Construction method of grid-connected micro-grid power guarantee dynamic capability evaluation model

Abstract

The invention discloses a construction method of a grid-connected micro-grid power guarantee dynamic capability evaluation model, which belongs to the technical field of micro-grid power generation, and comprises the following steps: determining a power guarantee load; performing multi-type information perception on the micro-grid; configuring an electricity protection strategy, and establishing a power supply-power grid-load-energy storage relation model; based on the relation model, setting a basic verification model of the power guarantee strategy, and verifying the basic verification model of the power guarantee strategy; performing real-time monitoring on the voltage of the grid-connected monitoring point based on the power protection strategy model; when the power failure of the power grid is monitored, entering a power guarantee operation state; and analyzing the data sensed by the multi-type information after entering the power guarantee operation state, and calculating the predicted power guarantee duration. According to the construction method of the evaluation model, the power guarantee duration can be measured and calculated in the power guarantee execution process, the obtained power guarantee duration can provide data reference and decision analysis for power guarantee management personnel, meanwhile, the optimal power guarantee scheme can be dynamically generated, and the development of power guarantee business is efficient and reliable.

Description

Technical Field

[0001] The present invention relates to the field of microgrid power generation, and in particular to a method for constructing a dynamic power conservation capability evaluation model for a grid-connected microgrid. Background Art

[0002] Microgrid is an important development direction of smart grid and the most effective form of distributed power source access to the grid. Microgrid uses a lot of power electronics technology to integrate distributed power sources such as distributed wind power generation, solar photovoltaic power generation, micro gas turbine power generation, fuel cell power generation, and various energy storage devices, protection devices and control devices to form a small power generation and distribution network, forming a smaller independent system.

[0003] Microgrids are divided into two types: independent microgrids and grid-connected microgrids. Independent microgrids operate independently and are not connected to the external grid. They independently ensure the balance and stability of power generation and power supply within the microgrid and provide stable power supply for the load within the grid. Grid-connected microgrids can be connected to the large grid or disconnected from the main grid to operate independently. Under normal circumstances, grid-connected microgrids are connected to the conventional distribution network and operate independently. When a conventional distribution network fault is detected or a power quality event occurs, the grid-connected microgrid will be disconnected from the conventional distribution network in a timely manner and operate independently.

[0004] Therefore, for grid-connected microgrids, their own power supply capabilities and the development of power supply services in off-grid situations should be considered during design. At present, the development of power supply services is mainly focused on the large power grid side, and is mainly used for power supply services in emergency situations. In the case of grid-connected microgrids, how to use energy storage, distributed power generation resources, loads and other elements, and the development of power supply services after the microgrid is switched from grid-connected to off-grid are very different from the power supply services of large power grids. Summary of the invention

[0005] The present invention aims to provide an evaluation model constructed by utilizing energy storage, distributed generation resources, load and other elements in a microgrid environment to ensure that key loads have available electricity and the power supply is maintained for a longer period of time.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A method for constructing a dynamic capability evaluation model for power supply protection of a grid-connected microgrid comprises the following steps:

[0008] Step S1, classify and define the loads in the microgrid and determine the power-saving loads;

[0009] Step S2, sensing multiple types of information for the entire microgrid, wherein the multiple types of information include energy storage device information, photovoltaic device information, wind turbine device information, and operating environment information;

[0010] Step S3, combining the results of the microgrid's multi-type information perception and the classification definition of the load in the microgrid, configuring a power protection strategy, and establishing a "power supply-grid-load-energy storage" relationship model under the power protection environment. The power protection strategy includes setting a grid-connected monitoring point, a power protection power source, and a power protection load;

[0011] Step S4, based on the "power supply-grid-load-energy storage" relationship model, set a basic verification model for the power protection strategy, and verify the basic verification model for the power protection strategy. If the verification passes, output the power protection strategy model; if the verification fails, return to step S3 to reconfigure the power protection strategy;

[0012] Step S5, based on the power conservation strategy model, real-time monitoring of the voltage of the grid-connected monitoring point is performed;

[0013] Step S6, when a power outage is detected in the grid, the entire microgrid is controlled to be off-grid and enter the power protection operation state, and the energy storage device, photovoltaic device, wind turbine device, and power protection load are gradually started;

[0014] Step S7, analyzing the data of multi-type information perception after entering the power protection operation state, combining the target demand for power protection, dynamically evaluating the power protection strategy model and adjusting the plan in the power protection operation state, and calculating the expected power protection time.

