Source network load storage coordinated control system and method for high-capacity multi-configuration network type energy storage combined transportation

Abstract

The invention discloses a source network load storage coordination control system and method for high-capacity multi-network energy storage combined transportation. The system comprises a master station layer which is responsible for receiving a superior scheduling instruction, issuing an emergency control instruction, and performing economic optimization scheduling and rapid coordination control on photovoltaic and energy storage resources; the substation layer is responsible for accessing photovoltaic, load and energy storage resource information and decomposing and issuing superior instructions to realize a local frequency voltage control function; and the terminal layer is used for receiving a generator tripping command or a power regulation command issued by the emergency state monitoring device. The system can effectively improve the network-related performance of a new energy station, enhance the stability and reliability of a power grid, improve the absorption capability of new energy, and optimize the economical efficiency of the system. Through combined operation of the network construction type energy storage equipment and the new energy, effective support for the power grid is realized, the problem of coordination control of parallel operation of multiple voltage sources is solved, oscillation and circulation are avoided, and the overall performance and the power supply guarantee capability of the system are improved.

Description

Technical Field

[0001] The present invention relates to a source-network-load-storage coordinated control system, and particularly to a source-network-load-storage coordinated control system and method for large-capacity multi-configuration network energy storage intermodal transport. Background Art

[0002] With the rapid development of new energy, especially photovoltaic and wind power, the access of large-capacity new energy to the power grid has become an important part of the power system. Existing technical solutions usually include converting new energy direct current into alternating current through large-capacity centralized inverters and then stepping up to access the large power grid. This solution meets the access requirements of new energy to a certain extent, but there are the following problems and challenges in practical applications:

[0003] In the prior art, large-scale photovoltaic power stations usually adopt centralized inverters, with a large number of photovoltaic modules concentrated in one area and the power transmitted to the load center through high-voltage transmission lines. The centralized access of large-capacity new energy may cause drastic changes in the power grid power flow, affecting the voltage and frequency stability of the power grid. After the access of large-capacity photovoltaic and energy storage, it causes power grid stability problems, such as voltage fluctuations and frequency fluctuations. For example, when the light intensity suddenly changes, the rapid fluctuation of the photovoltaic output power may cause power grid voltage fluctuations. Due to the limited regulation ability of the power grid, the volatility and intermittency of new energy make it difficult for the power grid to effectively absorb a large amount of new energy. The main possible reasons are as follows: First, the power grid planning and construction lag: In the case of the rapid growth of photovoltaic installed capacity, the power grid planning and construction fail to keep up in time, resulting in insufficient power transmission and distribution capabilities and being unable to effectively transmit and distribute a large amount of photovoltaic power generation. Second, the power demand and supply do not match: The power demand within the region is relatively low, while the photovoltaic power generation is large, exceeding the local actual electricity demand, thus causing a situation where it cannot be absorbed. Third, the power system regulation ability is limited: The regulation ability of the power grid, such as frequency modulation and voltage regulation, may not be able to adapt to the volatility and intermittency of photovoltaic power generation, resulting in the inability to effectively accept and allocate photovoltaic power. Fourth, the market mechanism is imperfect: The lack of an effective power market mechanism cannot fully stimulate the cross-regional transmission and absorption of electricity, which may also affect the absorption of photovoltaic power.

[0004] The failure of key equipment such as centralized inverters will affect the operation of the entire power station and may cause large-scale power outages. Due to the need for long-distance power transmission, there are certain power losses in the high-voltage transmission lines, reducing the energy utilization efficiency.

[0005] The transmission losses and the phenomenon of abandoning wind and light of new energy increase the overall operation cost of the system and affect the economic benefits. Due to the need for long-distance power transmission, there are certain power losses in the high-voltage transmission lines, reducing the energy utilization efficiency. Summary of the Invention

[0006] To address the deficiencies of the above-mentioned technologies, the present invention provides a source-network-load-storage coordinated control system and method for large-capacity multi-configuration network energy storage intermodal transportation.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is a source-network-load-storage coordinated control system for large-capacity multi-configuration network energy storage intermodal transportation, including:

[0008] A master station layer responsible for receiving superior dispatching instructions, issuing emergency control instructions, and performing economic optimization dispatching and rapid coordinated control of photovoltaic and energy storage resources;

[0009] A sub-station layer responsible for accessing information of photovoltaic, load, and energy storage resources and decomposing and issuing superior instructions to achieve local frequency and voltage control functions;

[0010] A terminal layer that receives the generator tripping command or power regulation command issued by the emergency state monitoring device.

[0011] Furthermore, the master station layer is arranged in the centralized control station and consists of the emergency state stability control master station, the rapid coordinated control master station, and the steady-state coordinated optimization dispatching part of the dispatching system.

