New energy and conventional power supply multi-scale collaborative frequency modulation method and system

Abstract

The invention discloses a new energy and conventional power supply multi-scale cooperative frequency modulation method and system, relates to the technical field of power system control, and aims to solve the problem that the stability and the regulation capability of a power grid are insufficient after new energy is accessed to a power system at present. The method comprises the steps of real-time detection, track determination, safety judgment and collaborative frequency modulation. In the new energy frequency modulation process, according to deviation information of an actually measured frequency time domain curve fg and a planned frequency track fp, new energy frequency modulation output is synchronously adjusted through complementary cooperation of a new energy power supply and a conventional power supply, and fg is made to operate close to fp, so that power grid frequency safety is ensured, and frequency modulation cost is minimized; and when the power grid frequency enters the security domain, the new energy quits frequency modulation. According to the technical scheme, the safety and the economical efficiency of the power system are effectively improved, and a new technical thought is provided for cooperative scheduling of new energy and a conventional power supply. By reasonably configuring frequency modulation resources, the frequency safety problem of the power system can be better solved, and sustainable development of new energy is promoted.

Description

Technical Field

[0001] The present invention relates to the field of power system control technology, and in particular to a frequency modulation method for multi-scale coordination of new energy and conventional power sources. Background Art

[0002] As the power system's demand for various types of regulating power sources continues to grow, the scale of new energy installations is also continuing to increase. However, due to the intermittent and volatile characteristics of new energy sources, the grid has poor adaptability to the access of new energy and limited capacity. Therefore, the large-scale grid connection of new energy poses a severe challenge to the frequency security of the power system.

[0003] When facing random disturbances, the frequency deviation and frequency change rate of the power grid are likely to exceed the prescribed limits, which in turn leads to frequency safety issues, such as machine cutting and load shedding. As the proportion of new energy in the power system gradually increases, frequency safety accidents such as frequency index exceeding the limit and machine cutting and load shedding will become more frequent.

[0004] At present, conventional new energy power sources usually operate under maximum power conditions and do not have frequency modulation inertia damping. In order to ensure the safety of the grid frequency, new energy must participate in frequency modulation. New energy power sources need to have a certain inertia so that they can provide effective frequency support when the grid frequency fluctuates violently. In addition, new energy power sources should also have the ability to quickly respond to changes in grid frequency and adjust output in time to reduce frequency deviation, thereby maintaining the stability of the grid frequency.

[0005] At present, a variety of converter control strategies have been proposed at home and abroad to provide virtual inertia damping support for the power grid and maintain frequency stability. The existing converter control strategies mainly include virtual synchronous machine control based on the swing equation and virtual inertia damping control based on proportional differential. Through inertia damping compensation, these converter control schemes can effectively increase the inertia damping parameters of the power grid, thereby reducing RoCoF (rate of change of frequency) and frequency deviation indicators, and have good frequency control performance.

[0006] However, although the existing inverter control method can increase the output of renewable energy frequency modulation, help ensure that the frequency index does not exceed the limit, and improve the frequency quality, it does not fully consider the economic cost required for renewable energy frequency modulation. Unlike conventional power sources, the economic cost of renewable energy power sources participating in frequency modulation is higher, and the more frequency modulation times, the longer the time, and the greater the power, the higher the frequency modulation cost. Therefore, the existing frequency modulation technology cannot ensure system safety while taking into account economic efficiency.

[0007] In order to achieve the safety and economic goals of renewable energy frequency regulation, it is necessary to rationally allocate various voltage and frequency regulation resources, make full use of conventional power sources and other flexible and adjustable renewable energy power sources, and effectively solve the frequency safety problems of the power system. Summary of the invention

[0008] The technical problem to be solved and the technical task proposed by the present invention are to improve and perfect the existing technical solutions, and provide a frequency modulation method and system for multi-scale coordination of new energy and conventional power sources, so as to ensure the frequency safety of the power grid while reducing the economic cost of frequency modulation of new energy. To this end, the present invention adopts the following technical solutions.

[0009] A frequency modulation method for multi-scale coordination of new energy and conventional power sources, comprising the following steps: Real-time detection: Get the measured frequency time domain curve at the common connection point in real time f g ; Determine trajectory: Determine the critical frequency time domain trajectory according to the threshold value specified in the grid code f c , and determine the planned frequency trajectory based on safety margin, measurement error and control error f p ; Safety judgment: Based on the time domain inversion model, using the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The position relationship of the grid frequency can be used to determine the safety of the grid frequency. f g Leaving the planning domain triggers the frequency modulation of new energy sources; Coordinated frequency modulation: In the process of frequency modulation of renewable energy, according to the measured frequency time domain curve f g and planning frequency trajectory f p By using the complementary cooperation between new energy power source and conventional power source, the frequency modulation output of new energy power source is adjusted synchronously. f g Close f p Operation, ensuring grid frequency security and minimizing frequency regulation costs; When the grid frequency enters the safe zone, new energy sources exit frequency modulation and re-enter standby mode.

[0010] This technical solution takes into account both safety and economy: by real-time monitoring of the grid frequency, according to the measured frequency time domain curve f g and planning frequency trajectory f p deviation, synchronously adjust the frequency modulation output of new energy, so that f g Close f pThis can not only ensure that the grid frequency is always within a safe range and guarantee safe and stable operation of the system, but also minimize the cost of frequency regulation of new energy sources, effectively solving the problem that existing technologies cannot take into account both system safety and economy.

[0011] Improve the rationality of renewable energy frequency regulation: Use the time domain inversion model based on the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The position relationship can accurately judge the frequency safety of the power grid, and then decide whether to trigger the frequency regulation of renewable energy. This judgment method is more scientific and reasonable, avoiding unnecessary frequency regulation of renewable energy and reducing the waste of frequency regulation resources.

[0012] Optimize frequency regulation strategy: Adopt the complementary and coordinated approach of new energy power source and conventional power source to carry out frequency regulation, giving full play to the advantages of both. New energy source has a quick response and can react quickly when the grid frequency is abnormal; conventional power source provides stable support, and the two work together to improve the overall frequency regulation effect. At the same time, the multi-scale complementary frequency regulation strategy can buy time for the synchronous machine to play the main frequency regulation role, further optimizing the frequency regulation strategy.

[0013] Flexible regulation: Renewable energy can flexibly adjust the frequency modulation output according to the real-time situation of the power grid frequency, and exit the frequency modulation in time when the power grid frequency enters the safe domain and re-enter the standby state. This enables renewable energy to adapt to the changes in power grid frequency more flexibly during the frequency modulation process, reserve resources for the next frequency modulation, and improve the efficiency of renewable energy participation in frequency modulation and resource utilization.

[0014] As a preferred technical means: the establishment of the time domain inversion model is based on the following parameters: initial frequency f 0. The positive and negative sign of the frequency deviation ( R ), the maximum frequency deviation specified in the guidelines F c and maximum frequency change rate R c .

[0015] The time domain inversion model is established based on key parameters (such as initial frequency, frequency deviation, maximum frequency deviation and change rate), which can accurately reflect the changing trend of the power grid frequency and effectively judge the safety status of the power grid frequency.

[0016] By considering the positive and negative sign of the frequency deviation ( R ) and other parameters, the model can be dynamically adjusted to adapt to different grid operation states and frequency fluctuations, thereby improving the regulation flexibility of the grid.

[0017] Based on the time domain inversion model, the system can make predictions before the grid frequency deviates from the safe range, trigger the frequency regulation response in time, and avoid the occurrence of frequency accidents.

[0018] The model combines the maximum frequency deviation specified in the grid code F c and maximum frequency change rate R c Parameters such as the frequency converter and the frequency converter can be adjusted to ensure high-precision frequency modulation under various working conditions and improve the reliability and stability of the system.

