Integrated control method and system of micro-grid system

Abstract

The invention discloses an integrated control method of a micro-grid system. The method comprises the following steps: acquiring data information of a target micro-grid system; calculating a Y bus admittance matrix of the target micro-grid system; determining the power state of the system based on the real-time output of the renewable energy of the target microgrid system; calculating a reactive power demand of the target micro-grid system and determining a capacitor specification of the system for correcting a power factor; 24 hours are taken as a cycle control period, load management and economy are taken as constraint conditions, and coordination control of a target micro-grid system is realized. The invention also discloses a system for realizing the integrated control method of the micro-grid system. According to the invention, the calculation of the Y bus admittance matrix and the determination of the real-time state of the target micro-grid system are carried out, 24 hours are taken as a cycle control period, and load management and economy are taken as constraint conditions, so that the integrated control of the micro-grid system is realized, and the reliability is higher and the accuracy is better.

Description

Technical Field

[0001] The present invention belongs to the field of electrical automation, and in particular relates to an integrated control method and system for a microgrid system. Background Art

[0002] With the development of economy and technology and the improvement of people's living standards, electricity has become an indispensable secondary energy source in people's production and life, bringing endless convenience to people's production and life. Therefore, ensuring a stable and reliable supply of electricity has become one of the most important tasks of the power system.

[0003] In the power system, traditional centralized power grids rely primarily on fossil fuel power generation, providing stable and predictable power output. However, with the widespread adoption of renewable energy, the grid structure is changing. Microgrids can integrate distributed energy resources (DERs), such as solar panels, wind turbines, energy storage systems, and controllable loads, to enable local power systems to operate independently or in parallel with the main grid. Microgrids can optimize energy distribution and management, thereby improving the flexibility and reliability of new power systems.

[0004] Currently, traditional microgrid control solutions don't adequately consider renewable energy generation systems, resulting in poor reliability and accuracy in existing integrated microgrid solutions. Furthermore, existing microgrid control solutions are relatively simple and no longer meet today's sophisticated control requirements. Summary of the Invention

[0005] One of the objectives of the present invention is to provide an integrated control method for a microgrid system with high reliability and good accuracy.

[0006] A second object of the present invention is to provide a system for implementing the integrated control method of the microgrid system.

[0007] The integrated control method of the microgrid system provided by the present invention comprises the following steps:

[0008] S1. Obtain data information of the target microgrid system;

[0009] S2. Calculate the Y bus admittance matrix of the target microgrid system based on the data information obtained in step S1;

[0010] S3. Determine the power status of the system based on the real-time output of renewable energy of the target microgrid system;

[0011] S4. Calculate the reactive power demand of the target microgrid system and determine the capacitor specifications for correcting the power factor of the system;

[0012] S5. With a 24-hour control cycle and load management and economy as constraints, achieve coordinated control of the target microgrid system.

[0013] The step S1 of acquiring the data information of the target microgrid system specifically includes the following steps:

[0014] Obtain data information of the target microgrid system;

[0015] The data information includes operating frequency, number of system buses, voltage of each bus, parallel admittance of each bus, line impedance, generator capacity, photovoltaic power station capacity, wind turbine capacity, battery energy storage capacity and power generation cost data.

[0016] Step S2, based on the data information obtained in step S1, calculates the Y bus admittance matrix of the target microgrid system, specifically including the following steps:

[0017] According to the data information obtained in step S1, it is assumed that the target microgrid system has n buses, and the elements in the Y bus admittance matrix of the target microgrid system are calculated using the following formula:

[0018]

[0019] Where Y ij is the mutual admittance between busbars i and j, and Y ij It is also the element in row i and column j of the Y bus admittance matrix; Y ik is the mutual admittance between busbars i and k, and Y ik It is also the element in the i-th row and k-th column of the Y-bus admittance matrix.

