Phase modifier energy storage excitation control method, system and controller

Abstract

The invention provides a phase modifier energy storage excitation control method and system and a controller. The method comprises the following steps: acquiring original phase modifier parameters, original power grid parameters and original energy storage system parameters; generating a power grid operation state according to the original phase modifier parameters, the original power grid parameters and the original energy storage system parameters; adjusting the energy storage system and the flexible excitation power unit according to the power grid operation state and a cooperative control strategy, and obtaining the adjusted current phase modifier parameters and the adjusted current power grid parameters; damping control is carried out according to current phase modifier parameters and current power grid parameters through preset double damping channels, data can be monitored and analyzed in real time, a cooperative control strategy is adopted, an energy storage system is effectively utilized to improve the transient stability of the phase modifier, and the effect of suppressing subsynchronous oscillation is enhanced through cooperative control of the double damping channels. Therefore, the dynamic stability of the grid voltage is improved.

Description

Technical Field

[0001] This invention relates to the field of flexible excitation technology, and in particular to a method, system and controller for controlling the energy storage excitation of a synchronous condenser. Background Technology

[0002] Traditional synchronous condenser excitation systems primarily employ thyristor rectification technology, controlling the excitation current by adjusting the thyristor firing angle to maintain stable output voltage. Additionally, power systems are equipped with basic energy storage devices, such as battery banks, to provide energy support during grid faults or special operating conditions. Synchronous condensers and energy storage systems operate independently, with other control strategies also relatively independent, lacking effective coordination and integration. For example, synchronous condenser excitation control mainly focuses on voltage regulation, while energy storage system control emphasizes its own charge and discharge management. With the increasing use of ultra-high voltage direct current (UHVDC), flexible direct current (Flexible DC), and wind and solar power inverters in power systems, the interactions between these devices have become complex, introducing the risk of subsynchronous oscillations to conventional generator sets. Related technologies include synchronous generator excitation damping control based on the excitation system, but the control effect is poor.

[0003] Traditional thyristor excitation systems suffer from limitations such as limited control methods and slow dynamic response. Furthermore, the lack of deep integration and coordinated control between energy storage and excitation systems prevents them from fully leveraging their respective advantages. For instance, during large grid disturbances, traditional excitation systems may fail to provide sufficient reactive power support quickly, and energy storage systems may not be able to cooperate effectively and promptly, thus impacting the dynamic stability of the grid voltage. Summary of the Invention

[0004] One objective of this invention is to provide a synchronous condenser energy storage excitation control method, which can monitor and analyze data in real time, adopt a coordinated control strategy to effectively utilize the energy storage system to improve the transient stability of the synchronous condenser, and enhance the suppression of subsynchronous oscillations through dual-damped channel coordinated control, thereby improving the dynamic stability of the power grid voltage. Another objective of this invention is to provide a synchronous condenser energy storage excitation control system. Another objective of this invention is to provide a controller. A further objective of this invention is to provide a computer-readable medium. Yet another objective of this invention is to provide a computer device.

[0005] To achieve the above objectives, this invention discloses a method for controlling the energy storage excitation of a synchronous condenser, comprising:

[0006] Obtain raw synchronous condenser parameters, raw power grid parameters, and raw energy storage system parameters;

[0007] Based on the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters, the power grid operating status is generated.

[0008] Based on the grid operating status, the energy storage system and flexible excitation power unit are adjusted according to the coordinated control strategy, and the current synchronous condenser parameters and current grid parameters are obtained after adjustment.

[0009] Damping control is performed based on the current synchronous condenser parameters and the current power grid parameters through a preset dual-damping channel.

[0010] Preferably, the grid operating status is generated based on the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters, including:

[0011] If the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters meet the preset normal operating conditions, the grid operating state is determined to be normal operating state;

[0012] If any one of the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters meets the preset strong excitation demand state conditions, the grid operating state is determined to be the strong excitation demand state.

[0013] If any one of the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters meets the preset inverter operation state conditions, the grid operation state is determined to be the inverter operation state.

[0014] Preferably, the power grid is in normal operating condition;

[0015] Based on the grid operating status, the energy storage system and flexible excitation power unit are adjusted according to a coordinated control strategy, including:

[0016] The energy storage system is controlled to maintain the intermediate DC bus voltage and to perform charging and discharging management according to the grid load cycle;

[0017] The peak excitation voltage multiple of the flexible excitation power unit is adjusted to a preset first multiple, and the flexible excitation power unit is controlled to output according to the voltage value of the first multiple.

[0018] Preferably, the power grid operates in a state of strong demand.

[0019] Based on the grid operating status, the energy storage system and flexible excitation power unit are adjusted according to a coordinated control strategy, including:

[0020] Control the energy storage system to enhance power supply;

[0021] The peak excitation voltage multiple of the flexible excitation power unit is adjusted to a preset second multiple, and the flexible excitation power unit is controlled to output according to the second multiple voltage value.

[0022] Preferably, the power grid is in inverter operation mode;

[0023] Based on the grid operating status, the energy storage system and flexible excitation power unit are adjusted according to a coordinated control strategy, including:

[0024] Control the energy storage system to take over the DC power supply for power generation;

[0025] According to the preset multiplier adjustment strategy, the peak excitation voltage multiplier of the flexible excitation power unit is dynamically adjusted, and the flexible excitation power unit is controlled to output voltage according to the dynamically adjusted peak excitation voltage multiplier.

[0026] Preferably, the dual damping channels include synchronous generator excitation damping control and static synchronous compensator damping control;

[0027] Damping control is performed through a preset dual-damping channel based on the current synchronous condenser parameters and the current power grid parameters, including:

[0028] Based on the current synchronous condenser parameters and the current power grid parameters, generate excitation current and reactive current;

[0029] By controlling the excitation damping of the synchronous generator, the synchronous condenser is adjusted according to the excitation current to suppress low-frequency oscillations;

[0030] By using static synchronous compensator damping control and injecting reactive current into the grid through an energy storage system, subsynchronous oscillations can be suppressed.

[0031] The present invention also discloses a synchronous condenser energy storage excitation control system, which is applied to the method described above. The system includes: a synchronous condenser, an energy storage system, a flexible excitation power unit and a controller. The flexible excitation power unit is connected to the synchronous condenser, the energy storage system and the controller respectively. The controller is connected to the energy storage system and the synchronous condenser respectively.

[0032] The flexible excitation power unit includes a bridge three-level voltage source converter, a DC-DC chopper converter, and a filter inductor;

[0033] The input terminal of the bridge three-level voltage source converter is connected to the synchronous condenser, and the output terminal is connected to the intermediate DC bus.

[0034] The DC-DC chopper converter is connected to the intermediate DC bus;

[0035] Filter inductors are used to filter out harmonic currents on the AC side;

[0036] Energy storage systems include energy storage batteries and DC capacitors;

[0037] The energy storage battery is connected in parallel to the intermediate DC bus;

[0038] DC capacitors are used to maintain the intermediate DC bus voltage;

[0039] A synchronous condenser is a power generation device used to regulate the excitation current and output reactive power to the power grid.

[0040] The present invention also discloses a controller, comprising:

[0041] The parameter acquisition unit is used to acquire raw synchronous condenser parameters, raw power grid parameters, and raw energy storage system parameters.

[0042] The power grid operation status generation unit is used to generate the power grid operation status based on the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters.

[0043] The regulating unit is used to regulate the energy storage system and flexible excitation power unit according to the grid operating status and the coordinated control strategy, and to obtain the current synchronous condenser parameters and the current grid parameters after regulation.

[0044] The damping control unit is used to perform damping control based on the current synchronous condenser parameters and the current power grid parameters through preset dual damping channels.

[0045] The present invention also discloses a computer-readable medium having a computer program stored thereon, which, when executed by a processor, implements the method described above.

[0046] The present invention also discloses a computer device, including a memory and a processor, wherein the memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions, wherein the processor executes the program to implement the method described above.

[0047] The present invention also discloses a computer program product, including a computer program / instructions, which, when executed by a processor, implement the method described above.

[0048] This invention acquires the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters; generates the grid operating status based on these parameters; adjusts the energy storage system and flexible excitation power unit according to a coordinated control strategy based on the grid operating status, and acquires the adjusted current synchronous condenser parameters and current grid parameters; through a preset dual-damping channel, damping control is performed based on the current synchronous condenser parameters and current grid parameters, enabling real-time data monitoring and analysis, and effectively utilizing the energy storage system to improve the transient stability of the synchronous condenser through a coordinated control strategy. The dual-damping channel coordinated control enhances the suppression of subsynchronous oscillations, thereby improving the dynamic stability of the grid voltage. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the structure of a synchronous condenser energy storage excitation control system provided in an embodiment of the present invention;

[0051] Figure 2 A flowchart of a synchronous condenser energy storage excitation control method provided in an embodiment of the present invention;

[0052] Figure 3 A flowchart of another synchronous condenser energy storage excitation control method provided in an embodiment of the present invention;

[0053] Figure 4 A schematic diagram illustrating the principle of wideband low-frequency oscillation suppression provided in an embodiment of the present invention;

[0054] Figure 5 A schematic diagram of the structure of a controller provided in an embodiment of the present invention;

[0055] Figure 6 This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Figure 1 This is a schematic diagram of the structure of a synchronous condenser energy storage excitation control system provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the system includes: a synchronous condenser 1, an energy storage system 2, a flexible excitation power unit 3, and a controller 4. The flexible excitation power unit 3 is connected to the synchronous condenser 1, the energy storage system 2, and the controller 4, respectively. The controller 4 is connected to the energy storage system 2 and the synchronous condenser 1, respectively.