[0019] This model provides a theoretical basis for the frequency modulation process, enabling the frequency modulation output to be controlled more efficiently while ensuring frequency safety, thereby reducing energy waste and economic costs.

[0020] The time domain inversion model can significantly improve the accuracy and economy of grid frequency control, while enhancing the adaptability and reliability of the system in a complex grid environment.

[0021] As the preferred technical means: New energy frequency modulation is achieved through inverter control. The inverter generates PWM signal according to the frequency modulation requirements to control the operation mode of the inverter.

[0022] This technical solution controls the frequency modulation through the converter, which can respond to the changes in the grid frequency in real time, use PWM signals to accurately control the output power and operation mode of the converter, effectively adjust the output of the new energy power source, and thus accurately realize frequency regulation. The converter control can make adjustments in a short time, especially when the frequency changes suddenly or rapidly. By generating PWM signals, the output power can be quickly adjusted to ensure the stability of the grid frequency. The converter control mode can adjust the operation mode according to different grid frequency requirements, has high flexibility, can meet the frequency modulation requirements of new energy under different operating conditions, and avoids the limitations of traditional frequency modulation methods. Through PWM signal generation and refined converter control, the frequency modulation process can be optimized, the impact on the grid can be reduced, the frequency modulation cost can be reduced, and the economy and stability of the system can be improved.

[0023] As a preferred technical means: the converter determines whether to start frequency modulation according to preset frequency deviation and frequency change rate thresholds; when the measured frequency deviation and frequency change rate do not exceed the thresholds, the converter maintains constant power control.

[0024] By setting the thresholds of frequency deviation and frequency change rate, the converter starts frequency modulation only when the grid frequency deviation or change rate exceeds the preset range, avoiding unnecessary frequency modulation operations, reducing over-regulation of new energy power sources, and thus optimizing the utilization of frequency modulation resources. When the measured frequency deviation and frequency change rate do not exceed the threshold, the converter maintains constant power control, avoids frequent adjustment of new energy output, reduces the frequency and economic cost of frequency modulation, and improves the economy of the system. By setting a reasonable threshold, the converter starts frequency modulation only when there is a significant deviation in the grid frequency, avoiding over-regulation of the grid due to minor fluctuations, thereby maintaining the stability and reliability of the grid. The technical solution can ensure that the converter determines whether it is necessary to start frequency modulation according to the actual grid situation, and only adjusts when necessary, avoiding unnecessary over-reaction, and making frequency regulation more accurate and efficient. When the frequency change is not significant, maintaining constant power control can reduce the regulation demand of new energy power sources, avoid frequent starting or adjustment of the power output of the converter, and thus reduce energy waste. By intelligently determining whether to start frequency modulation based on preset thresholds, the converter can respond quickly when needed and maintain stable operation when not needed, improving the overall response efficiency of the system.

[0025] As an optimal technical means: When new energy power sources and conventional power sources complement each other: The inverter of new energy source and the synchronous machine of conventional power source coordinate frequency modulation to ensure frequency safety; When the frequency is adjusted by new energy, the frequency adjustment output of the synchronous machine gradually increases, and the frequency trajectory is monitored in real time. f g To maintain the planned trajectory f p ; When the grid frequency enters the safety domain, the frequency regulation power of renewable energy is smoothly reduced to zero, and the synchronous machine takes over the subsequent frequency regulation tasks, shortening the frequency regulation time and reducing the frequency regulation cost.

[0026] New energy power sources and conventional power sources (synchronous machines) complement each other in frequency regulation, taking advantage of their complementary advantages to ensure the safety of the power grid frequency. When new energy power sources provide frequency regulation support, conventional power sources (synchronous machines) provide inertial support and additional regulation capabilities, enhancing the stability and reliability of frequency regulation capabilities.

[0027] During the frequency modulation process of new energy, the frequency modulation output of the synchronous machine gradually increases, and the new energy converter is based on the frequency trajectory monitored in real time. f g Adjust the output to ensure smooth frequency changes and avoid excessive system fluctuations. Through this smooth transition, the impact of drastic frequency changes on the power grid and equipment is avoided, ensuring stable operation of the power grid.

[0028] When the grid frequency enters the safe domain, the frequency modulation power of the new energy source is smoothly reduced to zero, and the frequency modulation task is gradually withdrawn, and the subsequent frequency modulation task is undertaken by the synchronous machine. This mechanism enables the frequency modulation function of the new energy source to be withdrawn in time when the frequency returns to the safe domain, reducing the long-term regulation demand of the new energy source, thereby effectively shortening the frequency modulation time and reducing the energy and cost required for frequency modulation.

[0029] Through coordinated frequency regulation, new energy power sources and conventional power sources (synchronous machines) play a role at different stages to ensure the accuracy and timeliness of frequency regulation. Synchronous machines take on more responsibilities in the subsequent frequency regulation process, which improves the efficiency of the frequency regulation process and reduces unnecessary frequency regulation operations.

[0030] During the frequency recovery process, the frequency modulation power of renewable energy is smoothly reduced to zero, thus reducing the need for long-term regulation of renewable energy power sources. This not only helps to improve the operating efficiency of renewable energy, but also reduces the economic cost of frequency modulation and improves the overall economic efficiency of frequency modulation.

[0031] Through the coordinated frequency regulation mechanism, new energy and conventional power sources can flexibly adjust the frequency regulation strategy according to the actual needs of the power grid, providing a more efficient and flexible response plan. When facing different loads and frequency fluctuations, it can ensure the safety of the power grid frequency while maximizing the reliability and economy of the system.

[0032] Another technical solution of the present invention is to provide a frequency modulation system for multi-scale coordination of new energy and conventional power sources. A frequency modulation system for a frequency modulation method for multi-scale coordination of new energy and conventional power sources includes: Frequency detection module, used to obtain the measured frequency time domain curve at the common connection point in real time f g ; Trajectory planning module, used to determine the critical frequency time domain trajectory according to the threshold specified in the grid code ( f c ), and determine the planned frequency trajectory based on the safety margin, measurement error, and control error f p ; The time domain inversion module is used to establish a time domain inversion model, using the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The position relationship of the power grid frequency safety situation can be judged; if f g If it leaves the planning domain, a frequency modulation trigger signal is generated; The coordinated frequency modulation module is used to respond to the frequency modulation trigger signal and f g and planning frequency trajectoryf p By using the complementary cooperation between new energy power source and conventional power source, the frequency modulation output of new energy power source is adjusted synchronously. f g Close f p run; When the grid frequency enters the safety domain, the renewable energy is controlled to exit frequency regulation and switch to standby mode.

[0033] This technical solution uses the frequency detection module to obtain the measured frequency time domain curve of the common connection point in real time f g , ensuring that the changes in power grid frequency can be grasped in real time, providing accurate data support for subsequent frequency regulation decisions.

[0034] The trajectory planning module accurately determines the planned frequency trajectory based on the thresholds specified in the grid guidelines as well as safety margins, measurement errors, and control errors. f p , and develop critical frequency time domain trajectory f c , providing a clear reference path for grid frequency control and effectively ensuring grid frequency safety.

[0035] The time domain inversion module is based on the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The relationship between the frequency and the frequency of the power grid can be used to determine the safety status of the power grid frequency and generate the frequency modulation trigger signal in time. Once the power grid frequency deviates from the planned trajectory, it can respond quickly and start the frequency modulation to reduce the impact of the system frequency deviation.

[0036] The coordinated frequency modulation module can respond to the frequency modulation trigger signal and optimize the frequency modulation process through the coordinated work of new energy power sources and conventional power sources. By synchronously adjusting the frequency modulation output of new energy sources, the grid frequency can be ensured to keep up with the planned trajectory. f p , ensuring the safety and stability of the power grid frequency and reducing the system regulation pressure.