[0020] The step S3 of determining the power state of the target microgrid system based on the real-time output of renewable energy in the target microgrid system specifically includes the following steps:

[0021] The real-time output of the photovoltaic power station in the target microgrid system is calculated using the following formula:

[0022]

[0023] Where P PV is the real-time output power of the photovoltaic power station in the target microgrid system; P STC is the photovoltaic power station power under standard test conditions; G is the actual solar irradiance; G STC is the solar irradiance under standard test conditions; α is the temperature coefficient of the photovoltaic cell; T is the actual temperature of the photovoltaic cell; T STC is the temperature of the photovoltaic cell under standard test conditions;

[0024] The real-time output of the wind turbine in the target microgrid system is calculated using the following formula:

[0025]

[0026] Where P wind is the real-time output power of the wind turbine in the target microgrid system; v is the real-time wind speed; v cut_in is the cut-in wind speed of the fan; P rated is the rated output power of the fan; v rated is the rated wind speed of the fan; v cut_out is the cut-off wind speed of the fan;

[0027] Determine the power status of the system based on the real-time output of the photovoltaic power station and the wind turbine in the target microgrid system and the system load of the target microgrid system:

[0028] If the sum of the real-time output of the photovoltaic power station and the real-time output of the wind turbine is greater than or equal to the system load of the target microgrid system, the power state of the system is determined to be a power surplus;

[0029] If the sum of the real-time output of the photovoltaic power station and the real-time output of the wind turbine is less than the system load of the target microgrid system, the power state of the system is determined to be power shortage.

[0030] The step S4 of calculating the reactive power demand of the target microgrid system and determining the capacitor specifications for correcting the power factor of the system specifically includes the following steps:

[0031] Calculate the reactive power demand Q of the target microgrid system demand ;

[0032] The following formula is used to determine the capacitor size for power factor correction in the target microgrid system:

[0033]

[0034] Where n is the number of capacitors used to correct the power factor in the target microgrid system; is the ceiling function; Q cap is the rated capacity of a single capacitor used to correct the power factor of the target microgrid system.

[0035] Step S5, in which the coordinated control of the target microgrid system is achieved with a 24-hour control cycle and load management and economy as constraints, specifically includes the following steps:

[0036] The control cycle is 24 hours;

[0037] Taking each hour as a single-loop control period, the target microgrid system predicts the renewable energy output and system load, and uses the following formula for operation control:

[0038]

[0039] Where P charge is the charging power of the energy storage battery; P load is the system load; P discharge is the discharge power of the energy storage battery; P n is the rated power of the energy storage battery; P generator is the power generated by the generator;

[0040] Use the following formula for load management to optimize the power factor:

[0041]

[0042] Where Q lag is the current inductive reactive power; P is the active power; cosφ is the current power factor; Q cap is the capacitive reactive power to be compensated, cosφ target is the target power factor;

[0043] According to the current inductive reactive Q lag and the capacitive reactive power Q to be compensated cap Real-time switching of capacitor banks dynamically maintains the system power factor between 0.95 and 1.0 to address excess reactive power caused by inductive loads, reduce line losses, and improve voltage stability.

[0044] The following formula is used for economic constraints:

[0045] The following formula is used as the objective function of economic constraints:

[0046]

[0047] Where C total is the total power generation cost for 24 hours; P gen (t) is the power of the traditional generator at time t; c gen is the generator cost; P pv (t) is the photovoltaic power generation power at time t; c PV is the cost of photovoltaic power generation; P wind (t) is the wind turbine power generation at time t; c wind The cost of wind power generation;

[0048] To minimize the total 24-hour power generation cost C total As the goal, the coordinated control of the target microgrid system is achieved by optimizing the energy dispatch priority:

[0049] When P pv (t)+P wind (t)≥P load (t), the first-level scheduling is adopted, at this time P charge (t) = P pv (t)+P wind (t)-P load (t), P gen (t) = 0; where P load (t) is the target power system total load active power demand at time t, P gen (t) is the active power output of the traditional generator at time t, P charge (t) is the charging power of the energy storage system at time t;

[0050] Secondary scheduling: At this time, the energy storage system performs power regulation;

[0051] P discharge (t) = min(P load (t)-P pv (t)-P wind (t),SOC(t)·E batt )

[0052] P charge (t) = min(P pv (t)+P wind (t)-P load (t),E batt (1-SOC(t)))

[0053] Where P discharge (t) is the discharge power of the energy storage system at time t; SOC(t) is the state of charge value of the energy storage system at time t; E batt is the rated capacity of the energy storage system;

[0054] Three-level dispatch: Traditional generators provide a backup:

[0055] P gen (t) = max(P load (t)-P pv (t)-P wind (t)-P discharge (t),0)

[0056] Where P gen (t) is the active power output of the traditional generator at time t.

