Distributed architecture voltage frequency control method and system for sending out network construction energy storage new energy island through DRU

Abstract

The invention discloses a distributed architecture voltage frequency control method and a distributed architecture voltage frequency control system for a DRU-sent network construction energy storage new energy island. The island comprises a plurality of new energy stations, matched new energy storage stations and a DRU alternating current side energy storage station. Aiming at DRU side energy storage, on the basis of keeping active-frequency droop control, a reactive-voltage droop loop is replaced by a DC power-voltage control loop, and the DRU is controlled to send a power tracking scheduling instruction by adjusting an output voltage; for new energy side energy storage, active-frequency droop and reactive-voltage droop are adopted to construct a local voltage frequency, an active power compensation instruction distributed by a system-level constant-frequency control loop is received, a local active reference value is corrected, and system frequency indifference adjustment is realized. The method adapts to the specific power-voltage coupling characteristic of the DRU, the frequency can be kept stable when the new energy output fluctuates, the power is constantly sent out according to the scheduling instruction, and the operation reliability and schedulability of the island system are improved.

Description

Technical Field

[0001] This invention relates to the field of power technology, specifically to a distributed architecture voltage and frequency control method and system for transmitting power to grid-connected energy storage islands via DRUs. Background Technology

[0002] High-voltage direct current (HVDC) transmission technology is widely used in renewable energy grid integration due to its advantages of long-distance and large-capacity power transmission. Among them, HVDC technology based on diode rectifier units (DRUs) has attracted much attention due to its simple structure and low cost. However, DRUs themselves do not have active control capabilities, and their operation depends on the voltage and frequency support of the sending-end AC system. Therefore, in renewable energy islanding scenarios, a stable AC grid must be constructed through grid-building equipment (such as energy storage). With the continuous increase in the penetration rate of renewable energy and power electronic equipment, the proportion of traditional synchronous generators in the AC grid is gradually decreasing. The physical inertia and damping of the grid are much lower than those of traditional grids, which poses a huge challenge to the safe and stable operation of the grid. Grid-building control technology has been recognized by the industry as a key technology to ensure the safe and stable operation of a high proportion of renewable energy grids. Therefore, when using DRU-HVDC technology to transmit energy from renewable energy islands, it is necessary to construct and support the AC side voltage and frequency through grid-building units. In deep-sea wind farms, due to the constraints of converter station platform weight and space, large-scale energy storage is usually not feasible. Therefore, wind power grid is the recognized solution for constructing DRU-HVDC sending-end AC grid. For onshore renewable energy stations, grid-type energy storage with better dynamic performance and more flexible deployment is a better choice.

[0003] Active power exists in high-voltage inductive power grids ( P )-frequency( f ) / Reactive power ( Q )-Voltage( V Due to the coupling characteristics, it is often used in such power grids. P - f and Q - V Droop control enables the construction of voltage and frequency. However, in DRU-based HVDC systems, the active power transmitted by the DRU is coupled with its AC-side voltage, making traditional grid control strategies applicable to inductive grids difficult to apply. Therefore, for deep-sea wind farms using DRU-HVDC systems, the industry has proposed... P - V / Q - fThe "anti-sag" control strategy has been studied accordingly. However, this anti-sag control based on wind turbine grid-forming still has certain limitations and is difficult to be directly applied to the DRU-HVDC system using energy storage grid-forming: Firstly, the main power disturbances in new energy islands come from the power fluctuations of renewable energy such as wind and light. For an island system formed by wind turbines, the disturbances come from the changes in the power references of the grid-forming units themselves. For an island system formed by energy storage, the disturbances come from the units connected to the grid. Therefore, the sources of power disturbances are different, and the mechanisms for constructing voltage and frequency are completely different. Secondly, deep-sea off-shore wind farms usually aim to send out as much of the wind turbine output power as possible to reduce curtailment. The DRU converter station needs to adjust the transmitted power according to the wind turbine output power to maintain power balance. Onshore new energy power stations are equipped with large-scale energy storage and need to send out a constant power according to the dispatching instructions. The energy storage device absorbs or compensates for power fluctuations. Their control purposes are completely different. Finally, in an inductive power grid P - f , Q - V the coupling characteristics still exist. The additional P - V and the Q - f coupling introduced by anti-sag makes the coupling mechanism more complex, and its system stability is worse than that of traditional positive sag.

[0004] Generally speaking, there is currently no systematic research on the grid-forming energy storage new energy island of the system transmitted through DRU, and there is a lack of a voltage and frequency construction strategy suitable for the grid-forming energy storage new energy island of the system transmitted through DRU. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides a distributed architecture voltage and frequency control method and system for a grid-forming energy storage new energy island transmitted through DRU. This method can adapt to the special P-V coupling characteristics of DRU and the new energy island with a high proportion of new energy penetration rate, and can achieve sending out a constant active power according to the dispatching instructions when the new energy output fluctuates.

[0006] The present invention is realized through the following technical solutions: A distributed architecture voltage and frequency control method for a grid-forming energy storage new energy island transmitted through DRU. The new energy island includes multiple new energy power stations, multiple new energy energy storage stations supporting each new energy power station, and a DRU energy storage station arranged on the DRU AC side bus. The method includes: The DRU energy storage station adopts an improved DC power control, specifically: While maintaining the active power-frequency droop control loop, the reactive power-voltage droop control loop is replaced with a DC power-voltage control loop. The DC power delivered by the DRU is controlled by adjusting the output voltage amplitude of the DRU energy storage station, so that the DC power tracks the dispatch command. The new energy storage station adopts improved frequency control, specifically: it constructs a local voltage frequency using an active power-frequency droop control loop and a reactive power-voltage droop control loop, and receives active power compensation commands allocated by the system-level constant frequency control loop to correct the local active power reference value, thereby achieving error-free regulation of the system frequency.

[0007] Preferably, the DRU energy storage station employs improved DC power control, specifically including the following steps: S11, Collect the output voltage and output current of the DRU energy storage station, and calculate its first active power and first reactive power; S12, input the first active power into the active power-frequency droop control loop to obtain the first frequency reference value; S13, collect the DC power sent by the DRU and compare it with the DC power scheduling command to obtain the DC power deviation; S14, The DC power deviation is processed by the first proportional-integral controller to generate the first voltage compensation amount; S15, the first voltage compensation amount is superimposed on the rated voltage reference value to obtain the first voltage reference value; S16, Based on the first frequency reference value and the first voltage reference value, generate a first modulation signal to control the converter of the DRU energy storage station.