[0015] In a preferred embodiment of the present invention, the energy storage device information includes the capacity of the energy storage device, the SOC value of the energy storage device, the charging and discharging power of the energy storage device, etc.; the photovoltaic device information includes the photovoltaic installed capacity and the photovoltaic power generation power; the wind turbine device information includes the wind turbine installed capacity and the wind turbine power generation power; the environmental information includes weather conditions, temperature, humidity, wind speed, and wind direction.

[0016] In a preferred embodiment of the present invention, the grid-connected monitoring point monitors the grid-connected voltage value in real time.

[0017] In a preferred embodiment of the present invention, the parameter setting of the grid-connected monitoring point includes setting a reference grid-connected voltage value, and the user configures the reference grid-connected voltage value according to the grid-connected voltage; and setting a power-saving voltage value threshold range, and the power-saving voltage value threshold range is a range interval set based on the reference grid-connected voltage value; the grid-connected monitoring point monitors the real-time grid-connected voltage value once at a fixed interval, and if it is determined that a deviation from the power-saving voltage value threshold range has occurred, it is determined that the grid voltage is abnormal.

[0018] In a preferred embodiment of the present invention, the setting of the basic verification model for the power protection strategy includes that the basic verification model for the power protection strategy requires that the maximum power value of the power protection load is less than or equal to the maximum power value of the energy storage device; if the maximum power value of the power protection load is greater than the maximum power value of the energy storage device, and "the maximum power value of the power protection load / the maximum power value of the energy storage device ≤120%", then during the verification, it is prompted that the power protection strategy is abnormal, but it can still be saved; if "the maximum power value of the power protection load / the maximum power value of the energy storage device>120%", the power protection strategy is not allowed to be saved, and it is necessary to return to step S3 to reconfigure the power protection strategy.

[0019] In a preferred embodiment of the present invention, in step S5, real-time monitoring of the voltage at the grid-connected monitoring point includes real-time monitoring of the voltage at the grid-connected monitoring point. If the number of consecutive occurrences of the real-time grid-connected voltage value exceeding the power protection voltage value threshold range exceeds the threshold, it is determined that a large power grid fault has caused a power outage, a power outage alarm message is generated, and the power protection process is started.

[0020] In a preferred embodiment of the present invention, in step S6, entering the power protection operation state includes, according to the demand of the power protection load, preferentially using the photovoltaic device as a power source to supply power to the power protection load; if the output power of the photovoltaic device is greater than the power of the power protection load, the excess power will charge the energy storage device; if the output power of the photovoltaic power source is less than the load of the power protection load, the energy storage device will discharge as a supplement to the power supply; if the energy storage device is full, the output of the photovoltaic device is adjusted in real time to prevent the battery of the energy storage device from overcharging.

[0021] In a preferred embodiment of the present invention, in step S7, when the scheme adjustment is executed, the initial capacity is first calculated according to the current power conservation strategy model, and the calculation steps are as follows:

[0022] Step S71, performing energy storage capacity analysis, obtaining data such as the capacity of the energy storage device in the current microgrid system, the SOC value of the energy storage device, and the charge and discharge power of the energy storage device from the energy storage device information;

[0023] Step S72, predicting photovoltaic power generation, combining the operating environment information of the day, i.e., weather conditions, temperature, and humidity information, and comparing and matching with historical weather data, matching a date with similar weather conditions in the recent period, and obtaining the photovoltaic power generation data on that date as a photovoltaic power generation prediction curve;

