Reactive voltage combined regulation integration method and system for accessing network-forming type new energy power station to 220kV power grid

Abstract

The invention discloses a reactive voltage joint regulation integration method for accessing a network-building type new energy power station to a 220kV power grid, and the method comprises the steps: building a network-building type new energy cluster, connecting equipment in the network-building type new energy cluster in parallel to a power station collection bus, and configuring a super capacitor module; an intelligent coordination controller is established, and the intelligent coordination controller collects the electrical quantity of a collection bus in real time based on a DSP + FPGA multi-core architecture and obtains a power grid dispatching instruction through a high-speed communication network; determining a hierarchical control strategy of the intelligent coordination controller, and generating a control instruction of the network-forming type new energy cluster based on the power grid dispatching instruction through the hierarchical control strategy; an energy storage-network construction cooperation module is established, an energy storage system in the energy storage-network construction cooperation module is coupled with a network construction type converter through a direct current bus, and a hybrid control mode of active frequency modulation and reactive voltage regulation is adopted; and establishing a power grid interaction interface, wherein the power grid interaction interface comprises a 220kV booster station, an optical CT / PT measuring device and a fault recording device.

Description

Technical Field

[0001] This invention relates to the field of new energy grid connection technology, and more specifically, to an integrated method and system for reactive power and voltage joint regulation of grid-connected new energy power plants connected to a 220kV power grid. Background Technology

[0002] Against the backdrop of today's energy transition and the "dual carbon" trend, new energy power generation, with its advantages of being clean and renewable, has seen explosive and rapid growth in installed capacity. However, the rapid development of new energy power generation has also brought a series of severe challenges to the safe and stable operation of the power system.

[0003] Traditional grid-connected renewable energy power plants, encompassing various forms such as wind and solar power, rely heavily on the voltage and frequency support of the power grid. This characteristic makes them highly susceptible to cascading grid disconnections in weak grid environments or during grid failures, leading to insufficient inertia and significant voltage fluctuations throughout the power system. For example, when a short-circuit fault occurs in the grid, traditional renewable energy power plants, due to limitations in their design principles, cannot provide sufficient short-circuit current to support grid stability. In such cases, to avoid further damage to their equipment, these plants are forced to disconnect from the grid. The concentrated disconnection of numerous power plants further exacerbates power system instability, creating a vicious cycle that seriously threatens the safe and stable operation of the power grid. Furthermore, renewable energy generation is highly intermittent and volatile, significantly increasing the difficulty of reactive power and voltage regulation in the 220kV grid. While existing automatic voltage control systems (AVCs) can achieve reactive power optimization within a region to some extent, their design concepts and technical architecture limitations make it difficult to meet the active grid support requirements of grid-connected renewable energy power plants and adapt to the new grid structure with a high proportion of renewable energy integration.

[0004] Currently, grid-based renewable energy technologies, by simulating the characteristics of synchronous generators, endow renewable energy power plants with the ability to autonomously construct voltage and frequency. This technological breakthrough provides a key direction for solving the aforementioned problems. For example, grid-based power storage converters (PCS) can achieve millisecond-level inertial response through virtual synchronous generator (VSG) technology, which can quickly suppress grid frequency disturbances and play a positive role in maintaining grid frequency stability. However, despite the enormous potential shown by grid-based renewable energy technologies, existing technologies still have many shortcomings in practical applications and require further improvement and refinement.

[0005] First, there is the problem of insufficient multi-source coordinated control. Grid-based renewable energy power plants typically include various types of power sources, such as grid-based wind turbines, energy storage devices, and SVG (Static Var Generators). These devices each have their own strategies and mechanisms for reactive power and voltage regulation. However, there is currently a lack of a unified coordination mechanism to manage the operation of these devices, leading to timing mismatches when responding to grid changes. This mismatch not only reduces the overall regulation efficiency of the power plant but may also cause mutual interference in some cases, affecting the stable operation of the grid. Second, there is limited adaptability to weak grids. In the terminal areas of the 220kV grid, or in areas with a dense distribution of renewable energy power plants, the grid structure is relatively weak, and the operating conditions are more complex. The voltage support capability of existing grid-based equipment in these areas is limited by its own topology and control algorithms, making it difficult to effectively cope with broadband oscillations and unable to achieve black start functionality. Black start functionality is crucial for the rapid recovery of the grid after a large-scale power outage, and the shortcomings of grid-based equipment in this regard affect the grid's resilience and recovery speed. Finally, there is the difficulty in balancing economic efficiency and reliability. Traditional grid-based systems often rely on high-cost supercapacitors or customized hardware to ensure performance, significantly increasing initial investment costs. Furthermore, these systems lack dynamic parameter self-tuning capabilities, requiring substantial manual intervention for parameter adjustments during operation. This not only increases maintenance costs but also fails to guarantee optimal system performance, resulting in high total lifecycle costs. Over-reliance on specific hardware can also reduce system reliability; failure of these critical components can severely impact the entire system's operation. Summary of the Invention

[0006] The present invention provides a method and system for the joint regulation and integration of reactive power and voltage of grid-connected new energy power plants connected to the 220kV power grid, in order to solve the problem of how to perform joint regulation and integration of reactive power and voltage of grid-connected new energy power plants connected to the 220kV power grid.

[0007] To address the aforementioned problems, this invention provides an integrated method for reactive power and voltage joint regulation of grid-connected new energy power plants connected to a 220kV power grid. The method includes:

[0008] Establish a grid-type new energy cluster, wherein the equipment in the grid-type new energy cluster is connected in parallel to the power station's collection bus and configured with supercapacitor modules;

[0009] An intelligent coordination controller is established, which is based on a DSP+FPGA multi-core architecture to collect electrical quantities of the collection bus in real time and obtain power grid dispatch instructions through a high-speed communication network.

[0010] Determine the hierarchical control strategy of the intelligent coordination controller, and generate control instructions for the grid-type new energy cluster based on the power grid dispatch instructions using the hierarchical control strategy;

[0011] An energy storage-grid collaborative module is established, in which the energy storage system is coupled to the grid-type converter through a DC bus, and a hybrid control mode of active frequency regulation + reactive voltage regulation is adopted.

[0012] A power grid interaction interface is established, which includes a 220kV step-up substation, an optical CT / PT measurement device, and a fault recording device.

[0013] The equipment in the grid-type new energy cluster includes: multiple grid-type wind turbines (GWT), multiple grid-type energy storage converters (PCS), and multiple grid-type static var generators (SVG); the grid-type wind turbines (GWT) adopt a doubly-fed converter + virtual synchronous generator (VSG) control strategy, and the grid-type energy storage converter integrates a three-level topology and model prediction algorithm.

[0014] Preferably, the hierarchical control strategy includes: upper-layer MPC optimization and lower-layer improved droop control;

[0015] The upper-layer MPC optimization is based on the model predictive control MPC algorithm, which combines the real-time operation status of the power grid and the power output prediction of new energy sources to dynamically generate reactive power commands and voltage reference values ​​for each device in the grid-type new energy cluster.

[0016] The improved droop control at the lower level adjusts the virtual impedance and damping coefficient of each device by improving the droop control strategy, thereby achieving reactive power sharing and oscillation suppression when multiple machines are connected in parallel.