[0008] Preferably, the first voltage compensation amount is received by the station-level coordination controller of the DRU energy storage station, and then distributed according to the operating status of multiple parallel converters in the station before being issued.

[0009] Preferably, the new energy storage station adopts improved frequency control, specifically including the following steps: S21, Collect the output voltage and output current of the new energy storage station, and calculate its second active power and second reactive power; S22, input the second active power and the second reactive power into the active power-frequency droop control loop and the reactive power-voltage droop control loop respectively to obtain the second frequency reference value and the second voltage reference value. S23, Receive the individual active power compensation amount calculated and allocated to this station by the system-level constant frequency control loop; S24, use the individual active power compensation amount to correct the local active power reference value of the new energy storage station; S25. Generate a second modulation signal according to the corrected frequency reference value and the second voltage reference value to control the converter of the new energy energy storage station.

[0010] Preferably, the system-level constant frequency control loop is configured to: measure the system frequency, compare it with the rated frequency to obtain a frequency deviation, and generate a total system active power compensation amount by processing the frequency deviation through a second proportional-integral controller; distribute the total system active power compensation amount to each of the new energy energy storage stations through a centralized controller.

[0011] Preferably, the centralized controller distributes the total system active power compensation amount to each station according to the rated capacity and / or real-time state of charge of each new energy energy storage station.

[0012] Preferably, it further includes: Control the grid-connected inverter of the new energy power station to operate in a constant power mode so that its output active power tracks the maximum power point.

[0013] Preferably, it further includes: Control the receiving-end converter station of the HVDC transmission system where the DRU is located to operate in a constant DC voltage mode.

[0014] A distributed architecture voltage and frequency control system for a new energy island with a grid-forming energy storage via DRU. The new energy island includes multiple new energy power stations, multiple new energy energy storage stations supporting each of the new energy power stations, and a DRU energy storage station disposed on the DRU AC side bus. The system includes: A DRU energy storage control module for the DRU energy storage station to adopt an improved DC power control, specifically: On the basis of maintaining the active power-frequency droop control loop, replace the reactive power-voltage droop control loop with a DC power-voltage control loop, and control the DC power sent out by the DRU by adjusting the output voltage amplitude of the DRU energy storage station so that the DC power tracks the dispatching instruction; A new energy energy storage control module for the new energy energy storage station to adopt an improved frequency control, specifically: construct a local voltage and frequency using an active power-frequency droop control loop and a reactive power-voltage droop control loop, and receive an active power compensation instruction distributed by the system-level constant frequency control loop to correct the local active power reference value to achieve an error-free regulation of the system frequency.

[0015] A grid-forming energy storage new energy island includes: Multiple new energy power stations; Multiple new energy energy storage stations supporting each of the new energy power stations; A DRU energy storage station disposed on the DRU AC side bus; The voltage frequency of the grid-connected energy storage new energy island is controlled by the control system according to the method described above.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This application provides a distributed architecture voltage and frequency control method for renewable energy islands constructed via DRU (Dynamic Energy Storage Unit). For DRU-side energy storage, while retaining the active power-frequency droop loop to maintain system frequency synchronization, the reactive power-voltage loop is replaced with a DC power-voltage control loop. Utilizing the power-voltage coupling characteristics of the DRU, the DC power is directly controlled by adjusting the output voltage amplitude of the energy storage station, achieving rapid power tracking and dispatch follow-up. For renewable energy-side energy storage, active power-frequency droop and reactive power-voltage droop are used to construct the local voltage and frequency, and a system-level constant frequency control loop is introduced. Active power compensation commands are centrally distributed to correct the active power reference values ​​of each station, achieving error-free frequency regulation across the entire system. The advantages of this scheme are: it solves the problem of the inapplicability of traditional control strategies due to power-voltage coupling in DRU systems, and achieves precise power control and stable frequency maintenance through hierarchical coordination, improving the system's robustness and dispatchability under renewable energy fluctuations and changes in dispatch commands.

[0017] This application also proposes a distributed architecture voltage and frequency control system for grid-connected energy storage and new energy islands via DRU, an electronic device, and a computer storage medium, which possess all the advantages of the aforementioned distributed architecture voltage and frequency control method for grid-connected energy storage and new energy islands via DRU. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the 100% new energy island DRU transmission system studied in this invention; Figure 2 This is a schematic diagram of the topology of the twelve-pulse diode rectifier station studied in this invention; Figure 3 To simplify the grid-connected circuit topology of wind, solar, and energy storage on the primary side of this invention; Figure 4 This is a control structure diagram of the constant PQ grid-connected control of the grid-connected inverter for new energy power plants according to the present invention; Figure 5 This is a diagram of the constant DC voltage control structure of the receiving end VSC of the present invention; Figure 6 This is a control structure diagram of the current loop and voltage loop used in the converter control of this invention; Figure 6 (a) is a diagram of the current loop control structure; Figure 6 (b) is a diagram of the voltage loop control structure; Figure 7 Diagram of the control structure for the traditional positive droop control strategy in grid-connected energy storage; Figure 8 This invention provides an improved droop control strategy for DRU-side energy storage with a constant power control loop. Figure 9 This invention provides an improved droop control strategy for all grid-connected energy storage systems, including a constant-frequency control loop. Figure 10 This is a DC voltage waveform diagram of the power output fluctuation of the new energy power station according to the present invention; Figure 11 This is a waveform diagram of the DC current when the power output of a new energy power station fluctuates, as shown in the present invention. Figure 11 (a) shows the overall trend of DC current change from 2 to 6 seconds. Figure 11 (b) is a magnified view of the DC current waveform over 2-3 seconds; Figure 12 This is a waveform diagram of the DC power delivered by the DRU when the output of the new energy power station fluctuates according to the present invention. Figure 13 This is a waveform diagram of the system frequency when the output of the new energy power station fluctuates according to the present invention; Figure 14 The waveforms of active and reactive power of each energy storage station when the output of the new energy power station fluctuates are shown in the present invention. Figure 15 This invention addresses the power output fluctuations of various renewable energy sources at renewable energy power plants. Figure 16 This is a DC voltage waveform diagram when the DC power dispatch command changes according to the present invention; Figure 17 This is a waveform diagram of the DC current when the DC power dispatch command changes according to the present invention; Figure 18 This is a waveform diagram of the DC power sent by the DRU when the DC power scheduling command changes according to the present invention. Figure 19 This is a waveform diagram of the system frequency when the DC power dispatch command changes according to the present invention; Figure 20 The waveforms of active and reactive power of each energy storage station when the DC power dispatch command changes according to the present invention are shown. Figure 21 The waveforms of active and reactive power at each renewable energy power station when the DC power dispatch command changes according to the present invention are shown. Detailed Implementation To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Usually, the components of the embodiments of this application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application that is claimed, but merely represents selected embodiments of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0021] A distributed architecture voltage and frequency control method for a network-forming energy storage new energy island sent out by a DRU. The network-forming energy storage new energy island includes multiple new energy power stations, multiple new energy energy storage stations supporting each new energy power station, and a DRU energy storage station arranged on the AC side bus of the DRU; it includes the following steps: Step 1: Control the energy storage station on the AC bus side of the DRU using an improved droop control strategy, so that the energy storage station on the AC bus side of the DRU synchronizes with other energy storage stations through active power droop, and at the same time can control the port voltage through an improved reactive power loop to control the DC power of the DRU, achieving the purpose of constant power output of the DRU.