[0024] Step S73, predicting the wind turbine power generation, combining the operating environment information of the day, i.e., weather conditions, wind speed, and wind direction information, and comparing and matching with historical weather data, matching a date with similar weather conditions in the recent period, and obtaining the wind turbine power generation data on that date as a wind turbine power generation prediction curve;

[0025] Step S74, through the energy storage device information, photovoltaic power generation prediction curve, wind turbine power generation prediction curve, and power conservation load data, with fixed time intervals as time nodes, simulate and calculate the change curve of the SOC value of the energy storage device in the energy storage device information. When the SOC value of the energy storage device is lower than the set discharge lower limit, the corresponding time node is used as the termination time, and the power conservation capability is evaluated in real time.

[0026] In a preferred embodiment of the present invention, matching dates with similar weather conditions in recent times includes selecting multiple days of historical weather data as dates with similar weather conditions, and fitting the power generation prediction curve by superimposing and averaging the multiple days of historical weather data.

[0027] In a preferred embodiment of the present invention, the construction method of the dynamic power protection capability evaluation model of the grid-connected microgrid further includes adjusting the classification definition of the load during the execution of the power protection operation; among the power protection loads that have executed the power protection, according to the demand, some of the power protection loads are selected to be closed to extend the power protection capability; after some of the original power protection loads are downgraded and closed, the power protection time of the microgrid power protection system can be extended; when adjusting the power protection load, the SOC value of the energy storage device monitored at the current time node is used as a reference, and the power protection capability is recalculated according to the adjusted power protection load. The specific calculation process is as follows: the SOC value of the energy storage device monitored at the current time node is defined as SOC0, and the capacity of the energy storage device is C 总 , calculate the renewable energy power generation W at the first time node based on the photovoltaic power generation prediction curve predicted at the first time node and the renewable energy power generation corresponding to the wind turbine power generation prediction curve 发 And the adjusted power load L 负 The power difference between 发 -L 负 ) / (60 / t), where t is the time interval for collecting data, in minutes; then, the SOC value of the energy storage device at the first time node is calculated based on this SOC1=(C 总 *SOC0+(W 发 -L 负 ) / (60 / t)) / C 总 After calculating the first time node, the SOC values ​​SOC2 to SOCx of the energy storage device from the second time node to the x-th time node are calculated by analogy. When the calculated SOC value of the energy storage device is lower than the preset threshold, it is considered that the power conservation capacity of this time node is insufficient, and the power conservation is terminated. At the current time node, the estimated power conservation time is calculated.

[0028] Beneficial effect: The method for constructing a grid-connected microgrid power protection dynamic capability evaluation model of the present invention can construct a grid-connected microgrid power protection model used when the external large power grid is out of power. The power protection duration can be calculated during the power protection execution process. The calculated reliable power protection duration can provide data reference and decision analysis for power protection management personnel. At the same time, the optimal power protection plan can be dynamically generated, making the development of power protection business more efficient and reliable.

[0029] In order to make the above features and advantages of the invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of a method for constructing a dynamic power conservation capability evaluation model for a grid-connected microgrid according to the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The grid-connected microgrid involved in the present invention is connected to an external large power grid, and the grid-connected microgrid includes a plurality of loads, an energy storage device, a photovoltaic device, and a wind turbine device.

[0033] Figure 1 Schematic diagram of the construction method of the grid-connected microgrid power protection dynamic capability evaluation model of the present invention. Figure 1 As shown, in the present invention, the method for constructing a grid-connected microgrid power supply dynamic capability evaluation model includes the following steps.

[0034] Step S1, classify and define the loads in the microgrid and determine the power-saving loads.

[0035] The above-mentioned classification and definition of loads in the microgrid specifically means that microgrid users can classify and define loads in the microgrid operating environment according to power management requirements and methods. For example, corporate users can classify and define loads in daily load management, and gradually divide them into Class I loads (power-keeping loads), Class II loads (important loads) and Class III loads (general loads). Power-keeping loads refer to loads that need to be guaranteed to be supplied by the power system under specific circumstances, and are also the key loads that need to be guaranteed to be supplied by the present invention.

