Source network load storage island monitoring system and control method thereof

Abstract

The invention provides a source network load storage island monitoring system and a control method, and the system comprises a main station layer, a network layer and a substation layer, and aims at achieving the multi-time scale monitoring of a source network load storage island. The master station layer communicates with the substation layer through the network layer; and the substation layer is controlled. When the system is in a steady-state mode, a source-load interactive scheduling optimization strategy is constructed through power prediction and load prediction, and an off-grid operation energy cascade management strategy is constructed by taking the electric quantity of an energy storage battery as a core variable; in a transient-steady state mode, corresponding modules of the master station and the substation are interconnected and tightly matched through a private network, so that transient stability control of instantaneous networking support, millisecond-level rapid control and second-level coordination control of the converter is realized; in the emergency mode, a control command is issued in real time to maintain system safety. The method can efficiently solve the problem of random fluctuation of new energy, improves the stability and anti-interference capability of the system, optimizes the operation cost, and is suitable for precise monitoring and management in a complex energy scene.

Description

Technical Field

[0001] This invention belongs to the field of novel power system dispatch optimization technology, and more specifically, relates to a source-grid-load-storage islanding monitoring system and its control method. Background Technology

[0002] With the rapid development and widespread application of new energy technologies, the structure and operation mode of power systems have undergone significant changes. Especially for isolated source-grid-load-storage systems in remote areas or special application scenarios, achieving efficient and stable monitoring and management has become an important research topic. Traditional power system monitoring and management methods have many shortcomings when facing the volatility and uncertainty of new energy sources. Therefore, developing a highly adaptable and reliable source-grid-load-storage isolated monitoring system architecture is particularly important.

[0003] Existing isolated monitoring systems and their control strategies are ill-suited to the operational needs following large-scale integration of new energy sources, exhibiting the following significant drawbacks: low source-load matching at different time scales under steady-state conditions, imperfect energy management strategies, and poor stability; slow real-time response, small stability margin, and high control difficulty in transient steady-state conditions; and lack of rapid response mechanisms and low system security under emergency conditions.

[0004] In summary, existing technologies have significant shortcomings in real-time response, energy management, and emergency control. This invention aims to address these issues and improve system stability and resource utilization efficiency through multi-level, multi-timescale optimized scheduling and dynamic energy management strategies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an islanded monitoring system architecture that enables coordinated control of power generation, grid, load, and storage. This overcomes the drawbacks of existing technologies, such as low source-load matching at different time scales in steady-state renewable energy power systems, imperfect energy management strategies, poor stability, slow real-time response in transient steady-state, small stability margin, high control difficulty, lack of rapid response mechanisms in emergency states, and low system security.

[0006] The first aspect of the present invention provides a source-grid-load-storage island monitoring system, comprising: a master station layer, a network layer, and a substation layer;

[0007] The main station layer communicates with the sub-station layer via the network layer;

[0008] The main station layer is equipped with a source-load interaction scheduling optimization model for steady-state control and an off-grid operation energy cascade management model. The source-load interaction scheduling optimization model is generated based on the data sent from the substation layer to ensure source-load matching. The off-grid operation energy cascade management model is generated based on the energy storage capacity and power supply coordination strategy to achieve energy balance within the system.

[0009] The substation layer is equipped with a grid-type energy storage module, a fast control module, and a stability control module. The grid-type energy storage module and the fast control module are used by the master station layer to implement transient stability control of the converter at the substation layer, including instantaneous grid support, millisecond-level fast control, and / or second-level coordinated control. The stability control module is used by the master station layer to implement emergency control of the substation layer.

[0010] Preferably, the master station layer includes: an integrated control master station module, a stable coordination and rapid control master station module, and a power generation plan and power / load forecasting master station module;

[0011] The integrated control master station module receives real-time data from the substation layer through a dedicated network channel in the network layer, which is used for the generation, inference, and calculation output of the source-load interaction scheduling optimization model and the off-grid operation energy cascade management model;

[0012] The stable coordination and rapid control master station module and the substation layer network-type energy storage module and rapid control module interact with each other through a dedicated network channel of the network layer to implement transient stability control of instantaneous grid support, millisecond-level rapid control and / or second-level coordinated control of the converter.