[0022] S1.1: Collect the three-phase AC voltage and current of the DRU energy storage station, use them as the input of the three-phase power calculation module, and obtain the active power and reactive power actually output by the energy storage station. S1.2: Use the actual active power and reactive power of the DRU energy storage station as the input of the droop controller, and send them into the active power - frequency loop ( P - f ) and reactive power - voltage loop ( Q - V ) of the droop controller respectively to obtain the frequency reference value and voltage reference value of the DRU energy storage station.

[0023] S1.3: According to the actual frequency of the DRU output system and the system rated frequency, obtain the input error amount of the constant frequency control loop of the system, use the input error amount as the input of the constant frequency control, and obtain the total power difference that the system needs to adjust. S1.4: Use the total central controller of the system to distribute the total power difference, obtain the active power compensation amount corresponding to each new energy energy storage station, use this power compensation amount to correct the active power reference value in the active power - frequency loop, and obtain the final frequency reference value through the active power - frequency loop (P - f) of the droop control. S1.5: Based on the actual power on the DC side of the DRU and the power reference value on the DC side, obtain the DC power error of the constant DC power loop input of the DRU energy storage station; S1.6: The DC power error is fed into the PI controller of the constant DC power loop to obtain the voltage compensation amount of the DRU energy storage station. The voltage compensation amount is used to correct the voltage reference value in the reactive power-voltage loop (QV). The final voltage reference value is obtained through the droop control of the reactive power-voltage loop (QV). S1.7: Based on the corrected frequency reference value and voltage reference value, obtain the d-axis and q-axis voltage reference values, and send them into the voltage and current double closed loop to obtain the modulation signal of the energy storage converter of the DRU side energy storage station; S1.8: Input the modulation signal into the PWM generator to generate pulse control signals for the converter switching devices and control the converter, thereby realizing the control of the DC power output by the DRU.

[0024] To address the direct coupling between DC power and AC voltage in a DRU system, a structural improvement was made to the control strategy of the DRU-side energy storage station. While retaining the traditional active-frequency droop loop to maintain system frequency synchronization, the reactive-voltage droop control loop was replaced with a voltage control loop based on DC power feedback. This improved loop converts the deviation between the actual power output of the DRU and the dispatch command into a precise compensation amount for the AC voltage amplitude via a PI controller. This directly utilizes the inherent power-voltage coupling relationship of the DRU, achieving the goal of linearly and rapidly controlling the power output of the entire HVDC system by adjusting the port voltage of a single energy storage station.

[0025] The advantages of this control strategy are as follows: Firstly, it bypasses the complex multivariate coupling problems in traditional or anti-droop control, resulting in a simple control structure and clear mechanism, which significantly improves the dynamic response speed and steady-state accuracy of the system during power point tracking. Secondly, it enables renewable energy islands to strictly follow upper-level dispatch instructions and achieve constant power output, effectively meeting the grid's requirements for dispatchable and predictable grid connection of renewable energy stations. At the same time, through coordinated control, it avoids circulating current problems caused by integral links in multiple converters within the station, enhancing the system's reliability and engineering practicality.

[0026] Step 2: For the new energy storage station on the new energy power plant side, an improved constant frequency droop control strategy is adopted for control, so that the new energy storage station can synchronize with other energy storage stations through active power droop, and at the same time, it can compensate for the power reference value of active power droop through the constant frequency control link, keep the system frequency at the rated value, and accurately adjust the distribution of active power among energy storage stations.

[0027] S2.1: Collect the three-phase AC voltage and current of the new energy storage station and use them as input to the three-phase power calculation module to obtain the actual active power and reactive power delivered by the new energy storage station. S2.2: The actual active power and reactive power of the new energy storage station are used as inputs to the droop controller, and sent to the active power-frequency loop (Pf) and reactive power-voltage loop (QV) of the droop controller respectively to obtain the frequency reference value and voltage reference value of the new energy storage station.

[0028] S2.3: Based on the actual frequency and the rated frequency of the system, obtain the input error of the constant frequency control loop, use it as the input of the constant frequency control, and obtain the total power difference that the system needs to adjust. S2.4: The obtained power difference is sent to the centralized controller. The centralized controller allocates the total power difference to obtain the power compensation amount corresponding to each new energy storage station. The power compensation amount is used to correct the active power reference value in the active power-frequency loop. The final frequency reference value and voltage reference value are obtained through the droop controller. S2.5: Based on the corrected frequency reference value and voltage reference value, obtain the d-axis and q-axis voltage reference values, and send them into the voltage and current double closed loop to obtain the modulation signal of the energy storage converter of the new energy storage station; S2.6: Input the modulation signal into the PWM generator to generate pulse control signals for the converter switching devices and control the converter, thereby keeping the system frequency constant and accurately tracking the active power reference.