[0037] After the grid frequency returns to the safe zone, the coordinated frequency modulation module promptly controls the renewable energy to exit the frequency modulation and switch to the standby state. This avoids excessive frequency modulation, reduces the energy consumption and economic costs caused by long-term frequency modulation of renewable energy, and ensures the economy and sustainability of the frequency modulation process.

[0038] The automated control mechanism of this technical solution can automatically perform frequency response and frequency control based on real-time data and algorithms, reduce human intervention, and improve the efficiency and accuracy of grid frequency regulation.

[0039] Through multi-scale coordination of new energy and conventional power sources, the burden of a single power source is reduced, the power output during the frequency modulation process is optimized, and the frequency modulation time is shortened, thereby effectively reducing the cost of frequency modulation and improving the safety and stability of the power grid.

[0040] As a preferred technical means: the model construction of the time domain inversion module is based on the following parameters: initial frequency f 0. The positive and negative sign of the frequency deviation ( R ), the maximum frequency deviation specified in the guidelines F c and maximum frequency change rate R c .

[0041] Through the parameters based on the time domain inversion module, this technical solution can effectively improve the accuracy of power grid frequency security assessment, optimize the frequency regulation process, improve the response speed and stability of the system, and ensure that the frequency regulation operation meets the power grid operation requirements and economic goals.

[0042] As a preferred technical means: the coordinated frequency modulation module includes: The converter control unit is used to generate PWM signals according to the frequency modulation requirements and control the operation mode of the new energy converter; Coordinated dispatching unit, used to coordinate the frequency modulation output distribution of new energy power sources and conventional power sources; Synchronous machine frequency modulation unit, used to gradually increase the frequency modulation output of synchronous machines in conventional power sources during the frequency modulation process of new energy sources; The power smoothing unit is used to smooth the frequency regulation power of renewable energy to zero when the grid frequency enters the safety domain, and the synchronous machine will take on the subsequent frequency regulation tasks.

[0043] The coordinated frequency modulation module generates PWM signals through the converter control unit, accurately controls the operation mode of the new energy converter, and ensures that the new energy power source can quickly respond to the frequency modulation demand. At the same time, the coordinated dispatching unit can flexibly coordinate the frequency modulation output distribution of the new energy power source and the conventional power source, optimize the frequency modulation contribution of both, and enhance the regulation capability of the system.

[0044] The synchronous machine frequency regulation unit gradually increases the frequency regulation output of the synchronous machine in the conventional power source, so that during the frequency regulation process of renewable energy, the conventional power source can gradually take over the frequency regulation task, ensuring a smooth transition of the frequency regulation process and avoiding impact on the grid frequency due to sudden interruption of renewable energy frequency regulation.

[0045] The power smoothing unit ensures that when the grid frequency enters the safety zone, the frequency modulation power of the renewable energy source will be smoothly reduced to zero, thereby reducing unnecessary frequency modulation resource consumption, and allowing the synchronous machine to undertake subsequent frequency modulation tasks, ensuring the efficiency of frequency modulation and the stability of the grid. Such an exit mechanism not only ensures the smooth recovery of the frequency, but also avoids unnecessary energy waste.

[0046] By combining the coordinated regulation of new energy power sources with conventional power sources, the system can minimize the frequency regulation costs while ensuring the safety of the power grid frequency; enabling the system to respond quickly to different frequency fluctuations, thereby improving the system's response speed and stability.

[0047] By smoothing the frequency modulation power of renewable energy and gradually letting the synchronous machine take on the frequency modulation task, the frequent adjustment of renewable energy power sources is effectively reduced, and the energy and economic costs required for frequency modulation are reduced. After the frequency is restored to the safe domain, the renewable energy power source can immediately exit the frequency modulation, avoiding long-term occupation of frequency modulation resources and further reducing the frequency modulation cost of the system.

[0048] The close cooperation of each unit in the coordinated frequency regulation module makes the frequency regulation process more accurate and efficient, avoiding the threat of frequency fluctuations to the security of the power grid, while ensuring that the power grid frequency operates in the best state, thereby improving the control efficiency of the overall system.

[0049] As a preferred technical means: the system also includes: Data storage module, used to store the measured frequency time domain curve f g , critical frequency time domain trajectory f c and planning frequency trajectory f p ; The communication module is used for real-time data exchange with new energy power sources, conventional power sources and power grid dispatching centers.

[0050] The data storage module can effectively store the measured frequency time domain curve f g , critical frequency time domain trajectory f c and planning frequency trajectory f p , ensuring that historical data during the frequency modulation process is archived in a timely manner to facilitate subsequent analysis, optimization and fault diagnosis. This provides a solid data foundation for the system's scheduling decisions and fault recovery.

[0051] The communication module enables the system to exchange data with new energy sources, conventional power sources and the grid dispatch center in real time, ensuring that each device and system can obtain grid frequency information and frequency modulation requirements in a timely manner. Real-time data exchange helps all parties' equipment respond quickly to frequency changes, ensuring the real-time and accuracy of frequency modulation operations, thereby enhancing the overall coordination and response speed of the system.

[0052] Through the connection between the communication module and the power grid dispatch center, the system can monitor the changes in power grid frequency in real time and adjust the strategy in time. In addition, the dispatch center can remotely control and adjust the frequency regulation strategy, increase the flexibility and adaptability of the system, and ensure the stable operation of the power grid.

[0053] The data storage module not only ensures the backup and safe storage of frequency data, but also cooperates with the communication module to ensure the accurate transmission of real-time data and reduce frequency modulation errors caused by data loss or transmission delay. Accurate data support further improves the reliability of frequency safety control.

[0054] The data storage module provides complete historical data for subsequent analysis, research and optimization. Through retrospective analysis of frequency time domain curves, it can help power grid dispatchers identify potential risks, optimize frequency regulation strategies, reduce energy consumption, and further improve the cost-effectiveness of power grid frequency regulation.

[0055] The communication module can realize the real-time linkage of new energy power sources, conventional power sources and power grid dispatching centers, and promote the rational allocation and joint regulation of multiple resources. When the power grid frequency fluctuates, it can ensure that the dispatching center can quickly obtain and respond to frequency regulation requirements, realize the overall coordinated control of the system, and improve the stability and reliability of the system.

[0056] Through continuous data collection and interaction, the system can generate frequency regulation reports and status monitoring in real time, supporting the decision-making analysis of the power grid dispatch center. Combining real-time data with historical data, the system can perform intelligent prediction and early warning, identify potential frequency fluctuation problems in advance, achieve preventive dispatch, and reduce the risk of failures.

[0057] As a preferred technical means: the system also includes a simulation verification module for performing simulation verification on the system. When the simulation results show that the response time of the new energy converter exceeds 50ms or the frequency trajectory tracking error exceeds ±0.05Hz, it indicates to reformulate or adjust the time domain inversion model.

[0058] By introducing a simulation verification module, this technical solution can fully simulate and verify the performance of the system before actual operation, ensure that the performance of the system under different working conditions meets the predetermined technical standards and safety requirements, and promptly discover and correct potential problems, thereby improving the reliability and accuracy of the system.

[0059] When the simulation results show that the response time of the new energy converter exceeds 50ms or the frequency trajectory tracking error exceeds ±0.05Hz, the system can automatically identify and send an adjustment signal, requiring the time domain inversion model to be re-formulated or adjusted. This ensures that the system can be adjusted in time during actual operation, avoiding grid frequency instability due to control strategy failure or excessive errors, and ensuring that the system has good responsiveness and flexibility.