[0017] Preferably, the energy storage system in the energy storage-grid collaborative module is coupled to the grid-type converter via a DC bus, and adopts a hybrid control mode of active power frequency regulation + reactive power voltage regulation, including:

[0018] When the grid frequency deviation exceeds a preset threshold, the energy storage system provides inertia support by releasing or absorbing energy.

[0019] By adjusting reactive power distribution based on the dynamic droop coefficient relationship, a rapid response to voltage fluctuations can be achieved.

[0020] Preferably, it also includes determining the operating mode, including: steady-state operating mode, fault ride-through operating mode, and black start and islanded operating mode;

[0021] The steady-state operation mode is as follows: the intelligent coordination controller optimizes the reactive power distribution of each device in the grid-type new energy cluster according to the grid dispatch instructions and new energy output prediction through the MPC algorithm; the grid-type wind turbine adopts VSG control to simulate the inertia and damping characteristics of synchronous generators to maintain the stability of the bus frequency; the grid-type energy storage converter dynamically adjusts the reactive power output according to the droop curve to compensate for the reactive power deficit of the grid; the energy storage system achieves continuous support under extreme operating conditions through state of charge (SOC) optimization control.

[0022] The fault ride-through mode is as follows: when a grid fault is detected, the grid-type static var generator (SVG) immediately engages the supercapacitor module to release short-term active power to maintain its voltage source characteristics, and provides fault current support through virtual synchronous machine control; the intelligent coordination controller triggers the multi-device collaborative protection strategy in the grid-type new energy cluster: the grid-type wind turbine (GWT) quickly switches to current source control mode, and the grid-type energy storage converter (PCS) starts overcurrent protection and adjusts the virtual impedance to prevent the system oscillation from amplifying;

[0023] The black start and islanding operation are as follows: In a completely dark grid scenario, the grid-type energy storage converter PCS serves as the main power source and autonomously establishes voltage and frequency references through the black start program; the grid-type wind turbine GWT and the table-type grid-type static var generator SVG are then connected to the grid in sequence to form an islanded microgrid; the intelligent coordination controller dynamically adjusts the output distribution of each device according to the load demand to ensure continuous power supply to critical loads.

[0024] Based on another aspect of the present invention, the present invention provides an integrated reactive power and voltage regulation system for grid-connected new energy power plants connected to a 220kV power grid, the system comprising:

[0025] A grid-type new energy cluster, wherein the equipment in the grid-type new energy cluster is connected in parallel to the power station's collecting bus and configured with supercapacitor modules;

[0026] The intelligent coordination controller is based on a DSP+FPGA multi-core architecture to collect electrical quantities of the aggregation bus in real time and obtain grid dispatch instructions through a high-speed communication network. The intelligent coordination controller adopts a hierarchical control strategy and generates control instructions for the grid-type new energy cluster based on the grid dispatch instructions.

[0027] The energy storage-grid collaborative module, wherein the energy storage system in the energy storage-grid collaborative module is coupled to the grid-type converter through a DC bus, and adopts a hybrid control mode of active frequency regulation + reactive voltage regulation;

[0028] The power grid interaction interface includes a 220kV step-up substation, an optical CT / PT measurement device, and a fault recording device.

[0029] Preferably, the equipment of the grid-type new energy cluster includes: multiple grid-type wind turbines (GWT), multiple grid-type energy storage converters (PCS), and multiple grid-type static var generators (SVG); the grid-type wind turbines (GWT) adopt a doubly fed converter + virtual synchronous generator (VSG) control strategy, and the grid-type energy storage converter integrates a three-level topology and model prediction algorithm.

[0030] Preferably, the hierarchical control strategy includes: upper-layer MPC optimization and lower-layer improved droop control;

[0031] The upper-layer MPC optimization is based on the model predictive control MPC algorithm, which combines the real-time operation status of the power grid and the power output prediction of new energy sources to dynamically generate reactive power commands and voltage reference values ​​for each device in the grid-type new energy cluster.

[0032] The improved droop control at the lower level adjusts the virtual impedance and damping coefficient of each device by improving the droop control strategy, thereby achieving reactive power sharing and oscillation suppression when multiple machines are connected in parallel.

[0033] Preferably, the energy storage system in the energy storage-grid collaborative module is coupled to the grid-type converter via a DC bus, and adopts a hybrid control mode of active power frequency regulation + reactive power voltage regulation, including:

[0034] When the grid frequency deviation exceeds a preset threshold, the energy storage system provides inertia support by releasing or absorbing energy.

[0035] By adjusting reactive power distribution based on the dynamic droop coefficient relationship, a rapid response to voltage fluctuations can be achieved.

[0036] Preferably, it is also used to determine the operating mode, including: steady-state operating mode, fault ride-through operating mode, and black start and islanded operating mode;

[0037] The steady-state operation mode is as follows: the intelligent coordination controller optimizes the reactive power distribution of each device in the grid-type new energy cluster according to the grid dispatch instructions and new energy output prediction through the MPC algorithm; the grid-type wind turbine adopts VSG control to simulate the inertia and damping characteristics of synchronous generators to maintain the stability of the bus frequency; the grid-type energy storage converter dynamically adjusts the reactive power output according to the droop curve to compensate for the reactive power deficit of the grid; the energy storage system achieves continuous support under extreme operating conditions through state of charge (SOC) optimization control.

[0038] The fault ride-through mode is as follows: when a grid fault is detected, the grid-type static var generator (SVG) immediately engages the supercapacitor module to release short-term active power to maintain its voltage source characteristics, and provides fault current support through virtual synchronous machine control; the intelligent coordination controller triggers the multi-device collaborative protection strategy in the grid-type new energy cluster: the grid-type wind turbine (GWT) quickly switches to current source control mode, and the grid-type energy storage converter (PCS) starts overcurrent protection and adjusts the virtual impedance to prevent the system oscillation from amplifying;

[0039] The black start and islanding operation are as follows: In a completely dark grid scenario, the grid-type energy storage converter PCS serves as the main power source and autonomously establishes voltage and frequency references through the black start program; the grid-type wind turbine GWT and the table-type grid-type static var generator SVG are then connected to the grid in sequence to form an islanded microgrid; the intelligent coordination controller dynamically adjusts the output distribution of each device according to the load demand to ensure continuous power supply to critical loads.

