lowest operating cost achieved under the constraint of minimizing the energy deficit, with the objective of minimizing operating costs. It is the operating cost of the energy hub; When considering energy trading, the marginal cost of electricity is expressed as follows:

[0112] The expression for the marginal cost of thermal energy is:

[0113] The expressions for the marginal cost of the package are as follows: .

[0114] The trading scope of an energy hub is determined by the upper and lower limits of its energy deficit. The upper limit of the energy deficit for an energy hub is expressed as the maximum power generation minus the minimum power consumption of energy equipment and buildings. The lower limit of the energy deficit for an energy hub can be expressed as the minimum power generation minus the maximum power consumption of energy equipment and buildings. The trading scope of an energy hub is determined by the upper and lower limits of its energy deficit.

[0115] The scope of trading is determined based on the electricity and heat energy gaps of the energy hubs, specifically including: The upper limit of the power deficit of the energy hub is determined by the following expression:

[0116] in, It is the upper limit of the power shortage of the energy hub. That is the maximum power generation capacity of hydrogen fuel cells. This is the maximum power generation capacity of the gas generator set. This is the maximum power generation capacity of the energy storage battery. This is the minimum power consumption capacity of a heat pump; The lower limit of the energy gap of the energy hub is determined by the following expression:

[0117] in, It is the lower limit of the power shortage in the energy hub. This is the minimum power generation capacity of a hydrogen fuel cell. This is the minimum power generation capacity of a gas generator set. This is the minimum power generation capacity of an energy storage battery. This is the maximum power consumption capacity of the heat pump; Based on the upper limit and lower limit of the energy gap of the energy hub, the trading scope of the energy hub's electricity is determined as follows: .

[0118] Similarly, the upper limit of the thermal energy range of an energy hub is expressed as the maximum heat output minus the minimum heat consumption of energy equipment and buildings. Its lower limit can be expressed as the minimum heat output minus the maximum heat consumption of energy equipment and buildings.

[0119] The upper limit of the thermal energy gap of the energy hub is determined by the following expression:

[0120] in, It is the upper limit of the thermal energy gap of the energy hub. This is the maximum heating capacity of the heat pump. This is the maximum heating capacity of the gas-fired boiler. This is the maximum heating capacity of the thermal storage tank; The lower limit of the thermal energy gap of the energy hub is determined by the following expression:

[0121] in, It is the lower limit of the thermal energy gap of the energy hub. This is the minimum heat output of the heat pump. This is the minimum calorific value of a gas-fired boiler. It is the minimum heat output of the thermal storage tank.

[0122] Based on the upper limit and lower limit of the thermal energy gap of the energy hub, the trading range of thermal energy of the energy hub is determined as follows: .

[0123] Calculating the transmission loss in peer-to-peer energy transactions specifically includes: Calculating the energy loss in peer-to-peer energy trading specifically includes: The energy loss of the cable is calculated, and the energy loss in point-to-point energy trading is calculated based on the cable's energy loss. The expression is as follows:

[0124] in, It is the energy loss in peer-to-peer energy trading. It is the collection of all cables along the shortest power supply path; This is the energy loss of a single cable, expressed as:

[0125] in, It is the branch resistance. It is a branch circuit reactor. It is the branch voltage. It is the active power of the branch circuit. It is the reactive power of the branch circuit; The expression for calculating heat transfer losses in point-to-point energy trading based on heat loss in thermal pipelines is as follows:

[0126] in, It refers to the heat transfer loss in point-to-point energy trading. and It is the collection of all heat pipes along the shortest heating path and the shortest heat return path, respectively; This is the heat loss of a single cable, expressed as:

[0127] in, It is the branch circuit thermal resistance. It is the branch temperature. It is the branch circuit thermal power.

[0128] C. Microgrid Model Cables and conduits in smart city microgrids connect and support energy exchange between energy hubs, power plants, and heating stations. When seeking energy trading, energy losses during transmission are calculated using energy flow calculation methods. Optimal energy flow methods can reduce transmission losses when executing trade outcomes.