[0060] The simulation verification module can identify potential risks or performance bottlenecks in advance by simulating various possible system states and fault situations, thereby making necessary adjustments and optimizations to the time domain inversion model, and continuously improving the system's frequency regulation strategy to make it more accurate, economical and efficient, ensuring the safety and stability of the power grid frequency.

[0061] The simulation verification module can adjust the system model according to the feedback of real-time simulation results to ensure the adaptability of the model to the actual environment.

[0062] Through simulation verification, problems can be identified and resolved before the system is actually put into use, avoiding debugging delays and unnecessary downtime during troubleshooting that may occur in traditional methods. Simulation verification can discover and correct potential design defects in advance, helping to save resources and time in actual deployment.

[0063] The simulation verification module supports simulating and adjusting system behavior under different working conditions, facilitating multiple verification and optimization, which not only improves the stability of the existing system, but also provides strong support for subsequent system expansion and upgrades. Through continuous simulation and adjustment, the system can maintain a high degree of adaptability when facing new technical requirements or complex environments.

[0064] The simulation verification module can not only perform verification in the early stage, but also continuously simulate and evaluate during the system operation. This enables the system to be continuously optimized according to the actual performance in operation, avoiding long-term performance degradation or failure, and ensuring stability and efficiency in long-term operation.

[0065] Beneficial effects: This technical solution solves the core problem of the difficulty in balancing safety and economy in frequency modulation of new energy through a multi-scale coordinated frequency modulation mechanism and dynamic safety and economic optimization. The specific advantages are as follows: 1. Improve frequency safety Dynamic safety assessment: The time domain inversion model is used to determine the degree of deviation between the frequency trajectory and the critical safety boundary in real time, ensuring that the power grid frequency is always within the planned domain ( f p ) to avoid frequent accidents such as machine cutting and load shedding.

[0066] Multi-scale coordinated response: New energy quickly responds to initial disturbances, and synchronous machines undertake medium- and long-term frequency regulation tasks, effectively suppressing frequency deviations (Δ f ) and rate of change of frequency (RoCoF) limit violations.

[0067] 2. Significantly reduce frequency modulation costs Precise economic optimization: By planning the trajectory ( f p ) Dynamically constrain frequency modulation output to avoid excessive frequency modulation of renewable energy (such as “overcompensation” or “premature exit”), and reduce frequency modulation power, duration and energy loss.

[0068] Smooth exit mechanism: When the frequency enters the safety domain, the frequency modulation power of renewable energy is smoothly returned to zero to avoid secondary disturbances caused by power mutations, while releasing frequency modulation resources for subsequent needs.

[0069] 3. Enhance the adaptability of the power grid to a high proportion of renewable energy Flexible configuration of virtual inertia: New energy simulates the inertia characteristics of synchronous machines through converter control, making up for the defect that the inertia of traditional power sources decreases with the increase of new energy penetration, and improving the anti-disturbance ability of the power grid.

[0070] Adaptive parameter adjustment: Dynamically update critical trajectories based on the time domain inversion model ( f c ) and the planned trajectory ( f p ), adapt to complex working conditions such as new energy output fluctuations and load changes.

[0071] 4. Optimize the efficiency of multiple power sources Complementary frequency regulation strategy: New energy and conventional power sources have clear division of labor, and new energy is responsible for quickly tracking the planned trajectory ( f p ), conventional power supplies provide steady-state support and reduce frequency modulation resource conflicts.

[0072] Reduce dependence on traditional frequency regulation resources: Through precise frequency regulation of new energy, the frequency and amplitude of synchronous machine frequency regulation output can be reduced, extending the life of traditional units.

[0073] 5. High reliability and scalability Closed-loop verification mechanism: The simulation module verifies the effectiveness of the frequency modulation strategy and dynamically optimizes the control parameters (such as K p , K d ), to ensure that the theoretical design is consistent with the actual scenario.

[0074] Compatible with multiple power types: Suitable for power systems that combine wind power, photovoltaic power, energy storage and synchronous machines, and supports the access of a high proportion of renewable energy in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is the frequency trajectory under the time-varying inertia damping model of the present invention.

[0076] Figure 2 It is a trajectory planning control block diagram of the complementary and coordinated frequency modulation of new energy and conventional power sources of the present invention.

[0077] Figure 3 It is a flow chart of trajectory planning for complementary and coordinated frequency modulation of new energy and conventional power sources according to the present invention.

[0078] Figure 4 It is a simulation model for trajectory planning of complementary and coordinated frequency modulation of new energy and conventional power sources of the present invention.

[0079] FIG5( a ) is a frequency variation curve when the converter does not participate in frequency modulation.

[0080] FIG5( b ) is a frequency variation curve diagram of the complementary and coordinated frequency modulation of various power sources of the present invention.

[0081] FIG6 (a) is a diagram showing the output curve of the converter when the converter does not participate in frequency modulation.

[0082] FIG6( b ) is a diagram showing the output curve of the converter when various power sources are complementary and coordinated in frequency modulation according to the present invention. DETAILED DESCRIPTION

[0083] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0084] Embodiment 1: A frequency modulation method for multi-scale coordination of new energy and conventional power sources, comprising the following steps: S1: Real-time detection The voltage signal of the common connection point (PCC) is collected in real time through the converter frequency detection algorithm, and the system frequency is tracked using the phase-locked loop (PLL) to generate the measured frequency time domain curve f g ( t ), the sampling frequency is 1kHz to ensure the real-time nature of the data.

[0085] S2: Determine the trajectory 1. Critical trajectory calculation: according to the maximum frequency deviation specified in the grid guidelines F c and maximum frequency change rate R c , generating critical frequency trajectories through the time domain inversion model f c ( t ).

[0086] 2. Planning trajectory correction:f c ( t ) plus a 10% safety margin ( δ =0.1 F c ), measurement error compensation (±0.02 Hz) and control delay compensation (50 ms) to generate the planned frequency trajectory f p ( t ).

[0087] f p ( t )= f c ( t )± δ (Dynamic adjustment direction is determined by sign( R )Decide) S3: Safety judgment and time domain inversion 1. Model construction: Dynamic inversion of system equivalent inertia based on the second-order frequency response equation M and damping D :

[0088] The input parameters include the initial frequency f 0. Frequency deviation direction sign( R ), F c and R c .

[0089] 2. Security domain determination: like f g ( t ) is always located in the planning domain If it is judged to be safe, the new energy source will not be adjusted; like f g ( t ) exceeds the planning domain, triggers the frequency modulation signal, and updates in real time M and D (Update period is 100 ms).

[0090] Based on the time domain inversion model, using the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The position relationship of the grid frequency can be used to determine the safety of the grid frequency. f g Leaving the planning domain triggers the frequency modulation of new energy sources; In the power system, it is difficult to obtain the critical inertia damping parameters of the system, but the initial frequency f 0. The positive and negative sign of the frequency deviation ( R ) can be measured directly, the maximum frequency deviation specified in the guidelines F c With the maximum frequency change rate R c Then you can directly query and derive the time domain inversion model describing the process based on the above parameters.

[0091] use f g and f c The position relationship directly reflects the current frequency security situation of the power grid. f g Is it in f p Within the determined planning domain, intuitively determine whether new energy sources require frequency regulation: like f g If the grid frequency is always within the planning domain, the grid frequency is safe and new energy sources do not need to adjust the frequency, thus reducing the frequency adjustment cost. like f g If the new energy source leaves the planning area, it must adjust the frequency to ensure f g Always f c Within a certain security zone, and as close as possible f p , in order to maintain the necessary safety margin until f g Exit frequency modulation when entering the planning domain to minimize the frequency modulation cost.

