A Frequency Modulation Method and System for Multi-Scale Coordination of New Energy and Conventional Power Sources

Abstract

The present invention discloses a frequency modulation method and system for multi-scale coordination of new energy and conventional power sources, which relates to the technical field of power system control. At present, after the access of new energy to the power system, the stability and regulation ability of the power grid are insufficient. The present invention includes steps of real-time detection, trajectory determination, safety judgment, and coordinated frequency modulation; during the new energy frequency modulation process, according to the deviation information between the measured frequency time-domain curve f g and the planned frequency trajectory f p , through the complementary coordination of new energy power sources and conventional power sources, the new energy frequency modulation output is synchronously adjusted to make f g closely follow f p operation to ensure the safety of the power grid frequency and minimize the frequency modulation cost; when the power grid frequency enters the safety domain, the new energy exits the frequency modulation. This technical solution effectively improves the safety and economy of the power system, provides a new technical idea for the coordinated dispatching of new energy and conventional power sources. By reasonably allocating frequency modulation resources, it can better cope with the power system frequency safety problem and promote the sustainable development of new energy.

Description

Technical Field

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

[0002] With the continuous growth of the demand for various regulating power sources in the power system, the installed capacity of new energy is also continuously increasing. However, due to the intermittent and fluctuating characteristics of new energy power sources, the power grid has poor adaptability to the access of new energy and limited accommodation capacity. Therefore, the large-scale grid connection of new energy poses a severe challenge to the frequency security of the power system.

[0003] In the face of random disturbances, the frequency deviation and rate of change of frequency of the power grid are prone to exceed the specified limits, thereby triggering frequency security problems such as generator tripping and load shedding. As the proportion of new energy in the power system gradually increases, frequency security accidents such as frequency index over-limit, generator tripping and load shedding will become more frequent.

[0004] Currently, conventional new energy power sources usually operate under the condition of maximum power and do not have frequency modulation inertia damping. To ensure the frequency security of the power grid, new energy must participate in frequency modulation. New energy power sources need to have a certain amount of inertia so that they can provide effective frequency support when the power grid frequency fluctuates violently. In addition, new energy power sources should also have the ability to quickly respond to the change of the power grid frequency and adjust the output in time to reduce the frequency deviation, so as to maintain the stability of the power 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 thus 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 derivative. Through inertia damping compensation, these converter control schemes can effectively increase the inertia damping parameter of the power grid, thereby reducing the RoCoF (rate of change of frequency) and frequency deviation index and having good frequency control performance.

[0006] However, although the existing converter control methods can increase the output of new energy frequency modulation, help ensure that the frequency index does not exceed the limit, and improve the frequency quality, they do not fully consider the economic cost required for new energy frequency modulation. Different from conventional power sources, the economic cost of new energy power sources participating in frequency modulation is relatively high, and the more frequent the frequency modulation, the longer the time, and the greater the power, the higher the generated frequency modulation cost. Therefore, the existing frequency modulation technologies cannot take into account the economy while ensuring the system security.

[0007] To achieve the safety and economic objectives of new energy frequency modulation, it is necessary to reasonably allocate various voltage regulation and frequency modulation resources, make full use of conventional power sources and other flexible and adjustable new energy power sources, and thus effectively solve the frequency security problem 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:

[0010] Real-time detection: Get the measured frequency time domain curve at the common connection point in real time f g ;

[0011] 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 ;

[0012] 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;

[0013] 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;

[0014] When the grid frequency enters the safe zone, new energy sources exit frequency modulation and re-enter standby mode.

[0015] 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 gClose f p This 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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 .

[0020] 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.

[0021] 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.

[0022] Based on the time-domain inversion model, the system can predict in advance before the grid frequency deviates from the safe range, trigger the frequency regulation response in a timely manner, and avoid the occurrence of frequency accidents.

[0023] The model combines the maximum frequency deviation specified in the grid guidelines F c and the maximum frequency change rate R c and other parameters to ensure high-precision frequency regulation under various working conditions, and improve the reliability and stability of the system.

[0024] This model provides a theoretical basis for the frequency regulation process, enabling more efficient control of the frequency regulation output while ensuring frequency safety during the frequency regulation process, thereby reducing energy waste and economic costs.

[0025] The time-domain inversion model can significantly improve the accuracy and economy of grid frequency control, and at the same time enhance the adaptability and reliability of the system in a complex grid environment.

[0026] As a preferred technical means: The new energy frequency regulation is realized through converter control. The converter generates a PWM signal according to the frequency regulation demand to control the operation mode of the converter.