[0129] In energy flow calculations, transmission losses in point-to-point energy transactions are related to energy intensity, transmission volume, and transmission path. Electrical energy passing through a cable can be represented by an AC power flow equation. The expression for the electrical energy loss of a cable is:

[0130] in, It is the branch resistance (Ω). It is the branch reactance (Ω). It is the branch voltage (V). It is the active power of the branch circuit (kW). It is the reactive power of the branch circuit (kW). It is the branch circuit power loss (kW).

[0131] The energy loss in a point-to-point energy transaction is the sum of the energy losses of all cables along the shortest path between the energy hubs in the transaction, expressed as:

[0132] in, It is the energy loss in peer-to-peer energy trading. It collects all cables along the shortest path.

[0133] The difference is that the heat energy flowing through a pipe can be expressed using a direct current power flow formula. The expression for the heat loss of a cable is:

[0134] in, It is the branch thermal resistance (Ω). It is the branch temperature (K). It is the branch circuit thermal power (kW). It is the heat loss of the branch circuit (kW).

[0135] The heat loss in a point-to-point energy transaction is the sum of the heat losses of all cables along the supply and return paths between the energy hubs in that transaction, expressed as:

[0136] in, It is the heat loss in point-to-point energy trading. and It is the collection of all heat pipes along the shortest heating path and the shortest heat return path, respectively.

[0137] The energy loss of a smart city microgrid is the sum of the energy losses of all cables and pipes after all energy transactions have been offset and superimposed.

[0138]

[0139] in, It is the energy loss of smart city microgrids. It is a collection of all cables and pipes.

[0140] The operating cost of a smart city microgrid is the sum of energy losses from all cables and pipes after all electricity transactions are offset.

[0141]

[0142] in, It is the operating cost of a smart city microgrid. It refers to the number of energy hubs. It is the electricity price sold by the power grid. It is the price of heat sold by the heating system.

[0143] The smart city micro-energy grid energy trading blockchain provides energy hubs for publishing transaction information, forming a fully information-based trading market. The blockchain consensus protocol aims to automatically match and complete energy transactions. For example... Figure 2 As shown, each energy hub acts as a consensus node in the blockchain, managing the signing, execution, and settlement of transactions through smart contracts. The execution process and content of the smart contracts are as follows.

[0144] The consensus protocol among energy hubs defines the basic rules for energy trade. Each trading cycle is divided into three phases: supply and demand matching, efficiency optimization, and settlement. During the supply and demand matching phase, each node publishes energy trading information, including the range of energy exports and imports for the current cycle, the marginal cost of energy exports, the marginal cost of energy imports, and the energy export emission coefficient. Each node can calculate this information using its own energy hub model.

[0145] At the end of the supply and demand matching phase, the smart contract automatically matches supply and demand quantities and prices to complete the transaction based on the order in which each node publishes its transaction information. Earlier published lower-priced electricity supply is allocated to earlier published higher-priced electricity demand. After accounting for transmission losses, any remaining export capacity or unmet import quantity will generate new transaction information in the transaction pool.

[0146] After entering the efficiency optimization phase, the smart contract aggregates the energy imported by all energy hubs. Assuming this energy originates from the power grid and thermal energy system, energy savings costs are calculated as a reciprocal benefit for both parties in the peer-to-peer transaction. The shared benefit for both parties in the peer-to-peer energy transaction is calculated based on transmission losses, expressed as follows:

[0147] in, It is a shared benefit for both parties in a peer-to-peer transaction. It is the electricity price sold by the power grid. It is the price of heat sold by the heating system.