[0012] Furthermore, the sub-station layer is respectively installed near the photovoltaic side, the energy storage side, and the load side; the superior instructions received by the sub-station layer are the instructions of the rapid coordinated control master station, the instructions of the emergency state stability control master station, or the manual remote instructions of the dispatching system; after the sub-station layer receives the instructions of the rapid coordinated control master station, the emergency state stability control master station, and the manual remote instructions of the dispatching system, it issues cut-off or adjustment instructions to the control terminal device; the sub-station layer completes the information access and statistical processing of the photovoltaic inverter and uploads it to the source-network-load-storage coordinated control device.

[0013] Furthermore, the energy storage coordination control device is installed near the energy storage container to realize the information access and coordinated management and control of the energy storage converter, respond to the control instructions of the source-network-load-storage coordinated controller, and decompose and issue them to the execution end of the energy storage converter to achieve rapid coordinated control of the energy storage system.

[0014] Furthermore, the terminal layer consists of the emergency state stability execution stations located on the side of each substation and the rapid power control terminals on the new energy side.

[0015] A control method for a source-network-load-storage coordinated control system for large-capacity multi-configuration network energy storage intermodal transportation, the control method including a steady-state optimization control method, a rapid coordinated control method, and an emergency stability control method.

[0016] Furthermore, the steady-state optimization control method collects historical power data, weather forecast data, and real-time load data, and based on the prediction results, optimally allocates the source-network-load-storage resources. It uses power prediction and load prediction technologies, combines economic and clean energy consumption goals, formulates power generation plans and optimizes dispatching, and adjusts the optimization strategy according to real-time operation data and prediction errors to improve prediction accuracy and system operation efficiency.

[0017] Furthermore, the fast coordination control method includes grid-connected operation control, off-grid operation control, and seamless grid-connected / off-grid switching control. The grid-connected operation control maintains the stability of the tie-line power by adjusting the power of the photovoltaic, energy storage, and load, provides frequency modulation and voltage regulation services, and suppresses fluctuations to achieve peak shaving and valley filling; the off-grid operation control uses the energy storage as the main power source to provide voltage and frequency support in the off-grid state, and the photovoltaic operates according to the instructions of the microgrid energy management system; the grid-connected / off-grid switching control quickly switches to off-grid operation when the voltage and frequency are abnormal and realizes grid-connected switching when the external power grid is restored.

[0018] Furthermore, the emergency stability control method monitors the current and voltage of the photovoltaic, load, system tie-line, and main transformer in real time, calculates the power and system frequency, and according to the fault situation, calculates the power loss and control amount in real time, and executes emergency control measures such as generator tripping and load shedding to ensure the rapid execution of control instructions, and adjusts the control strategy through a feedback mechanism.

[0019] The present invention discloses a source-network-load-storage coordinated control system and method for large-capacity multi-configuration network energy storage interconnection. The system can effectively improve the grid-connected performance of new energy power stations, enhance the stability and reliability of the power grid, improve the consumption capacity of new energy, and optimize the economy of the system. By jointly operating the configuration network energy storage device with new energy, it effectively supports the power grid, solves the coordinated control problem of multi-voltage source parallel operation, avoids oscillation and circulating current, and improves the overall performance and power supply guarantee ability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the composition of the source-network-load-storage coordinated control system for large-capacity multi-configuration network energy storage interconnection of the present invention.

[0021] Figure 2 It is a schematic diagram of the positions of the three defense lines formed by the present invention before, during, after an accident, and during system restoration. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0023] Such as Figure 1The source-network-load-storage coordinated control system for large-capacity multi-configuration networked energy storage interconnection shown forms the hierarchical structure of the source-network-load-storage integrated coordinated control system, including:

[0024] The master station layer responsible for receiving superior dispatching instructions, issuing emergency control instructions, and performing economic optimization dispatching and rapid coordinated control on photovoltaic and energy storage resources;

[0025] The sub-station layer responsible for accessing information of photovoltaic, load, and energy storage resources and decomposing and issuing superior instructions to achieve local frequency and voltage control functions;

[0026] The terminal layer that receives the generator tripping command or power regulation command issued by the emergency state monitoring device.

[0027] The so-called large-capacity multi-configuration networked energy storage interconnection means the joint operation of large-capacity multi-configuration networked energy storage. Specifically, multiple networked energy storage devices above ten megawatts are operated in parallel, and multi-machine active controllability is achieved through an advanced control system. This operation mode can solve the coordinated control problem of multiple voltage sources in parallel operation, avoid oscillation and circulating current problems between units, and thus realize the stable operation of large-capacity energy storage systems at the large power grid level. Through multi-machine self-synchronizing parallel operation control, the joint operation of large-capacity multi-configuration networked energy storage not only improves the overall capacity of the system but also enhances the power grid's acceptance capacity for new energy, providing strong support for the stable operation of the new power system.