[0058] The flexible excitation power unit 3 includes a bridge three-level voltage source converter (AC / DC) 31, a DC chopper converter (DC / DC) 32, and a filter inductor 33.

[0059] In this embodiment of the invention, the bridge three-level voltage source converter 31 adopts a T-type three-level structure. The input terminal of the bridge three-level voltage source converter 31 is connected to the synchronous condenser 1, and its output terminal is connected to the intermediate DC bus. The bridge three-level voltage source converter 31 is used to rectify the three-phase AC voltage into a stable DC voltage, and achieves independent control of active and reactive power through pulse width modulation (PWM) rectification technology, and optimizes harmonic voltage and harmonic current control.

[0060] The fast response mechanism of a PWM rectifier enables it to rapidly adjust the output pulse width according to changes in the grid frequency, thereby achieving precise excitation current regulation. The fast response mechanism of a PWM rectifier includes grid frequency change monitoring, output pulse width adjustment, and excitation current regulation.

[0061] Specifically, power grid frequency change monitoring: real-time monitoring of power grid frequency changes, acquiring power grid frequency information through high-precision frequency sensors, and responding quickly when the power grid frequency changes.

[0062] Output pulse width adjustment: The output pulse width of the PWM rectifier is quickly adjusted according to changes in the grid frequency. When the grid frequency increases, the output pulse width is shortened, the output voltage amplitude is reduced, and the active power output is decreased; conversely, when the grid frequency decreases, the output pulse width is increased, the output voltage amplitude is increased, and the active power output is increased.

[0063] Excitation current regulation: By adjusting the output pulse width, the output current of the converter is precisely controlled, thereby achieving rapid regulation of the excitation current of the synchronous condenser. Specifically, when it is necessary to increase the excitation current, the output pulse width is increased, the output voltage amplitude is increased, and more current flows into the excitation winding of the synchronous condenser; conversely, when it is necessary to decrease the excitation current, the output pulse width is decreased, the output voltage amplitude is reduced, and the current flowing into the excitation winding of the synchronous condenser is reduced.

[0064] It should be noted that the PWM control principle is based on PWM (Pulse Width Modulation) rectification technology, which achieves precise control of AC power by adjusting the width of the output pulse. Specifically, by changing the pulse width, the amplitude and phase of the AC side output voltage can be adjusted, thereby enabling independent regulation of active and reactive power.

[0065] Specifically, active power control includes adjusting the phase difference between the output voltage of the PWM rectifier and the grid voltage to control the flow of active power on the AC side. When the output voltage phase leads the grid voltage phase, active power flows from the grid to the converter; conversely, active power flows from the converter to the grid.

[0066] Reactive power control: By adjusting the difference between the output voltage amplitude of the PWM rectifier and the grid voltage amplitude, the flow of reactive power on the AC side can be controlled. Specifically, when the output voltage amplitude is higher than the grid voltage amplitude, reactive power flows from the converter to the grid; conversely, reactive power flows from the grid to the converter.

[0067] This invention employs an advanced decoupling control strategy, decoupling the control of active power and reactive power, allowing them to be adjusted independently. Specifically, using instantaneous reactive power theory, the AC current is decomposed into active and reactive current components, and separate active and reactive current controllers are designed to achieve independent control of active and reactive power.

[0068] The bridge-type three-level voltage source converter 31 adopts a three-level topology, enabling it to output three different voltage levels, making the output waveform closer to a sine wave and reducing harmonic content. Compared to traditional two-level converters, the three-level converter has lower harmonic distortion and higher power quality at the same output voltage level. It uses insulated-gate bipolar transistors (IGBTs) as power switching devices, which have advantages such as fast switching speed, low on-resistance, and high withstand voltage, enabling efficient power conversion.

[0069] Among them, harmonic detection and analysis: using algorithms such as Fast Fourier Transform (FFT), the harmonic components in the grid voltage and converter output current are detected in real time, and the amplitude and phase of the harmonics are analyzed.

[0070] Harmonic compensation control: Based on the harmonic detection results, a harmonic compensation controller is designed to generate a compensation current that is equal in magnitude and opposite in phase to the harmonic components. This compensation current is then injected into the power grid to cancel out the harmonic components and reduce the harmonic voltage of the power grid and the harmonic current of the converter.

[0071] During fault ride-through and protection, when the grid voltage drops below a threshold, the system automatically switches to the energy storage system power supply mode. Once the voltage recovers, the bridge three-level voltage source converter 31 is reactivated. The energy storage system 2 continuously provides a stable DC power supply to the excitation system during grid voltage drops, ensuring the reliability and stability of the excitation system. The following is the reconnection mechanism after grid voltage recovery:

[0072] Grid voltage recovery monitoring: During a grid voltage drop, controller 4 continuously monitors the grid voltage recovery. When the grid voltage amplitude is detected to rise back to the set recovery threshold and remain stable for a period of time, the grid voltage is determined to have returned to normal.

[0073] Reactivation of the bridge three-level voltage source converter 31: Controller 4 gradually restores the operation of the bridge three-level voltage source converter 31 based on the grid voltage recovery status. First, controller 4 adjusts the output voltage of the bridge three-level voltage source converter 31 to synchronize its phase and amplitude with the grid voltage; then, it gradually increases the output power of the bridge three-level voltage source converter 31 until the normal excitation power supply mode is fully restored. During this process, energy storage system 2 continues to provide auxiliary power to ensure a smooth transition of the flexible excitation system. Simultaneously, controller 4 monitors the operating status of the bridge three-level voltage source converter 31 in real time. If any abnormality is detected, it immediately switches back to the energy storage system power supply mode to ensure system reliability.

[0074] The DC-DC chopper converter 32 is a key back-end device in the system. Its input section connects to the intermediate DC bus, and its output section connects to the excitation winding of the synchronous condenser 1. It converts a stable DC voltage into an adjustable excitation voltage, supporting five-level characteristics to achieve normal (rated), forced excitation, and inverter operation. The DC-DC chopper converter 32 can generate a five-level adjustable excitation voltage to meet the excitation requirements of the synchronous condenser 1 under different operating conditions. The DC-DC chopper converter 32 supports bidirectional output, providing a solid guarantee for the flexible operation of the synchronous condenser 1, enabling it to operate stably under various complex conditions and effectively regulate the grid voltage.

[0075] The filter inductor 33 is used to filter out harmonic currents on the AC side to ensure power quality on the grid side.

[0076] Energy storage system 2 is used for short-term active power regulation and energy buffering, charging during off-peak periods and discharging during peak periods or emergencies. Energy storage system 2 includes an energy storage battery 21 and a DC capacitor 22. The energy storage battery 21 and DC capacitor 22 are connected in parallel to the intermediate DC bus to store electrical energy and charge during off-peak periods, discharging during peak periods or emergencies. The energy storage battery can respond to grid demands within milliseconds, providing rapid active and reactive power support; the DC capacitor 22 is used to maintain the stability of the intermediate DC bus voltage, ensuring the stability of the grid system.

[0077] It should be noted that the energy storage battery 21 can be a battery pack. The battery pack consists of multiple high-performance battery cells connected in series and parallel to meet the system's voltage and capacity requirements. The battery uses lithium-ion battery technology, which has advantages such as high energy density, long cycle life, and low self-discharge rate, maintaining stable performance during frequent charge-discharge cycles. The total capacity of the battery pack is determined based on the grid load characteristics and the operating requirements of the synchronous condenser, ensuring sufficient active power support during peak grid periods or emergencies. Battery pack charge and discharge management: During periods of low grid load, the battery pack draws power from the grid through the energy storage system's charging circuit for charging. The charging process employs an intelligent charging management system, automatically adjusting the charging strategy based on parameters such as battery voltage, current, and temperature to ensure safe and rapid charging of the battery, while extending its lifespan. During peak grid load periods or emergencies, the battery pack releases power back to the grid through the discharging circuit, providing rapid active power support and balancing the grid's power supply and demand.

[0078] DC capacitor 22 and energy storage battery 21 are connected in parallel on the intermediate DC bus for short-term active power regulation and energy buffering. DC capacitor 22 has rapid charging and discharging characteristics, enabling it to respond to transient power demands from the grid within milliseconds, providing rapid energy support to the system. When grid voltage fluctuates or transient disturbances occur, DC capacitor 22 can quickly absorb or release electrical energy, stabilizing the voltage of the intermediate DC bus and ensuring stable system operation.

[0079] The charging and discharging process of DC capacitor 22 is controlled in real time by controller 4. Controller 4 adjusts the charging and discharging power of DC capacitor 22 according to the operating status of the power grid and the voltage of the intermediate DC bus. Meanwhile, to protect the safe operation of the DC capacitor, the system is equipped with overvoltage, overcurrent, and overheat protection measures. When the voltage or current of DC capacitor 22 exceeds the set threshold, the protection device will quickly activate, cutting off the charging and discharging circuit of the capacitor to prevent damage.