[0057] The present invention also provides a system for implementing the integrated control method of the microgrid system, comprising a data acquisition module, an admittance calculation module, a state determination module, a capacitance calculation module and an integrated control module; the data acquisition module, the admittance calculation module, the state determination module, the capacitance calculation module and the integrated control module are connected in series in sequence; the data acquisition module is used to acquire data information of the target microgrid system and upload the data information to the admittance calculation module; the admittance calculation module is used to calculate the Y-bus admittance matrix of the target microgrid system based on the received data information and the acquired data information, and upload the data information to the state determination module; the state determination module is used to determine the power state of the system based on the received data information and the real-time output of renewable energy of the target microgrid system, and upload the data information to the capacitance calculation module; the capacitance calculation module is used to calculate the reactive power demand of the target microgrid system based on the received data information, and determine the capacitor specifications of the system for correcting the power factor, and upload the data information to the integrated control module; the integrated control module is used to realize coordinated control of the target microgrid system based on the received data information, with a 24-hour cycle control period, and load management and economy as constraints.

[0058] The integrated control method and system of the microgrid system provided by the present invention calculates the Y-bus admittance matrix and determines the real-time status of the target microgrid system, uses a 24-hour cycle control period, and takes load management and economy as constraints. This not only realizes the integrated control of the microgrid system, but also has higher reliability and better accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Schematic diagram of the process flow of the present invention.

[0060] Figure 2 Schematic diagram of the functional modules of the system of the present invention. DETAILED DESCRIPTION

[0061] like Figure 1 The method flow diagram of the present invention is shown as follows: The integrated control method of the microgrid system disclosed in the present invention includes the following steps:

[0062] S1. Acquire data information of the target microgrid system; specifically, the following steps are included:

[0063] Obtain data information of the target microgrid system;

[0064] The data includes operating frequency, number of system buses, bus voltages, parallel admittance of each bus, line impedance, generator capacity, photovoltaic power station capacity, wind turbine capacity, battery energy storage capacity, and power generation cost data. These parameters serve as data input to comprehensively outline the physical architecture, energy supply capabilities, and economic cost characteristics of the microgrid system.

[0065] S2. Calculate the Y bus admittance matrix of the target microgrid system based on the data information obtained in step S1; specifically comprising the following steps:

[0066] According to the data information obtained in step S1, it is assumed that the target microgrid system has n buses, and the elements in the Y bus admittance matrix of the target microgrid system are calculated using the following formula:

[0067]

[0068] Where Y ij is the mutual admittance between busbars i and j, and Y ij It is also the element in row i and column j of the Y bus admittance matrix; Y ik is the mutual admittance between busbars i and k, and Y ik It is also the element in the i-th row and k-th column of the Y-bus admittance matrix. This formula is based on circuit principles and is derived by analyzing the electrical connection relationship between each line and busbar, ensuring that the Y-bus matrix can accurately reflect the electrical characteristics of the system.

[0069] S3. Determine the power status of the target microgrid system based on the real-time output of renewable energy resources; specifically, the steps include:

[0070] The real-time output of the photovoltaic power station in the target microgrid system is calculated using the following formula:

[0071]

[0072] Where P PV is the real-time output power of the photovoltaic power station in the target microgrid system; P STC is the photovoltaic power station power under standard test conditions; G is the actual solar irradiance; G STC is the solar irradiance under standard test conditions; α is the temperature coefficient of the photovoltaic cell; T is the actual temperature of the photovoltaic cell; T STC is the temperature of the photovoltaic cell under standard test conditions;

[0073] The real-time output of the wind turbine in the target microgrid system is calculated using the following formula:

[0074]

[0075] Where P wind is the real-time output power of the wind turbine in the target microgrid system; v is the real-time wind speed; v cut_in is the cut-in wind speed of the fan; P rated is the rated output power of the fan; v rated is the rated wind speed of the fan; v cut_out is the cut-off wind speed of the fan;