[0036] Preferably, intelligent circuit breakers can be installed on the circuits of each load to achieve accurate collection of load data and remote control of disconnection and other functions, thereby achieving accurate identification of the load and providing a basis for subsequent data analysis.

[0037] Step S2, performing multi-type information perception on the entire microgrid, wherein the multi-type information includes but is not limited to energy storage device information, photovoltaic device information, wind turbine device information, and operating environment information.

[0038] In the entire microgrid environment, in addition to the basic power load, there will also be information about energy storage devices, photovoltaic devices, wind turbine devices, and operating environment information, which will affect the evaluation of the microgrid's power conservation capability. For this type of information, it is necessary to add sensor devices to collect data information of multiple types.

[0039] The energy storage device information includes the capacity of the energy storage device, the SOC value of the energy storage device (i.e., State of Charge, also commonly referred to as the battery state of charge or remaining power), the charge and discharge power of the energy storage device, etc. Photovoltaic device information includes photovoltaic installed capacity, photovoltaic power generation, etc. Wind turbine device information includes wind turbine installed capacity, wind turbine power generation, etc. Environmental information is mainly weather data information, including weather conditions, temperature, humidity, wind speed, wind direction, etc.

[0040] Step S3, combining the results of the microgrid's multi-type information perception and the classification definition of the load in the microgrid, configures the power protection strategy and establishes a "power supply-grid-load-energy storage" relationship model under the power protection environment. The power protection strategy includes setting a power protection start monitoring point, a power protection power source, and a power protection load.

[0041] In the above step S3, the power protection start monitoring point is mainly a grid-connected monitoring point. Other electrical connection nodes within the microgrid can also be selected according to the power protection scenario. The grid-connected monitoring point is used to monitor grid voltage anomalies. The parameter settings of the grid-connected monitoring point include setting the reference grid-connected voltage value, setting the power protection voltage value threshold range, and monitoring the real-time grid-connected voltage value. The user configures the reference grid-connected voltage value according to the grid voltage, for example, setting the commonly used 220V or 380V; the power protection voltage value threshold range sets a range interval based on the reference grid-connected voltage value, for example, the reference grid-connected voltage value is within the range of -10% to +10% above and below, which is defined as the power protection voltage value threshold range. The grid-connected monitoring point monitors the real-time grid-connected voltage value once at a fixed interval. If it is determined that a deviation from the power protection voltage value threshold range has occurred, it is determined that the grid voltage is abnormal.

[0042] Preferably, in order to prevent false alarms caused by a single voltage anomaly, the parameter settings of the grid-connected monitoring point can also set a threshold for the number of consecutive offsets. After setting, if the number of consecutive offsets of the real-time grid-connected voltage value outside the power-saving voltage value threshold range reaches the threshold for the number of consecutive offsets, it is deemed to be a grid-connected voltage anomaly.

[0043] In the above step S3, in the power protection environment, the microgrid operator performs its own business management requirements from the business level and establishes the topological relationship.

[0044] In the above step S3, setting the power supply includes the main power supply setting and the slave power supply setting in the power supply mode. The main power supply refers to a storage power supply with stable capability, which can be used as the starting power supply for the entire microgrid to ensure the normal startup and operation of the microgrid. The slave power supply refers to an unstable power supply such as photovoltaics and wind turbines. The main power supply, which is a stable power supply, drives the slave power supply, which is an unstable power supply, to operate continuously.

[0045] In the above step S3, the power-protection load refers to the key load information that needs to be protected after the microgrid is off-grid. When configuring the power-protection strategy, the load equipment that needs power protection can be quickly found.

[0046] Step S4, based on the "power supply-grid-load-energy storage" relationship model, set the basic verification model of the power protection strategy, and verify the basic verification model of the power protection strategy. If the verification passes, output the power protection strategy model; if the verification fails, return to step S3 to reconfigure the power protection strategy.