[0029] To address the lack of autonomous frequency recovery capability in isolated new energy systems without a synchronous network, a creative two-layer collaborative control architecture of local droop primary frequency regulation and centralized secondary frequency regulation was constructed. While retaining the local active power-frequency droop control of each supporting energy storage station to achieve rapid power distribution and frequency support, a unified system-level constant frequency control loop was added. This control loop monitors the deviation between the actual system frequency and the rated value, calculates the total power adjustment required to eliminate the deviation via a PI controller, and then accurately distributes it to each supporting energy storage station according to a preset strategy (such as based on capacity and SOC) through a central coordinator, serving as a correction instruction for their local active power reference value.

[0030] The advantages of this control strategy are as follows: First, it effectively solves the steady-state frequency deviation problem inherent in traditional single active power droop control in grid-connected systems, achieving error-free frequency regulation and significantly improving power quality. Second, through a centralized allocation mechanism, while meeting the overall frequency regulation requirements of the system, it allows for optimized power allocation based on the real-time status (such as SOC) of each energy storage station, ensuring the rational utilization of frequency regulation resources and extending the overall lifespan of energy storage equipment. Finally, the improved control of DRU-side energy storage in step 2 works in tandem with the improved control in step 1, enabling the entire islanded system to maintain both frequency stability and power point tracking simultaneously when dealing with fluctuations in new energy output and changes in dispatch commands, fundamentally improving system robustness and control performance.

[0031] Step 3: For grid-connected inverters in new energy power plants, a PQ control strategy is adopted to ensure that the grid-connected inverters in new energy power plants can always deliver the maximum power of the power generation equipment under this operating condition.

[0032] S3.1: Use the voltage and current output of the power generation equipment at the new energy station as input to the MPPT algorithm to obtain the output power of the power generation equipment at the maximum power point under the current operating conditions; The power generation equipment at new energy power stations consists of wind turbines or photovoltaic panels.

[0033] S3.2: Based on the output power at the maximum power point and the actual output power of the grid-connected inverter at the new energy power station, obtain the input error of the active power control of the grid-connected inverter; S3.3: Use the input error of the active power control as the input of the PI controller to obtain the reference value of the d-axis component of the current loop; S3.4: Set the reference value of the q-axis component of the current loop to 0, input the reference values ​​of the d-axis and q-axis components of the current loop into the current loop, and obtain the modulation signal of the grid-connected inverter of the new energy power station through the current loop; S3.5: Input the modulation signal into the PWM generator to generate pulse control signals for the inverter switching devices and control the inverter to achieve AC / DC power balance of the grid-connected inverter, ensuring that the inverter delivers the maximum power to the wind turbine or photovoltaic panel under the current operating conditions.

[0034] This strategy operates the grid-connected inverters of renewable energy power plants (wind turbines, photovoltaics) in constant power (PQ) grid-following control mode, supplemented by a maximum power point tracking (MPPT) algorithm. It uses the maximum available power of the renewable energy power generation equipment under specific operating conditions as a reference command for its active power. The inverter calculates the actual output power by collecting grid connection point voltage and current, and compares it with the reference power given by MPPT. This generates a d-axis reference value for the inner current loop (the q-axis reference value is usually set to zero), thereby quickly and accurately adjusting its output current to achieve tracking of the maximum power reference value.

[0035] Step 4: For the receiving-end converter station of HVDC, implement a grid-following control strategy with constant DC voltage to enable the receiving-end converter station to maintain a constant DC voltage, thereby maintaining the stability of HVDC voltage.

[0036] The receiving-end converter station refers to a converter station located at the receiving end of the HVDC line, which adopts a voltage source converter topology and is configured to operate in constant DC voltage control mode to maintain the stability of the HVDC DC voltage and convert DC power into AC power to be sent to the receiving-end power grid.

[0037] S4.1: Determine the input error of constant voltage control based on the DC-side capacitor voltage of the receiving-end converter station and the reference value of the DC-side capacitor voltage; S4.2: Use the voltage control input error as the input to the PI controller to obtain the reference value of the d-axis component of the current loop; S4.3: Set the reference value of the q-axis component of the current loop to 0, input the reference values ​​of the d-axis and q-axis components of the current loop into the current loop, and obtain the modulation signal of the receiving-end converter station through the current loop; S4.4: Input the modulation signal into the PWM generator to generate pulse control signals for the switching devices of the converter station and control the receiving-end converter station to achieve AC / DC power balance of the grid-connected inverter, ensuring constant DC-side capacitor voltage and maintaining HVDC voltage stability.

[0038] This strategy is applied to voltage source converter stations at the receiving end of HVDC. By acquiring the DC line voltage in real time and comparing it with a set reference value, the error is processed by a proportional-integral controller to generate a command to adjust the active power output of the converter station, thereby stabilizing the DC voltage of the high-voltage DC transmission system at the rated value.

[0039] Through the control of the DRU energy storage station, new energy storage station, receiving-end converter station and grid-connected inverter of new energy power plant in steps 1-4 above, the voltage and frequency of the grid-connected new energy island system transmitted by the DRU-HVDC are finally realized to achieve stable and reliable construction. The island can transmit power to the outside through the DRU at a constant power, and the system frequency can be maintained at the rated value.

[0040] Example 1 Taking a 100% renewable energy island system transmitted via DRU as an example, the distributed architecture voltage and frequency control method for renewable energy islands transmitted via DRU proposed in this application is applied to control the key equipment in the system. The specific steps are as follows: Step 1: Construct this new energy island, including: 1. One wind farm (33MW) and two photovoltaic farms (33MW and 34MW respectively), with a total rated power of 100MW for new energy.

[0041] 2. Multiple supporting grid-connected energy storage stations: 5MW of energy storage is configured on the wind farm's collection bus, and 10MW of energy storage is configured on the collection bus of each photovoltaic farm, totaling 25MW.

[0042] 3. Dedicated energy storage station on the AC side of DRU: An additional 15MW energy storage station is configured on the AC side bus of DRU, which is dedicated to the voltage amplitude control of DRU AC side.