[0028] The master station layer is arranged in the centralized control station and consists of the emergency state stability control master station, the rapid coordinated control master station, and the steady-state coordinated optimization dispatching part of the dispatching system. Among them, the layout of the master station needs to comprehensively consider multiple key factors to ensure that it can efficiently and reliably perform the coordinated control function:

[0029] In terms of location selection: The master station should be close to the power dispatching center to facilitate efficient data interaction and coordinated control with the power grid dispatching system. In addition, the master station also needs to be located in an area with perfect communication infrastructure to ensure stable, reliable, and low-latency communication between all links of the power source, power grid, load, and energy storage.

[0030] In terms of hardware facilities: The master station needs to be equipped with high-performance servers to process a large amount of data and complex computing tasks to ensure the rapid response and stable operation of the system. At the same time, to store important information such as historical data and operation logs, the master station also needs to be equipped with reliable storage devices.

[0031] In terms of software systems: The master station should select a stable and secure operating system and configure a high-performance database management system to meet the needs of data storage and query. In addition, install professional source-network-load-storage coordinated control software to achieve real-time monitoring, analysis, and control of each link. At the same time, deploy security protection software such as firewalls and intrusion detection to ensure the secure operation of the master station system.

[0032] In terms of environmental requirements: The main station should be arranged in a computer room with good temperature, humidity control and ventilation conditions to ensure the normal operation of the equipment. In addition, backup power supply equipment such as uninterruptible power supplies (UPS) should be equipped to ensure that the main station can still operate normally in case of unstable power supply.

[0033] In short, the layout of the main station for source-grid-load-storage coordinated control needs to comprehensively consider multiple factors such as location, hardware facilities, software systems and environment to ensure that it can efficiently and reliably execute the coordinated control function.

[0034] The main station layer has functions such as power prediction, economic optimal dispatching, emergency state stability control, fast coordinated control, and broadband oscillation monitoring, realizes off-grid operation control function, realizes power coordinated control at multiple time scales, is mainly used for economic optimal dispatching and fast coordinated control of photovoltaic and energy storage resources during off-grid transient and steady-state operation, receives superior dispatching instructions, issues emergency control instructions, uniformly coordinates photovoltaic energy storage, and issues fast adjustment instructions.

[0035] Among them, to achieve power prediction or load prediction under source-grid-load-storage coordinated control, the following measures are required:

[0036] I. Data source collection

[0037] 1. Power source side data

[0038] For traditional energy power generation, such as thermal power generation, collect information such as the operating parameters of the generator set, fuel supply situation, and equipment status. These parameters can reflect the current output capacity of the generator set and the possible future change trends.

[0039] For new energy power generation, such as wind power generation and photovoltaic power generation, collect meteorological data such as wind speed, wind direction, light intensity, temperature, and the operating status data of power generation equipment. These data are closely related to the power generation of new energy and can be obtained through equipment such as meteorological monitoring stations and sensors.

[0040] 2. Grid side data

[0041] Collect electrical parameters such as the voltage, current, and frequency of the power grid, as well as information such as the topological structure of the power grid and line impedance. These data can reflect the operating status and transmission capacity of the power grid and have an important impact on power prediction.

[0042] Monitor the load situation of the power grid, including the load demands in different regions and different time periods, to understand the power consumption trend of the power grid.

[0043] 3. Load side data

[0044] Collect the electricity consumption behavior data of users, such as the electricity consumption patterns of different types of users, load curves, etc. Real-time electricity consumption data can be obtained through devices such as smart meters and analyzed and statistically processed.

[0045] Consider the data of interruptible loads and demand response resources, and understand the response capabilities and potentials of these resources under different conditions.

[0046] 4. Energy storage side data

[0047] Monitor parameters such as the capacity, charge and discharge status, and charge and discharge efficiency of energy storage devices. Understand the current status and available capacity of energy storage devices so as to reasonably consider the regulation role of energy storage in power prediction.

[0048] II. Coordinated control strategy

[0049] 1. Power source side control

[0050] For traditional energy power generation, adjust the output power of the generator set according to the power prediction results, optimize the operating status of the unit, and improve the power generation efficiency.

[0051] For new energy power generation, by predicting future meteorological conditions and power generation power, reasonably arrange the grid connection strategy of new energy to reduce the impact on the power grid. For example, when strong winds are predicted, the grid connection power of wind power generation can be increased in advance; when the light intensity is predicted to weaken, the output power of photovoltaic power generation can be appropriately reduced.