[0092] The time domain inversion model is a mathematical model that reversely deduce the dynamic characteristics of the power system (such as inertia and damping) through real-time frequency data. Its core goal is to dynamically evaluate the frequency safety status of the power grid based on the measured frequency trajectory and the preset safety threshold, and trigger the decision of new energy frequency regulation. The following is a detailed description of the model: 1. Basis for building a time domain inversion model Input parameters: Initial frequency f 0: Steady-state frequency value before the disturbance occurs.

[0093] Frequency deviation direction sign (R): The positive or negative sign of the rate of change of frequency (RoCoF), reflecting the rising or falling trend of the frequency.

[0094] Maximum allowable frequency deviation F c: The upper limit of frequency deviation specified in the grid code (e.g. ±0.5 Hz).

[0095] Maximum allowable frequency change rate R c : The upper limit of the frequency change rate specified in the grid code (such as ±1 Hz / s).

[0096] Output Target: Critical Frequency Track f c :The frequency deviation and rate of change just reach F c and R c Theoretical frequency-time domain curve when .

[0097] Planning frequency trajectory f p :exist f c Add a safety margin (such as 90%) to the foundation F c ), measurement error compensation and actual FM target trajectory after control delay.

[0098] 2. Mathematical expression and inverse logic The time-domain inversion model derives the dynamic relationship between the frequency trajectory and the system parameters by following the steps below: Step 1: Establish the system frequency response equation Assume that after the grid disturbance, the frequency dynamic response satisfies the second-order differential equation:

[0099] in: M : System equivalent inertia (including conventional power supply inertia and new energy virtual inertia); D : System equivalent damping coefficient; K : Frequency-power regulation coefficient; Δ P : Power shortage or excess.

[0100] Step 2: Inversely solve the critical inertia damping parameters According to the grid security constraints ( F c , R c ), the critical inertia required for the reverse system ( M c ) and critical damping ( D c ): When the frequency deviation reaches Fc When , the critical frequency trajectory satisfies: Solve the problem satisfying the above constraints by numerical methods (such as the Newton-Raphson method) or analytical solutions. M c and D c .

[0101] Step 3: Generate critical frequency trajectory ( f c ) The critical parameter ( M c , D c ) is substituted into the frequency response equation and the theoretical critical trajectory is obtained by simulation. f c ( t ), which represents the frequency change process of the system under the extreme safety state.

[0102] 3. Safety judgment logic Planning domain definition: On the critical trajectory f c ( t ) based on the engineering safety margin (e.g. 10%) F c ), defining the planned frequency trajectory f p ( t ): Real-time safety assessment: The measured frequency trajectory f g ( t ) and planning domain contrast: like f g ( t ) is always within the planning domain, judged to be safe, and new energy sources are not frequency-regulated; like f g ( t ) exceeds the planning domain and is judged as out of limit, triggering new energy frequency modulation.

[0103] 4. Application of the model in frequency modulation control Dynamic parameter update: based on real-time frequency data f g ( t ) and disturbance types (such as load mutations, new energy output fluctuations), periodically update the inversion model parameters ( M , D ), to ensure the accuracy of trajectory prediction.

[0104] Frequency modulation output calculation: When frequency modulation is triggered, calculate the power Δ required to be supplemented by new energy Preq , so that the measured trajectory f g ( t ) Tracking planning trajectory f p ( t ):

[0105] in, K p , K d is the proportional-derivative control coefficient.

[0106] 5. Differences from traditional methods

[0107] 6. Practical Application Examples Scenario: A sudden increase in grid load causes a drop in frequency.

[0108] Inversion process: Detected f g ( t ) deviates from the planning domain, triggering model update; Inverse calculation of current system inertia M Insufficient, new energy is needed to provide virtual inertia; Generate frequency modulation instructions to increase the output of new energy and promote f g ( t ) Close f p ( t ); The synchronous machine gradually increases its output, new energy is smoothly withdrawn, and the system returns to a steady state.

[0109] S4: Coordinated frequency modulation and exit control: 1. Fast response of converter: The new energy converter adopts frequency trajectory tracking control, according to the deviation Generate power compensation command Δ P req:

[0110] ( K p =0.8, K d =0.2, and the converter output is adjusted by PWM modulation).

[0111] Progressive frequency modulation of synchronous machine: The synchronous machine gradually increases its output at a rate of 20% rated power / s to avoid mechanical shock.

[0112] 2. Power smooth exit: when f g ( t ) Enter the security domain (satisfy 3 consecutive cycles ≤0.05Hz), the frequency modulation power of new energy decays to zero according to the exponential curve; The synchronous machine completely takes over the frequency regulation task, and the new energy switches to constant power standby mode.

[0113] In the process of frequency modulation of renewable energy, according to the measured frequency time domain curve f g and planning frequency trajectory f p By using the complementary cooperation between new energy power source and conventional power source, the frequency modulation output of new energy power source is adjusted synchronously. f g Close f p Operation, ensuring grid frequency security and minimizing frequency regulation costs; Specific: such as Figure 1 , the frequency change in the power system goes through three processes, namely primary frequency regulation, secondary frequency regulation and tertiary frequency regulation. Among them, in the blocking section of the primary frequency regulation, the frequency index is the worst and frequency accidents are most likely to occur. Therefore, it is very important to ensure the frequency safety in the primary frequency regulation, and the converter must actively participate in the frequency regulation to ensure the stability and safety of the power system frequency. The processes after the primary frequency regulation (such as secondary frequency regulation and tertiary frequency regulation) are all error-free control, so that the system frequency returns to the rated value, and the frequency quality safety level is relatively high. In summary, this embodiment, in response to the frequency safety problem in the primary frequency regulation stage, proposes a control strategy for coordinated frequency regulation of the converter and the synchronous machine to ensure that the system frequency is maintained within the safety threshold, prevent the system frequency from becoming unstable, and cause frequency safety accidents such as machine cutting and load shedding.

[0114] like Figure 2 This embodiment is mainly composed of a new energy power source, a conventional power source, and a load part. The power system composed of a new energy converter and a synchronous machine transmits power to the load and can reduce the frequency modulation output of the converter while ensuring that the frequency does not exceed the limit, thereby reducing costs. The converter control is based on Figure 3 The process determines whether the converter participates in frequency modulation. If the converter does not participate in frequency modulation, a constant power control strategy is adopted, and a PWM signal is generated by using the power outer loop and the converter inner loop to control the converter operation mode. If the converter participates in frequency modulation, a frequency trajectory planning strategy is adopted, and the power adjustment and scheduling instructions are used as power instructions. The PWM signal is generated by using the power outer loop and the converter inner loop, thereby changing the converter operation mode.

[0115] like Figure 3 As shown, according to the flowchart of complementary and coordinated frequency modulation of new energy and conventional power sources in the present invention, the specific method of complementary and coordinated frequency modulation control of new energy power sources and conventional power sources can be obtained as follows: the output voltage of the converter is decomposed into dq, and the system frequency is tracked by a phase-locked loop. When there is no disturbance, the converter adopts constant power control. After receiving the disturbance, the measured frequency time domain curve at the common connection point obtained in real time by the converter frequency detection algorithm is f g , if the disturbance is small, f g The frequency deviation and frequency change rate are both less than the specified action value F act and R act , then it means f g Always in the safety zone: This means that the power grid can ensure frequency safety even if the renewable energy source does not regulate the frequency. f g Will continue to stay away f c This safety margin increases the frequency safety margin, but consumes new energy frequency regulation resources and generates unnecessary frequency regulation costs. From the perspective of reducing new energy frequency regulation costs, new energy does not need to participate in grid frequency regulation at this time. This mode is both safe and economical. f g The frequency deviation or frequency change rate is greater than the specified action value F act and R act , then the action signal is triggered. The control of the present invention determines the critical frequency trajectory according to the specified maximum frequency change rate and maximum frequency deviation. f c , and plan a certain safety margin to obtain the planned frequency trajectory f p , f g Leaving the safety domain indicates that the time-varying inertia damping provided by the synchronous machine and the load is insufficient and cannot always meet the safety constraints. At this time, the new energy source must adjust the frequency to ensure f g Still in the safe zone, after tuning f g Clearly away from the safety boundary f c , indicating that the safety margin is large, but the cost of frequency regulation of renewable energy is also increased, so it is necessary to ensure that f g Close f pThen, wait until the frequency regulation of the power grid can make f g Cross f c When the frequency is adjusted, the new energy can immediately exit the frequency modulation. f g and f c The deviation information is used to change the frequency modulation output synchronously, so that f g By running exactly along the critical trajectory that is both safe and economical, and offsetting the over-limit frequency components caused by the time-varying power structure / operating parameters, the power grid can always be kept in a critical inertia damping state that is both safe and economical.