[0043] 4. DRU-HVDC output stage: The DRU AC side bus is connected to a twelve-pulse diode rectifier station (rated power 30MW, topology see...) via a phase-shifting transformer. Figure 2 It is connected to the receiving end via an HVDC line (rated DC voltage ±20kV).

[0044] 5. Receiving-end converter station: It adopts a voltage source converter (VSC), operates in constant DC voltage control mode, and is connected to the 110kV receiving-end power grid.

[0045] Specifically, the architecture of this 100% new energy islanded DRU-HVDC power delivery system is as follows: Figure 1 As shown, this new energy island structure consists of multiple grid-connected energy storage (new energy power stations) and grid-connected wind and solar power stations (energy storage stations), and an additional energy storage station is configured on the AC side bus of the DRU for the control of the AC side voltage amplitude of the DRU.

[0046] The wind farm has a rated power of 33MW, the two photovoltaic farms have rated powers of 33MW and 34MW respectively, and the total rated power of the island's new energy is 100MW. The energy storage station on the wind farm's busbar has a rated power of 5MW, the energy storage station on the busbar of the two photovoltaic farms has a rated power of 10MW, and the energy storage station on the AC side busbar of the DRU has a rated power of 15MW. The total rated power of the energy storage station is 40MW, accounting for 40% of the rated power of the new energy station.

[0047] The wind farm collection point is connected to the DRU AC bus via a 5.2km overhead line and a 0.3km cable, while the photovoltaic farm collection point is connected to the DRU AC bus via a 6.8km overhead line. The DRU AC bus, after passing through a phase-shifting transformer, sends power to a twelve-pulse diode rectifier station. This station consists of two three-phase bridge diode rectifiers connected in parallel on the AC side and in series on the DC side, with a rated power of 30MW. The topology of the three-phase bridge diode rectifier is as follows: Figure 2 As shown. The HVDC receiving end uses a voltage source converter (VSC) as the receiving-end converter station, and the rated DC voltage of the HVDC is... At 20kV, the receiving-end VSC employs constant DC voltage control to ensure DC voltage stability. After passing through the converter station, the receiving end is connected to the 110kV power grid, ultimately achieving 100% power transmission from the renewable energy island.

[0048] Taking a twelve-pulse diode rectifier as an example, under ideal conditions, its DC voltage is the envelope of its AC side line voltage, with twelve pulses within one power frequency cycle. Its average DC voltage... U dc It can be represented as: (1) in It is the effective value of the AC side line voltage of the rectifier. The valve current is the current in the flat current segment. This refers to the leakage reactance of the phase-shifting transformer.

[0049] The DC current can be obtained by adjusting formula (1). I dc The expression can be further used to obtain the DC power of the twelve-pulse diode rectifier. It can be expressed as shown in equation (2): (2) From the power characteristic equation (2) of the twelve-pulse diode rectifier, it can be seen that when the DC voltage U dc When the DC voltage is controlled to a constant value by the VSC at the receiving end converter station, the active power delivered by the DRU is related to the AC voltage amplitude. E Therefore, to control the power output of the DRU, it is necessary to control the AC side voltage of the DRU.

[0050] Step 2: The DRU energy storage station on the DRU side is controlled by an improved droop control strategy to ensure that the DRU delivers constant power.

[0051] In this embodiment of the DRU output system, all energy storage sites in the grid-connected energy storage island utilize grid-connected control. Due to the complex coupling mechanism of anti-droop control, traditional positive droop control is used, and its control structure block diagram is as follows. Figure 7 As shown in the figure. k p This is the active power droop coefficient. k q The reactive power droop factor is the coefficient at the first... i The common coupling point PCC of the energy storage converter PCS collects the AC voltage. U iabc Current I iabc Its output active power was then calculated. P i and reactive power Qi Enter Figure 6 The droop control shown enables the construction of an AC power grid.

[0052] To achieve constant power output, this invention proposes a distributed architecture voltage and frequency control strategy for DRU-HVDC power transmission systems in grid-connected energy storage islands. This strategy improves the positive droop control of DRU-side energy storage. Since the power output of the DRU is closely related to its AC voltage amplitude, this invention addresses the traditional positive droop control issue. Q - V Control loop adjusted to P dc - V The active power loop uses traditional droop control. P - f The ring, like other energy storage systems, participates in the frequency synchronization process.

[0053] Figure 8 The figure shows an improved droop control strategy applied to DRU-side energy storage. P dc This is the actual DC power. P dcref This is the DC power output command given to the dispatcher. The core of this strategy lies in replacing the traditional reactive power-voltage droop loop with a DC power-voltage control loop. P dc - V ): Will P dc and P dcref The deviation is fed into the PI controller to generate an AC voltage compensation quantity. u ;Will u Superimposed to rated voltage u On 0, the target voltage is formed on the AC side of the DRU. By controlling the output voltage of the energy storage station, the target can be tracked, thereby precisely adjusting the DC power delivered by the DRU.

[0054] Considering that energy storage sites typically contain multiple parallel-connected power storage converters (PCS), directly adopting distributed generation would be problematic. P dc - V Controlling the PI controller's integral stage can lead to inconsistent voltages at each PCS port, causing circulating current issues. Therefore, in this strategy... P dc - V The output of the loop is not executed independently by a single PCS, but is processed uniformly by the energy storage site's coordination controller: Voltage compensation signal output by PI controller u First, the data is sent to the coordination controller, which allocates power according to the operating status of the PCS within the station (such as capacity, SOC, etc.). Then, the allocated commands are sent to each PCS for execution, thereby ensuring consistent voltage within the station, avoiding circulating current, and achieving stable and precise control of DRU transmission power. The control structure diagram of the DRU-side grid energy storage is shown below. Figure 8 As shown.

[0055] Step 3: The energy storage station on the side of the new energy power station adopts an improved constant frequency droop control strategy to keep the system frequency constant and accurately track the active power reference.

[0056] In the grid-connected energy storage system of this embodiment, since there is no traditional synchronous generator, the secondary frequency regulation (i.e., zero-delay regulation) of the system frequency must be entirely undertaken by the grid-connected energy storage. To achieve this goal, this invention adds a system-level constant frequency control loop (its structure is as follows) to the local active power-frequency droop control of the energy storage. Figure 10 (As shown).