[0052] 2. Power grid side control

[0053] According to the power prediction results, optimize the operation mode and dispatching strategy of the power grid. For example, adjust the tap of the transformer, optimize the power flow distribution of the line, reasonably arrange the reserve capacity, etc. to improve the stability and reliability of the power grid.

[0054] Utilize smart grid technology to achieve real-time monitoring and control of the power grid, respond to power changes in a timely manner, and ensure the safe operation of the power grid.

[0055] 3. Load side control

[0056] Based on the power prediction results, implement demand side management to guide users to use electricity reasonably. For example, through incentive measures such as time-of-use electricity prices, encourage users to use electricity during off-peak hours and reduce the load demand during peak hours.

[0057] Utilize interruptible loads and demand response resources to adjust the load in a timely manner when the power grid is under stress to relieve the pressure on the power grid.

[0058] 4. Energy storage side control

[0059] According to the power prediction results, reasonably arrange the charge and discharge strategies of energy storage devices. When the new energy generation power is excessive, store the excess electric energy; when the load demand is at a peak or the new energy generation is insufficient, release the electric energy in the energy storage devices to achieve power balance and regulation.

[0060] Optimize the operating parameters of energy storage devices to improve energy storage efficiency and service life.

[0061] III. Real-time Monitoring and Correction

[0062] 1. Real-time Monitoring

[0063] Establish a real-time monitoring system to monitor the operating status and power data of each link of the power source, grid, load, and energy storage in real time. Timely detect abnormal situations and power fluctuations to provide a basis for correcting power prediction.

[0064] 2. Prediction Correction

[0065] According to the real-time monitoring data, correct and update the power prediction results. For example, if there is a large deviation between the actual power and the predicted power, the reason for the deviation can be analyzed, the parameters of the prediction model can be adjusted, or a new prediction method can be adopted to improve the accuracy of the prediction.

[0066] 3. Feedback Adjustment

[0067] Feed back the results of power prediction and coordinated control to each link of the power source, grid, load, and energy storage, and continuously adjust the control strategies and parameters to achieve the optimal operation of the system. For example, if it is found that a certain control strategy has poor effects, the strategy can be adjusted in a timely manner to adapt to the changes in the actual operating conditions.

[0068] Through the above measures, power prediction and load prediction under the coordinated control of the power source, grid, load, and energy storage can be realized, meeting the collaborative control of various functions, and improving the stability, reliability, and economy of the system. At the same time, with the continuous progress of technology and the continuous accumulation of data, the accuracy and reliability of the prediction will continue to improve, providing more powerful support for the coordinated control of the power source, grid, load, and energy storage.

[0069] The sub-station layer is respectively installed near the photovoltaic side, energy storage side, and load side. The superior instructions received by the sub-station layer are the instructions of the fast coordination control master station, the instructions of the emergency state stability control master station, or the manual remote instructions of the dispatching system. After receiving the instructions of the fast coordination control master station, the emergency state stability control master station, and the manual remote instructions of the dispatching system, the sub-station layer issues cut-off or adjustment instructions to the control terminal device. The sub-station layer completes the information access and statistical processing of the photovoltaic inverter and uploads it to the coordinated control device of the power source, grid, load, and energy storage. The energy storage coordination control device is installed near the energy storage container to realize the information access and coordinated management and control of the energy storage converter, respond to the control instructions of the coordinated controller of the power source, grid, load, and energy storage, and decompose and issue them to the execution end of the energy storage converter to achieve the fast coordinated control of the energy storage system.

[0070] The terminal layer consists of emergency state stable execution stations on the side of each substation and fast power control terminals on the new energy side. The source control terminal quickly acquires and identifies the operating conditions of the power generation units, and uploads the operating information of the power generation units required for millisecond-level emergency control to the emergency state monitoring device. It monitors its own operating status and uploads the operating status information to the emergency state monitoring device. It acquires the three-phase voltage and three-phase current of the power generation unit (AC side of the photovoltaic inverter), and the sampling frequency is not less than 1200 Hz. It receives the generator tripping command or power adjustment command issued by the emergency state monitoring device and quickly issues it.