[0116] In this embodiment, a multi-scale complementary frequency modulation strategy is adopted; the multi-scale complementary frequency modulation characteristics determine that the new energy and the synchronous machine should coordinate the frequency modulation, and the optimal frequency modulation strategy for the new energy should ensure frequency safety, and use the planned frequency trajectory as a basis to monitor or regulate the actual frequency trajectory of the power grid in real time, so as to buy time for the synchronous machine to play the main frequency modulation role.

[0117] When new energy does not adjust the frequency, the frequency index will exceed the limit. Although the deteriorated frequency index can maximize the frequency modulation output of the synchronous machine, it leads to unacceptable frequency safety issues. At this time, new energy is urgently needed to play the advantage of rapid response to maintain the safety bottom line. If the frequency is over-adjusted: the frequency index can be improved, but it will also increase the frequency modulation cost and limit the frequency modulation output of the synchronous machine; if the frequency is only adjusted to the planned trajectory, the goal of safe and economical frequency regulation can be achieved: not only the safety of the system frequency is guaranteed, but also the frequency modulation output of the synchronous machine is significantly improved, the frequency modulation cost of new energy is also significantly reduced, the frequency modulation power is significantly reduced and smoothly reduced to 0; the frequency modulation time is shortened; the frequency modulation energy is reduced; it can also exit the frequency modulation smoothly in time and re-enter the standby state to reserve resources for the next frequency modulation.

[0118] The multi-scale complementary frequency modulation characteristics of the converter and synchronous machine are shown in the following table:

[0119] S5: Simulation verification and parameter optimization In order to fully simulate and verify the performance of the system before actual operation, ensure that the performance of the system under different working conditions meets the predetermined technical standards and safety requirements, and timely discover potential problems and correct them, thereby improving the reliability and accuracy of the system. A simulation verification step can be added: the effect of this method is achieved through simulation verification. When the simulation results show that the response time of the new energy converter exceeds 50ms or the frequency trajectory tracking error exceeds ±0.05Hz, it is indicated to reformulate or adjust the time domain inversion model.

[0120] In this embodiment, a simulation model built in MATLAB environment is used, such as Figure 4 As shown in the figure, a synchronous machine model with adjustable system parameters is used to simulate the conventional power supply in practice. The grid-connected converter is a typical inverter. The control scheme in the figure adopts frequency trajectory planning control. The voltage and current of the three-phase static abc coordinate system are transformed into the voltage and current of the two-phase rotating dq coordinate system through dq transformation, and the converter is controlled by the phase-locked loop to track the grid frequency. Since the frequency trajectory planning control needs to determine whether the converter participates in frequency modulation based on the system frequency deviation and RoCoF, the system frequency needs to be sampled to obtain the frequency change rate. If the converter needs to participate in frequency modulation, the converter output response power provides power support for the system. If the converter does not need to participate in frequency modulation, it still operates according to the initial working point. After the control of the power outer loop and the current inner loop, the PWM control signal is output to regulate the converter operating conditions.

[0121] The effectiveness of the frequency modulation method of multi-scale coordination of renewable energy and conventional power sources in the present invention is verified by simulating waveforms: after the system frequency index (such as frequency deviation or frequency change rate) exceeds the given action value, the converter quickly participates in the frequency modulation, so that the system frequency is close to the planned frequency trajectory and always remains within the frequency safety domain, avoiding frequency safety accidents in the system, resulting in power system cutting and load shedding; the red line in Figure 5 (a) represents the planned frequency curve f tp , the blue line represents the frequency variation curve when the converter does not participate in frequency modulation, and the red line in Figure 5 (b) represents the planned frequency curve f tp , the blue line represents the frequency change curve of the converter participating in frequency modulation. From the comparison of the two frequency change curves, it can be seen that after the converter participates in frequency modulation, the frequency change tends to be stable and can maintain a relatively stable operating state after external disturbance (as shown in Figure 5 (b)). In Figure 5 (a), the frequency change curve that does not participate in frequency modulation shows greater volatility and instability.

[0122] By comparing the output curves of the converter when the converter does not participate in frequency modulation and when various power sources are complementary and coordinated in frequency modulation, the effectiveness of the frequency modulation method of multi-scale coordination of new energy and conventional power sources is intuitively reflected. It can be seen that the converter quickly participates in frequency modulation and changes its operating point, increasing the frequency modulation power and ensuring the safety of the system frequency. When the system frequency enters the safety domain, the frequency modulation power is significantly reduced and smoothly decreases to 0, reducing the converter frequency modulation cost and ensuring the economy of the system frequency modulation. Figure 6 (a) is the output curve of the converter when the converter does not participate in frequency modulation, and Figure 6 (b) is the output curve of the converter when various power sources are complementary and coordinated in frequency modulation. Combined with the frequency curve of the converter not participating in frequency modulation in Figure 5 (a) and the frequency curve of the converter participating in frequency modulation in Figure 5 (b), the effect of the converter participating in frequency modulation can be better analyzed: When the converter does not participate in frequency modulation (Figure 6 (a)), the output curve shows a relatively stable characteristic, and the output power of the converter is basically maintained at a certain set value, lacking a dynamic response to grid frequency fluctuations. This shows that when the converter does not participate in frequency modulation, the grid frequency fluctuates greatly, as shown in Figure 5 (a). The frequency fluctuation amplitude is large and the recovery is slow, and it cannot be adjusted quickly to compensate for the frequency deviation.

[0123] When the converter participates in frequency modulation (Figure 6 (b)), the output curve shows obvious fluctuations, which is closely related to the converter's rapid adjustment of output power to respond to grid frequency changes when the frequency fluctuates. Combined with Figure 5 (b), it can be seen that after the converter participates in frequency modulation, the frequency fluctuation amplitude is significantly reduced and the frequency recovery speed is accelerated. Although there are fluctuations in the output curve, these fluctuations correspond to the real-time response of the converter during the frequency modulation process, and the final effect is to greatly improve the frequency stability of the grid.

[0124] The following is a further explanation of simulation verification and parameter optimization. 1. Simulation model construction: A test system including a synchronous machine (rated power 100 MW), a new energy converter (50 MW), and a load (120 MW) was built in MATLAB / Simulink.

[0125] Set the disturbance scenario: a sudden load increase of 20 MW and a simulated frequency drop.

[0126] 2. Performance indicator verification: Scenario 1: When there is no frequency modulation of renewable energy, the frequency deviation reaches -0.8 Hz, triggering the machine shutdown; Scenario 2: After enabling this method, the frequency deviation is limited to -0.1 Hz, the frequency modulation time of renewable energy is shortened to 8 s, and the frequency modulation cost is reduced.

[0127] 3. Dynamic parameter adjustment: If the simulation shows that the tracking error is > 0.05Hz, automatic optimization K p and K d (Genetic algorithm iterates 10 times); If the response time is >50ms, adjust the PWM switching frequency to 5 kHz.