[0013] The power generation planning and power / load forecasting master station module performs ultra-short-term forecasts based on historical data and real-time collected information, generating power and load forecast curves for a set future time period; based on the forecast results, it generates power planning curves for each power source of the substation and formulates charging and discharging strategies for energy storage batteries.

[0014] Preferably, the network layer includes a dedicated network channel module;

[0015] The main station layer's stability coordination and rapid control module interacts with the sub-station layer's stability control module and rapid control module via a dedicated network channel module.

[0016] The communication between the fast control module and the main control equipment of the substation adopts the GOOSE fast communication protocol.

[0017] Preferably, the substation layer includes: a remote control module, a power prediction module, a load prediction module, a stability control module, a fast control module, a data acquisition control module, a protection module, an automatic generation / voltage control module (AGC / AVC), a synchronization module, and a grid-type energy storage module;

[0018] By combining modules, different types of substations can be constructed by combining them with corresponding functional devices.

[0019] Preferably, the grid-type energy storage module includes: an energy storage battery, a battery management system (BMS), an energy management system (EMS), an energy storage converter (PCS), and a virtual synchronous generator unit built based on the energy storage converter. It changes the power by controlling the internal potential amplitude and phase angle, and exhibits voltage source characteristics as a whole, with simulated external characteristics of a rotating motor.

[0020] A second aspect of the present invention provides a control method for the aforementioned source-grid-load-storage islanding monitoring system, comprising:

[0021] In steady-state mode, the substation layer collects all data and sends it to the master station layer through the network layer to build a source-load interaction scheduling optimization model and an off-grid operation energy cascade management model, and performs model inference and calculation output.

[0022] In the transient stable mode, the grid-type energy storage module and fast control module of the substation layer, together with the stable coordination and fast control master station module of the master station layer, realize the transient stable control of the converter instantaneous grid support, millisecond-level fast control and / or second-level coordinated control, and maintain the system's anti-interference capability under all operating conditions.

[0023] In emergency mode, the main station layer's stable coordination and rapid control main station module, in cooperation with the substation layer's stable control module, enables the rapid output of control commands to cut off or adjust photovoltaic, energy storage, and load.

[0024] Preferably, the source-load interaction scheduling optimization strategy includes:

[0025] The system uses wind and solar power forecasting, load forecasting, and meteorological changes as input data, while also using energy balance, energy storage charging and discharging, and operational targets as constraints.

[0026] Generate power planning curves for each power source and initially formulate charging and discharging strategies for energy storage batteries.

[0027] Intraday rolling optimization combines data from ultra-short-term forecasts to revise the power plans of each power source, the charging and discharging strategies of energy storage batteries, and the load control plans for a future set time period, generating a baseline value for real-time control setpoints; this is used to address the "source-load" matching problem at different time scales, ensuring that power generation and load remain balanced at all times.

[0028] Preferably, the load forecasting module of the substation layer classifies the predicted process load into different load types based on the classification of users;

[0029] Modeling is performed for different load types, corresponding prediction models are established using feature selection techniques, and the prediction results are corrected by making full use of production planning information and interference factors.

[0030] Based on the load characteristics of different processes, the best available forecasting schemes are selected, and different forecasting algorithms are adopted to provide data support for making reliable decisions. The total load of the enterprise is then forecasted by superimposing the forecasting results.

[0031] Preferably, the power prediction module of the substation layer receives historical data from the early stage of the substation project, receives real-time data and prediction data from the new energy substation through the local network, and receives regional wind and solar resource weather and climate forecast data provided by numerical weather prediction agencies. It establishes a prediction model for power generation, uses refined numerical weather forecast data as input to the model, and calculates the future short-term and ultra-short-term predicted power based on the equipment status and operating conditions of the substation. Based on this, it calculates the predicted data for the future power generation of the substation.