[0076] These formulas take into account the main factors affecting renewable energy power generation and can simulate the dynamic changes of its power output more accurately;

[0077] Determine the power status of the system based on the real-time output of the photovoltaic power station and the wind turbine in the target microgrid system and the system load of the target microgrid system:

[0078] If the sum of the real-time output of the photovoltaic power station and the real-time output of the wind turbine is greater than or equal to the system load of the target microgrid system, the power state of the system is determined to be a power surplus;

[0079] If the sum of the real-time output of the photovoltaic power station and the real-time output of the wind turbine is less than the system load of the target microgrid system, the power state of the system is determined to be power shortage;

[0080] S4. Calculate the reactive power demand of the target microgrid system and determine the capacitor specifications for power factor correction in the system; specifically, the steps include:

[0081] Calculate the reactive power demand Q of the target microgrid system demand ;

[0082] The following formula is used to determine the capacitor size for power factor correction in the target microgrid system:

[0083]

[0084] Where n is the number of capacitors used to correct the power factor in the target microgrid system; is the ceiling function; Q cap is the rated capacity of a single capacitor used to correct the power factor of the target microgrid system;

[0085] S5. Implement coordinated control of the target microgrid system using a 24-hour control cycle and load management and economy as constraints. This specifically includes the following steps:

[0086] The control cycle is 24 hours;

[0087] Taking each hour as a single-loop control period, the target microgrid system predicts the renewable energy output and system load, and uses the following formula for operation control:

[0088]

[0089] Where P charge is the charging power of the energy storage battery; P load is the system load; P discharge is the discharge power of the energy storage battery; P n is the rated power of the energy storage battery; P generator is the power generated by the generator;

[0090] Use the following formula for load management to optimize the power factor:

[0091]

[0092] Where Q lag is the current inductive reactive power; P is the active power; cosφ is the current power factor; Q cap is the capacitive reactive power to be compensated, cosφ target is the target power factor;

[0093] According to the current inductive reactive Q lag and the capacitive reactive power Q to be compensated cap Real-time switching of capacitor banks dynamically maintains the system power factor between 0.95 and 1.0 to address excess reactive power caused by inductive loads, reduce line losses, and improve voltage stability.

[0094] The following formula is used for economic constraints:

[0095] The following formula is used as the objective function of economic constraints:

[0096]

[0097] Where C total is the total power generation cost for 24 hours; P gen (t) is the power of the traditional generator at time t; c gen is the generator cost; P pv (t) is the photovoltaic power generation power at time t; c PV is the cost of photovoltaic power generation; P wind (t) is the wind turbine power generation at time t; c wind The cost of wind power generation;

[0098] To minimize the total 24-hour power generation cost C total As the goal, the coordinated control of the target microgrid system is achieved by optimizing the energy dispatch priority:

[0099] When P pv (t)+P wind (t)≥Pload (t), the first-level scheduling is adopted, at this time P charge (t) = P pv (t)+P wind (t)-P load (t), P gen (t) = 0; where P load (t) is the target power system total load active power demand at time t, P gen (t) is the active power output of the traditional generator at time t, P charge (t) is the charging power of the energy storage system at time t;

[0100] Secondary scheduling: At this time, the energy storage system performs power regulation;

[0101] P discharge (t) = min(P load (t)-P pv (t)-P wind (t),SOC(t)·E batt )

[0102] P charge (t) = min(P pv (t)+P wind (t)-P load (t),E batt (1-SOC(t)))

[0103] Where P discharge (t) is the discharge power of the energy storage system at time t; SOC(t) is the state of charge value of the energy storage system at time t; E batt is the rated capacity of the energy storage system;

[0104] Three-level dispatch: Traditional generators provide a backup:

[0105] P gen (t) = max(P load (t)-P pv (t)-P wind (t)-P discharge (t),0)

[0106] Where P gen (t) is the active power output of the traditional generator at time t;

[0107] Ultimately, the microgrid system achieves optimized control by integrating elastic load management with economic constraints: real-time data collection and analysis of power status, dynamic switching of capacitor banks to optimize power factor and improve voltage stability; and scheduling according to the three-level strategy of "direct supply of renewable energy → energy storage regulation → traditional generator backup", giving priority to the use of low-cost energy and enabling traditional power generation only when necessary.