[0040] This invention provides a method and system for the integrated regulation of reactive power and voltage in a grid-connected renewable energy power plant connected to a 220kV power grid. The method includes: establishing a grid-connected renewable energy cluster, with equipment in the cluster connected in parallel to the power plant's collection bus and configured with supercapacitor modules; establishing an intelligent coordination controller, which, based on a DSP+FPGA multi-core architecture, collects electrical quantities from the collection bus in real time and obtains grid dispatch instructions via a high-speed communication network; determining a hierarchical control strategy for the intelligent coordination controller, generating control instructions for the grid-connected renewable energy cluster based on the grid dispatch instructions; establishing an energy storage-grid coordination module, where the energy storage system is coupled to the grid-connected converter via a DC bus, employing a hybrid control mode of active power frequency regulation and reactive power voltage regulation; and establishing a grid interaction interface, which includes a 220kV step-up substation, an optical CT / PT measurement device, and a fault recording device. This invention aims to provide an integrated system for the integrated regulation of reactive power and voltage in a grid-connected renewable energy power plant connected to a 220kV power grid, addressing the multi-dimensional technical bottlenecks in existing technologies and comprehensively improving the coordinated operation performance of renewable energy power plants and the power grid. Attached Figure Description

[0041] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0042] Figure 1 This is a flowchart of a preferred embodiment of the present invention for a method of integrated reactive power and voltage regulation of a grid-connected new energy power station connected to a 220kV power grid;

[0043] Figure 2This is a schematic diagram of the integrated reactive power and voltage regulation system architecture for a seed-grid type new energy power station connected to a 220kV power grid according to a preferred embodiment of the present invention.

[0044] Figure 3 This is a flowchart of a hierarchical control strategy according to a preferred embodiment of the present invention;

[0045] Figure 4 This is a voltage and frequency diagram of the fault ride-through process according to a preferred embodiment of the present invention;

[0046] Figure 5 A flowchart illustrating the phased execution of a black start according to a preferred embodiment of the present invention; and

[0047] Figure 6 This is a structural diagram of the reactive power and voltage joint regulation integrated system for a seed-grid type new energy power station connected to a 220kV power grid according to a preferred embodiment of the present invention. Detailed Implementation

[0048] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0049] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0050] Figure 1 This is a flowchart of a preferred embodiment of the present invention for a method of integrated reactive power and voltage regulation of a grid-connected new energy power plant connected to a 220kV power grid.

[0051] The present invention aims to provide an integrated reactive power and voltage regulation system for grid-connected new energy power plants connected to the 220kV power grid, in order to solve the multi-dimensional technical bottlenecks existing in the prior art and comprehensively improve the coordinated operation performance of new energy power plants and the power grid.

[0052] Currently, with the large-scale integration of grid-connected renewable energy power plants into the 220kV grid, traditional regulation schemes have revealed several limitations: First, the lack of a unified coordination mechanism for various types of grid-connected equipment (such as grid-connected wind turbines, energy storage converters, SVG, etc.) leads to misaligned reactive power and voltage regulation response timing, which can easily cause voltage fluctuations and power distribution imbalances in high-proportion renewable energy scenarios. Second, existing control algorithms are not adaptable enough to grid topology changes and renewable energy output fluctuations. When the 220kV grid is in a weakly connected state, the system damping characteristics deteriorate, easily inducing stability problems such as subsynchronous oscillations. Third, hardware topology design fails to fully match the dynamic characteristics of grid-connected equipment. Traditional converter topologies cannot provide sufficient short-circuit current support during fault ride-through, and the energy interaction efficiency between energy storage and grid-connected equipment is low, restricting the active support capability. Fourth, existing systems lack robustness in extreme scenarios such as black start and islanded operation, failing to meet the grid's core functional requirements for renewable energy power plants as "virtual synchronous machines."

[0053] To this end, this invention achieves breakthroughs through three major technical paths: First, it constructs a multi-source collaborative control architecture, which dynamically allocates reactive power and voltage commands for grid-connected wind turbines, energy storage, and SVG based on a hierarchical optimization strategy, solving the problem of inconsistent responses among multiple devices; second, it develops an adaptive parameter optimization algorithm, which dynamically adjusts key parameters such as virtual impedance and damping coefficient by real-time sensing of grid strength and equipment status, thereby improving the stability of the system under a wide range of operating conditions; and third, it innovates hardware topology design by adopting a hybrid energy storage and modular converter integration scheme to enhance the active / reactive power support capability during fault ride-through and reduce the total life cycle cost.

[0054] like Figure 1 As shown, this invention provides an integrated method for reactive power and voltage joint regulation of grid-connected new energy power plants connected to a 220kV power grid. The method includes:

[0055] Step 101: Establish a grid-type new energy cluster, and connect the equipment in the grid-type new energy cluster to the power station's collection bus and configure supercapacitor modules;

[0056] Preferably, the equipment in the grid-type new energy cluster includes: multiple grid-type wind turbines (GWT), multiple grid-type energy storage converters (PCS), and multiple grid-type static var generators (SVG); the grid-type wind turbines (GWT) adopt a doubly fed converter + virtual synchronous generator (VSG) control strategy, and the grid-type energy storage converter integrates a three-level topology and model prediction algorithm.

[0057] The grid-based renewable energy cluster provided by this invention comprises N grid-based wind turbines (GWT), M grid-based power storage converters (PCS), and K grid-based static var generators (SVG). Each device is connected in parallel to the power station's busbar via a power electronic interface and is equipped with a supercapacitor module to provide short-term active power support. The grid-based wind turbines employ a doubly-fed converter + VSG control strategy to achieve decoupled regulation of active power frequency and reactive power voltage. The grid-based power storage converters integrate a three-level topology and model prediction algorithms, supporting seamless switching between grid and off-grid operation.

[0058] Step 102 establishes an intelligent coordination controller. The intelligent coordination controller is based on a DSP+FPGA multi-core architecture to collect electrical quantities of the collection bus in real time and obtain power grid dispatch instructions through a high-speed communication network.

[0059] Step 103 determines the hierarchical control strategy of the intelligent coordinating controller, and generates control instructions for the grid-type new energy cluster based on the grid dispatch instructions through the hierarchical control strategy;

[0060] Preferably, the hierarchical control strategy includes: upper-layer MPC optimization and lower-layer improved droop control;

[0061] The upper-level MPC optimization is based on the model predictive control MPC algorithm, which combines the real-time operation status of the power grid and the power output prediction of new energy sources to dynamically generate reactive power commands and voltage reference values ​​for each device in the grid-type new energy cluster.

[0062] The improved droop control at the lower level achieves reactive power sharing and oscillation suppression when multiple machines are connected in parallel by adjusting the virtual impedance and damping coefficient of each device through improved droop control strategies.

[0063] The intelligent coordination controller provided by this invention is based on a DSP+FPGA multi-core architecture, which collects electrical quantities such as voltage, current and frequency of the collection bus in real time, and obtains power grid dispatching instructions through a high-speed communication network.

[0064] The controller provided by this invention adopts a hierarchical control strategy: the upper optimization layer is based on the model predictive control (MPC) algorithm, combined with the real-time operation status of the power grid and the power output prediction of new energy sources, to generate reactive power commands and voltage reference values ​​for each device; the lower execution layer is improved by adjusting the virtual impedance and damping coefficient of the grid-connected devices through the improved droop control strategy, so as to realize reactive power sharing and oscillation suppression when multiple devices are connected in parallel.

[0065] Step 104: Establish an energy storage-grid collaborative module. The energy storage system in the energy storage-grid collaborative module is coupled to the grid-type converter through a DC bus and adopts a hybrid control mode of active frequency regulation + reactive voltage regulation.

[0066] Preferably, the energy storage system in the energy storage-grid co-location module is coupled to the grid-type converter via a DC bus, and adopts a hybrid control mode of active power frequency regulation + reactive power voltage regulation, including:

[0067] When the grid frequency deviation exceeds a preset threshold, the energy storage system provides inertia support by releasing or absorbing energy.