[0032] Preferably, the off-grid energy cascade management strategy includes:

[0033] Wind and solar power limit: When the battery charge exceeds the "wind and solar power limit", the photovoltaic power is limited to avoid tripping caused by the battery being fully charged;

[0034] Relaxing wind and solar power restrictions: When the battery capacity is below the "relaxing wind and solar power restrictions threshold", the photovoltaic power restrictions will be relaxed to maximize the utilization of photovoltaic power.

[0035] Diesel engine start threshold: When the battery charge is below the "diesel engine start threshold" and is discharging, the diesel engine starts and runs in PQ mode, with the diesel engine driving the load power and storing energy to charge the photovoltaic power.

[0036] Diesel generator shutdown threshold: When the battery charge is higher than the "diesel generator shutdown threshold" and the battery is charging, the diesel engine will be shut down and the battery will be powered by the photovoltaic and energy storage system.

[0037] PCS shutdown threshold: When the battery level is below the "PCS shutdown threshold", PCS will be stopped to prevent the battery from being completely discharged.

[0038] Compared with existing technologies, through hierarchical architecture design and multi-timescale scheduling optimization, the beneficial technical effects of this invention include at least the following:

[0039] 1. Based on the characteristics of new energy sources and load fluctuations, the advanced optimization scheduling technology uses ultra-short-term forecasting technology to assess the matching degree of source and load in advance and formulate a multi-dimensional coordinated control strategy, which solves the power balance problem caused by the dual random fluctuations of source and load in a high proportion of new energy power system.

[0040] 2. A smart energy management strategy for off-grid operation is provided, which dynamically adjusts charge and discharge control based on the SOC (State of Charge) of the energy storage battery to prevent overcharging or over-discharging of the system and ensure stable power supply in off-grid mode.

[0041] 3. By adopting a multi-timescale coordinated stability control system based on grid-connected converters, the system can quickly enter a stable state under metastable conditions through the combination of instantaneous grid support of converters, millisecond-level fast control, and second-level coordinated control. This enhances the system's safety and anti-interference capability under metastable conditions and solves industry problems such as low stability margin and high control requirements in high-proportion new energy power systems.

[0042] 4. Construct a stable, coordinated, and rapid control master station and stable control substation modules to ensure that when the islanded system encounters a large disturbance and other means fail, it can take the final measures such as switching off the machine and shedding the load to ensure system safety. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of an embodiment of a novel islanded monitoring system architecture for source-grid-load-storage according to the present invention;

[0044] Figure 2 This is a schematic diagram illustrating the implementation process of the source-load interaction scheduling optimization strategy of the present invention;

[0045] Figure 3 This is a schematic diagram of the off-grid energy cascade management strategy of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0047] This invention relates to the field of power systems, and more particularly to a technical solution for a source-grid-load-storage islanded monitoring system architecture. Specifically, it is used for the coordinated control and optimized scheduling of new energy and energy storage systems, and is applicable to multi-timescale monitoring and operation management in distributed energy access scenarios, encompassing steady-state, transient steady-state, and emergency states. This invention relates to both power system dispatch optimization technology and energy management methods based on energy storage systems.

[0048] like Figure 1-3 As shown, Embodiment 1 of the present invention provides a source-grid-load-storage island monitoring system, including: a master station layer, a network layer and a substation layer, which aims to realize multi-time-scale monitoring of source-grid-load-storage islands.

[0049] The main station layer is equipped with a source-load interaction scheduling optimization model for steady-state control and an off-grid operation energy cascade management model. The source-load interaction scheduling optimization model is generated based on the data sent from the substation layer to ensure source-load matching. The off-grid operation energy cascade management model is generated based on the energy storage capacity and power supply coordination strategy to achieve energy balance within the system.

[0050] The main station layer communicates with the sub-station layer via the network layer;

[0051] The substation layer is equipped with a grid-type energy storage module, a fast control module, and a stability control module. The grid-type energy storage module and the fast control module are used by the master station layer to implement transient stability control of the converter at the substation layer, including instantaneous grid support, millisecond-level fast control, and / or second-level coordinated control. The stability control module is used by the master station layer to implement emergency control of the substation layer.