[0108] like Figure 2 The system of the present invention is shown as a schematic diagram of the functional modules: the system disclosed in the present invention for implementing the integrated control method of the microgrid system includes a data acquisition module, an admittance calculation module, a state determination module, a capacitance calculation module and an integrated control module; the data acquisition module, the admittance calculation module, the state determination module, the capacitance calculation module and the integrated control module are connected in series in sequence; the data acquisition module is used to acquire data information of the target microgrid system and upload the data information to the admittance calculation module; the admittance calculation module is used to calculate the Y bus admittance matrix of the target microgrid system based on the received data information and the acquired data information, and upload the data information to the state determination module; the state determination module is used to determine the power state of the system based on the real-time output of renewable energy of the target microgrid system according to the received data information, and upload the data information to the capacitance calculation module; the capacitance calculation module is used to calculate the reactive power demand of the target microgrid system according to the received data information, and determine the capacitor specifications of the system for correcting the power factor, and upload the data information to the integrated control module; the integrated control module is used to realize coordinated control of the target microgrid system based on the received data information, with a 24-hour cycle control period and load management and economy as constraints.

Claims

1. An integrated control method for a microgrid system, comprising the following steps: S1. Obtain data information of the target microgrid system; S2. Calculate the Y bus admittance matrix of the target microgrid system based on the data information obtained in step S1; S3. Determine the power status of the system based on the real-time output of renewable energy of the target microgrid system; S4. Calculate the reactive power demand of the target microgrid system and determine the capacitor specifications for correcting the power factor of the system; S5. With a 24-hour control cycle and load management and economy as constraints, achieve coordinated control of the target microgrid system.

2. The integrated control method of the microgrid system according to claim 1, characterized in that The step S1 of acquiring the data information of the target microgrid system specifically includes the following steps: Obtain data information of the target microgrid system; The data information includes operating frequency, number of system buses, voltage of each bus, parallel admittance of each bus, line impedance, generator capacity, photovoltaic power station capacity, wind turbine capacity, battery energy storage capacity and power generation cost data.

3. The integrated control method of the microgrid system according to claim 2, characterized in that Step S2, based on the data information obtained in step S1, calculates the Y bus admittance matrix of the target microgrid system, specifically including the following steps: According to the data information obtained in step S1, it is assumed that the target microgrid system has n buses, and the elements in the Y bus admittance matrix of the target microgrid system are calculated using the following formula: Where Y ij is the mutual admittance between busbars i and j, and Y ij It is also the element in row i and column j of the Y bus admittance matrix; Y ik is the mutual admittance between busbars i and k, and Y ik It is also the element in the i-th row and k-th column of the Y-bus admittance matrix.

4. The integrated control method of the microgrid system according to claim 3, characterized in that The step S3 of determining the power state of the target microgrid system based on the real-time output of renewable energy in the target microgrid system specifically includes the following steps: The real-time output of the photovoltaic power station in the target microgrid system is calculated using the following formula: Where P PV is the real-time output power of the photovoltaic power station in the target microgrid system; P STC is the photovoltaic power station power under standard test conditions; G is the actual solar irradiance; G STC is the solar irradiance under standard test conditions; α is the temperature coefficient of the photovoltaic cell; T is the actual temperature of the photovoltaic cell; T STC is the temperature of the photovoltaic cell under standard test conditions; The real-time output of the wind turbine in the target microgrid system is calculated using the following formula: Where P wind is the real-time output power of the wind turbine in the target microgrid system; v is the real-time wind speed; v cut_in is the cut-in wind speed of the fan; P rated is the rated output power of the fan; v rated is the rated wind speed of the fan; v cut_out is the cut-off wind speed of the fan; Determine the power status of the system based on the real-time output of the photovoltaic power station and the wind turbine in the target microgrid system and the system load of the target microgrid system: If the sum of the real-time output of the photovoltaic power station and the real-time output of the wind turbine is greater than or equal to the system load of the target microgrid system, the power state of the system is determined to be a power surplus; If the sum of the real-time output of the photovoltaic power station and the real-time output of the wind turbine is less than the system load of the target microgrid system, the power state of the system is determined to be power shortage.