[0128] Embodiment 2: The FM system includes: 1. Frequency detection module, used to obtain the measured frequency time domain curve at the common connection point in real time f g ; Hardware: high-precision voltage sensor (accuracy ±0.01%) + FPGA phase-locked loop (response time <1 ms).

[0129] Output: f g ( t ) data stream (1 kHz sampling rate).

[0130] 2. Trajectory planning module, used to determine the critical frequency time domain trajectory according to the threshold specified in the grid guidelines ( f c ), and determine the planned frequency trajectory based on the safety margin, measurement error, and control error f p ; Can be based on C++ and other time domain inversion solvers, real-time calculation f c ( t )and f p ( t ).

[0131] Adaptive setting based on new energy penetration rate (20%-80%) δ Realize dynamic adjustment of safety margin.

[0132] 3. Time domain inversion module, used to establish a time domain inversion model, using the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The position relationship of the power grid frequency safety situation can be judged; if f g If it leaves the planning domain, a frequency modulation trigger signal is generated; The model construction of the time domain inversion module is based on the following parameters: initial frequency f 0. Positive and negative sign of frequency deviation (R), maximum frequency deviation specified in the guidelines F c and maximum frequency change rate R c .

[0133] 4. Coordinated frequency modulation module, used to respond to the frequency modulation trigger signal, according to the measured frequency time domain curve f g and planning frequency trajectory f p By using the complementary cooperation between new energy power source and conventional power source, the frequency modulation output of new energy power source is adjusted synchronously. f g Close f p run; The coordinated frequency modulation module includes: 1. The converter control unit is used to generate PWM signals according to the frequency modulation requirements and control the operation mode of the new energy converter; Working mode switching: constant power (PQ mode) ↔ frequency modulation mode (droop control + virtual inertia).

[0134] PWM generation: Space vector modulation (SV PWM), switching frequency 4 kHz.

[0135] 2. Coordinated dispatching unit, used to coordinate the frequency modulation output distribution of new energy power sources and conventional power sources; Output distribution logic: New energy = min(Δ P req, P max), P Synchronous machine = Δ P req− P New Energy ( P max is the maximum frequency modulation capacity of new energy).

[0136] 3. Synchronous machine frequency modulation unit, used to gradually increase the frequency modulation output of the synchronous machine in the conventional power supply during the frequency modulation process of new energy; 4. The power smoothing unit is used to smoothly reduce the frequency modulation power of renewable energy to zero when the grid frequency enters the safety domain, and the synchronous machine will take on the subsequent frequency modulation tasks; the renewable energy will exit the frequency modulation and switch to standby status.

[0137] Exit Algorithm: First-Order Inertia Link ( τ =5s) to ensure that there is no sudden change in power.

[0138] 5. The simulation verification module is used to simulate and verify the system. When the simulation results show that the response time of the new energy converter exceeds 50ms or the frequency trajectory tracking error exceeds ±0.05Hz, it indicates to reformulate or adjust the time domain inversion model.

[0139] Function: Pre-deployment test: 12 scenarios simulating new energy penetration rates of 30%-70%; Parameter self-healing: When K p / K d When the limit is exceeded, the historical optimal parameter library is called and automatically rolled back; Report generation: output frequency deviation, frequency modulation cost, equipment loss rate and other indicators.

[0140] 6. Data storage module, used to store the measured frequency time domain curve f g, critical frequency time domain trajectory f c and planning frequency trajectory f p ; 7. Communication module, used for real-time data interaction with new energy power sources, conventional power sources and power grid dispatching center.

[0141] This technical solution uses the frequency detection module to obtain the measured frequency time domain curve of the common connection point in real time f g , ensuring that the changes in power grid frequency can be grasped in real time, providing accurate data support for subsequent frequency regulation decisions.

[0142] The trajectory planning module accurately determines the planned frequency trajectory based on the thresholds specified in the grid guidelines as well as safety margins, measurement errors, and control errors. f p , and develop critical frequency time domain trajectory f c , providing a clear reference path for grid frequency control and effectively ensuring grid frequency safety.

[0143] The time domain inversion module is based on the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The relationship between the frequency and the frequency of the power grid can be used to determine the safety status of the power grid frequency and generate the frequency modulation trigger signal in time. Once the power grid frequency deviates from the planned trajectory, it can respond quickly and start the frequency modulation to reduce the impact of the system frequency deviation.

[0144] The coordinated frequency modulation module can respond to the frequency modulation trigger signal and optimize the frequency modulation process through the coordinated work of new energy power sources and conventional power sources. By synchronously adjusting the frequency modulation output of new energy sources, the grid frequency can be ensured to keep up with the planned trajectory. f p , ensuring the safety and stability of the power grid frequency and reducing the system regulation pressure.

[0145] After the grid frequency returns to the safe zone, the coordinated frequency modulation module promptly controls the renewable energy to exit the frequency modulation and switch to the standby state. This avoids excessive frequency modulation, reduces the energy consumption and economic costs caused by long-term frequency modulation of renewable energy, and ensures the economy and sustainability of the frequency modulation process.

[0146] The automated control mechanism of this technical solution can automatically perform frequency response and frequency control based on real-time data and algorithms, reduce human intervention, and improve the efficiency and accuracy of grid frequency regulation.

[0147] Through multi-scale coordination of new energy and conventional power sources, the burden of a single power source is reduced, the power output during the frequency modulation process is optimized, and the frequency modulation time is shortened, thereby effectively reducing the cost of frequency modulation and improving the safety and stability of the power grid.

[0148] The data storage module can effectively store the measured frequency time domain curve f g , critical frequency time domain trajectory f c and planning frequency trajectory f p , ensuring that historical data during the frequency modulation process is archived in a timely manner to facilitate subsequent analysis, optimization and fault diagnosis. This provides a solid data foundation for the system's scheduling decisions and fault recovery.

[0149] The communication module enables the system to exchange data with new energy sources, conventional power sources and the grid dispatch center in real time, ensuring that each device and system can obtain grid frequency information and frequency modulation requirements in a timely manner. Real-time data exchange helps all parties' equipment respond quickly to frequency changes, ensuring the real-time and accuracy of frequency modulation operations, thereby enhancing the overall coordination and response speed of the system.

[0150] Through the connection between the communication module and the power grid dispatch center, the system can monitor the changes in power grid frequency in real time and adjust the strategy in time. In addition, the dispatch center can remotely control and adjust the frequency regulation strategy, increase the flexibility and adaptability of the system, and ensure the stable operation of the power grid.

[0151] The data storage module not only ensures the backup and safe storage of frequency data, but also cooperates with the communication module to ensure the accurate transmission of real-time data and reduce frequency modulation errors caused by data loss or transmission delay. Accurate data support further improves the reliability of frequency safety control.

[0152] The data storage module provides complete historical data for subsequent analysis, research and optimization. Through retrospective analysis of frequency time domain curves, it can help power grid dispatchers identify potential risks, optimize frequency regulation strategies, reduce energy consumption, and further improve the cost-effectiveness of power grid frequency regulation.

[0153] The communication module can realize the real-time linkage of new energy power sources, conventional power sources and power grid dispatching centers, and promote the rational allocation and joint regulation of multiple resources. When the power grid frequency fluctuates, it can ensure that the dispatching center can quickly obtain and respond to frequency regulation requirements, realize the overall coordinated control of the system, and improve the stability and reliability of the system.

[0154] Through continuous data collection and interaction, the system can generate frequency regulation reports and status monitoring in real time, supporting the decision-making analysis of the power grid dispatch center. Combining real-time data with historical data, the system can perform intelligent prediction and early warning, identify potential frequency fluctuation problems in advance, achieve preventive dispatch, and reduce the risk of failures.