[0047] Setting the basic verification model of the power conservation strategy includes: assuming that in the energy storage device information obtained, the maximum power value of a single energy storage device is W. If N identical energy storage devices are selected (N is a natural number greater than or equal to 1), the maximum power value of the energy storage device is Then calculate the power of the power-saving load, and calculate the maximum power value of the required power-saving load based on the rated power of the selected power-saving load. If you choose to set n identical power-saving loads (n is a natural number greater than or equal to 1), assuming that the rated power of a single power-saving load is L, the maximum power value of the power-saving load is calculated by accumulation. The basic verification model of the power supply strategy requires the maximum power value L of the power supply load max Must be less than or equal to the maximum power value W of the energy storage device max , that is, the set power-saving load demand cannot exceed the maximum discharge capacity of the energy storage. max >W max , and L max / W max ≤120%, the power conservation strategy will be prompted to be abnormal during verification, but it can still be saved; if L max / W max>120%, the power conservation strategy is not allowed to be saved, and it is necessary to return to step S3 to reconfigure the power conservation strategy.

[0048] In the basic verification model of the power conservation strategy, the discharge capacity of the energy storage device is used as the basic power supply capacity to prevent the power supply capacity from being insufficient due to abnormal unstable power supply in the power supply, resulting in the load being unable to use power normally, thereby affecting the overall operation of the microgrid. A microgrid can set multiple power conservation strategies according to different needs, but only one power conservation strategy can be effective at the same power conservation start monitoring point.

[0049] Step S5: Based on the power conservation strategy model, real-time monitoring of the voltage of the grid-connected monitoring point is performed.

[0050] After the power conservation strategy based on the power conservation strategy model is activated and takes effect, the voltage of the grid-connected monitoring point is monitored in real time. If the real-time grid-connected voltage value exceeds the power conservation voltage value threshold range, that is, the voltage value is deviated from the power conservation voltage value threshold range, then when the deviation is detected for the first time, the number of consecutive deviations is recorded as 1, and monitoring is continued. If the real-time grid-connected voltage is still abnormal during the second monitoring, the number of consecutive deviations is recorded as 2. Similarly, if the real-time grid-connected voltage is still abnormal during the Mth monitoring, the number of consecutive deviations is recorded as M. If M exceeds the threshold of the number of consecutive deviations, it is considered that the large power grid has a power outage, and a power outage alarm information is generated. The management personnel start the power conservation process as needed. If the real-time grid-connected voltage value is normal once during the monitoring process, the number of consecutive deviations is reset to 0, and this is repeated.

[0051] Preferably, the grid-connected monitoring point is also used as a judgment point for whether the power grid has restored power supply. When the real-time grid-connected voltage value of the grid-connected monitoring point is normal for three consecutive times, it is judged that power has been restored. The management personnel can be prompted by an alarm to end power protection and restore normal power supply.

[0052] Step S6, when a power outage is detected in the grid, the entire microgrid is controlled to be off-grid and enter into a power-saving operation state, and the energy storage device, photovoltaic device, wind turbine device, and power-saving load are gradually started.

[0053] The said entering into the power-saving operation state can be carried out by gradually starting the energy storage device, photovoltaic device, fan device, and power-saving load equipment in an orderly manner through a pre-set electrical secondary control circuit, so that the entire microgrid enters the power-saving operation state. At this time, according to the needs of the power-saving load, the photovoltaic device can be used as a power source to supply power to the power-saving load. If the output power of the photovoltaic device is greater than the power of the power-saving load, the excess power will charge the energy storage device; if the output power of the photovoltaic power source is less than the load of the power-saving load, the energy storage device will discharge at this time as a supplement to the power supply. At the same time, if the energy storage device is full, the output of the photovoltaic device is adjusted in real time to prevent the battery of the energy storage device from overcharging.

[0054] Step S7, analyzing the data of multi-type information perception after entering the power protection operation state, combining the target demand for power protection, dynamically evaluating the power protection strategy model and adjusting the plan in the power protection operation state, and calculating the expected power protection time.