[0080] Energy storage system 2 can respond to grid demands within milliseconds, providing rapid active and reactive power support. This is mainly due to the high-speed signal processing capability of controller 4 and the rapid charging and discharging characteristics of energy storage system 2. Controller 4 monitors grid parameters such as voltage, current, and frequency in real time. When it detects a power deficit or voltage fluctuation in the grid, it quickly issues control commands to adjust the charging and discharging power of energy storage system 2. Upon receiving the control commands, energy storage system 2 can adjust its output power in a very short time to provide the required active or reactive power support to the grid. When a short-circuit fault in the grid causes a momentary voltage drop, controller 4 detects the voltage drop in less than 10 milliseconds and immediately activates the discharge control strategy of energy storage system 2. Energy storage battery 21 and DC capacitor 22 simultaneously release electrical energy to the grid, providing a large amount of reactive power support to help the grid voltage recover quickly. In the event of a sudden increase in grid load, controller 4 can also respond quickly, adjusting the output power of the energy storage system to provide additional active power to meet the grid load demand.

[0081] Energy management and protection mechanisms of energy storage system 2:

[0082] Energy Management Strategy: During grid voltage dips, energy storage system 2 discharges to maintain the operation of the flexible excitation system. To ensure the sustainable power supply capability of energy storage system 2, controller 4 implements an energy management strategy. This strategy rationally allocates the output power of energy storage system 24 based on the state of charge (SOC) of energy storage system 2 and the severity of the grid voltage dip. For example, when the SOC of energy storage system 2 falls below a set threshold, controller 4 appropriately reduces the output power, extending the power supply time of energy storage system 2 to ensure that the flexible excitation system can continue to operate stably until the grid voltage recovers.

[0083] Protection Mechanisms: Energy storage system 2 is equipped with comprehensive protection mechanisms, including overvoltage protection, overcurrent protection, and overheat protection. When the voltage or current of energy storage system 2 exceeds the set protection threshold, the protection devices will quickly activate and disconnect the output circuit of energy storage system 2 to prevent damage. Simultaneously, controller 4 has fault diagnosis capabilities, enabling it to monitor the operating status of energy storage system 2 in real time, promptly detect and handle faults, and ensure the safe and reliable operation of energy storage system 2.

[0084] Synchronous condenser 1 is a power generation device used to regulate the excitation current and output reactive power to the power grid. Specifically, the excitation winding of synchronous condenser 1 is regulated by the excitation voltage provided by a DC-DC chopper converter, thereby supporting the grid voltage.

[0085] The system is equipped with high-precision voltage transformers (PTs) to monitor the amplitude and phase of the grid voltage in real time. These transformers are installed at key locations at the grid connection point and the output of the synchronous condenser 1 to ensure timely detection of even minor changes in grid voltage. The collected voltage data is transmitted to the controller 4 at high frequency, providing real-time data for fault detection.

[0086] Controller 4 incorporates an advanced fault detection algorithm that can quickly and accurately determine whether a severe voltage drop has occurred in the power grid. This algorithm makes a comprehensive judgment based on the magnitude and rate of change of the power grid voltage. When the magnitude of the power grid voltage falls below a set threshold and the rate of change exceeds a preset value, the fault ride-through and protection mechanism is immediately triggered. This dual judgment standard effectively avoids false triggering of the protection mechanism due to normal fluctuations in the power grid voltage, improving the reliability and stability of the system.

[0087] When the grid voltage drops significantly, the system automatically switches to the power supply mode of energy storage system 2. At this time, energy storage system 2 becomes the main power source for the flexible excitation system, providing a stable DC power supply to synchronous condenser 1. The following is a detailed implementation of the power supply mode of energy storage system 2:

[0088] Rapid connection of energy storage system 2: Upon triggering of the fault detection algorithm, controller 4 immediately sends a control signal to activate the discharge circuit of energy storage system 2. Energy storage battery 21 and DC capacitor 22 simultaneously begin discharging within a very short time, providing the required DC power to the flexible excitation system. Through a reasonable control strategy, the discharge current of the battery pack and DC capacitor is ensured to be stable and precisely controllable, maintaining the stability of the intermediate DC bus voltage.

[0089] Stable operation of the flexible excitation system: In the power supply mode of energy storage system 2, the DC chopper converter 32 continues to adjust the output voltage according to the instructions of controller 4 to ensure that the excitation winding of synchronous condenser 1 receives a stable DC current. Controller 4 monitors the operating status of synchronous condenser 1 and the output power of energy storage system 2 in real time, and dynamically adjusts the duty cycle of DC chopper converter 32 to adapt to changes in excitation demand during grid voltage dips. For example, when the grid voltage dip worsens, controller 4 increases the duty cycle of DC chopper converter 32, increases the output voltage, maintains the reactive power output of synchronous condenser 1, and enhances the voltage support of the grid.

[0090] Controller 4 has the ability to execute method steps, ensuring that the system can operate stably according to the preset control logic. Controller 4 includes an upper-level control module 41, a middle-level control module 42, and a lower-level control module 43, with each module having a clear division of labor and cooperating with each other.

[0091] The upper-level control module 41 is primarily responsible for real-time monitoring and accurate judgment of the power grid status, and dynamically adjusting the excitation voltage reference value according to the power grid status. It can quickly identify various abnormal conditions in the power grid, such as voltage fluctuations and frequency changes, and issue macroscopic control commands accordingly. For example, when the power grid voltage drops, it quickly determines the degree and duration of the drop, providing a basis for subsequent control actions. The upper-level control module 41 has the following key functions:

[0092] Power Grid Status Monitoring and Analysis: The upper-level control module 41 collects key operating parameters of the power grid in real time through an integrated high-precision sensor network, including but not limited to grid frequency, voltage amplitude and phase, current magnitude, and power flow direction. These sensors are distributed at key nodes of the power grid to ensure the comprehensiveness and accuracy of the collected data. For example, precision voltage transformers (PTs) and current transformers (CTs) are deployed at the grid connection points and the output terminals of synchronous condensers to obtain real-time voltage and current signals. The collected data is transmitted to the upper-level control module 41 at high frequency to ensure timely capture of transient changes in the power grid.

[0093] Dynamic adjustment of excitation voltage reference value: Based on in-depth analysis of the power grid state, the upper-level control module 41 incorporates an advanced control algorithm capable of intelligently and dynamically adjusting the excitation voltage reference value. It employs a predictive control algorithm based on the power grid state-space model, combined with real-time monitoring data, to predict the power grid's operating trend over a future period. Based on the prediction results, the upper-level control module 41 calculates and updates the excitation voltage reference value in real time to guide the middle-level control module 42 in precisely adjusting the excitation voltage. For example, when the power grid frequency deviates or the voltage amplitude deviates from the set range, the upper-level control module 41 can respond quickly, adjusting the excitation voltage reference value according to a preset control strategy to ensure that the power grid parameters rapidly return to a stable state.

[0094] The intermediate control module 42, acting as a crucial link between the upper control module 41 and the lower control module 43, is used for fine-tuning the excitation voltage. It achieves independent excitation voltage control by adjusting the duty cycle of the DC-DC chopper converter 32 using a proportional-integral-derivative (PID) controller. Based on the grid status information transmitted from the upper control module 41 and combined with the current operating parameters of the synchronous condenser 1, it uses advanced control algorithms to accurately calculate the required excitation voltage value and issues corresponding adjustment commands to the lower control module 43. During the adjustment process, the dynamic characteristics of the system are fully considered to ensure a smooth transition and stable output of the excitation voltage. The implementation details of the intermediate control module 42 are as follows:

[0095] Optimized Implementation of PID Control Algorithm: The mid-level control module 42 adopts the classic PID controller algorithm to adjust the duty cycle of the DC-DC chopper converter 32 in real time. To adapt to the complex dynamic characteristics of the power system, this PID controller has undergone careful design and optimization. The proportional term (P) can quickly respond to excitation voltage deviations, providing an adjustment proportional to the deviation to ensure system speed. The integral term (I) is mainly used to eliminate steady-state errors of the system, gradually adjusting the duty cycle by accumulating the deviation until the excitation voltage stabilizes near the reference value. The derivative term (D) predicts the trend of deviation changes and adjusts the duty cycle in advance, effectively suppressing system overshoot and oscillation. In actual control, the parameters (Kp, Ki, Kd) of the PID controller are optimized and tuned based on the operating characteristics of the power grid and the dynamic response characteristics of the synchronous condenser through extensive simulation calculations and on-site debugging to ensure that the system can achieve accurate excitation voltage control under different operating conditions.

[0096] Chopper Duty Cycle Adjustment Mechanism: As a key device in DC-DC power conversion, the DC-DC chopper converter 32's middle-level control module 42 precisely controls the excitation voltage by adjusting its duty cycle. The DC-DC chopper converter 32 works by periodically switching on and off high-speed switching devices (such as IGBTs) to convert the input DC voltage into a pulse voltage waveform with an adjustable duty cycle, thereby regulating the output voltage. The middle-level control module 42 calculates the required duty cycle adjustment based on the deviation between the excitation voltage reference value issued by the upper-level control module 41 and the actual measured excitation voltage value, using a PID controller algorithm. Subsequently, this module generates a control signal corresponding to the calculation result, driving the switching devices in the DC-DC chopper converter 32 to precisely adjust its duty cycle. For example, when the actual excitation voltage is lower than the reference value, the intermediate control module will increase the duty cycle of the DC-DC chopper converter 32 to raise the output voltage until the excitation voltage reaches the set reference value; conversely, it will decrease the duty cycle to lower the output voltage. In this way, the intermediate control module 42 achieves independent and precise control of the excitation voltage, ensuring that the synchronous condenser 1 can operate stably under different power grid conditions and meet the reactive power regulation requirements of the power grid.