[0052] The system architecture is based on a substation-layered grid-type energy storage module, enabling multi-timescale monitoring of source-grid-load-storage islands at steady, transient, and emergency states. Figure 1 In this context, m represents the type of substation, such as but not limited to energy storage, photovoltaic, wind power, diesel generator, load, etc.; n represents the number of substations, which can be multiple; grid-type energy storage modules are only configured for energy storage substations.

[0053] From the perspective of operation mode, in steady state mode, the system constructs a source-load interaction scheduling optimization strategy through power prediction and load prediction, and constructs an off-grid energy cascade management strategy with the energy storage battery power as the core variable.

[0054] In the transient stable mode, the corresponding modules of the master station and the substation are interconnected and work closely together through a dedicated network to achieve transient stable control of the converter, which includes instantaneous network support, millisecond-level fast control, and second-level coordinated control.

[0055] In emergency mode, control commands are issued in real time to maintain system security.

[0056] This invention can efficiently solve the problem of random fluctuations in new energy sources, improve system stability and anti-interference capabilities, optimize operating costs, and is suitable for precise monitoring and management in complex energy scenarios.

[0057] Specifically, the master station layer includes: an integrated control master station module, a stable coordination and rapid control master station module, and a power generation plan and power / load forecasting master station module.

[0058] Preferably, but not restrictively, the hardware equipment at the main station layer includes: a front-end data acquisition server, various back-end application servers, workstations, and auxiliary equipment; the hardware equipment is connected using an open network system, and is isolated between different network areas using firewalls or physical security devices. Among these, the various back-end application servers include, but are not limited to, SCADA, historical storage, coordination and control, and power generation planning, while auxiliary equipment includes, but is not limited to, printers and GPS devices.

[0059] The integrated control master station module of the master station layer is used to collect and process data from the sub-station layer, build a unified data support platform, and realize overall scheduling optimization.

[0060] The integrated control master station module receives real-time data from the substation layer through a dedicated network channel in the network layer, including but not limited to information such as power, load, voltage, and current; it processes this real-time data using advanced data analysis algorithms to generate a unified data model; based on the generated data model, it uses optimization algorithms to generate the optimal scheduling scheme to ensure the overall efficiency and stability of the system, such as, but not limited to, a source-load interaction scheduling optimization model representing the source-load interaction scheduling optimization strategy, and an off-grid operation energy cascade management model representing the off-grid operation energy cascade management strategy.

[0061] The advanced data analysis algorithms include, but are not limited to, data cleaning, feature extraction, and anomaly detection; the optimization algorithms include, but are not limited to, linear programming and genetic algorithms.

[0062] The master station layer's stable coordination and rapid control master station module is used for the system's coordinated control, rapid control, and stable control, ensuring the system's stable operation under various working conditions.

[0063] The stable coordination and rapid control master station module works closely with the substation layer network-type energy storage module and rapid control module, and exchanges information through a dedicated network channel in the network layer to achieve transient stable control of the converter with instantaneous network support, millisecond-level rapid control and second-level coordinated control, maintaining the system's anti-interference capability under all operating conditions.

[0064] The master station layer's power generation plan and power / load forecasting master station module is used to generate power generation plans and predict future power and load demands, providing a basis for scheduling optimization.

[0065] The power generation planning and power / load forecasting master station module collects relevant data based on historical data and real-time acquisition information; it uses machine learning algorithms to make ultra-short-term forecasts and generates power and load forecast curves for the next 4 hours; based on the forecast results, it generates power planning curves for wind turbines, photovoltaic power generation, diesel power generation, etc., and initially formulates charging and discharging strategies for energy storage batteries.

[0066] Machine learning algorithms include, but are not limited to, neural networks and support vector machines.

[0067] The network layer includes a dedicated network channel module to ensure the security and real-time performance of data transmission. The information exchange between the main station layer stable coordination and rapid control main station module and the sub-station layer stable control module and rapid control module adopts a dedicated network channel. The communication between the rapid control module and the sub-station main control device adopts the GOOSE fast communication protocol to achieve rapid response and control.