[0068] By adjusting reactive power distribution based on the dynamic droop coefficient relationship, a rapid response to voltage fluctuations can be achieved.

[0069] The energy storage-grid collaborative module provided by this invention: The energy storage system is coupled to the grid-type converter through a DC bus, and adopts a hybrid control mode of "active power frequency regulation + reactive power voltage regulation". When the grid frequency deviation exceeds the threshold, the energy storage system releases / absorbs energy to provide inertia support; at the same time, it adjusts the reactive power distribution based on the dynamic droop coefficient relationship to achieve rapid response to voltage fluctuations.

[0070] Step 105 establishes the power grid interaction interface, which includes a 220kV step-up substation, an optical CT / PT measurement device, and a fault recording device.

[0071] The power grid interaction interface provided by this invention includes a 220kV step-up substation, an optical CT / PT measuring device, and a fault recording device. The step-up substation is equipped with an on-load tap-changing transformer (OLTC) and intelligent switches, supporting flexible connection between grid-connected substations and the power grid; the optical CT / PT device enables high-precision electrical quantity acquisition, providing real-time data support for the coordinating controller.

[0072] Preferably, it also includes determining the operating mode, including: steady-state operating mode, fault ride-through operating mode, and black start and islanded operating mode;

[0073] The steady-state operation mode is as follows: the intelligent coordination controller optimizes the reactive power distribution of each device in the grid-type renewable energy cluster through the MPC algorithm based on the grid dispatch instructions and renewable energy output forecasts; the grid-type wind turbines use VSG control to simulate the inertia and damping characteristics of synchronous generators to maintain the stability of the bus frequency; the grid-type energy storage converter dynamically adjusts the reactive power output according to the droop curve to compensate for the reactive power deficit of the grid; the energy storage system achieves continuous support under extreme operating conditions through state of charge (SOC) optimization control.

[0074] The fault ride-through mode is as follows: When a grid fault is detected, the grid-type static var generator (SVG) immediately engages the supercapacitor module to release short-term active power to maintain its voltage source characteristics and provides fault current support through virtual synchronous machine control; the intelligent coordination controller triggers the multi-device collaborative protection strategy in the grid-type renewable energy cluster: the grid-type wind turbine (GWT) quickly switches to current source control mode, and the grid-type energy storage converter (PCS) starts overcurrent protection and adjusts the virtual impedance to prevent the system oscillation from amplifying;

[0075] Black start and islanded operation are as follows: In a completely dark grid scenario, the grid-type energy storage converter PCS serves as the main power source and autonomously establishes voltage and frequency references through the black start program; the grid-type wind turbine GWT and the table-type grid-type static var generator SVG are then connected to the grid in sequence to form an islanded microgrid; the intelligent coordination controller dynamically adjusts the output distribution of each device according to the load demand to ensure continuous power supply to critical loads.

[0076] The steady-state operation mode of this invention is as follows: The intelligent coordination controller optimizes the reactive power distribution of each device through the MPC algorithm based on grid dispatch instructions and new energy output forecasts. The grid-connected wind turbines use VSG control to simulate the inertia and damping characteristics of synchronous generators, maintaining stable bus frequency; the grid-connected energy storage converter dynamically adjusts reactive power output according to the droop curve to compensate for grid reactive power deficits. Simultaneously, the energy storage system ensures continuous support under extreme operating conditions through state of charge (SOC) optimization control.

[0077] The fault ride-through mode of this invention: When a grid fault (such as a three-phase short circuit) is detected, the grid-type SVG immediately activates the supercapacitor module, releasing short-term active power to maintain its voltage source characteristics, and provides fault current support through virtual synchronous machine control. Simultaneously, the intelligent coordination controller triggers a multi-device collaborative protection strategy: the grid-type wind turbine quickly switches to current source control mode, and the grid-type energy storage converter activates overcurrent protection and adjusts the virtual impedance to prevent system oscillations from amplifying.

[0078] The black start and islanded operation of this invention: In a completely dark grid scenario, the grid-connected energy storage converter acts as the main power source, autonomously establishing voltage and frequency references through a black start procedure. The grid-connected wind turbine and SVG are then sequentially connected to the grid, forming an islanded microgrid. An intelligent coordination controller dynamically adjusts the output distribution of each device according to load demand, ensuring continuous power supply to critical loads.

[0079] This invention proposes an integrated method for reactive power and voltage joint regulation of grid-connected new energy power plants connected to a 220kV power grid, which can achieve the following objectives: First, it constructs a multi-source collaborative control architecture, and realizes dynamic allocation of reactive power and voltage commands for grid-connected wind turbines, energy storage, and SVG based on a hierarchical optimization strategy, solving the problem of inconsistent response among multiple devices; Second, it develops an adaptive parameter optimization algorithm, which dynamically adjusts key parameters such as virtual impedance and damping coefficient by real-time sensing of grid strength and equipment status, thereby improving the stability of the system under a wide range of operating conditions; Third, it innovates hardware topology design, adopting a hybrid energy storage and modular converter integration scheme to enhance the active / reactive power support capability during fault ride-through and reduce the total life cycle cost.

[0080] The superior effects of this invention are:

[0081] (1) Multi-source coordinated control: Through hierarchical control strategy and improved droop control algorithm, the reactive power and voltage of grid-type wind turbines, energy storage and SVG are dynamically coordinated, and the response speed is significantly improved compared with the traditional AVC system;

[0082] (2) Wideband oscillation suppression: The virtual impedance dynamic adjustment technology can increase the system damping ratio to above 0.15, effectively suppressing subsynchronous oscillation and high-frequency harmonic interference;

[0083] (3) Economic optimization: The modular multilevel converter (MMC) topology and supercapacitor-battery hybrid energy storage are adopted to reduce equipment costs and extend energy storage life through parameter self-tuning algorithm;

[0084] (4) Enhanced grid adaptability: In the scenario of a 220kV weak grid, the system can control the voltage fluctuation amplitude within the allowable range and improve the short-circuit capacity of the system.

[0085] To make this invention clearer and easier to understand, the following detailed explanation of the system's hardware configuration, software design, and operation process is based on a 220kV grid-type new energy power station demonstration project (installed capacity 500MW).

[0086] I. Hardware Configuration Details

[0087] In this embodiment of the invention, the reactive power and voltage joint regulation integrated system for grid-connected new energy power plants connected to the 220kV power grid consists of four parts: a grid-connected new energy cluster, an intelligent coordination controller, an energy storage-grid coordination module, and a power grid interaction interface. The hardware parameters and connection relationships of each part are as follows:

[0088] 1. Grid-type new energy clusters

[0089] The cluster comprises a 300MW grid-connected wind farm, a 150MW grid-connected energy storage system, and a 50MW grid-connected SVG. It is connected to the grid via a 35kV busbar and then via a 220kV step-up substation. Specific equipment parameters are as follows:

[0090] Grid-connected wind turbines (GWT): 60 units of Goldwind GW171-5.0MW turbines are selected, each equipped with a doubly-fed induction generator and a full-power converter (rated power 5.5MW). The converter adopts a grid-side converter + turbine-side converter topology, integrating a virtual synchronous generator (VSG) control module. Key parameters are as follows:

[0091] DC bus voltage: 1200V;

[0092] Maximum reactive power adjustment range: ±2Mvar;

[0093] Inertia simulation range: 0.5~5s (can be dynamically adjusted via controller);

[0094] Overload capacity: 1.5 times rated current / 2s;

[0095] Cooling method: Forced air cooling + water cooling hybrid heat dissipation (suitable for environments from -30℃ to 55℃).