[0097] The bottom-level control module 43 focuses on the efficient operation of the PWM rectifier and DC-DC chopper converter 32, and achieves real-time decoupled control. It directly controls the switching action of the converter, achieving efficient conversion and transmission of electrical energy through precise PWM signal generation and control. Simultaneously, the bottom-level control module 43 can quickly respond to and adjust the converter's output according to the instructions of the middle-level control module 42, ensuring the real-time performance and accuracy of the flexible excitation system. The core functions of the bottom-level control module 43 are as follows:

[0098] High-efficiency operation and control of the PWM rectifier: The underlying control module 43 implements an advanced control strategy for the PWM rectifier to ensure its efficient operation and achieve independent control of active and reactive power on the AC side. Specifically, the underlying control module 43 employs PWM control technology based on space vector modulation (SVM), generating a high-precision PWM signal by rationally arranging the switching sequence of the switching devices to drive the power semiconductor devices in the PWM rectifier. During the control process, the underlying control module 43 monitors the voltage and current waveforms on the AC side in real time, calculates the active and reactive current components of the power grid using instantaneous reactive power theory, and compares them with the set active and reactive current reference values. Based on the comparison results, the duty cycle and phase of the PWM signal are adjusted in real time through a feedback control algorithm to achieve precise control of the PWM rectifier output current, ensuring independent adjustment of active and reactive power on the AC side. Meanwhile, in order to improve the system efficiency and power quality, the underlying control module 43 also integrates harmonic compensation function, which detects and suppresses harmonic current on the grid side in real time, so that the total harmonic distortion (THD) of the input current of the PWM rectifier is controlled at an extremely low level (e.g., THD ≤ [specific harmonic distortion value]%), thereby improving the power conversion efficiency and grid compatibility of the entire system.

[0099] Real-time decoupling control of DC-DC chopper converter 32: In terms of controlling the DC-DC chopper converter 32, the underlying control module 43 adopts a decoupling strategy based on average current mode control, realizing real-time decoupling control of input voltage and output current. Specifically, the underlying control module 43 establishes an input-output dynamic model by real-time monitoring of the input voltage and output current of the DC-DC chopper converter 32, and uses feedforward compensation technology to compensate for the impact of input voltage fluctuations on the output current in real time. Simultaneously, combined with feedback control, the output current is precisely adjusted to ensure that the DC-DC chopper converter 32 can quickly and stably output the expected DC current under conditions of input voltage changes and load disturbances. For example, when the input voltage changes abruptly due to grid fluctuations, the underlying control module 43 can respond quickly by adjusting the chopper's duty cycle and switching frequency to suppress the impact of input voltage changes on the output current, ensuring the stability and accuracy of the output current. This real-time decoupling control technology not only improves the dynamic performance and steady-state accuracy of the DC chopper converter 32, but also enhances the anti-interference capability and reliability of the entire flexible excitation system, ensuring that the excitation winding of the synchronous condenser 1 can obtain a stable and accurate DC excitation current, thereby ensuring the stable operation of the synchronous condenser 1 and the normal functioning of the power grid's reactive power regulation function.

[0100] The controller 4 can dynamically adjust the coordinated control strategy between the energy storage system 2 and the flexible excitation power unit 3 according to the real-time state of the power grid. When the grid load increases or disturbances occur, the controller 4 can quickly coordinate the release of electrical energy by the energy storage battery 21, while adjusting the output of the DC-DC chopper converter 32 to increase the reactive power output of the synchronous condenser 1 and enhance the voltage support of the power grid. Conversely, when the grid load decreases, the controller 4 rationally arranges the charging of the energy storage battery 21 and reduces the excitation power of the synchronous condenser 1 to achieve economical operation of the system. This dynamic coordinated control mechanism not only improves the overall performance of the system but also enhances the system's adaptability and flexibility to changes in the power grid.

[0101] Through the design of the controller 4 with the above hierarchical architecture, the present invention realizes precise and stable control of the integrated control system for synchronous condenser energy storage excitation, effectively improving the operating efficiency and stability of the power system.

[0102] In the technical solution provided by this invention, the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters are obtained; based on the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters, the grid operating state is generated; based on the grid operating state, the energy storage system and flexible excitation power unit are adjusted according to a coordinated control strategy, and the adjusted current synchronous condenser parameters and current grid parameters are obtained; through a preset dual-damping channel, damping control is performed based on the current synchronous condenser parameters and current grid parameters, enabling real-time monitoring and analysis of data, and adopting a coordinated control strategy to effectively utilize the energy storage system to improve the transient stability of the synchronous condenser. Through coordinated control via the dual-damping channel, the effect of suppressing subsynchronous oscillations is enhanced, thereby improving the dynamic stability of the grid voltage.

[0103] It is worth noting that, Figure 1 The synchronous condenser energy storage excitation control system shown is also applicable to Figure 2 or Figure 3 The method for controlling the energy storage excitation of the synchronous condenser will not be elaborated here.

[0104] The following uses a controller as the execution subject to illustrate the implementation process of the synchronous condenser energy storage excitation control method provided in this embodiment of the invention. It is understood that the execution subject of the synchronous condenser energy storage excitation control method provided in this embodiment of the invention includes, but is not limited to, a controller.

[0105] Figure 2 A flowchart of a synchronous condenser energy storage excitation control method provided in an embodiment of the present invention is shown below. Figure 2 As shown, the method includes:

[0106] Step 101: Obtain the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters.

[0107] In this embodiment of the invention, a topology is constructed, which includes a flexible excitation power unit, an energy storage system, and a synchronous condenser. The flexible excitation power unit includes a bridge three-level voltage source converter, a DC-DC chopper converter, and a filter inductor.

[0108] In this embodiment of the invention, the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters are monitored and collected in real time. These original synchronous condenser parameters, grid parameters, and energy storage system parameters are the same as those before coordinated control. The synchronous condenser parameters include, but are not limited to, rotor angular velocity, terminal voltage signal, and current signal; the grid parameters include, but are not limited to, grid voltage, active power, and grid frequency; and the energy storage system parameters include, but are not limited to, state of charge, voltage, and temperature.

[0109] Step 102: Generate the grid operating status based on the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters.

[0110] In this embodiment of the invention, if the original synchronous condenser parameters, the original power grid parameters, and the original energy storage system parameters meet the preset normal operation conditions, the power grid operation state is determined to be a normal operation state; if any one of the original synchronous condenser parameters, the original power grid parameters, and the original energy storage system parameters meets the preset forced excitation demand conditions, the power grid operation state is determined to be a forced excitation demand state; if any one of the original synchronous condenser parameters, the original power grid parameters, and the original energy storage system parameters meets the preset inverter operation conditions, the power grid operation state is determined to be an inverter operation state.

[0111] It is worth noting that the normal operation conditions, the forced excitation demand conditions, and the inverter operation conditions can all be set according to actual needs, and the embodiments of the present invention do not limit this.

[0112] Step 103: Based on the grid operating status, adjust the energy storage system and flexible excitation power unit according to the coordinated control strategy, and obtain the adjusted current synchronous condenser parameters and current grid parameters.

[0113] In this embodiment of the invention, the energy storage system and the flexible excitation power unit achieve coordinated control. Specifically, when the power grid is in normal operation, the peak excitation voltage multiple is dynamically adjusted according to the power grid operation status, and the output peak is the half-value intermediate capacitor voltage. The energy storage system maintains the intermediate DC bus voltage stable, charges during the off-peak period of the power grid load, and discharges during the peak period or in emergency situations.

[0114] When the grid is operating in inverter mode, the peak excitation voltage multiple is dynamically adjusted according to the grid operating status, and the peak excitation voltage is adjusted according to a preset rule to maintain safe system operation. The energy storage system takes over the DC power supply to ensure the continuous operation of the excitation system and improves grid stability through rapid reactive power regulation. Specifically, when the grid voltage drops significantly, the energy storage system can seamlessly switch to DC power supply to prevent excitation system failure and achieve fault ride-through and protection functions.

[0115] When the power grid is in a state of strong excitation demand, the top excitation voltage multiple is dynamically adjusted according to the power grid operating status to increase the top excitation voltage to the strong excitation value; the energy storage system provides additional energy support to increase the excitation voltage multiple and enhance transient stability.

[0116] The control process under typical operating conditions includes: under normal operating conditions, by adjusting the excitation current of the synchronous condenser, the reactive power required by the power grid is provided and the grid voltage is stabilized; the energy storage system has primary frequency regulation and inertia support functions, which can realize active power regulation in a short period of time and maintain the active dynamic balance and steady-state balance of the power grid.

[0117] In inverter operation, when a transient drop in grid voltage is detected, the grid-side converter can maintain a stable DC voltage. If the grid voltage drops further, the grid-side converter will be suspended to prevent overcurrent. At this time, the DC chopper converter is powered by the energy storage battery to maintain the normal operation of the excitation system. After the grid voltage recovers, the system automatically resumes the operation of the three-level voltage source converter.