[0057] This control loop measures the actual system frequency and compares it with the rated frequency. The resulting frequency deviation is then sent to a PI controller for processing. The controller calculates the total active power adjustment required to eliminate the frequency deviation, i.e., the change in the energy storage power reference value. P ref ,Should P ref Its mechanism of action is similar to the frequency regulation command issued by the Automatic Generation Control (AGC) in a synchronous grid: it will be added as a common compensation signal to the local active power reference value of each grid-connected energy storage station. P ref This allows for the correction of the output setpoint, achieving error-free frequency adjustment.

[0058] Since all grid-connected energy storage stations need to participate in secondary frequency regulation, therefore, by P ref The total power demand of the system, as represented, needs to be rationally allocated through a centralized control system (or upper-level coordinator). Allocation can be optimized based on factors such as the capacity and state of charge (SOC) of each energy storage site. The allocated instructions are first sent to the coordination controller at each energy storage site level, and then further distributed by the site coordination controller to each energy storage converter (PCS) within the site for execution. Through this hierarchical coordination control architecture, the system ultimately achieves error-free frequency tracking of the rated value and ensures precise and controllable allocation of frequency-regulated power among multiple energy storage sites and multiple PCS.

[0059] The power balance relationship of the system can be expressed as shown in equation (3), where P N The total contribution to new energy power stations P ESS The total output of energy storage stations P dc The DC power supplied to the DRU, the first i Taiwan PCS contributes to P i In the researched new energy islands, there are N PCS, then P ESS It can be represented as .

[0060] (3) No. i The active loop expression for the droop control of the PCS can be expressed as shown in equation (4), where k pi Indicates the first i Active droop coefficient of PCS.

[0061] (4) Since the system frequency is constant throughout the system in steady state, the active power relationship between different grid-connected units can be obtained: (5) Combining equations (3) and (5), we can solve for any PCS, P refk - P k It can be represented as: (6) Observing equation (6), it can be seen that in order to satisfy the condition that the frequency is no different from the rated frequency in steady state, it is only necessary to satisfy that the numerator of equation (6) is zero, that is: (7) The above derivation shows that constant frequency control only needs to constrain the overall power to meet the requirements, without constraining how the power is distributed among multiple PCS. Therefore, power can be allocated according to factors such as the capacity and SOC of the energy storage device without affecting the steady-state frequency of the system. Since the primary side of this invention is simplified to an ideal voltage source, the control signal is directly and evenly distributed to each PCS.

[0062] Step 4: The grid-connected inverter of the new energy power station adopts the PQ control strategy to ensure that the grid-connected inverter of the new energy power station can always deliver the maximum power of the power generation equipment under this operating condition.

[0063] In this embodiment, in the grid-connected energy storage island of the DRU-transmitting system, the grid-connected control of the power generation equipment all uses a constant PQ grid-following control strategy. Since this invention does not involve the study of the primary side of wind, solar, and energy storage, its primary side is simplified to an ideal voltage source, and this simplification does not affect the effectiveness of this invention. For ease of explanation, and because the AC grid-connected circuit topology of wind, solar, and energy storage is completely identical when the primary side is ignored, therefore... Figure 3 This represents the circuit topology for grid-connected wind, solar, and energy storage systems. For example... Figure 3 As shown, C f It is a filter capacitor. L f It is a filter inductor. L g and R g Indicates the resistance on the mesh side. U abc Indicates the three-phase voltage of the AC power grid. I abc This represents the three-phase current flowing out of the inverter.

[0064] Voltage was collected at the PCC point. U abc and current I abc The active power output of the inverter was then calculated. P and reactive power Q Send in as Figure 4 The constant power grid control shown in the figure. P ref and Q ref These are the active and reactive power reference values ​​of the converter, respectively. The active power reference value is determined in practice by the MPPT algorithm to achieve the maximum power output of the wind turbine and solar power system. The input... P and Q The difference between the value and the reference value is used as follows: I d and I q The reference value is input into the current loop, and adjusted by... I d and I q Size to achieve P ref and Q ref track.

[0065] Step 5: At the receiving-end converter station, implement a grid-following control strategy with constant DC voltage to maintain HVDC voltage stability.

[0066] The receiving-end converter station adopts a voltage source converter (VSC) and operates in constant DC voltage control mode. Its control structure is as follows: Figure 5 As shown. The collected DC voltage V dc Compared with reference value V dcref The difference is generated by the PI controller. i d The reference value is fed into the current loop, and the DC side voltage is stabilized by adjusting the output power, thereby maintaining the constant DC voltage of the entire HVDC system and sending the power to the receiving end 110kV grid. Figure 4 , Figure 5 The structure of the current and voltage loops involved is as follows: Figure 6 As shown. Figure 6 (a) is a current loop control structure. Figure 6 (b) is a voltage loop control structure.

[0067] The constant power control strategy for grid-connected energy storage and new energy islanding proposed in this invention is an improvement on the positive droop control strategy. It simplifies system coupling characteristics and avoids the limitations of traditional positive droop control. P - f and QV The voltage frequency of the ring-based power grid is adjusted using improved methods. P dc - V The loop delivers constant power according to scheduling instructions; simultaneously, it can rely on a constant-frequency control loop to ensure error-free frequency operation under different operating conditions. The voltage-frequency construction strategy proposed in this invention can achieve stable frequency operation and track the commanded power delivery under different power output and wind and solar power output fluctuations.

[0068] A simulation model of a grid-connected energy storage system for new energy islanding was built in MATLAB / Simulink according to the parameters in Table I, and the voltage and frequency construction strategy proposed in this invention was used. To demonstrate that the voltage and frequency construction strategy proposed in this invention can operate stably and reliably under various scenarios, simulations were conducted under two operating conditions: fluctuations in new energy output and changes in dispatch commands.