[0155] By introducing a simulation verification module, this technical solution can fully simulate and verify the performance of the system before actual operation, ensure that the performance of the system under different working conditions meets the predetermined technical standards and safety requirements, and promptly discover and correct potential problems, thereby improving the reliability and accuracy of the system.

[0156] When the simulation results show that the response time of the new energy converter exceeds 50ms or the frequency trajectory tracking error exceeds ±0.05Hz, the system can automatically identify and send an adjustment signal, requiring the time domain inversion model to be re-formulated or adjusted. This ensures that the system can be adjusted in time during actual operation, avoiding grid frequency instability due to control strategy failure or excessive errors, and ensuring that the system has good responsiveness and flexibility.

[0157] The simulation verification module can identify potential risks or performance bottlenecks in advance by simulating various possible system states and fault situations, thereby making necessary adjustments and optimizations to the time domain inversion model, and continuously improving the system's frequency regulation strategy to make it more accurate, economical and efficient, ensuring the safety and stability of the power grid frequency.

[0158] The simulation verification module can adjust the system model according to the feedback of real-time simulation results to ensure the adaptability of the model to the actual environment.

[0159] Through simulation verification, problems can be identified and resolved before the system is actually put into use, avoiding debugging delays and unnecessary downtime during troubleshooting that may occur in traditional methods. Simulation verification can discover and correct potential design defects in advance, helping to save resources and time in actual deployment.

[0160] The simulation verification module supports simulating and adjusting system behavior under different working conditions, facilitating multiple verification and optimization, which not only improves the stability of the existing system, but also provides strong support for subsequent system expansion and upgrades. Through continuous simulation and adjustment, the system can maintain a high degree of adaptability when facing new technical requirements or complex environments.

[0161] The simulation verification module can not only perform verification in the early stage, but also continuously simulate and evaluate during the system operation. This enables the system to be continuously optimized according to the actual performance in operation, avoiding long-term performance degradation or failure, and ensuring stability and efficiency in long-term operation.

[0162] The frequency modulation method for multi-scale coordination of new energy and conventional power sources shown above is a specific embodiment of the present invention, which has embodied the substantial characteristics and progress of the present invention. According to actual use needs and under the guidance of the present invention, equivalent modifications in shape, structure, etc. can be made to the method, which are all within the protection scope of this scheme.

Claims

1. A frequency modulation method for multi-scale coordination of new energy and conventional power sources, characterized in that: The following steps are involved: Real-time detection: Get the measured frequency time domain curve at the common connection point in real time f g ; Determine trajectory: Determine the critical frequency time domain trajectory according to the threshold value specified in the grid code f c , and determine the planned frequency trajectory based on safety margin, measurement error and control error f p ; Safety judgment: Based on the time domain inversion model, using the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The position relationship of the grid frequency can be used to determine the safety of the grid frequency. f g Leaving the planning domain triggers the frequency modulation of new energy sources; Coordinated frequency modulation: In the process of frequency modulation of renewable energy, according to the measured frequency time domain curve f g and planning frequency trajectory f p By using the complementary cooperation between new energy power source and conventional power source, the frequency modulation output of new energy power source is adjusted synchronously. f g Close f p Operation to ensure grid frequency security and minimize frequency regulation costs; When the grid frequency enters the safe zone, new energy sources exit frequency modulation and re-enter standby mode.

2. The frequency modulation method for multi-scale coordination of new energy and conventional power sources according to claim 1 is characterized by: The time domain inversion model is established based on the following parameters: initial frequency f 0. The positive and negative sign of the frequency deviation ( R ), the maximum frequency deviation specified in the guidelines F c and the maximum frequency change rate R c .

3. The frequency modulation method for multi-scale coordination of new energy and conventional power sources according to claim 2 is characterized by: Renewable energy frequency modulation is achieved through inverter control. The inverter generates PWM signals according to the frequency modulation requirements to control the operating mode of the inverter.

4. The frequency modulation method for multi-scale coordination of new energy and conventional power sources according to claim 3 is characterized by: The converter determines whether to start frequency modulation according to preset frequency deviation and frequency change rate thresholds; when the measured frequency deviation and frequency change rate do not exceed the thresholds, the converter maintains constant power control.

5. The frequency modulation method of multi-scale coordination of new energy and conventional power sources according to claim 4 is characterized by: When new energy power sources and conventional power sources complement each other: The inverter of new energy source and the synchronous machine of conventional power source coordinate frequency modulation to ensure frequency safety; When the frequency is adjusted by new energy, the frequency adjustment output of the synchronous machine gradually increases, and the frequency trajectory is monitored in real time. f g To maintain the planned trajectory f p ; When the grid frequency enters the safety domain, the frequency regulation power of renewable energy is smoothly reduced to zero, and the synchronous machine takes over the subsequent frequency regulation tasks, shortening the frequency regulation time and reducing the frequency regulation cost.

6. A frequency modulation system with multi-scale coordination of new energy and conventional power sources, characterized in that: A frequency modulation method for multi-scale coordination of new energy and conventional power sources as described in any one of claims 1 to 5 is applied, wherein the system comprises: Frequency detection module, used to obtain the measured frequency time domain curve at the common connection point in real time f g ; Trajectory planning module, used to determine the critical frequency time domain trajectory according to the threshold specified in the grid code ( f c ), and determine the planned frequency trajectory based on the safety margin, measurement error, and control error f p ; The time domain inversion module is used to establish a time domain inversion model, using the measured frequency time domain curve f g Time domain trajectory with critical frequency f c The position relationship of the power grid frequency safety situation can be judged; if f g If it leaves the planning domain, a frequency modulation trigger signal is generated; The coordinated frequency modulation module is used to respond to the frequency modulation trigger signal and f g and planning frequency trajectory f p By using the complementary cooperation between new energy power source and conventional power source, the frequency modulation output of new energy power source is adjusted synchronously. f g Close f p Operation; and when the grid frequency enters the safe domain, control the renewable energy to exit frequency regulation and switch to standby status.

7. The frequency modulation system for multi-scale coordination of new energy and conventional power sources according to claim 6 is characterized by: The model construction of the time domain inversion module is based on the following parameters: initial frequency f 0. The positive and negative sign of the frequency deviation ( R ), the maximum frequency deviation specified in the guidelines F c and maximum frequency change rate R c .

8. The frequency modulation system for multi-scale coordination of new energy and conventional power sources according to claim 7 is characterized by: The coordinated frequency modulation module includes: The converter control unit is used to generate PWM signals according to the frequency modulation requirements and control the operation mode of the new energy converter; Coordinated dispatching unit, used to coordinate the frequency modulation output distribution of new energy power sources and conventional power sources; Synchronous machine frequency modulation unit, used to gradually increase the frequency modulation output of synchronous machines in conventional power sources during the frequency modulation process of new energy sources; The power smoothing unit is used to smooth the frequency regulation power of renewable energy to zero when the grid frequency enters the safety domain, and the synchronous machine will take on the subsequent frequency regulation tasks.

9. The frequency modulation system for multi-scale coordination of new energy and conventional power sources according to claim 8 is characterized by: The system further comprises: Data storage module, used to store the measured frequency time domain curve f g , critical frequency time domain trajectory f c and planning frequency trajectory f p ; The communication module is used for real-time data exchange with new energy power sources, conventional power sources and power grid dispatching centers.

10. A frequency modulation system for multi-scale coordination of new energy and conventional power sources according to claim 9, characterized in that: The system also includes a simulation verification module for performing simulation verification on the system. When the simulation results show that the response time of the new energy converter exceeds 50ms or the frequency trajectory tracking error exceeds ±0.05Hz, it indicates to reformulate or adjust the time domain inversion model.

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