[0096] The wind turbine and the 35kV busbar adopt YJV22-3×240mm 2 Cross-linked cable connection, with every 10 fans connected to the collection bus after being stepped up by a 35kV box-type transformer (capacity 6300kVA).

[0097] Grid-type energy storage converter (PCS): Wolong Transmission 215kW modular PCS (700 units total, 150.5MW total capacity) is selected, employing a three-level NPC (neutral-point clamped) topology, integrating a lithium battery energy storage system (lithium iron phosphate batteries, single cell voltage 3.2V, total capacity 300MWh, SOC operating range 20%–80%). Key parameters are as follows:

[0098] Rated AC voltage: 380V (connected to the collection bus via a 35kV step-up transformer);

[0099] Switching frequency: 5kHz (using SiC-MOSFET devices to reduce switching losses);

[0100] Reactive power adjustment range: ±100kvar / unit (total adjustment range ±70Mvar);

[0101] Response time: Active / reactive command step response ≤ 5ms;

[0102] Communication interface: Supports IEC 61850-9-2 sample value transmission and GOOSE message exchange (for real-time communication with the intelligent coordination controller).

[0103] Grid-type SVG: Equipped with NARI PCS-9550 static var generators (2 sets, 25MW capacity per set), using a modular multilevel converter (MMC) topology, each phase contains 60 sub-modules (half-bridge structure), and integrates a 100kWh supercapacitor module (for short-term active power support during faults). Core parameters:

[0104] Access voltage level: 35kV (directly connected in parallel to the busbar);

[0105] Reactive power adjustment range: ±50Mvar (total capacity ±100Mvar);

[0106] Response speed: ≤10ms from 0 to rated reactive power output;

[0107] Short-circuit current support capability: 2 times rated current / 100ms;

[0108] Cooling method: Water cooling (flow rate 50L / min, inlet and outlet water temperature difference ≤15℃).

[0109] 2. Intelligent Coordination Controller

[0110] The controller adopts a "DSP+FPGA" multi-core architecture (the main chip is a TI TMS320C6678DSP + Xilinx Kintex-7 FPGA), is installed in the power plant control building, and communicates with all devices in the cluster through a fiber optic ring network. The hardware details are as follows:

[0111] Processor performance: DSP clock speed 1.2GHz (responsible for MPC algorithm optimization), FPGA logic units 190k (responsible for real-time data acquisition and instruction issuance, latency ≤1ms);

[0112] Input / output interfaces:

[0113] Analog input: 32 channels (acquiring 35kV bus voltage and current, accuracy class 0.2, sampling rate 20kHz);

[0114] Digital inputs / outputs: 64 channels each (used to receive device status signals and issue control commands);

[0115] Communication interface: 16-channel Gigabit Ethernet (fiber optic), supporting IEC 61850MMS service and SV / GOOSE messages;

[0116] Power supply module: Dual-circuit redundant 220VDC power supply (switching time ≤5ms), adaptable to voltage fluctuation range of 85%~115% of rated value;

[0117] Protection rating: IP40 (The cabinet is dustproof and has a built-in temperature-controlled fan. Operating temperature: -10℃~60℃).

[0118] 3. Energy storage-grid collaborative module

[0119] The module couples the energy storage system to the grid-type converter via a DC bus, achieving coordinated control of "active power frequency regulation + reactive power voltage regulation". The hardware configuration is as follows:

[0120] Hybrid energy storage unit: It adopts a hybrid topology of "lithium battery + supercapacitor", in which the lithium battery (150MW / 300MWh) is responsible for long-term active power support, and the supercapacitor (10MW / 10MWh) is responsible for millisecond-level high-frequency response. The two are connected in parallel to the DC bus (1500V) through a DC / DC converter.

[0121] DC / DC converter: adopts bidirectional Buck-Boost topology, switching frequency 20kHz, maximum conversion efficiency 98.5%, and supports current / voltage dual-mode control (current mode for power distribution, voltage mode for bus regulation);

[0122] Energy Management Unit (EMU): Independent of the intelligent coordinating controller, it collects parameters such as energy storage SOC, temperature, and charging / discharging current in real time (sampling frequency 1kHz) and uploads status information to the intelligent coordinating controller (communication delay ≤50ms).

[0123] 4. Power Grid Interaction Interface

[0124] The interface includes a 220kV step-up substation, high-precision measuring devices, and fault protection equipment. Specific configuration:

[0125] 220kV substation:

[0126] Main transformer: 1 500MVA autotransformer (turn ratio 220kV / 35kV), equipped with on-load tap changer (OLTC, adjustment range ±8×1.25%), supporting remote control (response time ≤10s);

[0127] Circuit breakers: SF6 circuit breakers (rated current 4000A, breaking time 2 cycles) are used on the 220kV side, and vacuum circuit breakers (rated current 6300A) are used on the 35kV side.

[0128] Grounding switch: Equipped with an intelligent grounding switch (with position sensor) to achieve five-proof interlocking with the circuit breaker.

[0129] Measuring devices: Optical CT (current transformer): Rogowski coil type optical CT (range 0~6000A, accuracy 0.2S class, bandwidth 0~2kHz) is used on the 220kV side; Optical PT (voltage transformer): Capacitive voltage divider type optical PT (range 0~40.5kV, accuracy 0.2 class, transient response time ≤10μs) is used on the 35kV side.

[0130] Synchronization clock: It adopts Beidou + GPS dual-mode synchronization (time synchronization accuracy ≤1μs) to provide a unified time standard for the entire system.

[0131] Fault protection equipment:

[0132] Surge arresters: Zinc oxide surge arresters (residual voltage ≤ 520kV) are installed on the 220kV side, and metal oxide surge arresters (residual voltage ≤ 95kV) are installed on the 35kV side.

[0133] Fault waveform recorder: with a sampling rate of 1MHz, it can record electrical waveforms (including voltage, current, frequency, power, etc.) from 200ms before the fault to 1s after the fault, and supports the IEC 60255-24 standard.

[0134] II. Software Design Details

[0135] The system software consists of three parts: the intelligent coordinating controller algorithm, the local control program for networked devices, and the communication protocol stack. The core logic is as follows:

[0136] 1. Intelligent Coordination Controller Algorithm

[0137] The controller adopts a hierarchical control strategy of "upper-level optimization + lower-level execution". The algorithm runs on a DSP+FPGA platform, specifically implemented as follows:

[0138] Upper MPC optimization layer:

[0139] Objective function: With the optimization objectives of "minimizing 220kV bus voltage deviation", "minimizing reactive power loss", and "balancing energy storage SOC", the mathematical expression is as follows:

[0140]

[0141] Where ω1, ω2, and ω3 are weighting coefficients (taken as 0.6, 0.3, and 0.1 respectively), ΔU 220kV P represents the deviation of the 220kV bus voltage from its rated value (220kV). loss For the reactive power loss of the 35kV collection network, SOC i Let i be the state of charge of the i-th energy storage group. The average SOC.