[0118] Energy storage system management includes: charging the energy storage device with excess electricity during periods of low grid load to improve the overall system efficiency; and rapidly discharging the energy storage system during periods of high grid load or in emergencies to provide necessary active power support and ensure stable grid operation.

[0119] In this embodiment of the invention, the adjusted current synchronous condenser parameters and current grid parameters are monitored and collected in real time. The adjusted synchronous condenser parameters, the adjusted current synchronous condenser parameters, and the current grid parameters are the synchronous condenser parameters, grid parameters, and energy storage system parameters after coordinated control. The synchronous condenser parameters include, but are not limited to, rotor angular velocity, terminal voltage signal, and current signal; the grid parameters include, but are not limited to, grid voltage, active power, and grid frequency; the energy storage system parameters include, but are not limited to, state of charge, voltage, and temperature.

[0120] Step 104: Perform damping control based on the current synchronous condenser parameters and the current power grid parameters through the preset dual damping channels.

[0121] In this embodiment of the invention, the dual-damping channel includes synchronous generator excitation damping control (SEDC) and static synchronizing compensator damping control (SSDC). The SSDC enhances the suppression of subsynchronous oscillations by injecting reactive current through the energy storage system. Furthermore, the SEDC and SSDC can work collaboratively at different frequency bands to cover a wider range of oscillation frequencies. The dual-damping channel can suppress subsynchronous oscillations and low-frequency oscillations.

[0122] In this embodiment of the invention, the controller can calculate the reactive current and excitation current based on the current synchronous condenser parameters and the current power grid parameters, so that the synchronous generator excitation damping control (SEDC) and static synchronous compensator damping control (SSDC) can dampen the oscillations of the power system based on the reactive current and excitation current.

[0123] In the technical solution provided by this invention, the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters are obtained; based on the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters, the grid operating state is generated; based on the grid operating state, the energy storage system and flexible excitation power unit are adjusted according to a coordinated control strategy, and the adjusted current synchronous condenser parameters and current grid parameters are obtained; through a preset dual-damping channel, damping control is performed based on the current synchronous condenser parameters and current grid parameters, enabling real-time monitoring and analysis of data, and adopting a coordinated control strategy to effectively utilize the energy storage system to improve the transient stability of the synchronous condenser. Through coordinated control via the dual-damping channel, the effect of suppressing subsynchronous oscillations is enhanced, thereby improving the dynamic stability of the grid voltage.

[0124] Figure 3 A flowchart of another synchronous condenser energy storage excitation control method provided in an embodiment of the present invention is shown below. Figure 3 As shown, the method includes:

[0125] Step 201: Obtain the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters.

[0126] In this embodiment of the invention, each step is executed by the controller.

[0127] In this embodiment of the invention, the synchronous condenser parameters include, but are not limited to, rotor angular velocity, terminal voltage signal, and current signal; the grid parameters include, but are not limited to, grid voltage, active power, and grid frequency; and the energy storage system parameters include, but are not limited to, state of charge, voltage, and temperature.

[0128] In this embodiment of the invention, the system is also equipped with various sensors, such as voltage sensors, current sensors, frequency sensors, and temperature sensors. Specifically, the voltage sensor collects the generator terminal voltage signal, grid voltage, active power, and energy storage system voltage; the current sensor collects the current signal; the frequency sensor collects the grid frequency; the encoder or resolver collects the rotor angular velocity; the power meter obtains the active power; the state of charge can be obtained by directly measuring the energy storage system; and the temperature sensor collects the temperature of the energy storage system. By monitoring parameters such as the state of charge, voltage, and temperature of the energy storage battery, the operating status of the energy storage system can be understood.

[0129] In this embodiment of the invention, sensors and other data acquisition tools transmit the collected raw synchronous condenser parameters, raw power grid parameters, and raw energy storage system parameters to the controller via a high-speed communication interface for real-time analysis and decision-making, thereby enabling dynamic adjustment of the power grid's operating status.

[0130] Step 202: Generate the grid operating status based on the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters. If the grid operating status is normal operation, proceed to step 203; if the grid operating status is strong excitation demand status, proceed to step 205; if the grid operating status is inverter operation status, proceed to step 207.

[0131] In this embodiment of the invention, a grid frequency deviation Δf is generated based on the grid frequency and the rated frequency; the generator terminal voltage U is determined based on the generator terminal voltage signal; the active power fluctuation rate ΔP is generated based on the active power at the first time point and the active power at the second time point; and the rotor angular velocity deviation Δω is generated based on the synchronous condenser rotor angular velocity and the desired rotor angular velocity.

[0132] It is worth noting that the first and second time points can be set according to actual needs, and this embodiment of the invention does not limit this.

[0133] In this embodiment of the invention, step 202 specifically includes:

[0134] Step 2021: If the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters meet the preset normal operating conditions, the grid operating state is determined to be normal operating state.

[0135] In this embodiment of the invention, the controller adopts a multivariate threshold determination method and sets the following normal operating state conditions (A1-A4). When all of the following conditions are met, the system is determined to be in normal operating state, ensuring the feasibility and stability of the power grid operating state determination strategy:

[0136] A1. Power grid frequency deviation |Δf|≤0.2Hz;

[0137] A2. Terminal voltage U ≥ 0.95UN, where UN is the rated voltage;

[0138] A3. Active power fluctuation rate |ΔP / Δt|≤5%PN / s, where PN is the rated active power, and |ΔP / Δt|≤5%PN / s means that the maximum allowable power change per second does not exceed 5% of the rated power;

[0139] A4. The state of charge (SOC) of the energy storage system is 20% ≤ SOC ≤ 80%.

[0140] Step 2022: If any one of the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters meets the preset strong excitation demand state conditions, the grid operating state is determined to be the strong excitation demand state.

[0141] In this embodiment of the invention, the controller adopts a multivariate threshold determination method and sets the following forced excitation demand state conditions (B1-B4). When any one of the following conditions is met, the system is determined to be in a forced excitation demand state, ensuring the feasibility and stability of the power grid operation state determination strategy:

[0142] B1. The terminal voltage drops to U<0.9UN and remains there for more than 100 milliseconds (ms), where UN is the rated voltage;

[0143] B2. Camera rotor angular velocity deviation Δω>0.05pu;

[0144] B3. During a specified duration, the active power fluctuation rate ΔP > 10%PN, where PN is the rated active power, the specified duration is less than 1 second (s), and ΔP > 10%PN means that within less than 1 second, the active power suddenly decreased by more than 10% of its rated power.

[0145] B4. The rate of change of grid frequency deviation Δf / dt > 0.2 Hz / s, where Δf / dt > 0.2 Hz / s indicates that the grid frequency is decreasing at a rate of more than 0.2 Hz per second.

[0146] Step 2023: If any one of the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters meets the preset inverter operation state conditions, the grid operation state is determined to be the inverter operation state.

[0147] In this embodiment of the invention, the controller adopts a multivariate threshold determination method and sets the following inverter operation state conditions (C1-C4). When any one of the following conditions is met, the system determines that it is in inverter operation state, ensuring the feasibility and stability of the power grid operation state determination strategy:

[0148] C1. Terminal voltage U < 0.7UN for more than 50ms, where UN is the rated voltage;

[0149] C2, The power grid frequency f < 49.5Hz lasts for more than 200ms;

[0150] C3. Active power fluctuation rate ΔP > 15%PN and the grid frequency shows a downward trend, where PN is the rated active power;

[0151] C4. External protection signals (such as line trip signals) are triggered.

[0152] Step 203: Control the energy storage system to maintain the intermediate DC bus voltage and perform charging and discharging management according to the grid load cycle.

[0153] In this embodiment of the invention, under normal operating conditions, the energy storage system maintains a stable intermediate DC bus voltage while managing charging and discharging according to the grid load cycle, performing short-term active power regulation and energy buffering. When the grid load is low, the energy storage system charges; when the grid load is high, the energy storage system discharges appropriately, smoothing power fluctuations in the grid and improving the economy and stability of grid operation.

[0154] Charging and discharging management during grid load cycles specifically includes: starting charging during grid load off-peak periods (grid frequency f ≥ 50.1 Hz or charging dispatch instructions); and entering discharging mode during grid load peak periods (grid frequency f ≤ 49.9 Hz or discharging dispatch instructions).

[0155] The charging process specifically includes: inputting three-phase AC power to the bridge three-level voltage source converter to charge the DC capacitor and battery to 90% of their rated values; unlocking the bridge three-level voltage source converter to raise the voltage of the capacitor and battery to the target value; and then converting the intermediate DC voltage into an adjustable DC voltage to supply the rotor winding of the synchronous condenser, thereby achieving excitation control of the synchronous condenser.

[0156] In this embodiment of the invention, the energy storage system dynamically switches its operating mode according to the grid operating status, and works in conjunction with the flexible excitation system to achieve precise control of the excitation voltage of the synchronous condenser, thereby ensuring the reliability of power supply.

[0157] Step 204: Adjust the peak excitation voltage multiple of the flexible excitation power unit to the preset first multiple, control the flexible excitation power unit to output according to the voltage value of the first multiple, and continue to execute step 209.