[0069] Table I Simulation Parameters

[0070] At t=3s, the wind farm output increased from 0.5 pu to 1.0 pu, and at t=5s, the output of both photovoltaic power stations suddenly dropped from 1.0 pu to 0.5 pu to simulate the output fluctuations of real-world renewable energy power stations. The simulation results are as follows: Figures 10-15 The waveform diagram is shown below. The DC voltage is shown in the diagram. V dc Waveform as Figure 10 As shown, after the two disturbances occurred, V dc A small disturbance occurred, with an amplitude of less than 1%, and returned to the rated value within 0.05 seconds under the control of the receiving-end VSC. DC current I dc Waveform as Figure 11 As shown, when the output of the new energy power station changes, I dc There will be small disturbances, but it will return to steady state within 0.05s, and I dc Steady state exhibits certain fluctuations, such as Figure 11 As shown in (b), but the fluctuation range is less than 1%. Power output P dc The waveform is as follows Figure 12 As shown, its changing trend is similar to I dc The same, as can be seen from the figure, P dc It can remain stable at the value given by the scheduling instruction. For example... Figure 13 The figure shows the system frequency. f When the output of a renewable energy power station increases, since the output power of the DRU remains constant, the output power of the energy storage decreases accordingly based on the power balance relationship. Therefore, under droop control... P - f The frequency increases under the action of the loop, but under the action of constant frequency control f The frequency gradually returns to its rated value; when the output of the renewable energy power station decreases, the frequency decreases accordingly, and then gradually returns to its rated value. For example... Figure 14 The figure shows the active power of each energy storage unit. P PCS and reactive power Q PCS The waveform shows that when the output of a renewable energy power station increases, the active power of energy storage will decrease to absorb more power, and vice versa. For example... Figure 15 As shown, the power output of the renewable energy power plant fluctuates according to the command, but its steady-state reactive power remains constant. Simulation results demonstrate that the control strategy proposed in this invention can operate stably and reliably under fluctuating power output conditions of the renewable energy power plant, and can achieve the control objectives of constant power delivery and constant frequency.

[0071] To demonstrate that the voltage frequency construction strategy proposed in this invention can effectively track the instructions given by the scheduler, the DC power scheduling instructions were changed in a MATLAB / Simulink simulation. P dcref At t=3s, the dispatch command suddenly drops from the rated 30MW to 20MW, and then suddenly increases to 50MW at t=5s. The simulation results are as follows. Figures 16-21 The waveform diagram is shown below. The DC voltage is shown in the diagram.V dc Waveform as Figure 16 As shown, after the two disturbances occurred, V dc A small disturbance occurred, but it quickly returned to its rated value under the control of the receiving-end VSC. DC current. I dc Waveform as Figure 17 As shown, the DC current increases when the scheduling command increases and decreases when the scheduling command decreases. I dc The power output of the HVDC decreases, and it reaches a new steady state within 1 second in both instances of disturbance; correspondingly, the power delivered by the HVDC... P dc like Figure 18 As shown, its changing trend is similar to I dc Same. As can be seen from the figure, P dc It can perfectly track scheduling instructions and respond quickly and smoothly to the next steady state. For example... Figure 19 The figure shows the system frequency. f When dispatch commands suddenly increase, the output power increases. In order to maintain the system power balance, the energy storage output increases accordingly, which is reflected in the droop control. P - f The frequency decreases under the action of the loop, but due to the effect of the constant frequency control loop, the final frequency decreases. f It slowly returns to the rated frequency; correspondingly, when the dispatch command decreases, the energy storage output decreases. f The frequency increases, but eventually returns to the rated frequency in steady state. For example... Figure 20 The figure shows the active power of each energy storage unit. P PCS and reactive power Q PCS Waveform. As can be seen from the figure, the energy storage output will increase when the dispatch command increases, and decrease when the dispatch command decreases. Figure 21 The diagram illustrates the active and reactive power of a renewable energy power station. As shown in the figure, the active power remains constant, following a given value, while the steady-state reactive power also remains unchanged, with reactive voltage support provided by energy storage. Simulation results demonstrate that, under conditions of sudden changes in dispatch commands, the voltage-frequency construction strategy proposed in this invention can ensure stable and reliable system operation, while simultaneously quickly adjusting the power output from the DRU (Distributed Power Unit) to follow changes in dispatch commands and maintaining system frequency stability.

[0072] Example 2 Correspondingly, the present application also provides a distributed architecture voltage and frequency control system for a grid-forming energy storage new energy island sent out by DRU. The new energy island includes multiple new energy power stations, multiple new energy energy storage stations supporting each of the new energy power stations, and a DRU energy storage station arranged on the AC side bus of the DRU. The system includes: A DRU energy storage control module, used for the DRU energy storage station to adopt improved DC power control, specifically: On the basis of maintaining the active power - frequency droop control loop, replacing the reactive power - voltage droop control loop with a DC power - voltage control loop, and controlling the DC power sent out by the DRU by adjusting the output voltage amplitude of the DRU energy storage station, so that the DC power tracks the dispatching instruction; A new energy energy storage control module, used for the new energy energy storage station to adopt improved frequency control, specifically: constructing a local voltage and frequency using an active power - frequency droop control loop and a reactive power - voltage droop control loop, and receiving an active power compensation instruction allocated by a system - level constant frequency control loop to correct the local active power reference value to achieve non - differential regulation of the system frequency.

[0073] Embodiment 3 A grid - forming energy storage new energy island includes: Multiple new energy power stations; Multiple new energy energy storage stations配套设置with each of the new energy power stations; A DRU energy storage station arranged on the AC side bus of the DRU; Among them, the voltage and frequency of the grid - forming energy storage new energy island are controlled by a control system according to the distributed architecture voltage and frequency control for the grid - forming energy storage new energy island sent out by DRU as described above.

[0074] It should be noted that in the several embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of each module is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules can be combined or integrated into another device, or some features can be ignored or not executed. The modules described as separate components may or may not be physically separated. The components shown as modules can be one physical unit or multiple physical units, that is, they can be located in one place or distributed to multiple different places. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0075] Furthermore, in the various embodiments of the present invention, the modules can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit. The integrated unit described above can be implemented in hardware or as a software functional unit.

[0076] An electronic device provided in this application includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the distributed architecture voltage and frequency control method for sending out grid-connected energy storage new energy islands via DRU as described in any of the above embodiments.