[0148] The smart contract calculates the optimal energy flow of the microgrid and provides the state parameters that each branch node should satisfy during transaction execution. The objective function for the optimal energy flow is to minimize transmission losses. After all point-to-point energy transactions are completed within a single transaction cycle, constraints on transmission losses are constructed, and the optimal power flow of the entire microgrid is recalculated to minimize transmission losses, thereby maximizing the total transaction revenue of the energy hub within this transaction cycle, including: The constraints for the electrical energy flow are expressed as follows:

[0149]

[0150] in, Represents the square of the branch current (A). It is the square of the voltage (V); The constraints for the thermal energy flow are expressed as follows:

[0151]

[0152] in, This indicates the volumetric flow rate of hot water (m³ / h). It is the specific heat capacity of water (kWh / m3 / K); The energy loss of a smart city microgrid is calculated as the sum of the energy losses from all cables and pipes after all energy transactions have been offset. Its expression is:

[0153] in, It is the energy loss of smart city microgrids. It is a collection of all cables and pipes; The operating cost of a smart city microgrid is calculated as the sum of energy losses from all cables and conduits after all electricity transactions have been offset. The expression for this cost is:

[0154] in, It is the operating cost of a smart city microgrid. It refers to the number of energy hubs. It is the electricity price sold by the power grid. It is the price of heat sold by the heating system; After the energy hub imports and exports energy according to optimal power flow, revenue and fees are settled through smart contracts during the settlement phase. The energy hub importing energy pays for the traded energy and corresponding transmission losses based on the transaction results, with the price being the transaction price plus the carbon emission price. Since this transaction only covers the energy cost of the exported energy from the energy hub, half of the mutually beneficial cost must also be paid as compensation.

[0155] The expression for calculating the point-to-point transaction cost of imported energy at the energy hub is as follows:

[0156] in, This indicates the cost of point-to-point transactions for imported energy at the energy hub. It's the cost of importing electricity. It is the cost of importing thermal energy; The total transaction revenue and fees of the energy hub during this trading period are the sum of all peer-to-peer transaction orders, expressed as follows:

[0157] in, This represents the total transaction revenue and transaction fees of the energy hub. It is the collection of all transaction orders in the energy center; The total trading revenue of an energy hub during this trading period is its total trading income and fees minus its operating costs for these trading orders. The total trading revenue of an energy hub during this trading period is calculated based on its total trading income and fees, and the expression is as follows:

[0158] in, This represents the total trading revenue of the energy hub during this trading cycle.

[0159] It is important to note that if the energy hub fails to complete the transaction, the microgrid will supplement or consume energy through the grid and heating system, and the resulting costs will be borne by the energy hub.

[0160] Case Analysis Taking the IEEE 33-node power system as an example, it was transformed into an electrothermal microgrid with three building energy hubs. Two control cases were established. In Case 1, the energy hubs could only trade energy with the power grid and the heating system; in Case 2, the energy hubs traded energy within the microgrid. The energy devices, energy hubs, microgrid, blockchain smart contracts, and optimal energy flow algorithms were modeled and simulated using MATLAB software.

[0161] A. Parameter settings for microgrids The annual energy demands of these buildings are divided into year-round electricity demand, summer cooling demand, and winter heating demand. Available energy sources for these buildings include solar, wind, and geothermal energy. The power grid and natural gas network are the only external systems from which these buildings can draw energy. IEEE 33 was initially designed for 10kV voltage levels. To adapt to the environment of smart city microgrids, this paper makes several adjustments to IEEE 33, including proportionally reducing branch resistance and reactance. Resistance ranges are approximately [0.0001, 0.01] in Ω. We specify the voltage intervals for the AC subsystems as [360, 420] in V and the temperatures for the thermal subsystems as [320, 340] in K. Branch resistance and reactance of cables and conduits within the energy hubs are negligible. Hourly and daily fluctuations of energy demand for each building are shown below. Figure 4 As shown.

[0162] Table 1 lists the installed capacity of energy equipment in each building's energy center. Table 2 shows the prices and emission coefficients for the power grid, natural gas, hydrogen, and thermal energy systems.