[0142] Constraints include: equipment capacity constraints (e.g., maximum reactive power output of wind turbine ≤ 2 Mvar), voltage safety constraints (35kV bus voltage ≥ 33kV and ≤ 37kV), and energy storage charging and discharging power constraints (≤ 1.2 times rated power).

[0143] Solution method: The interior point method is used to solve the quadratic programming problem. The prediction time is 10s and the control period is 10ms (the reactive power command is updated every 10ms).

[0144] Lower execution layer:

[0145] Improved droop control: To address the reactive power sharing problem of multiple devices in parallel, a virtual impedance dynamic adjustment mechanism is introduced. The reactive power-voltage droop formula is as follows:

[0146] Q i =Q ref +K q (U ref -U i )-Z v I qi

[0147] Among them, Q i Q is the reactive power output of the i-th device.ref K is the reference reactive power issued by MPC. q U is the droop factor (0.1 pu / kV). ref U is the reference voltage for the 35kV bus (35kV). i Z is the voltage at the grid connection point of the equipment. v The virtual impedance is 0.05–0.2Ω, dynamically adjusted according to the voltage deviation at the grid connection point: the larger the voltage deviation, the greater the Z. v The smaller the value, the faster the response speed.

[0148] Oscillation suppression: The high-frequency component (10-200Hz) of the device output current is acquired in real time by FPGA. When subsynchronous oscillation is detected (e.g., the amplitude of the 10Hz component exceeds 5% of the rated current), the damping coefficient is dynamically increased (from 0.1 to 0.3) to suppress the oscillation amplitude to within 2%.

[0149] 2. Local control program for network-type equipment

[0150] Grid-type fan control:

[0151] The converter's local program adopts "VSG+PID" composite control. VSG simulates the inertia (H=2s) and damping (D=5pu) of a synchronous generator to achieve active power-frequency closed loop. The generator-side converter achieves reactive power-voltage decoupling through rotor current-oriented control (RFO), with a response time ≤20ms.

[0152] Grid-based energy storage PCS control:

[0153] The local program supports seamless switching between "voltage source mode" (islanding operation) and "current source mode" (grid-connected operation): when connected to the grid, it tracks the reactive power command issued by the MPC; when islanded, it establishes the 35kV bus voltage (35kV±0.5%) and frequency (50Hz±0.1Hz) through VSG control.

[0154] Networked SVG control:

[0155] The Direct Power Control (DPC) algorithm is adopted, and the instantaneous active / reactive power is calculated in real time through FPGA. After comparing with the reference value, the switching signal is directly output, with a reactive power response delay of ≤5ms. In case of fault, the supercapacitor discharge logic is triggered (discharge depth ≤80%) to maintain the voltage source characteristics of the converter.

[0156] 3. Communication Protocol Stack

[0157] The system adopts a three-layer communication architecture to ensure the real-time performance and reliability of data transmission.

[0158] At the lower level: Sampled values ​​(such as voltage and current) are transmitted between devices using IEC 61850-9-2SV messages at a transmission rate of 100Mbps and a delay of ≤1ms;

[0159] Middle layer: Control commands are exchanged via GOOSE messages (such as reactive power commands, start / stop signals), with message priority levels (fault commands are the highest level, preempting bandwidth);

[0160] Upper layer: Communicates with the power grid dispatching system using the IEC 60870-5-104 protocol, uploads real-time data of the power plant (such as total active power, reactive power, and voltage) and receives dispatching curves (update cycle 15 minutes).

[0161] III. Detailed Explanation of Operation Process

[0162] The system automatically switches between three modes—steady-state operation, fault ride-through, and black start—based on the power grid status. The specific process is as follows:

[0163] 1. Steady-state operation mode (when the power grid is normal)

[0164] Data Acquisition: The intelligent coordination controller collects 220kV bus voltage, wind turbine / energy storage output, energy storage SOC and dispatch commands every 10ms;

[0165] Instruction generation: The MPC optimization layer solves the objective function based on real-time data and generates reactive power instructions for wind turbines, energy storage, and SVG (e.g., total reactive power of wind turbines is 100Mvar, energy storage is 20Mvar, and SVG is -30Mvar, so as to maintain the 220kV bus voltage at 220kV).

[0166] Execution feedback: After receiving the instruction, the device adjusts the reactive power output by improving the droop control. The controller compares the deviation between the actual output and the instruction (≤5%) every 10ms. If the deviation exceeds the limit, the droop coefficient is corrected.

[0167] 2. Fault ride-through mode (during power grid short circuit)

[0168] Fault Detection: When the optical CT detects a sudden increase in current to 15kA on the 220kV side (more than 3 times the rated current), and the optical PT simultaneously acquires data showing an instantaneous drop in the 220kV bus voltage to below 0.8pu (rated voltage 220kV, voltage drop below 176kV), a power grid short-circuit fault is determined. The fault recorder triggers recording, and simultaneously the controller sends a "fault signal" to all devices via a GOOSE message (delay ≤ 1ms).

[0169] Device response:

[0170] SVG: Triggers supercapacitor discharge within 0-5ms, outputting 200Mvar reactive power support voltage, reducing virtual impedance from 0.1Ω to 0.05Ω, reducing reactive power transmission loss, improving voltage support efficiency, and ensuring that the minimum value of 220kV bus voltage is not lower than 0.75pu.

[0171] Wind turbine: Switches from VSG mode to current source mode within 5-10ms, limiting the output current to 1.5 times the rated value to avoid overcurrent damage; at the same time, it maintains the reactive power regulation capability of the grid-side converter, and supplements 20-30Mvar reactive power with SVG to help stabilize the 35kV bus voltage.

[0172] Energy storage: Within 10-20ms, the reactive power emergency support mode is activated, the original charging and discharging plan is suspended, and 50Mvar reactive power is injected into the 35kV bus first; at the same time, through DC side capacitor voltage closed-loop control, the converter is prevented from experiencing DC bus overvoltage fault due to AC side voltage drop, thus ensuring the safe operation of the energy storage system itself.

[0173] Fault clearing: The fault is cleared after 200ms, and the controller gradually restores the equipment to normal mode (first SVG, then the fan, and finally the energy storage). The 220kV voltage is restored to 220kV±1% within 500ms.

[0174] 3. Black Start Mode (when the power grid is completely shut down)

[0175] Start-up trigger: The controller detects that the 220kV voltage is 0 for 5 seconds, determines that the power grid is completely dark, and automatically starts the black start procedure;

[0176] Main power establishment: The energy storage PCS switches to voltage source mode and establishes the 35kV bus voltage to 35kV within 300ms through the pre-charging circuit (current limit 10A) at a frequency of 50Hz.