[0158] In this embodiment of the invention, the first multiplier can be set according to actual needs. As an optional solution, the first multiplier is 0.5.

[0159] Specifically, the peak excitation voltage multiple of the flexible excitation power unit is adjusted to 0.5, and the output peak of the flexible excitation power unit is the half-value intermediate capacitor voltage (0.5×V dc, where V is the rated excitation voltage and dc is DC current), in order to reduce the risk of overvoltage in the excitation winding and improve the regulation resolution and stability.

[0160] In this embodiment of the invention, during normal grid operation, the adaptive adjustment mechanism for the peak excitation voltage multiple sets the output spike to the half-value intermediate capacitor voltage. This setting satisfies the normal excitation requirements of the synchronous condenser while significantly improving regulation resolution and stability. By reducing the output spike voltage, the rotor overvoltage level is reduced, thereby effectively protecting the insulation performance of the rotor windings and extending the service life of the synchronous condenser.

[0161] In this embodiment of the invention, the controller monitors parameters such as voltage, frequency, and load of the power grid in real time to ensure that the synchronous condenser operates stably under normal operating conditions. When the power grid parameters fluctuate slightly, the controller maintains the stability of the synchronous condenser's output voltage by finely adjusting the excitation current, thus ensuring normal power supply to the power grid.

[0162] Step 205: Control the energy storage system to enhance power supply.

[0163] In this embodiment of the invention, under strong excitation demand conditions, an energy storage system provides additional energy support to enhance the transient stability of the system.

[0164] In this embodiment of the invention, the energy storage system dynamically switches its operating mode according to the grid operating status, and works in conjunction with the flexible excitation system to achieve precise control of the excitation voltage of the synchronous condenser, thereby ensuring the reliability of power supply.

[0165] Step 206: Adjust the peak excitation voltage multiple of the flexible excitation power unit to the preset second multiple, control the flexible excitation power unit to output according to the second multiple voltage value, and continue to execute step 209.

[0166] In this embodiment of the invention, the second multiple can be set according to actual needs. As an optional solution, the range of the second multiple is 1.2 to 1.5.

[0167] Specifically, the peak excitation voltage multiple of the flexible excitation power unit is adjusted to 1.2 to 1.5, and the output peak of the flexible excitation power unit is the strong excitation value (1.2 to 1.5 × V dc, where V is the rated excitation voltage and dc is DC current). The control system automatically increases the excitation voltage peak to the strong excitation value to cope with the risk of transient voltage drop or unit loss of synchronization.

[0168] In this embodiment of the invention, when a power grid fault or sudden load change occurs, the controller quickly detects the additional reactive power demand from the power grid. By monitoring the amplitude and rate of change of the grid voltage, as well as the reactive power output of the synchronous condenser, it determines whether to enter a forced excitation state. For example, when the grid voltage amplitude is lower than the set forced excitation threshold and the reactive power demand increases, the controller issues a forced excitation command. Upon receiving the forced excitation command, the adaptive adjustment mechanism of the peak excitation voltage multiple quickly raises the output peak to the forced excitation value. The forced excitation value is typically set to 1.5 to 2 times the intermediate capacitor voltage to ensure that the synchronous condenser can output sufficient reactive power to support the grid voltage. During this process, the controller monitors the excitation current and the operating status of the synchronous condenser in real time to prevent excessive excitation current from causing equipment overload.

[0169] By increasing the peak excitation voltage, the reactive power output capability of the synchronous condenser is significantly enhanced, which helps to quickly restore the grid voltage and improve the transient stability of the grid. Under strong excitation, the system can continuously output reactive power until the grid returns to normal operating conditions.

[0170] Step 207: Control the energy storage system to take over the DC power supply for power supply.

[0171] In this embodiment of the invention, during inverter operation, the energy storage system takes over the DC power supply for power supply. The energy storage battery and DC capacitor work simultaneously to provide a large amount of active and reactive power support, ensuring the continuous operation of the flexible excitation system. At the same time, it injects or absorbs reactive current into the grid through rapid reactive power regulation, thereby improving system stability.

[0172] In this embodiment of the invention, when the grid voltage drops, fault ride-through and protection are achieved, with the energy storage system taking over the DC power supply to maintain the normal operation of the excitation system. Specifically, after detecting a transient drop in grid voltage, the grid-side converter maintains a stable DC voltage; if the grid voltage drops further, to prevent overcurrent in the grid-side converter, its operation is suspended. At this time, the DC chopper converter is powered by the energy storage battery to maintain the normal operation of the excitation system; after the grid voltage recovers, the system automatically resumes operation of the bridge three-level voltage source converter. The energy storage system can continuously provide a stable DC power supply to the excitation system during grid voltage drops, ensuring the reliability and stability of the excitation system. The controller dynamically adjusts the coordinated control strategy between the energy storage system and the flexible excitation power unit according to the grid status to improve the overall system performance.

[0173] In this embodiment of the invention, the energy storage system dynamically switches its operating mode according to the grid operating status, and works in conjunction with the flexible excitation system to achieve precise control of the excitation voltage of the synchronous condenser, thereby ensuring the reliability of power supply.

[0174] Step 208: Dynamically adjust the ceiling excitation voltage multiple of the flexible excitation power unit according to a preset multiple adjustment strategy, and control the flexible excitation power unit to output according to the voltage value of the dynamically adjusted ceiling excitation voltage multiple.

[0175] In the embodiment of the present invention, the multiple adjustment strategy is a preset rule, and the multiple adjustment strategy is the corresponding relationship between the terminal voltage and the voltage adjustment method. As an optional solution, when the terminal voltage U is greater than or equal to the rated voltage of the first voltage multiple (U≥a×UN, where a is the first voltage multiple), the corresponding voltage adjustment method is to maintain the forced excitation value (1.2 - 1.5×Vdc, V is the rated excitation voltage, and dc is direct current); when the terminal voltage U is greater than or equal to the rated voltage of the second voltage multiple and less than the rated voltage of the first voltage multiple (b×UN≤U<a×UN, where b is the second voltage multiple), the corresponding voltage adjustment method is to reduce the excitation voltage in proportion (that is, reduce the ceiling excitation voltage multiple in proportion); when the terminal voltage U is less than the rated voltage of the second voltage multiple (U<b×UN), the corresponding voltage adjustment method is the inverter de-energization mode to prevent overvoltage.

[0176] It should be noted that both the first voltage multiple a and the second voltage multiple b can be set according to actual needs, and the embodiment of the present invention does not limit this. As an optional solution, the first voltage multiple a is 0.7, and the second voltage multiple b is 0.5.

[0177] In the embodiment of the present invention, the controller adjusts the ceiling excitation voltage multiple according to the multiple adjustment strategy, thereby adjusting the ceiling excitation voltage to prevent the unit from losing synchronization or equipment damage due to a serious voltage drop.

[0178] It should be noted that the above mechanism for adaptive adjustment of the ceiling excitation voltage multiple is implemented through a PID controller and a feedforward composite control algorithm to ensure that the excitation voltage responds quickly and smoothly, and to avoid overheating of the excitation winding or insulation breakdown.

[0179] In the embodiment of the present invention, when the terminal voltage undergoes a serious drop, the controller quickly detects the depth and duration of the voltage drop. By comparing the terminal voltage with multiple set voltage thresholds, the severity of the voltage drop is evaluated. At the same time, the controller monitors other parameters of the system, such as frequency and active power, to comprehensively understand the operating state of the power grid. According to the preset adjustment rule, the ceiling excitation voltage multiple adaptive adjustment mechanism dynamically adjusts the ceiling excitation voltage. The adjustment rule is usually based on the depth and duration of the voltage drop, as well as the stability requirements of the system. For example, in the initial stage of a serious voltage drop, quickly reduce the ceiling excitation voltage to reduce the excitation current and prevent the excitation system from being overloaded; as the voltage gradually recovers, gradually increase the ceiling excitation voltage to maintain the basic reactive power output of the synchronous condenser and support the recovery of the power grid voltage.

[0180] Throughout the voltage dip, the controller monitors the operating status of the synchronous condenser and excitation system in real time to ensure safe system operation. By appropriately adjusting the peak excitation voltage, the excitation current is maintained within a safe range to prevent equipment damage. Simultaneously, the energy storage system provides auxiliary support as needed, jointly ensuring the stability and reliability of the system.

[0181] Step 209: Obtain the adjusted current synchronous condenser parameters and current power grid parameters.

[0182] In this embodiment of the invention, the adjusted current synchronous condenser parameters and current grid parameters are monitored and collected in real time. The synchronous condenser parameters include, but are not limited to, rotor angular velocity, terminal voltage signal, and current signal; the grid parameters include, but are not limited to, grid voltage, active power, and grid frequency; and the energy storage system parameters include, but are not limited to, state of charge, voltage, and temperature.

[0183] Step 210: Generate excitation current and reactive current based on the current synchronous condenser parameters and the current power grid parameters.

[0184] In this embodiment of the invention, the controller calculates the excitation current based on the real-time monitored grid frequency and voltage signals; and calculates the reactive current based on the subsynchronous oscillation frequency and amplitude of the grid. The subsynchronous oscillation frequency can be obtained through on-site measurement using high-precision data acquisition equipment, or by capturing the subsynchronous oscillation characteristics of the acquired frequency signal through Fourier transform or wavelet transform.