5. The integrated control method of the microgrid system according to claim 4, characterized in that The step S4 of calculating the reactive power demand of the target microgrid system and determining the capacitor specifications for correcting the power factor of the system specifically includes the following steps: Calculate the reactive power demand Q of the target microgrid system demand ; The following formula is used to determine the capacitor size for power factor correction in the target microgrid system: Where n is the number of capacitors used to correct the power factor in the target microgrid system; is the ceiling function; Q cap is the rated capacity of a single capacitor used to correct the power factor of the target microgrid system.

6. The integrated control method of the microgrid system according to claim 5, characterized in that Step S5, in which the coordinated control of the target microgrid system is achieved with a 24-hour control cycle and load management and economy as constraints, specifically includes the following steps: The control cycle is 24 hours; Taking each hour as a single-loop control period, the target microgrid system predicts the renewable energy output and system load, and uses the following formula for operation control: Where P charge is the charging power of the energy storage battery; P load is the system load; P discharge is the discharge power of the energy storage battery; P n is the rated power of the energy storage battery; P generator is the power generated by the generator; Use the following formula for load management to optimize the power factor: Where Q lag is the current inductive reactive power; P is the active power; cosφ is the current power factor; Q cap is the capacitive reactive power to be compensated, cosφ target is the target power factor; According to the current inductive reactive Q lag and the capacitive reactive power Q to be compensated cap Real-time switching of capacitor banks dynamically maintains the system power factor between 0.95 and 1.0 to address excess reactive power caused by inductive loads, reduce line losses, and improve voltage stability. The following formula is used for economic constraints: The following formula is used as the objective function of economic constraints: Where C total is the total power generation cost for 24 hours; P gen (t) is the power of the traditional generator at time t; c gen is the generator cost; P pv (t) is the photovoltaic power generation power at time t; c PV is the cost of photovoltaic power generation; P wind (t) is the wind turbine power generation at time t; c wind The cost of wind power generation; To minimize the total 24-hour power generation cost C total As the goal, the coordinated control of the target microgrid system is achieved by optimizing the energy dispatch priority: When P pv (t)+P wind (t)≥P load (t), the first-level scheduling is adopted, at this time P charge (t) = P pv (t)+P wind (t)-P load (t), P gen (t) = 0; where P load (t) is the target power system total load active power demand at time t, P gen (t) is the active power output of the traditional generator at time t, P charge (t) is the charging power of the energy storage system at time t; Secondary scheduling: At this time, the energy storage system performs power regulation; P discharge (t)=min(P load (t)-P pv (t)-P wind (t),SOC(t)·E batt ) P charge (t)=min(P pv (t)+P wind (t)-P load (t),E batt ·(1-SOC(t))) Where P discharge (t) is the discharge power of the energy storage system at time t; SOC(t) is the state of charge value of the energy storage system at time t; E batt is the rated capacity of the energy storage system; Three-level dispatch: Traditional generators provide a backup: P gen (t)=max(P load (t)-P pv (t)-P wind (t)-P discharge (t),0) Where P gen (t) is the active power output of the traditional generator at time t.

7. A system for implementing the integrated control method of a microgrid system according to any one of claims 1 to 6, characterized in that It includes a data acquisition module, an admittance calculation module, a state determination module, a capacitance calculation module and an integrated control module; the data acquisition module, the admittance calculation module, the state determination module, the capacitance calculation module and the integrated control module are connected in series in sequence; the data acquisition module is used to acquire data information of the target microgrid system and upload the data information to the admittance calculation module; the admittance calculation module is used to calculate the Y bus admittance matrix of the target microgrid system based on the received data information and the acquired data information, and upload the data information to the state determination module; The state determination module is used to determine the power state of the system based on the received data information and the real-time output of renewable energy of the target microgrid system, and upload the data information to the capacitance calculation module; The capacitance calculation module is used to calculate the reactive power demand of the target microgrid system based on the received data information, determine the capacitor specifications for correcting the power factor of the system, and upload the data information to the integrated control module; The integrated control module is used to achieve coordinated control of the target microgrid system based on the received data information, with a 24-hour cycle control period and load management and economy as constraints.

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