[0071] On the basis of giving priority to meeting the requirements of the three lines of defense of the large power grid, the integrated coordinated control system of the source, grid, load, and energy storage is integrated. When a fault occurs in the large power grid, the first line of defense is given priority to be activated. When an accident occurs, the fast coordinated control mode is first activated. The integrated coordinated control system of the source, grid, load, and energy storage realizes the stable operation of the integrated coordinated control system and the off-grid state according to the operating conditions of the system after the fault occurs. According to different operating states, it usually includes grid-connected operation control, off-grid operation control, and seamless grid-connected and off-grid switching control, etc., to support the stable operation of the large power grid. Then it quickly enters the emergency state stable control mode. The emergency state stable control system acquires the three-phase current and voltage of each photovoltaic, load, system tie line, main transformer, and in-station collector line, and calculates the power and system frequency in real time, and counts the total cuttable and adjustable amounts of the photovoltaic and load. It discriminates the system operation mode in real time, detects the operating status of the line, main transformer, large load, and photovoltaic energy storage. When a fault occurs in the system, it calculates the power loss amount in real time, and calculates the control amount in real time according to the controllable and adjustable amount, and issues control commands to cut or adjust the photovoltaic, energy storage, and load, and each control unit executes them. When the large power grid system recovers, the entire system returns to the state before the fault.

[0072] The three lines of defense of the power grid are important mechanisms to ensure the safe and stable operation of the power system. They play roles in different operating states of the power system respectively to prevent the system from collapsing and reduce the power outage range. The following is a detailed explanation of the three lines of defense of the power grid:

[0073] The first line of defense: When the power system under normal operating mode is subjected to a single fault disturbance, the relay protection device correctly operates to quickly cut off the fault, maintaining the stable operation of the power system and the normal power supply of the power grid.

[0074] Main measures: Fast and reliable relay protection, effective preventive control measures, including regular maintenance and repair of equipment, and optimization and adjustment of the power grid operating mode, etc., to reduce the probability of faults occurring.

[0075] The second line of defense: When the power system under normal operating mode is subjected to a more serious fault disturbance, after the relay protection device correctly operates, through stable control measures such as generator tripping and load shedding, it ensures that the power grid can continue to operate stably.

[0076] Main measures: Stable control devices such as automatic voltage regulators (AVRs), power system stabilizers (PSSs), etc., are used to provide necessary stability support when the power grid is severely disturbed; emergency control measures such as generator tripping and load shedding are taken to reduce the burden on the power grid by removing some generators or loads when serious faults occur in the power grid, preventing the power grid from collapsing.

[0077] The third line of defense: After the stability of the power system is damaged, the stability control measures to prevent the expansion of accidents constitute the third line of defense. Measures such as disconnecting the power grid are taken to prevent the entire system from collapsing, ensuring power supply to some important users and avoiding long-term and large-scale power outages.

[0078] Main measures: Out-of-step splitting devices, emergency frequency and voltage control devices, etc. When the frequency or voltage of the power grid is abnormal, the output of generators is adjusted, some loads are removed, etc. to restore the frequency and voltage of the power grid to normal levels.

[0079] As Figure 2 shown, what is presented is the positions of the three lines of defense before, during, after an accident, and during system restoration. The first line of defense is established at the moment of the accident and is summarized as consisting of fast and reliable relay protection and effective preventive control measures to ensure that the power grid remains stable during common single faults and quickly cut off the faults. The second line of defense: During the accident, stable control devices and event-based emergency stability controls such as generator tripping and load shedding are used to ensure that the power grid can continue to operate stably when more serious faults occur. The third line of defense: After the accident, out-of-step splitting and emergency frequency and voltage control devices are set up. When the power grid encounters multiple serious accidents and stability is damaged, it prevents the expansion of accidents and avoids large-scale power outages. These three lines of defense are interconnected and cooperate with each other to jointly form the safety protection system of the power grid. The first line of defense ensures the stable operation of the power system in the face of single faults; the second line of defense provides additional stability support in the face of more serious faults; and the third line of defense takes final measures when the system stability is severely threatened to prevent the expansion of accidents and system collapse.

[0080] Meanwhile, the present invention also discloses a control method for a source-network-load-storage coordinated control system with large-capacity multi-configuration network energy storage interconnection. The control method includes a steady-state optimization control method, a fast coordination control method, and an emergency stability control method.

[0081] The steady-state optimization control method is to collect historical power data, weather forecast data, and real-time load data, and based on the prediction results, optimize the allocation of source-network-load-storage resources. Power prediction and load prediction technologies are used, combined with economic and clean energy consumption goals, to prepare power generation plans and optimize dispatching, and adjust the optimization strategy according to real-time operation data and prediction errors to improve prediction accuracy and system operation efficiency.

[0082] Specifically, the steady-state optimal control is as follows:

[0083] 1. Photovoltaic power prediction

[0084] The photovoltaic power prediction has the following functions: obtaining historical power prediction data, obtaining historical numerical weather forecast data, obtaining historical meteorological monitoring data, short-term power prediction, ultra-short-term power prediction, interface monitoring, prediction accuracy statistics, and prediction result release.

[0085] 2. Load prediction

[0086] The load prediction function module is a function module of the master station system for calculation and analysis, and can perform predictions based on SCADA real-time load data and load historical data.