[0068] Constructing a dedicated network channel module can either utilize the existing dispatch data network and establish a dedicated fiber optic channel within it, or it can establish a new dedicated fiber optic line to ensure the security and real-time performance of data transmission and prevent external interference. Understandably, given the large geographical span between the physical sites of wind power, photovoltaic, and energy storage components in a source-grid-load-storage project, utilizing the existing dispatch data network to establish a dedicated fiber optic channel can significantly reduce the difficulty of project implementation.

[0069] The substation layer includes: a remote control module, a power prediction module, a load prediction module, a stability control module, a fast control module, a data acquisition and control module, a protection module, an automatic generation / voltage control module (AGC / AVC), a synchronization module, and a grid-type energy storage module. Through the combination of the above modules and the corresponding functional equipment of the substation, complete energy storage substations, photovoltaic substations, wind power substations, diesel generator substations, load substations, etc. are constructed.

[0070] Each module in the substation layer is physically carried by different devices or servers, and they are interconnected and communicate with each other through conventional networks or high-speed data networks.

[0071] The telemetry module at the substation layer is used for daily data interaction between the substation and the master station, collection and outgoing of substation data under steady state, and issuance of commands from the master station.

[0072] The remote control module exchanges data with the master station layer through a dedicated network channel in the network layer to achieve remote monitoring and control; it supports multiple communication protocols, with preferred but not limited to the following, prioritizing the IEC 60870-5-104 power protocol for communication with upstream and the IEC 61850 protocol for communication with downstream, ensuring the reliability, real-time performance and compatibility of data transmission.

[0073] The power prediction module and load prediction module of the substation layer perform ultra-short-term predictions based on historical data and real-time collected information, providing decision support for source-load interaction scheduling optimization strategies.

[0074] The stability control module of the substation layer is used for emergency control of the substation, and the fast control module of the substation layer realizes fast transient stability control.

[0075] The acquisition and control module of the substation layer is responsible for data acquisition and control, while the protection module of the substation layer is responsible for the protection function of the substation.

[0076] The automatic generation / voltage control module (AGC / AVC) at the substation layer enables automatic generation and voltage control, while the synchronization module is responsible for the substation's synchronous grid connection.

[0077] The grid-type energy storage module of the substation layer uses chemical energy storage as a medium and constructs a virtual synchronous unit based on the energy storage converter. By controlling the internal potential amplitude and phase angle, the power is changed, and the overall characteristics of the module are presented as a voltage source. It realizes the external characteristics of the simulated rotating motor and provides high-performance functions such as primary frequency regulation, voltage regulation, and damping control.

[0078] Preferably, but not limitingly, the grid-type energy storage module includes: energy storage battery, battery management system (BMS), energy management system (EMS), energy storage converter (PCS), and virtual synchronous generator unit built based on the energy storage converter. By controlling the internal potential amplitude and phase angle to change the power, it exhibits voltage source characteristics and has simulated the external characteristics of a rotating motor. It provides high-performance primary frequency regulation, voltage regulation, damping control, and other functions. Through real-time control strategies, the grid-type energy storage module achieves a dynamic response at the level of hundreds of milliseconds, meeting the rapid regulation requirements of islanded systems.

[0079] Embodiment 2 of the present invention provides a control method for a source-grid-load-storage islanding monitoring system, comprising the following steps:

[0080] In steady-state mode, all data collected by the substation layer is transmitted to the master station layer through the network layer to build a unified data support platform using the integrated control master station module. The substation layer power prediction module and load prediction module work together with the master station layer power generation plan and power / load prediction master station module to build a source-load interactive scheduling optimization strategy. The off-grid energy cascade management strategy is built with the energy storage battery capacity of the grid-type energy storage module as the independent variable.

[0081] Preferredly but not limited to, in steady-state mode, the substation layer collects power and load data, which is then uploaded to the integrated control module of the master station layer through the network layer to construct a source-load interactive scheduling optimization strategy. Based on power forecasting, load forecasting, and energy storage battery power, the power generation plan is dynamically adjusted to ensure source-load matching. When operating off-grid, with energy storage battery power as the core variable, an energy cascade management strategy is constructed. By controlling thresholds, preferably but not limited to, wind and solar thresholds, and diesel generator start-up thresholds, the operating status of energy storage, photovoltaic, and diesel generators is dynamically managed to ensure system stability.