[0077] Another electronic device provided in this application embodiment may further include: an input port connected to a processor for transmitting multimodal data collected by an external acquisition device to the processor; a display unit connected to the processor for displaying the processor's processing results to the outside world; and a communication module connected to the processor for enabling communication between the electronic device and the outside world. The display unit may be a display panel, a laser scanning display, etc.; the communication method adopted by the communication module includes, but is not limited to, Mobile High Definition Link (HML), Universal Serial Bus (USB), High Definition Multimedia Interface (HDMI), and wireless connection (including Wi-Fi, Bluetooth, Bluetooth Low Energy, and IEEE 802.11s-based communication technology).

[0078] This application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the steps of the distributed architecture voltage and frequency control method for sending out grid-connected energy storage new energy islands via DRU as described in any of the above embodiments.

[0079] For descriptions of relevant parts of the distributed architecture voltage and frequency control system, electronic equipment, and computer-readable storage medium for grid-connected energy storage islands via DRU provided in this application's embodiments, please refer to the detailed description of the corresponding parts in the distributed architecture voltage and frequency control method for grid-connected energy storage islands via DRU provided in this application's embodiments; they will not be repeated here. Furthermore, parts of the technical solutions provided in this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0080] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A distributed architecture voltage frequency control method for a new energy island with DRU dispatching and energy storage networking, the new energy island comprising a plurality of new energy stations, a plurality of new energy storage stations matched with each of the new energy stations, and a DRU energy storage station arranged at a DRU AC side bus, the method characterized in that, The application relates to a new energy storage station control method and system. The DRU storage station adopts improved direct-current power control, specifically: On the basis of maintaining the active power-frequency droop control loop, the reactive power-voltage droop control loop is replaced by a direct-current power-voltage control loop, the output voltage amplitude of the DRU storage station is adjusted to control the direct-current power output by the DRU, and the direct-current power is tracked to the scheduling instruction; The new energy storage station adopts improved frequency control, specifically: The active power-frequency droop control loop and the reactive power-voltage droop control loop are adopted to construct the local voltage frequency, and the active power compensation instruction distributed by the system-level constant-frequency control loop is received to correct the local active power reference value, so that the system frequency is adjusted without difference.

2. The method according to claim 1, wherein, The DRU storage station adopts improved direct-current power control, specifically including the following steps: S11, the output voltage and output current of the DRU storage station are collected, and the first active power and the first reactive power output by the DRU storage station are calculated; S12, the first active power is input into the active power-frequency droop control loop to obtain a first frequency reference value; S13, the direct-current power output by the DRU is collected and compared with the direct-current power scheduling instruction to obtain a direct-current power deviation; S14, the direct-current power deviation is processed by a first proportional-integral controller to generate a first voltage compensation amount; S15, the first voltage compensation amount is superimposed to the rated voltage reference value to obtain a first voltage reference value; S16, a first modulation signal is generated according to the first frequency reference value and the first voltage reference value to control the converter of the DRU storage station.

3. The method according to claim 2, wherein, The first voltage compensation amount is received by the station-level coordination controller of the DRU storage station and distributed according to the operation state of multiple parallel converters in the station and then issued.

4. The method of claim 1, wherein the method is characterized by, The new energy storage station adopts improved frequency control, specifically including the following steps: S21, the output voltage and output current of the new energy storage station are collected, and the second active power and the second reactive power output by the new energy storage station are calculated; S22, the second active power and the second reactive power are input into the active power-frequency droop control loop and the reactive power-voltage droop control loop respectively to obtain a second frequency reference value and a second voltage reference value; S23, an individual active power compensation amount distributed by the system-level constant-frequency control loop to the station is received; S24, the individual active power compensation amount is used to correct the local active power reference value of the new energy storage station; S25, a second modulation signal is generated according to the corrected frequency reference value and the second voltage reference value to control the converter of the new energy storage station.

5. The method according to claim 1 or 4, wherein, The system-level constant-frequency control loop is configured to measure the system frequency, compare the system frequency with a rated frequency to obtain a frequency deviation, process the frequency deviation by a second proportional-integral controller to generate a system total active power compensation amount, and distribute the system total active power compensation amount to each new energy storage station through a centralized controller.

6. The method according to claim 5, wherein, The centralized controller distributes the system total active power compensation amount to each station according to the rated capacity and / or real-time state of charge of each new energy storage station.

7. The method of claim 1, wherein the method is a method of voltage frequency control of a distributed architecture of a new energy island delivered by a DRU, characterized by, The application further relates to a new energy storage station control system. The grid-connected inverter of the new energy station is controlled to operate in a constant power mode, so that the output active power tracks the maximum power point.

8. The method of claim 1, wherein the method is a method of voltage frequency control of a distributed architecture of a new energy island delivered by a DRU, characterized by, Further comprising: The receiving end converter station of the HVDC power transmission system where the DRU is located is controlled to operate in a constant DC voltage mode.

9. A distributed architecture voltage frequency control system for a new energy island with energy storage through DRU dispatch, the new energy island comprising a plurality of new energy stations, a plurality of new energy storage stations matched with each of the new energy stations, and a DRU energy storage station arranged at a DRU AC side bus, characterized in that, The system comprises: A DRU energy storage control module, configured to cause the DRU energy storage station to adopt improved DC power control, specifically: On the basis of maintaining an active power-frequency droop control loop, a reactive power-voltage droop control loop is replaced by a DC power-voltage control loop, the DC power sent by the DRU is controlled by adjusting the output voltage amplitude of the DRU energy storage station, so that the DC power tracks the dispatching instruction; A new energy energy storage control module, configured to cause the new energy energy storage station to adopt improved frequency control, specifically: an active power-frequency droop control loop and a reactive power-voltage droop control loop are adopted to construct a local voltage frequency, and an active power compensation instruction distributed by a system-level constant frequency control loop is received to correct a local active power reference value, so as to realize no-difference adjustment of system frequency.

10. A network-constructed energy storage new energy island, characterized in that, Comprise: A plurality of new energy stations; A plurality of new energy energy storage stations matched with the new energy stations; A DRU energy storage station arranged at the AC side bus of the DRU; The voltage frequency of the new energy island with networked energy storage is controlled by the control system according to the method in any one of claims 1 to 8.

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