[0087] The load prediction has the following functions: obtaining load historical data, short-term load prediction, ultra-short-term load prediction, influencing factor correction, error statistical analysis, prediction accuracy statistics, and prediction result release.

[0088] 3. Coordinated optimal scheduling of sources, grid, load, and energy storage

[0089] The system provides a function for compiling a power generation plan with the goals of economic optimization and maximum consumption of clean energy. Users can select optimization goals and adjust optimization constraint settings according to the requirements of different operation scenarios to achieve multi-objective optimization. Based on the dispatching automation system, research and application work on integrated control of sources, grid, load, and energy storage are carried out to improve the economy of the power grid and the consumption capacity of new energy while ensuring the safety of the power grid.

[0090] 4. Coordinated active power control of sources, grid, load, and energy storage

[0091] The active power coordination control master station is used to control the active power of energy sources other than energy storage, mainly including photovoltaic power control. Its main functions include area control and substation control, etc. Area control is to divide the power generation resources in the system, calculate the control objectives of each area, and formulate the active power distribution strategy of the control resources within the area. Substation control is to calculate control instructions and check control commands for photovoltaic substations under the area.

[0092] 5. Coordinated reactive power control of sources, grid, load, and energy storage

[0093] The basic principle of the coordinated reactive power control module of sources, grid, load, and energy storage is the "layered and partitioned, local balance" of reactive power. Based on the collected real-time operation data of new energy power stations, online optimization and closed-loop control are performed on reactive power equipment such as photovoltaic inverters, energy storage reactive power, on-load tap-changers of transformers, switchable shunt capacitors and reactors, and SVG to ensure the safe and stable operation of the power grid, ensure the qualified power grid voltage quality, achieve the layered and partitioned balance of reactive power, and reduce network losses.

[0094] The fast coordinated control method includes grid-connected operation control, off-grid operation control, and seamless grid-connected / off-grid switching control. Grid-connected operation control maintains the stability of tie-line power by adjusting the power of photovoltaic, energy storage, and load, provides frequency modulation and voltage regulation services, and suppresses fluctuations to achieve peak shaving and valley filling. Off-grid operation control uses the energy storage as the main power source in the off-grid state to provide voltage and frequency support, and the photovoltaic operates according to the instructions of the microgrid energy management system. Grid-connected / off-grid switching control quickly switches to off-grid operation when the voltage and frequency are abnormal, and realizes grid-connected switching when the external power grid is restored.

[0095] Specifically, the fast coordinated control is as follows:

[0096] According to different operating states, it usually includes grid-connected operation control, off-grid operation control, and seamless grid-connected / off-grid switching control, etc., and can be compatible with the recent off-grid operation and the long-term grid-connected operation conditions.

[0097] 1. Grid-connected operation control

[0098] Tie-line power control: To avoid the impact of large fluctuations in tie-line power on the power grid flow, by adjusting the power of photovoltaic, energy storage, and adjustable load, the tie-line power is maintained within a predetermined range, making the source-grid-load-storage system a controllable source / load, so that new energy can be friendly connected to the power grid. At the same time, maximize the use of the energy transfer ability of the energy storage. When there is an excess of new energy, control the energy storage to charge; when there is a shortage of new energy, control the energy storage to discharge, maximizing the reduction of the wind and light abandonment rate and improving the economic benefits of users.

[0099] Frequency modulation and voltage regulation: Photovoltaic energy storage responds to dispatch instructions or according to local voltage and frequency, quickly increases or decreases power to provide frequency modulation and voltage regulation services for the power grid;

[0100] Fluctuation suppression: The fluctuation of photovoltaic output leads to the fluctuation of tie-line power. According to the power fluctuation of the tie-line, control the charge and discharge of the energy storage to achieve the smoothing of tie-line power and improve the power quality of the regional power grid;

[0101] Peak shaving and valley filling: The energy storage output can be controlled according to the peak shaving and valley filling curve issued by the dispatch, making the source-grid-load-storage system a good citizen of the power grid system. It can also set the peak-valley output curve locally, generate electricity at peak electricity prices and absorb electricity at valley electricity prices to obtain the peak-valley electricity price difference profit and improve the economic benefits of the source-grid-load-storage system.

[0102] 2. Off-grid operation control

[0103] During off-grid operation, the energy storage serves as the main power source of the integrated coordinated control system, operates in the VSG mode, ensures the stability of the bus voltage and frequency, and the photovoltaic operates according to the power instructions of the microgrid energy management system to achieve off-grid stable operation control.

[0104] A. Frequency partition control

[0105] Frequency zoning is carried out according to the frequency deviation value caused by disturbances, and different frequency regulation means in different intervals are coordinated with each other: energy storage VSG frequency regulation (primary) + fast frequency regulation (secondary) + voltage and frequency emergency control (tertiary). Different deviations and different time scales are coordinated and controlled to ensure the frequency stability of the system.