[0082] Specifically, such as Figure 2As shown, the source-load interactive scheduling optimization strategy refers to using wind and solar power forecasts, load forecasts, and meteorological changes as input data, while simultaneously constraining conditions through overall scheduling such as energy balance, energy storage charging and discharging, and operational targets; generating power plan curves for wind turbines, photovoltaic power generation, and diesel power generation, and initially formulating charging and discharging strategies for energy storage batteries; intraday rolling optimization combined with ultra-short-term forecast data to revise the power plans for wind turbines, photovoltaic power generation, and diesel power generation, as well as the charging and discharging strategies for energy storage batteries and load control plans for the next 4 hours, generating benchmark values ​​for real-time control setpoints; solving the "source-load" matching problem at different time scales, ensuring that power generation and load can remain balanced at all times.

[0083] Further, but not restrictively, the load forecasting module at the substation layer extracts and mines the user's load volume for a future time period based on historical power load data of the load substation and other factors affecting user power consumption. Users are categorized to analyze power load characteristics. Statistical analysis is performed on the power load of each production unit. Based on the characteristics of sample data from each process and information on external influencing factors, the load characteristics of the process load are analyzed, and the predicted process load is divided into the following five categories based on the analysis results: residential load, production load, impact load, stable load, and fluctuating load. Modeling is performed for different load types, and appropriate forecasting models are established using feature selection technology. The forecasting results are corrected by fully utilizing production planning information and interference factors. A multi-model optimization forecasting framework is adopted to support the application of multiple models. Equivalent short-term load forecasting models for each power consumption link are established. Based on the load characteristics of different processes, the optimal forecasting scheme is selected from the available forecasting schemes, and different forecasting algorithms are used to provide data support for making reliable decisions. The total load of the enterprise is forecasted by superimposing the forecasting results.

[0084] Understandably, the substation's power / load forecasting module is responsible for collecting information and sending it to the master station. The master station module, responsible for the generation plan and power / load forecasting, is responsible for analyzing and calculating all forecast information. Finally, the corresponding module output interface of the substation executes the calculations. The master station module and the substation module form a logical whole and work together. The master station module uses the information sent by all substation modules as the basis for analysis and calculation. After comprehensive analysis and calculation by the master station, the substation obtains the substation execution plan with the overall optimal forecast model. A similar relationship exists between the stability coordination and rapid control master station module and the substation stability control and rapid control modules.

[0085] Further preferred, but not restrictive, the power prediction module of the substation layer receives historical data from the early stages of the substation project, receives real-time and predicted data from the new energy substation via the local network, and receives regional wind and solar resource weather and climate forecast data provided by numerical weather prediction agencies. This data is then uniformly received, analyzed, and stored on the integrated wind-solar-storage collaborative management platform. A power generation prediction model is established using data such as the power station's location information, surface type, historical power, historical meteorological measurements, numerical weather forecasts, and substation operating status. The model inputs data such as total irradiance, direct normal irradiance, horizontal diffuse irradiance, wind speed and direction at different altitudes, temperature, air pressure, and relative humidity from refined numerical weather forecasts. Combined with the substation's equipment status and operating conditions, the model calculates future short-term and ultra-short-term predicted power, and uses this to calculate the predicted future power generation data of the substation.

[0086] like Figure 3 As shown, preferably but not limitingly, in the off-grid energy cascade management strategy, in order to achieve energy balance within the system and prevent batteries from being fully charged or discharged, an energy management strategy based on battery capacity is set, including but not limited to: wind and solar power limit threshold, wind and solar power restriction threshold, diesel generator start threshold, diesel generator stop threshold, and PCS shutdown threshold, to prevent batteries from being fully charged or discharged and ensure system energy balance. It is worth noting that the five control parameters—wind and solar power limit threshold, wind and solar power restriction restriction threshold, PCS shutdown threshold, diesel generator start threshold, and diesel generator stop threshold—are set to fixed values, allowing the dispatcher to adjust them according to the actual operational needs of the system.