[0177] Equipment grid connection:

[0178] 10s: Start 10 grid-connected wind turbines (each with 5% active load) and connect them to the grid synchronously via VSG (voltage difference ≤ 5%, frequency difference ≤ 0.1Hz);

[0179] 30s: Start SVG (output 10Mvar reactive power) to stabilize 35kV bus voltage;

[0180] 60s: Gradually increase the output of wind turbines and energy storage to 200MW, forming an islanded microgrid (with a load of 150MW, including important loads such as control buildings and water pumps);

[0181] Grid connection preparation: When the power grid is restored, the controller achieves seamless grid connection with the 220kV power grid through the synchronization device (voltage difference ≤2%, frequency difference ≤0.05Hz), and the grid connection inrush current is ≤0.5 times the rated value.

[0182] Based on the above analysis, it can be concluded that the reactive power and voltage joint regulation integrated system for grid-connected new energy power plants connected to the 220kV power grid proposed in this invention can achieve the following objectives: First, it constructs a multi-source collaborative control architecture, and realizes dynamic allocation of reactive power and voltage commands for grid-connected wind turbines, energy storage, and SVG based on a hierarchical optimization strategy, solving the problem of inconsistent response among multiple devices; Second, it develops an adaptive parameter optimization algorithm, which dynamically adjusts key parameters such as virtual impedance and damping coefficient by real-time sensing of grid strength and equipment status, thereby improving the stability of the system under a wide range of operating conditions; Third, it innovates the hardware topology design, adopting a hybrid energy storage and modular converter integration scheme to enhance the active / reactive power support capability during fault ride-through and reduce the total life cycle cost.

[0183] Figure 6 This is a structural diagram of the reactive power and voltage joint regulation integrated system for a seed-grid type new energy power station connected to a 220kV power grid according to a preferred embodiment of the present invention.

[0184] like Figure 6 As shown, this invention provides an integrated reactive power and voltage regulation system for grid-connected new energy power plants connected to a 220kV power grid. The system includes:

[0185] The grid-type new energy cluster 601 consists of equipment connected in parallel to the power station's collection bus and equipped with supercapacitor modules.

[0186] Preferably, the equipment of the grid-type new energy cluster 601 includes: multiple grid-type wind turbines (GWT), multiple grid-type energy storage converters (PCS), and multiple grid-type static var generators (SVG); the grid-type wind turbines (GWT) adopt a doubly-fed converter + virtual synchronous generator (VSG) control strategy, and the grid-type energy storage converter integrates a three-level topology and model prediction algorithm.

[0187] The intelligent coordination controller 602 is based on a DSP+FPGA multi-core architecture to collect electrical quantities of the aggregation bus in real time and obtain grid dispatch instructions through a high-speed communication network. The intelligent coordination controller adopts a hierarchical control strategy to generate control instructions for the grid-type new energy cluster based on the grid dispatch instructions.

[0188] Preferably, the hierarchical control strategy includes: upper-layer MPC optimization and lower-layer improved droop control;

[0189] The upper-level MPC optimization is based on the model predictive control MPC algorithm, which combines the real-time operation status of the power grid and the power output prediction of new energy sources to dynamically generate reactive power commands and voltage reference values ​​for each device in the grid-type new energy cluster.

[0190] The improved droop control at the lower level achieves reactive power sharing and oscillation suppression when multiple machines are connected in parallel by adjusting the virtual impedance and damping coefficient of each device through improved droop control strategies.

[0191] The energy storage-grid coordinating module 603 is a hybrid control mode that combines active frequency regulation and reactive voltage regulation. The energy storage system in the energy storage-grid coordinating module is coupled to the grid-type converter through a DC bus.

[0192] Preferably, the energy storage system in the energy storage-grid coordination module 603 is coupled to the grid-type converter via a DC bus, and adopts a hybrid control mode of active power frequency regulation + reactive power voltage regulation, including:

[0193] When the grid frequency deviation exceeds a preset threshold, the energy storage system provides inertia support by releasing or absorbing energy.

[0194] By adjusting reactive power distribution based on the dynamic droop coefficient relationship, a rapid response to voltage fluctuations can be achieved.

[0195] The power grid interaction interface 604 includes a 220kV step-up substation, an optical CT / PT measurement device, and a fault recording device.

[0196] Preferably, the system is also used to determine the operating mode, including: steady-state operating mode, fault ride-through operating mode, and black start and islanded operating mode;

[0197] The steady-state operation mode is as follows: the intelligent coordination controller optimizes the reactive power distribution of each device in the grid-type renewable energy cluster through the MPC algorithm based on the grid dispatch instructions and renewable energy output forecasts; the grid-type wind turbines use VSG control to simulate the inertia and damping characteristics of synchronous generators to maintain the stability of the bus frequency; the grid-type energy storage converter dynamically adjusts the reactive power output according to the droop curve to compensate for the reactive power deficit of the grid; the energy storage system achieves continuous support under extreme operating conditions through state of charge (SOC) optimization control.

[0198] The fault ride-through mode is as follows: When a grid fault is detected, the grid-type static var generator (SVG) immediately engages the supercapacitor module to release short-term active power to maintain its voltage source characteristics and provides fault current support through virtual synchronous machine control; the intelligent coordination controller triggers the multi-device collaborative protection strategy in the grid-type renewable energy cluster: the grid-type wind turbine (GWT) quickly switches to current source control mode, and the grid-type energy storage converter (PCS) starts overcurrent protection and adjusts the virtual impedance to prevent the system oscillation from amplifying;

[0199] Black start and islanded operation are as follows: In a completely dark grid scenario, the grid-type energy storage converter PCS serves as the main power source and autonomously establishes voltage and frequency references through the black start program; the grid-type wind turbine GWT and the table-type grid-type static var generator SVG are then connected to the grid in sequence to form an islanded microgrid; the intelligent coordination controller dynamically adjusts the output distribution of each device according to the load demand to ensure continuous power supply to critical loads.

[0200] The reactive power and voltage joint regulation integration system for a seed-grid type new energy power station connected to a 220kV power grid according to a preferred embodiment of the present invention corresponds to the reactive power and voltage joint regulation integration method for a seed-grid type new energy power station connected to a 220kV power grid according to another preferred embodiment of the present invention, and will not be described again here.

[0201] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0202] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0203] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0204] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0205] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0206] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0207] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0208] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

Claims

1. A reactive voltage joint regulation integrated method for grid-forming new energy power station access to 220 kV power grid, the method comprising: establishing a grid-forming new energy cluster, the devices in the grid-forming new energy cluster being connected in parallel to a power station collection bus and being configured with a super capacitor module; establishing an intelligent coordination controller, the intelligent coordination controller collecting electrical quantities of the collection bus in real time based on a DSP+FPGA multi-core architecture, and obtaining power grid dispatching instructions through a high-speed communication network; determining a hierarchical control strategy of the intelligent coordination controller, and generating control instructions of the grid-forming new energy cluster based on the power grid dispatching instructions through the hierarchical control strategy; establishing an energy storage-grid coordination module, an energy storage system in the energy storage-grid coordination module being coupled with a grid-forming converter through a direct current bus, and adopting a hybrid control mode of active frequency regulation + reactive voltage regulation; establishing a power grid interaction interface, the power grid interaction interface comprising a 220 kV booster station, an optical CT / PT measuring device, and a fault recording device.