[0106] B. Fast power control technology

[0107] Based on the current system frequency and operating status, quickly adjust the power of energy storage / wind / solar, so that the power is quickly balanced.

[0108] C. Optimal control based on energy storage status

[0109] The off-grid system establishes voltage and frequency by energy storage. To ensure the stable operation of the energy storage, it is necessary to monitor the power and energy of the energy storage in real time: when the battery power is high, limit the output of new energy to avoid system collapse caused by the battery being fully charged; when the battery power is high, start other power sources or reduce the load to avoid system collapse caused by the battery being emptied; when the new energy power is too large and the energy storage charging power exceeds the limit, quickly limit the output of new energy to avoid system collapse caused by the battery charging power exceeding the limit; when the load power is too large and the energy storage discharge power exceeds the limit, quickly reduce the load to avoid system collapse caused by the battery discharge power exceeding the limit.

[0110] 3. Grid-connected and off-grid switching control

[0111] When voltage and frequency anomalies occur in the grid-connected state, quickly disconnect the grid connection point switch and switch the energy storage to the voltage source mode to achieve the switching from grid-connected to off-grid, improving the power supply reliability of the source-grid-load-storage system; when the external power grid resumes power supply in the off-grid state, monitor the voltage and frequency deviations on both sides of the grid connection point, issue frequency and voltage regulation commands to the energy storage until the synchronization conditions are met, synchronize and close the grid connection point switch, and switch the energy storage to the power source mode to achieve the switching from off-grid to grid-connected.

[0112] The emergency stability control method is to calculate the power and system frequency by real-time monitoring of the current and voltage of photovoltaic, load, system tie line, and main transformer, calculate the power loss and control amount according to the fault situation, execute emergency control measures such as generator tripping and load shedding, ensure the rapid execution of control commands, and adjust the control strategy through the feedback mechanism.

[0113] Specifically, the emergency stability control is as follows:

[0114] The emergency state stability control system collects the currents and voltages of each photovoltaic power source, load, system tie line, main transformer, and in-station collector line, calculates the power and system frequency in real time, and statistically calculates the total cuttable and adjustable amounts of the photovoltaic power sources and loads. It discriminates the system operation mode in real time, detects the operation states of the lines, main transformers, large loads, and photovoltaic-storage systems. When a system fault occurs, it calculates the power loss amount in real time, calculates the control amount based on the controllable and adjustable amounts in real time, issues control commands to cut or adjust the photovoltaic power sources, energy storage systems, and loads, and these commands are executed by each control unit.

[0115] It detects the system frequency and voltage in real time and can achieve local primary frequency regulation and fast voltage regulation functions according to the bus frequency and voltage. When the frequency exceeds the limit, it controls the active power output of the new energy power plant according to the primary frequency regulation setting value issued by the dispatching department. The primary frequency regulation function includes setting values such as frequency dead zone setting value, regulation rate, and amplitude regulation limit, which are set according to the primary frequency regulation setting value issued by the dispatching department.

[0116] It can communicate directly with the inverter controller (or data concentrator, communication management machine), fast coordination control sub-station, steady-state optimization control sub-station, etc., control the rapid power increase and decrease or direct cut-off of the photovoltaic power station, decompose the power regulation command and quickly issue it to each inverter (data collector) to achieve rapid power control. It has the high-speed communication ability with the inverter (data concentrator or communication management machine), receives the active power, reactive power, terminal voltage of the inverter and its operation states (grid-connected, standby, off-grid, low voltage ride-through, high voltage ride-through, etc.) sent by it. It realizes the panoramic monitoring of the new energy power plant. It can decompose the modulation amount to each inverter according to relevant control strategies and quickly issue it to achieve rapid power regulation.

[0117] In summary, the present invention is a pioneering design scheme for the integrated coordination control system of source-network-load-storage, which can improve the grid-connected performance of large-capacity "new energy + energy storage" power stations above megawatt level while ensuring the safety of the power grid and the joint operation of large-capacity multi-configuration energy storage, and simultaneously meet the operation reliability, economy, new energy access, and power supply guarantee capabilities of the large power grid. In the context of the access of large-capacity photovoltaic power and energy storage, there will be more and more scenarios of joint operation of large-capacity multi-configuration energy storage at the large power grid level, and the integrated coordination control of source-network-load-storage is particularly important. This system is mainly used to coordinate the control of multiple PCSs to achieve advanced control functions, such as fast power tracking response, frequency regulation, voltage regulation, etc., for multi-machine active controllability, solve the coordination control problem of parallel operation of multiple voltage sources, and avoid problems such as oscillation and circulating current between units. After the successful application of this system, it can greatly improve the regional power supply capacity and power supply reliability, and at the same time improve the new energy consumption capacity, with significant economic, social, and environmental benefits.