[0027] This technical solution controls the frequency regulation through the converter, can respond to the change of the grid frequency in real time, uses the PWM signal to accurately control the output power and operation mode of the converter, effectively adjusts the output of the new energy power source, and thus accurately realizes the frequency regulation. The converter control can make adjustments in a short time, especially when the frequency suddenly changes or rapidly changes. By generating a PWM signal, 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 demands, has high flexibility, can meet the frequency regulation requirements of new energy under different operating conditions, and avoids the limitations of traditional frequency regulation methods. Through the generation of PWM signals and refined converter control, the frequency regulation process can be optimized, the impact on the grid can be reduced, the frequency regulation cost can be lowered, and the economy and stability of the system can be improved.

[0028] As a preferred technical means: The converter judges whether to start frequency regulation according to the preset thresholds of frequency deviation and frequency change rate; when both the measured frequency deviation and frequency change rate do not exceed the thresholds, the converter maintains constant power control.

[0029] This technical solution sets the thresholds for 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 excessive 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 thresholds, the converter maintains constant power control, avoiding frequent adjustment of new energy output, reducing the frequency and economic cost of frequency modulation, and enhancing the economy of the system. By setting reasonable thresholds, the converter starts frequency modulation only when there are significant deviations in the grid frequency, avoiding excessive regulation of the grid due to minor fluctuations, and thus maintaining the stability and reliability of the grid. This technical solution can ensure that the converter determines whether to start frequency modulation according to the actual grid conditions and adjusts only when necessary, avoiding unnecessary overreactions and making frequency regulation more accurate and efficient. When the frequency change is not significant, maintaining constant power control can reduce the regulation requirements of new energy power sources, avoid frequent start-up or adjustment of the converter's power output, and thus reduce energy waste. By intelligently judging whether to start frequency modulation according to the preset thresholds, the converter can respond quickly when needed and maintain stable operation when not needed, enhancing the overall response efficiency of the system.

[0030] As a preferred technical measure: When the new energy power source and the conventional power source are complementary and coordinated:

[0031] The converter of the new energy and the synchronous machine of the conventional power source cooperate in frequency modulation to ensure frequency safety;

[0032] When the new energy performs frequency modulation, the frequency modulation 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 ;

[0033] When the grid frequency enters the safe area, the frequency modulation power of the new energy smoothly decreases to zero, and the synchronous machine undertakes the subsequent frequency modulation tasks, shortening the frequency modulation duration and reducing the frequency modulation cost.

[0034] The new energy power source and the conventional power source (synchronous machine) are complementary and coordinated in frequency modulation, leveraging their complementary advantages to ensure grid frequency safety. When the new energy power source provides frequency modulation support, the conventional power source (synchronous machine) provides inertial support and additional regulation capabilities, enhancing the stability and reliability of the frequency modulation capabilities.

[0035] During the frequency modulation process of the new energy, the frequency modulation output of the synchronous machine gradually increases, and the new energy converter adjusts the output according to the frequency trajectory monitored in real time f g to ensure smooth frequency changes and avoid excessive system fluctuations. Through this smooth transition, the impact of sharp frequency changes on the grid and equipment is avoided, ensuring the stable operation of the grid.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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:

[0041] Frequency detection module, used to obtain the measured frequency time domain curve at the common connection point in real time f g ;

[0042] 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 ;

[0043] 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;

[0044] The coordinated frequency modulation module is used to respond to the frequency modulation trigger signal and, according to the measured frequency time-domain curve f g and the deviation information from the planned frequency trajectory f p , through the complementary coordination of new energy power sources and conventional power sources, synchronously adjust the new energy frequency modulation output to make f g cling to f p operation;

[0045] When the grid frequency enters the safe area, control the new energy to withdraw from frequency modulation and switch to the standby state.

[0046] This technical solution obtains the measured frequency time-domain curve of the common connection point in real time through the frequency detection module f g , ensuring that the changes in the grid frequency can be grasped in real time and providing accurate data support for subsequent frequency modulation decisions.

[0047] The trajectory planning module accurately determines the planned frequency trajectory according to the thresholds specified in the grid guidelines, as well as the safety margin, measurement error, and control error f p , and formulates the critical frequency time-domain trajectory f c , providing a clear reference path for grid frequency control and effectively ensuring grid frequency safety.

[0048] The time-domain inversion module judges the safety state of the grid frequency according to the relationship between the measured frequency time-domain curve f g and the critical frequency time-domain trajectory f c , and generates a frequency modulation trigger signal in a timely manner. Once the grid frequency deviates from the planned trajectory, it can quickly respond and initiate frequency modulation to reduce the impact of system frequency deviation.

[0049] The coordinated frequency modulation module can respond to the frequency modulation trigger signal and optimize the frequency modulation process through the coordinated operation of new energy power sources and conventional power sources. By synchronously adjusting the new energy frequency modulation output, ensure that the grid frequency closely follows the planned trajectory f p , ensuring the safety and stability of the grid frequency and reducing the system regulation pressure.