[0163] Table 1 Installed Capacity of Energy Equipment

[0164] Table 2 Energy Prices and Emission Factors

[0165] The Enhanced Pareto Evolutionary Algorithm II (SPEA-II) was used to solve for the energy generation of the energy hubs and the optimal energy flow of the microgrids, and its constraints and objectives were programmed. Table 3 lists the SPEA-II settings for each building's energy hub and microgrid. Fifty parallel computing clusters were set up in MATLAB for the solution.

[0166] Table 3 Parameter settings for enhanced Pareto evolutionary algorithm II

[0167] Due to their different crossover and mutation methods, sequence variables are separated from other variables during evolution. In these case studies, the SPEA-II population was reprogrammed into multiple populations of equal length, including one complete population and two fragment populations. One fragment population carries the sequence variables, and the other fragment population carries the remaining variables. In each iteration, the fitness of the complete population, composed of the two fragment populations, is calculated, and then it is decomposed into new fragment populations for crossover and mutation.

[0168] The simulation covered continuous hourly operation for 365 days a year, with a 15-minute trading cycle preceding each hour. Within this cycle, the energy trading blockchain alliance's supply and demand matching phase was set for 10 minutes, the profit optimization phase for 5 minutes, and the settlement phase for a few seconds after each hour. Each energy trading center's account had an initial capital of 1 million yuan.

[0169] B. Results Analysis After 157 hours of simulation, the three energy hubs in the smart city microgrid completed 20,673 transactions, totaling 1.62 million yuan. The account balances of each energy hub are shown in Table 4. Compared to Case 1 before participating in microgrid energy trading, the operating costs of the energy hub in Case 2 decreased by 6.71%, 14.59%, and 12.58%, respectively, with an average reduction of 11.29%. These can all be considered as profits from energy trading. As shown in Table 5, the carbon emissions of the energy hub in Case 2 decreased by 11.88%, 13.90%, and 5.95%, respectively, with an average reduction of 10.58%. Table 6 shows that the energy efficiency of the energy hub in Case 2 increased by 5.97%, 12.73%, and 11.55%, respectively, with an average increase of 10.08%.

[0170] Table 4. Account Balances of Each Energy Hub After Annual Operation

[0171] Table 5 Annual carbon emissions from the operation of each energy hub

[0172] Table 6 Annual Energy Efficiency of Each Energy Hub

[0173] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0174] Any changes, modifications, substitutions, and variations made to the embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A distributed collaborative operation method for smart city energy hubs, characterized in that, The method includes: Establish an operational model for various energy devices in a building energy hub, including photovoltaic modules, wind turbines, hydrogen fuel cells, gas generator sets, heat pumps, gas boilers, energy storage batteries, and thermal storage tanks; The electricity gap and heat gap of the energy hub are calculated based on the operation model of the energy equipment, thereby determining the scope of the transaction; Within the scope of the transaction, the marginal cost of energy is calculated, and the goal is to minimize the operating cost of the energy hub to achieve peer-to-peer transactions; Calculate the transmission loss of peer-to-peer energy transactions, and calculate the shared benefits of both parties in the peer-to-peer transaction based on the transmission loss of peer-to-peer energy transactions; After all point-to-point energy transactions are completed within a single trading cycle, constraints on transmission losses are constructed, the optimal power flow of the entire energy microgrid is recalculated, and transmission losses are minimized.