[0185] Step 211: By controlling the excitation damping of the synchronous generator, the synchronous condenser is adjusted according to the excitation current to suppress low-frequency oscillations.

[0186] Figure 4 A schematic diagram of a wideband low-frequency oscillation suppression principle provided in an embodiment of the present invention is shown below. Figure 4 As shown, ET represents the power grid section; IGBT is an insulated-gate bipolar transistor, the core component of the static synchronous compensator (STATCOM), used to control reactive power injection; G represents the synchronous generator; Q and P represent reactive power and active power, respectively. The dual-damping channel includes synchronous generator excitation damping control and STATCOM damping control. The STATCOM damping control enhances the subsynchronous oscillation suppression effect by injecting reactive current through the energy storage system. Furthermore, the synchronous generator excitation damping control and the STATCOM damping control can work collaboratively in different frequency bands to cover a wider range of oscillation frequencies.

[0187] Synchronous generator excitation damping control alters the electromagnetic characteristics of the synchronous generator by adjusting its excitation current, thereby affecting the dynamic behavior of the system. When low-frequency oscillations are detected in the system, adjusting the excitation current can change the generator's output voltage and reactive power, thus damping the oscillations.

[0188] Specifically, synchronous generator excitation damping control modulates the reactive power output of the synchronous condenser by adjusting the magnitude and phase of its excitation current, thereby damping power system oscillations. The controller dynamically adjusts the magnitude and phase of the excitation current based on real-time monitoring of grid frequency and voltage changes to suppress low-frequency and subsynchronous oscillations.

[0189] Step 212: By controlling the damping of the static synchronous compensator, reactive current is injected into the power grid through the energy storage system to suppress subsynchronous oscillation.

[0190] In this embodiment of the invention, the static synchronous compensator damping control utilizes the energy storage system to inject reactive current into the power grid through the IGBT inverter to enhance the suppression effect of subsynchronous oscillations; when subsynchronous oscillations are detected in the system, the oscillation energy can be effectively offset by rapidly responding and injecting appropriate reactive current, thus playing a damping role.

[0191] Specifically, the static synchronous compensator (SRC) injects reactive current into the grid through an energy storage system, enhancing its ability to suppress subsynchronous oscillations. The controller calculates the required reactive current based on the frequency and amplitude of the grid's subsynchronous oscillations and injects it into the grid through the bidirectional converter of the energy storage system. This control method can quickly provide the necessary reactive power support and stabilize the grid voltage when subsynchronous oscillations occur.

[0192] This application proposes a supersynchronous instantaneous current injection control strategy for static synchronous compensator damping control, which combines dual-damping channel coordinated control with synchronous generator excitation damping control and static synchronous compensator damping control to enhance the effect of suppressing subsynchronous oscillations.

[0193] In this embodiment of the invention, in the cooperative working principle of the dual-damping channels, the synchronous generator excitation damping control mainly targets low-frequency oscillations (e.g., 0.1-2Hz). By adjusting the excitation current, the reactive power output of the synchronous condenser is changed, thereby producing a damping effect on low-frequency oscillations. The static synchronizing compensator damping control focuses on subsynchronous oscillations (e.g., 2-25Hz). By injecting reactive current through the energy storage system, it quickly responds to subsynchronous oscillations, providing additional damping torque to suppress the amplitude and frequency of the oscillations. The controller monitors the operating status of the power grid in real time, including parameters such as frequency, voltage, and current. When oscillation is detected, based on the frequency and amplitude of the oscillation, the synchronous generator excitation damping control and the static synchronizing compensator damping control are activated simultaneously. The two damping controls work together in different frequency bands to form a wide-band damping effect, effectively covering a wider range of oscillation frequencies.

[0194] It is worth noting that, based on the actual situation of the power grid and the operating characteristics of the synchronous condenser, the parameter settings of the controller need to be optimized. For example, the gain and time constant of the synchronous generator excitation damping control can be adjusted according to the damping requirements of the power grid and the response characteristics of the synchronous condenser, and the reactive current injection amplitude and frequency of the static synchronous compensator damping control can be optimized according to the characteristics of the subsynchronous oscillation.

[0195] Regarding the technical effects of the synergistic operation of the dual-damping channels, the power system's ability to suppress low-frequency oscillations and subsynchronous oscillations is significantly improved through their coordinated operation. Specifically, the amplitude and duration of oscillations are effectively reduced, directly enhancing the stability and reliability of the power grid. Simultaneously, the static synchronizing compensator's damping control fully utilizes the rapid charging and discharging characteristics of the energy storage system, playing an irreplaceable and crucial role in suppressing subsynchronous oscillations. This not only enhances the oscillation suppression effect but also significantly improves the utilization efficiency of the energy storage system, thereby enhancing the overall system's economic efficiency.

[0196] This application significantly improves grid voltage stability and dynamic response capabilities through integrated flexible excitation and energy storage control. The synchronous condenser can quickly respond to the grid's reactive power demand, precisely adjust the excitation current, and maintain grid voltage stability. When the grid is subjected to disturbances, the energy storage system can instantly release or absorb reactive power, enhancing the grid's transient stability, reducing voltage fluctuations, and ensuring the reliability of power supply. Simultaneously, based on the highly flexible control characteristics of the fully controlled PWM converter, millisecond-level dynamic response speed is achieved, three times faster than traditional thyristor excitation systems, effectively suppressing low-frequency oscillations and subsynchronous oscillations, and improving the overall stability of the power system.

[0197] This application optimizes the economy and safety of equipment operation. During steady-state operation, the system achieves a higher power factor and lower harmonic losses, improving the efficiency of the excitation transformer, reducing equipment temperature rise, extending equipment lifespan, and reducing maintenance costs. Furthermore, the adaptive adjustment strategy for the peak excitation voltage multiple reduces rotor overvoltage levels during normal operation, protecting the insulation safety of the synchronous condenser; in the event of a grid fault, it can rapidly increase the excitation voltage, enhancing transient stability and preventing equipment damage due to overvoltage, thus improving the operational safety of the synchronous condenser and the excitation system.

[0198] This application achieves efficient utilization of energy storage systems and significant improvement in power quality. The deep integration of the energy storage system with the synchronous condenser's excitation system enables the energy storage device to charge during off-peak hours and discharge rapidly during peak hours or emergencies, providing active power support. This efficient energy management method improves the utilization efficiency of the energy storage system and enhances the grid's regulation and fault response capabilities. Simultaneously, by reducing harmonic content and optimizing voltage waveforms, it improves the grid's power quality, reduces harmonic interference to other equipment in the grid, and ensures the power quality for users. Furthermore, by integrating the energy storage system, the synchronous condenser can provide primary frequency regulation and inertia support to the grid, maintaining grid frequency stability, enhancing the grid's ability to cope with load fluctuations, and improving the overall dynamic performance of the power system.

[0199] It is worth noting that the acquisition, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. The user information in the embodiments of this application was obtained through legal and compliant means, and the acquisition, storage, use, and processing of user information have been authorized and agreed upon by the client.

[0200] It is worth noting that the information collected in this application is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data all comply with the relevant laws, regulations and standards of the relevant countries and regions, necessary confidentiality measures have been taken, and they do not violate public order and good morals. Corresponding operation portals are provided for users to choose to authorize or refuse.

[0201] It is worth noting that the technical solution provided in this application provides users with a corresponding operation entry point, allowing users to choose to agree to or reject the automated decision-making result; if the user chooses to reject, the process will proceed to the expert decision-making process.

[0202] The technical solution of the synchronous condenser energy storage excitation control method provided in this invention involves obtaining the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters; generating the grid operating state based on the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters; adjusting the energy storage system and flexible excitation power unit according to the grid operating state and a coordinated control strategy, and obtaining the adjusted current synchronous condenser parameters and current grid parameters; and performing damping control based on the current synchronous condenser parameters and current grid parameters through a preset dual-damping channel. This enables real-time monitoring and analysis of data, effectively utilizing the energy storage system to improve the transient stability of the synchronous condenser through a coordinated control strategy, and enhancing the suppression of subsynchronous oscillations through coordinated control via the dual-damping channel, thereby improving the dynamic stability of the grid voltage.

[0203] Figure 5 This is a schematic diagram of a controller provided in an embodiment of the present invention. This device is used to execute the aforementioned synchronous condenser energy storage excitation control method, such as... Figure 5 As shown, the device includes: a parameter acquisition unit 11, a power grid operation status generation unit 12, an adjustment unit 13, and a damping control unit 14.

[0204] The parameter acquisition unit 11 is used to acquire the original synchronous condenser parameters, the original power grid parameters, and the original energy storage system parameters.

[0205] The power grid operation status generation unit 12 is used to generate the power grid operation status based on the original synchronous condenser parameters, the original power grid parameters, and the original energy storage system parameters.

[0206] The regulating unit 13 is used to regulate the energy storage system and the flexible excitation power unit according to the grid operating status and the coordinated control strategy, and to obtain the current synchronous condenser parameters and the current grid parameters after regulation.

[0207] The damping control unit 14 is used to perform damping control based on the current synchronous condenser parameters and the current power grid parameters through a preset dual damping channel.

[0208] In this embodiment of the invention, the power grid operation status generation unit 12 is specifically used to determine the power grid operation status as normal operation status if the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters meet preset normal operation status conditions; determine the power grid operation status as forced excitation demand status if any one of the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters meets preset forced excitation demand status conditions; and determine the power grid operation status as inverter operation status if any one of the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters meets preset inverter operation status conditions.