[0050] After the grid frequency recovers to the safe area, the coordinated frequency modulation module timely controls the new energy to withdraw from frequency modulation and switch to the standby state. It avoids over-frequency modulation, reduces the energy consumption and economic cost caused by long-term new energy frequency modulation, and ensures the economy and sustainability of the frequency modulation process.

[0051] The automatic control mechanism of this technical solution can automatically perform frequency modulation response and frequency control based on real-time data and algorithms, reducing human intervention and improving the efficiency and accuracy of power grid frequency regulation.

[0052] Through the multi-scale coordination of new energy and conventional power sources, the burden of a single power source is reduced, the power output during frequency modulation is optimized, the frequency modulation duration is shortened, thereby effectively reducing the cost of frequency modulation and improving the safety and stability of the power grid.

[0053] 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 of the frequency deviation sign( R ), the maximum frequency deviation specified by the guidelines F c and the maximum frequency change rate R c .

[0054] Based on the parameters on which the time-domain inversion module depends, this technical solution can effectively improve the accuracy of power grid frequency safety assessment, optimize the frequency modulation process, improve the response speed and stability of the system, and at the same time ensure that the frequency modulation operation meets the power grid operation requirements and economic objectives.

[0055] As a preferred technical means: The coordinated frequency modulation module includes:

[0056] A converter control unit for generating a PWM signal according to the frequency modulation demand and controlling the operation mode of the new energy converter;

[0057] A coordinated scheduling unit for coordinating the frequency modulation output distribution of new energy power sources and conventional power sources;

[0058] A synchronous machine frequency modulation unit for gradually increasing the frequency modulation output of the synchronous machine in the conventional power source during the new energy frequency modulation process;

[0059] A power smoothing unit for smoothly reducing the new energy frequency modulation power to zero when the power grid frequency enters the safe zone and having the synchronous machine undertake the subsequent frequency modulation tasks.

[0060] The coordinated frequency modulation module generates a PWM signal through the converter control unit to accurately control the operation mode of the new energy converter, ensuring that the new energy power source can quickly respond to the frequency modulation demand. At the same time, the coordinated scheduling unit can flexibly coordinate the frequency modulation output distribution of new energy power sources and conventional power sources, optimize the frequency modulation contributions of both, and enhance the regulation ability of the system.

[0061] The synchronous machine frequency modulation unit gradually increases the frequency modulation output of the synchronous machine in the conventional power source, so that during the new energy frequency modulation process, the conventional power source can gradually take over the frequency modulation task, ensuring a smooth transition of the frequency modulation process and avoiding an impact on the power grid frequency caused by a sudden interruption of new energy frequency modulation.

[0062] The power smoothing unit ensures that when the grid frequency enters the safe zone, the frequency modulation power of new energy will smoothly decrease to zero, thereby reducing unnecessary consumption of frequency modulation resources. At the same time, it allows the synchronous machine to undertake the subsequent frequency modulation tasks, ensuring the efficiency of frequency modulation and the stability of the power grid. Such an exit mechanism not only guarantees the smooth recovery of frequency but also avoids unnecessary energy waste.

[0063] By combining the coordinated regulation of new energy power sources and conventional power sources, the system can minimize the frequency modulation cost while ensuring the safety of the grid frequency; enabling the system to respond quickly to different frequency fluctuations, thereby improving the response speed and stability of the system.

[0064] By smoothing the frequency modulation power of new energy and gradually having the synchronous machine undertake the frequency modulation tasks, it effectively reduces the frequent regulation of new energy power sources and lowers the energy and economic costs required for frequency modulation. After the frequency returns to the safe zone, the new energy power source can immediately withdraw from frequency modulation, avoiding long-term occupation of frequency modulation resources and further reducing the frequency modulation cost of the system.

[0065] The close cooperation of each unit in the coordinated frequency modulation module enables the frequency modulation process to be more accurate and efficient, avoiding the threat of frequency fluctuations to the safety of the power grid. At the same time, it can ensure that the grid frequency operates in the best state, thereby improving the control efficiency of the overall system.

[0066] As a preferred technical means: The system further includes:

[0067] A data storage module for storing the measured frequency time-domain curve f g , the critical frequency time-domain trajectory f c and the planned frequency trajectory f p ;

[0068] A communication module for real-time data interaction with new energy power sources, conventional power sources, and the power grid dispatching center.

[0069] The data storage module can effectively store the measured frequency time-domain curve f g , the critical frequency time-domain trajectory f c and the planned frequency trajectory f p , ensuring that the historical data during the frequency modulation process is archived in a timely manner, facilitating subsequent analysis, optimization, and fault diagnosis. This provides a solid data foundation for the dispatching decision-making and fault recovery of the system.