[0055] When executing the scheme adjustment, firstly, the initial capacity is calculated according to the current power conservation strategy model, and the calculation steps are as follows:

[0056] Step S71, performing energy storage capacity analysis, obtaining data such as the capacity of the energy storage device in the current microgrid system, the SOC value of the energy storage device, and the charge and discharge power of the energy storage device from the energy storage device information;

[0057] Step S72, predicting photovoltaic power generation, combining the operating environment information of the day, i.e., weather conditions, temperature, humidity and other information, and comparing and matching with historical weather data, matching a date with similar weather conditions in recent times, and obtaining the photovoltaic power generation data on that date as a photovoltaic power generation prediction curve.

[0058] The historical weather data can be selected from the historical weather data of the past 15 days. Preferably, the step of "matching the dates with similar weather conditions in the recent period" can select the historical weather data of multiple days (for example, 3-5 days) as the dates with similar weather conditions, and fit a relatively accurate power generation prediction curve by superimposing and averaging the historical weather data of multiple days. The power generation prediction curve can also use the photovoltaic power generation curve with an interval of 5 minutes.

[0059] Step S73, forecast the wind turbine power generation, combine the operating environment information of the day, i.e., weather conditions, wind speed, wind direction and other information, compare and match with historical weather data, obtain a date with similar weather conditions in the recent period, obtain the wind turbine power generation data on that date, and use it as the wind turbine power generation forecast curve. At the same time, according to the pre-set power protection load requirements, obtain the power protection load data required for this power protection.

[0060] Step S74, through the energy storage device information, photovoltaic power generation prediction curve, wind turbine power generation prediction curve, and power conservation load data, with fixed time intervals as time nodes, simulate and calculate the change curve of the SOC value of the energy storage device in the energy storage device information. When the SOC value of the energy storage device is lower than the set discharge lower limit, the corresponding time node is used as the termination time, and the power conservation capability is evaluated in real time.

[0061] Business personnel can adjust the classification definition of the load during the execution of the power protection operation. Among the power protection loads that have been executed, they can choose to shut down some power protection loads according to needs to extend the power protection capacity. For example, in the above-mentioned step-by-step classification method, the loads that originally belonged to Class I loads (power protection loads) are downgraded to Class II loads (important loads). After some of the original power protection loads are downgraded and shut down, the power protection time of the microgrid power protection system can be extended. When making this type of power protection load adjustment, the SOC value of the energy storage device monitored at the current time node will be used as a reference, and the power protection capacity will be recalculated according to the adjusted power protection load. The specific calculation formula and process are as follows: The SOC value of the energy storage device monitored at the current time node is defined as SOC0, and the capacity of the energy storage device is C 总 , calculate the renewable energy power generation W within the first time node based on the photovoltaic power generation prediction curve predicted within the first time node (for example, 5 minutes) and the renewable energy power generation corresponding to the wind turbine power generation prediction curve 发 And the adjusted power load L 负 The power difference between 发 -L 负 ) / (60 / t), where t is the interval time for data collection, in minutes. Then, the SOC value of the energy storage device at the first time node is calculated based on this. SOC1=(C 总 *SOC0+(W 发 -L 负 ) / (60 / t)) / C 总 After calculating the first time node, the SOC values ​​SOC2 to SOCx of the energy storage device from the second time node to the x-th time node are calculated by analogy. When the calculated SOC value of the energy storage device is lower than the preset threshold, it is considered that the power conservation capacity of this time node is insufficient, and the power conservation is terminated. At the current time node, the estimated power conservation duration is calculated.

[0062] When the energy storage SOC value is lower than the set threshold during the power supply protection process, or when the voltage of the monitoring grid connection point is restored, the system will remind the management personnel, who can end the power supply protection by shutting down the equipment, etc. At the same time, the system automatically calculates the duration of this power supply protection, the power supply load, etc.