2. The method as described in claim 1, characterized in that, The expression for the operating model of photovoltaic modules is: in, It is the power output of the photovoltaic module. It refers to the installed capacity of photovoltaic modules. It refers to solar radiation that reaches the photovoltaic module; The expression for the operating model of a wind turbine is: in, It is the electrical energy output of the wind turbine. It refers to the installed capacity of the wind turbine. It is the wind speed through the plane of the wind turbine blades; The expression for the operating model of a hydrogen fuel cell is as follows: in, It is the electrical energy output of the hydrogen fuel cell. It refers to the installed capacity of hydrogen fuel cells. It is the loading rate of hydrogen fuel cells. It is the hydrogen energy input of hydrogen fuel cells. It is the thermal energy output of the hydrogen fuel cell; The expression for the operating model of the gas generator set is: In the formula, For the electrical energy output of the gas generator set, For the installed capacity of natural gas generator sets, For the load factor of the gas-fired power generation unit, For natural gas energy input to the gas generator set, For the thermal energy output of the gas generator set; The expression for the operating model of a heat pump is: In the formula, For the heat energy output of the heat pump, For the installed capacity of the heat pump, For heat pump load rate, For heat pump electrical energy input; The expression for the operating model of a gas-fired boiler is as follows: In the formula, For the heat energy output of the gas-fired boiler, For the installed capacity of the gas-fired boiler, For gas-fired boiler load rate, Natural gas energy input for the gas cooker; The expression for the operating model of energy storage batteries is: in, It refers to the state of charge of the energy storage battery. It refers to the load rate of the energy storage battery. It refers to the electrical energy input or output of an energy storage battery. It refers to the installed capacity of energy storage batteries; The expression for the operating model of the thermal storage tank is: in, It refers to the state of charge of the thermal storage tank. For the load rate of the thermal storage tank, For the thermal energy input or output of the thermal storage box. This refers to the installed capacity of the thermal storage tank.

3. The method as described in claim 2, characterized in that, The expression for the electrical energy gap of the energy hub is: in, It is the power shortage in the energy hub. It is the building's electrical energy consumption; The expression for the thermal energy gap of the energy hub is: in, It is a thermal energy gap in the energy hub. It refers to the building's heat energy consumption.

4. The method as described in claim 3, characterized in that, Based on the operating model of energy equipment, the electricity gap and heat gap of the energy hub are calculated to determine the scope of the transaction, specifically including: An energy consumption cost model for an energy hub is constructed based on the operating model of energy equipment, the electricity gap of the energy hub, and the heat gap of the energy hub. A carbon emission model for an energy hub is constructed based on the operating model of energy equipment, the electricity gap of the energy hub, and the heat gap of the energy hub. The scope of transactions is determined based on the electricity gap and thermal gap of the energy hub.

5. The method as described in claim 4, characterized in that, The expression for the energy consumption cost model of the energy hub is: in, It is the energy consumption cost of the energy hub. It's the energy price of hydrogen. It refers to the energy price of natural gas. It is the energy price of electricity. It is the energy price of thermal energy; The expression for the carbon emission model of the energy hub is: in, It is the carbon emission cost of the energy hub. It is the carbon emission coefficient of natural gas. It is the carbon emission coefficient of electricity. It is the carbon emission coefficient of thermal energy; The operating cost of an energy hub is calculated based on its energy consumption cost model and carbon emission model. The expression for the operating cost of an energy hub is as follows: in, It is the operating cost of the energy hub. It is the operating cost of the energy hub; The expression for the marginal cost of electricity is: The expression for the marginal cost of thermal energy is: The expressions for the marginal cost of the package are as follows: 。 6. The method as described in claim 5, characterized in that, The scope of trading is determined based on the electricity and heat energy gaps of the energy hubs, specifically including: The upper limit of the power deficit of the energy hub is determined by the following expression: in, It is the upper limit of the power shortage of the energy hub. That is the maximum power generation capacity of hydrogen fuel cells. This is the maximum power generation capacity of the gas generator set. This is the maximum power generation capacity of the energy storage battery. This is the minimum power consumption capacity of a heat pump; The lower limit of the energy gap of the energy hub is determined by the following expression: in, It is the lower limit of the power shortage in the energy hub. This is the minimum power generation capacity of a hydrogen fuel cell. This is the minimum power generation capacity of a gas generator set. This is the minimum power generation capacity of an energy storage battery. This is the maximum power consumption capacity of the heat pump; Based on the upper limit and lower limit of the energy gap of the energy hub, the trading scope of the energy hub's electricity is determined as follows: .