[0087] The specific implementation method is as follows:

[0088] Limiting wind and solar power thresholds: When the battery charge exceeds the "limiting wind and solar power thresholds", the photovoltaic power is limited to avoid tripping caused by the battery being fully charged.

[0089] Relaxing wind and solar power restrictions: When the battery charge is below the "relaxing wind and solar power restrictions threshold", the photovoltaic power restrictions will be relaxed to maximize the utilization of photovoltaic power output.

[0090] Diesel engine starting threshold: When the battery charge is below the "diesel engine starting threshold" and is discharging, the diesel engine starts and runs in PQ mode, with the diesel engine providing the load power. Energy storage is considered based on the electricity used for charging photovoltaics, thus improving economic efficiency.

[0091] Diesel generator stop threshold: When the battery charge is higher than the "diesel generator stop threshold" and the battery is charging, the diesel engine will stop and the battery will be powered by the photovoltaic and energy storage system.

[0092] PCS shutdown threshold: When the battery level is below the "PCS shutdown threshold", PCS will be stopped to prevent the battery from being completely discharged.

[0093] In the transient stable mode, the substation-level grid-type energy storage module and fast control module work together with the master station-level stable coordination and fast control master station module to achieve transient stable control of the converter's instantaneous grid support + millisecond-level fast control + second-level coordinated control, maintaining the system's anti-interference capability under all operating conditions.

[0094] In emergency mode, the master station layer's stability coordination and rapid control master station module, in conjunction with the substation layer's stability control module, enables the rapid output of control commands to cut off or adjust photovoltaic, energy storage, and load, thereby controlling photovoltaic, energy storage, and load. For example, but not limited to, when a serious system fault occurs, the master station layer quickly issues commands to cut off part of the photovoltaic output and start the diesel engine to ensure the safe operation of the system.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A source-grid-load-storage island monitoring system, characterized in that: include: Master station layer, network layer and substation layer; The master station layer communicates with the substation layer via the network layer; The master station layer is equipped with a source-load interactive scheduling optimization model for steady-state control and an off-grid operation energy cascade management model; the source-load interactive scheduling optimization model is generated based on the data sent from the substation layer to ensure source-load matching; the off-grid operation energy cascade management model is generated based on the energy storage power and power supply coordination strategy to achieve power balance in the system; The substation layer is provided with a networking type energy storage module, a fast control module and a stable control module; the networking type energy storage module and the fast control module are used for the main station layer to implement transient stability control of the converter instantaneous networking support, millisecond-level fast control and / or second-level coordinated control on the substation layer; the stable control module is used for the main station layer to implement emergency control on the substation layer.

2. A source-grid-load-storage island monitoring system according to claim 1, characterized in that: The master station layer includes: an integrated control master station module, a stable coordination and rapid control master station module, and a power generation plan and power / load forecast master station module; The integrated control master station module receives real-time data from the substation layer through the dedicated network channel of the network layer, which is used for the generation, reasoning and calculation output of the source-load interactive scheduling optimization model and the off-grid operation energy cascade management model; The stable coordination and rapid control master station module and the substation layer networking type energy storage module and rapid control module exchange information through the dedicated network channel of the network layer to implement transient stability control of the converter instantaneous networking support, millisecond-level rapid control and / or second-level coordinated control; The power generation plan and power / load forecasting master station module performs ultra-short-term forecasting based on historical data and real-time collected information, and generates power and load forecast curves for a set time period in the future. Based on the forecast results, it generates power plan curves for each power source in the substation and formulates charging and discharging strategies for energy storage batteries.

3. The source-grid-load-storage island monitoring system according to claim 2 is characterized by: The network layer includes a dedicated network channel module; The main station layer's stable coordination and rapid control master station module and the substation layer's stable control module and rapid control module exchange information via a dedicated network channel module; The communication between the fast control module and the substation main control device adopts the GOOSE fast communication protocol.