2. The method of claim 1, the devices of the networking-type new energy cluster comprising: a plurality of grid-forming wind turbines GWTs, a plurality of grid-forming energy storage converters PCSs, and a plurality of grid-forming static var generators SVGs; the grid-forming wind turbines GWTs adopt a doubly-fed converter + virtual synchronous generator VSG control strategy, and the grid-forming energy storage converters integrate a three-level topology and a model predictive algorithm.

3. The method of claim 1, the hierarchical control policy of the hierarchical control policy comprising: upper layer MPC optimization and lower layer improved droop control; the upper layer MPC optimization is based on a model predictive control MPC algorithm, combines real-time running states of the power grid and new energy output prediction, and dynamically generates reactive power instructions and voltage reference values of each device in the grid-forming new energy cluster; the lower layer improved droop control adjusts virtual impedance and damping coefficients of each device through an improved droop control strategy, and realizes reactive power sharing and oscillation suppression when multiple machines are connected in parallel.

4. The method of claim 1, the energy storage system in the energy storage-grid coordination module being coupled with a grid-forming converter through a direct current bus, and adopting a hybrid control mode of active frequency regulation + reactive voltage regulation, comprising: when a power grid frequency deviation exceeds a preset threshold, the energy storage system provides inertia support by releasing or absorbing energy; based on a dynamic droop coefficient relationship, adjusting reactive power distribution to realize rapid response of voltage fluctuation.

5. The method of claim 2, further comprising determining a mode of operation, the mode of operation comprising: steady state operation mode, fault ride-through operation mode, and black start and island operation mode; in the steady state operation mode, the intelligent coordination controller optimizes reactive power distribution of each device in the grid-forming new energy cluster through an MPC algorithm according to power grid dispatching instructions and new energy output prediction; the grid-forming wind turbine adopts a VSG control to simulate inertia and damping characteristics of a synchronous generator, and maintains stability of the collection bus frequency; the grid-forming energy storage converter dynamically adjusts reactive output according to a droop curve, and compensates for reactive power deficiency of the power grid; the energy storage system provides continuous support in extreme working conditions through state of charge SOC optimization control. The fault ride-through mode is that when a power grid fault is detected, a grid-forming static var generator SVG immediately puts into a super capacitor module, releases short-time active power to maintain its voltage source characteristics, and provides fault current support through virtual synchronous machine control; the intelligent coordination controller triggers a multi-device coordinated protection strategy in the grid-forming new energy cluster: the grid-forming wind turbine GWT quickly switches to a current source control mode, and the grid-forming energy storage converter PCS starts overcurrent protection and adjusts the virtual impedance to prevent system oscillation from expanding; The black start and island operation is that in a full black scenario of the power grid, the grid-forming energy storage converter PCS acts as a main power source, establishes a voltage and frequency reference through a black start program; the grid-forming wind turbine GWT and the grid-forming static var generator SVG are then connected to the grid in turn to form an island microgrid; the intelligent coordination controller dynamically adjusts the output distribution of each device according to the load demand to ensure continuous power supply for critical loads.

6. A reactive voltage joint regulation integrated system for a grid-forming new energy power station connected to a 220kV power grid, the system comprising: a grid-forming new energy cluster, devices in the grid-forming new energy cluster being connected in parallel to a power station collection bus and being provided with a super capacitor module; an intelligent coordination controller, the intelligent coordination controller collecting electrical quantities of the collection bus in real time based on a DSP+FPGA multi-core architecture, and obtaining power grid dispatching instructions through a high-speed communication network; the intelligent coordination controller generates control instructions for the grid-forming new energy cluster based on the power grid dispatching instructions through a hierarchical control strategy; an energy storage-grid cooperation module, an energy storage system in the energy storage-grid cooperation module being coupled with a grid-forming converter through a direct current bus, and adopting a hybrid control mode of active frequency regulation + reactive voltage regulation; a power grid interaction interface, the power grid interaction interface comprising a 220kV booster station, an optical CT / PT measuring device, and a fault recording device.

7. The system of claim 6, the devices of the meshed new energy cluster comprising: a plurality of grid-forming wind turbines GWT, a plurality of grid-forming energy storage converters PCS, and a plurality of grid-forming static var generators SVG; the grid-forming wind turbines GWT adopt a doubly-fed converter + virtual synchronous generator VSG control strategy, and the grid-forming energy storage converters integrate a three-level topology and a model prediction algorithm.

8. The system of claim 6, the hierarchical control strategy of the hierarchical control strategy comprises: upper layer MPC optimization and lower layer improved droop control; the upper layer MPC optimization is based on a model prediction control MPC algorithm, combines real-time running states of the power grid and new energy output prediction, and dynamically generates reactive power instructions and voltage reference values of each device in the grid-forming new energy cluster; the lower layer improved droop control adjusts virtual impedance and damping coefficients of each device through an improved droop control strategy to realize reactive power sharing and oscillation suppression when multiple machines are connected in parallel.

9. The system of claim 6, the energy storage system in the energy storage-grid cooperation module being coupled with a grid-forming converter through a direct current bus, and adopting a hybrid control mode of active frequency regulation + reactive voltage regulation, comprising: when a power grid frequency deviation exceeds a preset threshold, the energy storage system provides inertia support by releasing or absorbing energy; based on a dynamic droop coefficient relationship, reactive power distribution is adjusted to realize rapid response of voltage fluctuation.

10. The system of claim 7, further configured to determine a mode of operation, including: The steady-state operation mode, the fault ride-through operation mode, and the black start and island operation mode; The steady-state operation mode is that the intelligent coordination controller optimizes the reactive power distribution of each device in the grid-connected new energy cluster according to the grid dispatching instruction and new energy output prediction through an MPC algorithm; the grid-connected wind turbine adopts VSG control to simulate the inertia and damping characteristics of a synchronous generator, thereby maintaining the stability of the collection bus frequency; the grid-connected energy storage converter dynamically adjusts the reactive power output according to the droop curve, thereby compensating for the reactive power shortage of the power grid; the energy storage system is controlled by the state of charge (SOC) to provide continuous support in extreme conditions; The fault ride-through mode is that when a power grid fault is detected, the grid-connected static var generator (SVG) immediately releases short-term active power to maintain its voltage source characteristics by using a super capacitor module, and provides fault current support through virtual synchronous machine control; the intelligent coordination controller triggers the multi-device cooperative protection strategy in the grid-connected new energy cluster: the grid-connected wind turbine (GWT) quickly switches to a current source control mode, and the grid-connected energy storage converter (PCS) starts overcurrent protection and adjusts the virtual impedance to prevent system oscillation from expanding; The black start and island operation mode is that in the case of a black grid, the grid-connected energy storage converter (PCS) acts as the main power source and establishes a voltage and frequency reference through a black start program; the grid-connected wind turbine (GWT) and the grid-connected static var generator (SVG) are then sequentially connected to the grid to form an island microgrid; the intelligent coordination controller dynamically adjusts the output distribution of each device according to the load demand to ensure the continuous power supply of critical loads.

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