7. The method as described in claim 6, characterized in that, The scope of transactions is determined based on the electricity and heat energy gaps of energy hubs, and also includes: The upper limit of the thermal energy gap of the energy hub is determined by the following expression: in, It is the upper limit of the thermal energy gap of the energy hub. This is the maximum heating capacity of the heat pump. This is the maximum heating capacity of the gas-fired boiler. This is the maximum heating capacity of the thermal storage tank; The lower limit of the thermal energy gap of the energy hub is determined by the following expression: in, It is the lower limit of the thermal energy gap of the energy hub. This is the minimum heat output of the heat pump. This is the minimum calorific value of a gas-fired boiler. It is the minimum heat output of the thermal storage tank; Based on the upper limit and lower limit of the thermal energy gap of the energy hub, the trading range of thermal energy of the energy hub is determined as follows: .

8. The method as described in claim 7, characterized in that, Calculating the transmission loss in peer-to-peer energy transactions specifically includes: Calculating the energy loss in peer-to-peer energy trading specifically includes: The energy loss of the cable is calculated, and the energy loss in point-to-point energy trading is calculated based on the cable's energy loss. The expression is as follows: in, It is the energy loss in peer-to-peer energy trading. It is the collection of all cables along the shortest power supply path; This is the energy loss of a single cable, expressed as: in, It is the branch resistance. It is a branch reactor. It is the branch voltage. It is the active power of the branch circuit. It is the reactive power of the branch circuit; The expression for calculating heat transfer losses in point-to-point energy trading based on heat loss in thermal pipelines is as follows: in, It refers to the heat transfer loss in point-to-point energy trading. and It is the collection of all heat pipes along the shortest heating path and the shortest heat return path, respectively; This is the heat loss of a single cable, expressed as: in, It is the branch circuit thermal resistance. It is the branch temperature. It is the branch circuit thermal power.

9. The method as described in claim 8, characterized in that, The calculation of the shared revenue of both parties in a peer-to-peer energy transaction based on transmission losses is expressed as follows: in, It is a shared benefit for both parties in a peer-to-peer transaction. It is the electricity price sold by the power grid. It is the price of heat sold by the heating system.

10. The method as described in claim 9, characterized in that, After all peer-to-peer energy transactions are completed within a single trading cycle, constraints on transmission losses are constructed, and the optimal power flow of the entire energy microgrid is recalculated to minimize transmission losses, including: The constraints for the electrical energy flow are expressed as follows: in, This represents the square of the branch current. It is the square of the voltage; The constraints for the thermal energy flow are expressed as follows: in, This indicates the volumetric flow rate of hot water. It is the specific heat capacity of water; The energy loss of a smart city microgrid is calculated as the sum of the energy losses from all cables and pipes after all energy transactions have been offset. Its expression is: in, It is the energy loss of smart city micro-energy grids. It is a collection of all cables and pipes; The operating cost of a smart city microgrid is calculated as the sum of energy losses from all cables and conduits after all electricity transactions have been offset. The expression for this cost is: in, It is the operating cost of a smart city microgrid. It refers to the number of energy hubs. It is the electricity price sold by the power grid. It is the price of heat sold by the heating system; The expression for calculating the point-to-point transaction cost of imported energy at the energy hub is as follows: in, This indicates the cost of point-to-point transactions for imported energy at the energy hub. It's the cost of importing electricity. It is the cost of importing thermal energy; The total transaction revenue and transaction fees of the energy hub are the sum of all peer-to-peer transaction orders, expressed as: in, This represents the total transaction revenue and transaction fees of the energy hub. It is the collection of all transaction orders in the energy center; The total transaction revenue of an energy hub during this trading cycle is calculated based on its total transaction revenue and transaction fees. The expression for this calculation is as follows: in, This represents the total trading revenue of the energy hub during this trading cycle.

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