4. A source-grid-load-storage island monitoring system according to any one of claims 1 to 3, characterized in that: The substation layer includes: telecontrol module, power prediction module, load prediction module, stability control module, fast control module, acquisition control module, protection module, automatic generation / voltage control module AGC / AVC, synchronization module and grid-type energy storage module; Through the combination of modules, different types of substations can be constructed with the corresponding functional equipment of the substation.

5. The source-grid-load-storage island monitoring system according to claim 4 is characterized by: The grid-type energy storage module includes: energy storage batteries, battery management system BMS, energy management system EMS, energy storage inverter PCS and a virtual synchronous unit built based on the energy storage inverter. It changes the power by controlling the internal potential amplitude and phase angle, and the overall voltage source characteristics have the external characteristics of a simulated rotating motor.

6. A control method for a source-grid-load-storage island monitoring system according to any one of claims 1 to 5, characterized in that: include: In steady-state mode, the substation layer collects all data and sends it to the main station layer through the network layer to build a source-load interactive scheduling optimization model and an off-grid operation energy cascade management model, and perform model reasoning and calculation output; In the transient stable state mode, the grid-forming energy storage module and the fast control module of the substation layer cooperate with the stable coordination and fast control master station module of the master station layer to realize the transient stable control of the converter instantaneous grid-forming support, millisecond-level fast control and / or second-level coordinated control, and maintain the system's anti-interference capability under all working conditions; In emergency mode, the stable coordination and rapid control of the master station layer and the master station module cooperate with the stable control module of the substation layer to achieve rapid output of control commands for cutting off or adjusting photovoltaic, energy storage and load.

7. The control method according to claim 6, characterized in that: The optimization strategies for source-load interactive scheduling include: Using wind and solar power forecasts, load forecasts, and meteorological changes as input data, and using energy balance, energy storage charging and discharging, and operating targets to impose conditional constraints; Generate power planning curves for each power source and preliminarily formulate charging and discharging strategies for energy storage batteries; Intraday rolling optimization combines ultra-short-term forecast data to revise the power plan of each power source, the charging and discharging strategy of the energy storage battery, and the load control plan in the future set time period, and generate a benchmark value for the real-time control set value; it is used for "source-load" matching problems at different time scales to ensure that power generation and load are balanced at all times.

8. The control method according to claim 7, characterized in that: The load prediction module at the substation layer divides the predicted process load into different load types according to the classification of users; Modeling is carried out for different load types, and corresponding prediction models are established using feature selection technology, and the planning information and interference factors in production are fully utilized to correct the prediction results; According to the load characteristics of different processes, we select the best available forecasting schemes and adopt different forecasting algorithms to provide data support for making reliable decision-making information. By superimposing the forecast results, we can predict the total load of the enterprise.

9. The control method according to claim 7, characterized in that: The power prediction module at the substation layer receives historical data from the early stage of the substation project, receives real-time data and prediction data of the new energy substation through the local network, and receives regional wind and solar resource weather and climate forecast data provided by the numerical forecasting agency, establishes a prediction model for power generation, uses refined numerical weather forecast data as input to the model, and calculates the future short-term and ultra-short-term predicted power in combination with the equipment status and operating conditions of the substation, and uses this to calculate the predicted data of the substation's future power generation.

10. The control method according to claim 7, characterized in that: Off-grid operation energy cascade management strategies include: Wind and solar power limit threshold: When the battery power is greater than the "wind and solar power limit threshold", the photovoltaic power is limited to avoid tripping caused by the battery being fully charged; Release the wind and solar power restriction threshold: When the battery power is lower than the "wind and solar power restriction threshold", the photovoltaic power restriction is released to maximize the use of photovoltaic output; Diesel engine start threshold: When the battery power is lower than the "diesel engine start threshold" and is discharging, the diesel engine is started and runs in PQ mode, with the diesel engine carrying the load power and the energy storage charging the photovoltaic power; Stop diesel generator threshold: When the battery power is higher than the "stop diesel generator threshold" and is charging, the diesel engine is stopped and the solar energy storage system is used to carry the load; Stop PCS threshold: When the battery power is lower than the "stop PCS threshold", the PCS is stopped to avoid draining the battery.

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