[0209] In this embodiment of the invention, the power grid is in normal operation; the regulating unit 13 is specifically used to control the energy storage system to maintain the intermediate DC bus voltage and to perform charging and discharging management according to the power grid load cycle; the top excitation voltage multiple of the flexible excitation power unit is adjusted to a preset first multiple, and the flexible excitation power unit is controlled to output according to the voltage value of the first multiple.

[0210] In this embodiment of the invention, the power grid is in a strong excitation demand state; the regulating unit 13 is specifically used to control the energy storage system to enhance power supply; the top excitation voltage multiple of the flexible excitation power unit is adjusted to a preset second multiple, and the flexible excitation power unit is controlled to output according to the second multiple voltage value.

[0211] In this embodiment of the invention, the power grid is in inverter operation mode; the regulating unit 13 is specifically used to control the energy storage system to take over the DC power supply for power supply; according to the preset multiple adjustment strategy, the peak excitation voltage multiple of the flexible excitation power unit is dynamically adjusted, and the flexible excitation power unit is controlled to output voltage value according to the dynamically adjusted peak excitation voltage multiple.

[0212] In this embodiment of the invention, the dual-damping channel includes synchronous generator excitation damping control and static synchronous compensator damping control; the damping control unit 14 is specifically used to generate excitation current and reactive current according to the current synchronous condenser parameters and the current grid parameters; through synchronous generator excitation damping control, the synchronous condenser is adjusted according to the excitation current to suppress low-frequency oscillation; through static synchronous compensator damping control, reactive current is injected into the grid through the energy storage system to suppress subsynchronous oscillation.

[0213] In this embodiment of the invention, the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters are obtained; based on these parameters, a grid operating state is generated; according to the grid operating state, the energy storage system and flexible excitation power unit are adjusted according to a coordinated control strategy, and the adjusted current synchronous condenser parameters and current grid parameters are obtained; through a preset dual-damping channel, damping control is performed based on the current synchronous condenser parameters and current grid parameters, enabling real-time monitoring and analysis of data, and effectively utilizing the energy storage system to improve the transient stability of the synchronous condenser through a coordinated control strategy. The dual-damping channel coordinated control enhances the suppression of subsynchronous oscillations, thereby improving the dynamic stability of the grid voltage.

[0214] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer device, specifically, a computer device can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0215] This invention provides a computer device including a memory and a processor. The memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions. When the program instructions are loaded and executed by the processor, they implement the steps of the above-described embodiment of the synchronous condenser energy storage excitation control method. For a detailed description, please refer to the above-described embodiment of the synchronous condenser energy storage excitation control method.

[0216] The following is for reference. Figure 6 It shows a schematic diagram of the structure of a computer device 600 suitable for implementing the embodiments of this application.

[0217] like Figure 6 As shown, the computer device 600 includes a central processing unit (CPU) 601, which can perform various appropriate tasks and processes based on programs stored in read-only memory (ROM) 602 or programs loaded from storage section 608 into random access memory (RAM) 603. The RAM 603 also stores various programs and data required for the operation of the computer device 600. The CPU 601, ROM 602, and RAM 603 are interconnected via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0218] The following components are connected to I / O interface 605: an input section 606 including a keyboard, mouse, etc.; an output section 607 including a cathode ray tube (CRT), liquid crystal feedback (LCD), etc., and speakers, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to I / O interface 605 as needed. A removable medium 611, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 610 as needed so that computer programs read from it can be installed in storage section 608 as needed.

[0219] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program including program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 609, and / or installed from removable medium 611.

[0220] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0221] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0226] The acquisition, storage, use, and processing of data in this application all comply with the relevant provisions of national laws and regulations.

[0227] It should be noted that in the embodiments of this application, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of this application. However, it does not mean that the applicant has used or necessarily used the solution.

[0228] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied 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.

[0229] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0230] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0231] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for controlling the energy storage excitation of a synchronous condenser, characterized in that, The method includes: Obtain raw synchronous condenser parameters, raw power grid parameters, and raw energy storage system parameters; Based on the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters, the power grid operating status is generated; Based on the power grid operating status, the energy storage system and flexible excitation power unit are adjusted according to the coordinated control strategy, and the adjusted current synchronous condenser parameters and current power grid parameters are obtained. Damping control is performed based on the current synchronous condenser parameters and the current power grid parameters through a preset dual-damping channel.

2. The synchronous condenser energy storage excitation control method according to claim 1, characterized in that, The step of generating the grid operating status based on the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters includes: If the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters meet the preset normal operating conditions, the power grid operating state is determined to be a normal operating state. If any one of the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters meets the preset strong excitation demand state conditions, the power grid operating state is determined to be a strong excitation demand state. If any one of the original synchronous condenser parameters, original grid parameters, and original energy storage system parameters meets the preset inverter operation state conditions, the grid operation state is determined to be the inverter operation state.

3. The synchronous condenser energy storage excitation control method according to claim 2, characterized in that, The power grid is in normal operating condition. The adjustment of the energy storage system and flexible excitation power unit according to the grid operating status and in accordance with the coordinated control strategy includes: The energy storage system is controlled to maintain the intermediate DC bus voltage and to perform charge and discharge management according to the grid load cycle; The peak excitation voltage multiple of the flexible excitation power unit is adjusted to a preset first multiple, and the flexible excitation power unit is controlled to output according to the voltage value of the first multiple.

4. The synchronous condenser energy storage excitation control method according to claim 2, characterized in that, The power grid is operating under a strong excitation demand state. The adjustment of the energy storage system and flexible excitation power unit according to the grid operating status and in accordance with the coordinated control strategy includes: Control the energy storage system to enhance power supply; The peak excitation voltage multiple of the flexible excitation power unit is adjusted to a preset second multiple, and the flexible excitation power unit is controlled to output according to the voltage value of the second multiple.

5. The synchronous condenser energy storage excitation control method according to claim 2, characterized in that, The power grid is in inverter operation mode. The adjustment of the energy storage system and flexible excitation power unit according to the grid operating status and in accordance with the coordinated control strategy includes: The energy storage system is controlled to take over the DC power supply for power supply; According to a preset multiplier adjustment strategy, the peak excitation voltage multiplier of the flexible excitation power unit is dynamically adjusted, and the flexible excitation power unit is controlled to output voltage according to the dynamically adjusted peak excitation voltage multiplier.

6. The synchronous condenser energy storage excitation control method according to claim 1, characterized in that, The dual damping channels include synchronous generator excitation damping control and static synchronous compensator damping control. The damping control, achieved through a preset dual-damping channel based on the current synchronous condenser parameters and the current power grid parameters, includes: Based on the current synchronous condenser parameters and the current power grid parameters, generate excitation current and reactive current; By controlling the excitation damping of the synchronous generator, the synchronous condenser is adjusted according to the excitation current to suppress low-frequency oscillations; By controlling the damping of the static synchronous compensator, the reactive current is injected into the power grid through the energy storage system to suppress subsynchronous oscillations.

7. A synchronous condenser energy storage excitation control system, characterized in that, The method for controlling the energy storage excitation of a synchronous condenser according to any one of claims 1 to 6, wherein the system comprises: a synchronous condenser, an energy storage system, a flexible excitation power unit, and a controller, wherein the flexible excitation power unit is respectively connected to the synchronous condenser, the energy storage system, and the controller, and the controller is respectively connected to the energy storage system and the synchronous condenser; The flexible excitation power unit includes a bridge three-level voltage source converter, a DC-DC chopper converter, and a filter inductor; The input terminal of the bridge three-level voltage source converter is connected to the synchronous condenser, and the output terminal is connected to the intermediate DC bus. The DC-DC chopper converter is connected to the intermediate DC bus; The filter inductor is used to filter out harmonic currents on the AC side; The energy storage system includes an energy storage battery and a DC capacitor; The energy storage battery is connected in parallel to the intermediate DC bus; The DC capacitor is used to maintain the intermediate DC bus voltage; The synchronous condenser is a power generation device used to adjust the excitation current and output reactive power to the power grid.

8. A controller, characterized in that, The controller includes: The parameter acquisition unit is used to acquire raw synchronous condenser parameters, raw power grid parameters, and raw energy storage system parameters. The power grid operation status generation unit is used to generate the power grid operation status based on the original synchronous condenser parameters, original power grid parameters, and original energy storage system parameters. The regulating unit is used to regulate the energy storage system and the flexible excitation power unit according to the grid operating status and in accordance with the coordinated control strategy, and to obtain the current synchronous condenser parameters and the current grid parameters after regulation; The damping control unit is used to perform damping control based on the current synchronous condenser parameters and the current power grid parameters through a preset dual damping channel.

9. A computer-readable medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the synchronous condenser energy storage excitation control method according to any one of claims 1 to 6.

10. A computer device comprising a memory and a processor, the memory for storing information including program instructions, and the processor for controlling the execution of the program instructions, characterized in that, When the program instructions are loaded and executed by the processor, the synchronous condenser energy storage excitation control method according to any one of claims 1 to 6 is implemented.

11. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the synchronous condenser energy storage excitation control method according to any one of claims 1 to 6.

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