[0063] The method for constructing a dynamic capability evaluation model for power conservation of a grid-connected microgrid provided by the present invention, through physical modeling and data collection of the "source, grid, load and storage" elements in a microgrid environment, relying on big data analysis and automation technology in the processes of photovoltaic power generation prediction, wind power generation prediction, power conservation capability calculation, etc., dynamically evaluates the power conservation capability of the microgrid in off-grid mode, adjusts the equipment operating status according to the power conservation strategy formulated in advance, reduces the operation and maintenance pressure of microgrid operation and management personnel, and enhances the power conservation effect. A grid-connected microgrid power conservation model can be constructed for use when the external large power grid is out of power, and the power conservation duration can be calculated during the power conservation execution process. The calculated reliable power conservation duration can provide data reference and decision analysis for power conservation management personnel, and at the same time, the optimal power conservation plan can be dynamically generated, making the development of power conservation business more efficient and reliable.

[0064] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims

1. A method for constructing a dynamic power protection capability evaluation model for a grid-connected microgrid, characterized in that: The following steps are involved: Step S1, classify and define the loads in the microgrid and determine the power-saving loads; Step S2, sensing multiple types of information for the entire microgrid, wherein the multiple types of information include energy storage device information, photovoltaic device information, wind turbine device information, and operating environment information; Step S3, combining the results of the microgrid's multi-type information perception and the classification definition of the load in the microgrid, configuring the power protection strategy, and establishing the "power supply-grid-load-energy storage" relationship model under the power protection environment. The power protection strategy includes setting the grid-connected monitoring point, the power protection power source, and the power protection load; Step S4, based on the "power supply-grid-load-energy storage" relationship model, set a basic verification model for the power protection strategy, and verify the basic verification model for the power protection strategy. If the verification passes, output the power protection strategy model; if the verification fails, return to step S3 to reconfigure the power protection strategy; Step S5, based on the power conservation strategy model, real-time monitoring of the voltage of the grid-connected monitoring point is performed; Step S6, when a power outage is detected in the grid, the entire microgrid is controlled to be off-grid and enter the power protection operation state, and the energy storage device, photovoltaic device, wind turbine device, and power protection load are gradually started; Step S7, analyzing the data of multi-type information perception after entering the power protection operation state, combining the target demand for power protection, dynamically evaluating the power protection strategy model and adjusting the plan in the power protection operation state, and calculating the expected power protection time.

2. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 1, characterized in that: The energy storage device information includes the capacity of the energy storage device, the SOC value of the energy storage device, the charge and discharge power of the energy storage device, etc.; The photovoltaic device information includes photovoltaic installed capacity and photovoltaic power generation power; The wind turbine device information includes the installed capacity of the wind turbine and the power generation power of the wind turbine; The environmental information includes weather conditions, temperature, humidity, wind speed, and wind direction.

3. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 1, characterized in that: The grid-connected monitoring point monitors the grid-connected voltage value in real time.

4. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 3, characterized in that: The parameter settings of the grid-connected monitoring point include: Set the reference grid-connected voltage value. The user configures the reference grid-connected voltage value according to the grid-connected voltage; as well as, Setting a power-saving voltage threshold range, where the power-saving voltage threshold range is a range interval set based on a reference grid-connected voltage value; The grid-connected monitoring point monitors the real-time grid-connected voltage value at a fixed interval. If it is determined that a deviation out of the power-saving voltage value threshold range occurs, it is determined that the grid-connected voltage is abnormal.

5. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 1, characterized in that: The basic verification model for setting the power conservation strategy includes: The basic verification model of the power supply strategy requires that the maximum power value of the power supply load is less than or equal to the maximum power value of the energy storage device; If the maximum power value of the power-saving load is greater than the maximum power value of the energy storage device, and "the maximum power value of the power-saving load / the maximum power value of the energy storage device ≤ 120%", the power-saving strategy will be prompted to be abnormal during verification, but it can still be saved; If "the maximum power value of the power-saving load / the maximum power value of the energy storage device>120%", the power-saving strategy is not allowed to be saved, and it is necessary to return to step S3 to reconfigure the power-saving strategy.

6. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 1, characterized in that: In step S5, real-time monitoring of the voltage at the grid-connected monitoring point includes: Monitor the voltage of the grid-connected monitoring point in real time. If the real-time grid-connected voltage value exceeds the power protection voltage value threshold range for more than the threshold number of consecutive times, it is determined that the large power grid has failed and a power outage has occurred, a power outage alarm message is generated, and the power protection process is started.

7. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 1, characterized in that: In step S6, entering the power-saving operation state includes: According to the demand of the power-maintaining load, the photovoltaic device is used as the power source for the power-maintaining load in priority; if the output power of the photovoltaic device is greater than the power of the power-maintaining load, the excess power will be used to charge the energy storage device; if the output power of the photovoltaic power source is less than the load of the power-maintaining load, the energy storage device will discharge as a supplement to the power supply; if the energy storage device is full, the output of the photovoltaic device will be adjusted in real time to prevent the battery of the energy storage device from overcharging.

8. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 2, characterized in that: In step S7, when the scheme adjustment is executed, the initial capacity is first calculated according to the current power conservation strategy model, and the calculation steps are as follows: Step S71, performing energy storage capacity analysis, obtaining data such as the capacity of the energy storage device in the current microgrid system, the SOC value of the energy storage device, and the charge and discharge power of the energy storage device from the energy storage device information; Step S72, predicting photovoltaic power generation, combining the operating environment information of the day, i.e., weather conditions, temperature, and humidity information, and comparing and matching with historical weather data, matching a date with similar weather conditions in the recent period, and obtaining the photovoltaic power generation data on that date as a photovoltaic power generation prediction curve; Step S73, predicting the power generation of the wind turbine, combining the operating environment information of the day, i.e., weather conditions, wind speed, and wind direction information, and comparing and matching with historical weather data, matching a date with similar weather conditions in the recent period, and obtaining the power generation data of the wind turbine on that date as a prediction curve for wind turbine power generation; Step S74, through the energy storage device information, photovoltaic power generation prediction curve, (wind turbine power generation prediction curve), and power conservation load data, with fixed time intervals as time nodes, simulate and calculate the change curve of the SOC value of the energy storage device in the energy storage device information. When the SOC value of the energy storage device is lower than the set discharge lower limit, the corresponding time node is used as the termination time, and the power conservation capability is evaluated in real time.

9. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 8, characterized in that: The matching of dates with similar weather conditions in recent times includes selecting multiple days of historical weather data as dates with similar weather conditions, and fitting the power generation prediction curve by averaging the multiple days of historical weather data through data superposition.

10. The method for constructing a grid-connected microgrid power supply dynamic capability evaluation model according to claim 8, characterized in that: It also includes the classification definition of load adjustment during the power protection operation; Among the power-saving loads that have been implemented, some power-saving loads can be closed according to demand to extend the power-saving capacity; after some of the original power-saving loads are downgraded and closed, the power-saving time of the microgrid power-saving system can be extended; When adjusting the power-saving load, the SOC value of the energy storage device monitored at the current time node is used as a reference, and the power-saving capacity is recalculated according to the adjusted power-saving load. The specific calculation process is as follows: The SOC value of the energy storage device monitored at the current time node is defined as SOC0, and the capacity of the energy storage device is C 总 , calculate the new energy power generation W at the first time node based on the photovoltaic power generation prediction curve predicted at the first time node and the new energy power generation corresponding to the wind turbine power generation prediction curve 发 And the adjusted power load L 负 The power difference between 发 -L 负 ) / (60 / t), where t is the time interval between data collection, in minutes; Then, the SOC value of the energy storage device at the first time node is calculated based on this SOC1=(C 总 *SOC0+(W 发 -L 负 ) / (60 / t)) / C 总 After calculating the first time node, the SOC values ​​SOC2 to SOCx of the energy storage device from the second time node to the x-th time node are calculated by analogy. When the calculated SOC value of the energy storage device is lower than the preset threshold, it is considered that the power conservation capacity of this time node is insufficient, and the power conservation is terminated. At the current time node, the estimated power conservation duration is calculated.

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