[0118] The above embodiments are not limitations on the present invention, and the present invention is not limited to the above examples either. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the technical solution of the present invention also fall within the protection scope of the present invention.

Claims

1. A source-network-load-storage coordinated control system for large-capacity multi-configuration networked energy storage intermodal transportation, characterized in that Including: The master station layer responsible for receiving superior dispatching instructions, issuing emergency control instructions, and performing economic optimization dispatching and rapid coordinated control on photovoltaic and energy storage resources; The sub-station layer responsible for accessing the information of photovoltaic, load, and energy storage resources and decomposing and issuing superior instructions to achieve local frequency and voltage control functions; The terminal layer that receives the generator tripping command or power regulation command issued by the emergency state monitoring device.

2. The source-network-load-storage coordinated control system for large-capacity multi-configuration networked energy storage intermodal transportation according to claim 1, wherein: The master station layer is arranged in the centralized control station and consists of the emergency state stability control master station, the rapid coordinated control master station, and the steady-state coordinated optimization dispatching part of the dispatching system.

3. The source-network-load-storage coordinated control system for large-capacity multi-configuration networked energy storage intermodal transportation according to claim 1, characterized in that: The sub-station layer is respectively installed near the photovoltaic side, the energy storage side, and the load side.

4. The source-network-load-storage coordinated control system for large-capacity multi-configuration networked energy storage intermodal transportation according to any one of claims 1 to 3, characterized in that: The superior instructions received by the sub-station layer are the instructions of the rapid coordinated control master station, the instructions of the emergency state stability control master station, or the manual remote instructions of the dispatching system, and cut-off or regulation instructions are issued to the control terminal device; the sub-station layer completes the information access and statistical processing of the photovoltaic inverter and uploads it to the source-network-load-storage coordinated control device.

5. The source-network-load-storage coordinated control system for large-capacity multi-configuration networked energy storage intermodal transportation according to claim 4, wherein: The energy storage coordinated control device is installed near the energy storage container to realize the information access and coordinated management and control of the energy storage converter, responds to the control instructions of the source-network-load-storage coordinated controller, and decomposes and issues them to the execution end of the energy storage converter to achieve rapid coordinated control of the energy storage system.

6. The source-network-load-storage coordinated control system for large-capacity multi-configuration networked energy storage intermodal transportation according to claim 1 or 2, characterized in that: The terminal layer consists of the emergency state stability execution station located on the side of each substation and the rapid power control terminal on the new energy side.

7. A control method for a source-network-load-storage coordinated control system of large-capacity multi-configuration networked energy storage intermodal transportation, characterized in that: The control method includes a steady-state optimization control method, a rapid coordinated control method, and an emergency stability control method.

8. The control method of the source-network-load-storage coordination control system for large-capacity multi-configuration networked energy storage intermodal transportation according to claim 7, characterized in that: The steady-state optimization control method is to collect historical power data, weather forecast data, and real-time load data, and based on the prediction results, optimize the allocation of source-network-load-storage resources, adopt power prediction and load prediction technologies, combine economic and clean energy consumption goals, compile the power generation plan and optimize the dispatching, and adjust the optimization strategy according to the real-time operation data and prediction error to improve the prediction accuracy and system operation efficiency.

9. The control method of the source-network-load-storage coordination control system for large-capacity multi-configuration networked energy storage intermodal transportation according to claim 8, characterized in that: The rapid coordinated control method includes grid-connected operation control, off-grid operation control, and seamless grid-connected / off-grid switching control. The grid-connected operation control maintains the stability of the tie-line power by adjusting the power of photovoltaic, energy storage, and load, provides frequency modulation and voltage regulation services, and flattens the fluctuations to achieve peak shaving and valley filling; the off-grid operation control uses the energy storage as the main power source to provide voltage and frequency support in the off-grid state, and the photovoltaic operates according to the instructions of the microgrid energy management system; the grid-connected / off-grid switching control quickly switches to off-grid operation when the voltage and frequency are abnormal and realizes grid-connected switching when the external power grid is restored.

10. The control method of the source-network-load-storage coordination control system for large-capacity multi-configuration networked energy storage intermodal transportation according to claim 8, characterized in that: The emergency stability control method is to calculate the power and system frequency by real-time monitoring of the current and voltage of photovoltaic, load, system tie-line, and main transformer, calculate the power loss and control amount according to the fault situation, execute emergency control measures such as generator tripping and load shedding, ensure the rapid execution of control instructions, and adjust the control strategy through the feedback mechanism.

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