[0070] The communication module enables the system to conduct real-time data interaction with new energy power sources, conventional power sources, and the grid dispatching center, ensuring that each device and system can promptly obtain grid frequency information and frequency regulation requirements. The real-time data exchange helps the devices of all parties to quickly respond to frequency changes, ensuring the real-time and accuracy of frequency regulation operations, thereby enhancing the overall coordination and response speed of the system.

[0071] Through the connection of the communication module with the grid dispatching center, the system can monitor the changes in grid frequency in real time and adjust strategies promptly. In addition, the dispatching center can remotely control and adjust the frequency regulation strategy, increasing the flexibility and responsiveness of the system and ensuring the stable operation of the grid.

[0072] The data storage module not only ensures the backup and secure storage of frequency data, but also, in cooperation with the communication module, can ensure the accurate transmission of real-time data, reducing the frequency regulation errors caused by data loss or transmission delay. The precise data support further enhances the reliability of frequency safety control.

[0073] The data storage module provides complete historical data for subsequent analysis, research, and optimization. Through retrospective analysis of the frequency time-domain curve, it can help grid dispatching personnel identify potential risks, optimize the frequency regulation strategy, reduce energy consumption, and further improve the cost-effectiveness of grid frequency regulation.

[0074] The communication module can achieve real-time linkage of new energy power sources, conventional power sources, and the grid dispatching center, promoting the reasonable allocation and common regulation of multiple resources. When the grid frequency fluctuates, it can ensure that the dispatching center can quickly obtain and respond to the frequency regulation requirements, realizing the overall coordinated control of the system and improving the stability and reliability of the system.

[0075] 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 grid dispatching center. Combining real-time data and historical data, the system can conduct intelligent prediction and early warning, identify potential frequency fluctuation problems in advance, achieve preventive dispatching, and reduce the risk of faults.

[0076] As an optimal technical means: the system further includes a simulation verification module for simulating and verifying the system. When the simulation results show that the response time of the new energy converter exceeds 50 ms or the frequency trajectory tracking error exceeds ±0.05 Hz, it indicates to re-formulate or adjust the time-domain inversion model.

[0077] By introducing the 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, promptly discover potential problems and make corrections, thereby improving the reliability and accuracy of the system.

[0078] When the simulation results show that the response time of the new energy converter exceeds 50 ms or the frequency trajectory tracking error exceeds ±0.05 Hz, the system can automatically identify and send an adjustment signal, requiring the re - formulation or adjustment of the time - domain inversion model. This can ensure that the system can be adjusted in a timely manner during actual operation, avoiding grid frequency instability caused by ineffective control strategies or excessive errors, and ensuring that the system has good responsiveness and flexibility.

[0079] The simulation verification module can identify potential risks or performance bottlenecks in advance by simulating various possible system states and fault scenarios, thereby making necessary adjustments and optimizations to the time - domain inversion model, continuously improving the system's frequency modulation strategy to make it more accurate, economical and efficient, and ensuring the safety and stability of the grid frequency.

[0080] 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.

[0081] Through simulation verification, problems can be identified and solved before the system is actually put into use, avoiding the debugging delays and unnecessary downtime during the troubleshooting process that may occur in traditional methods. Simulation verification discovers and corrects potential design defects in advance, which helps save resources and time in actual deployment.

[0082] The simulation verification module supports simulating and adjusting the system behavior under different working conditions, facilitating multiple verifications and optimizations. This not only improves the stability of the existing system but also provides strong support for subsequent system expansion and upgrade. Through continuous simulation and adjustment, the system can maintain a high adaptability when facing new technical requirements or complex environments.

[0083] The simulation verification module can not only conduct verification in the initial stage but also continuously conduct simulation and evaluation during the operation of the system. This enables the system to be continuously optimized according to its actual performance during operation, avoiding long - term performance degradation or failure, and ensuring stability and efficiency during long - term operation.

[0084] Beneficial effects: Through the multi - scale collaborative frequency modulation mechanism and dynamic safety and economy optimization, this technical solution solves the core problem of difficult to balance safety and economy in new energy frequency modulation. The specific advantages are as follows:

[0085] 1. Improve frequency safety

[0086] Dynamic safety assessment: Real - time judgment of the deviation degree between the frequency trajectory and the critical safety boundary through the time - domain inversion model to ensure that the grid frequency always operates within the planned domain ( f p ) to avoid frequency accidents such as generator tripping and load shedding.

[0087] Multi-scale collaborative response: In the initial stage of new energy's rapid response to disturbances, synchronous machines undertake medium- and long-term frequency regulation tasks, effectively suppressing the over-limit risks of frequency deviation (Δ f ), and the rate of change of frequency (RoCoF).

[0088] 2. Significantly reduce the frequency regulation cost

[0089] Precise economic optimization: Dynamically constrain the frequency regulation output through the planned trajectory ( f p ), avoiding excessive frequency regulation of new energy (such as "overcompensation" or "premature withdrawal"), and reducing frequency regulation power, duration, and energy losses.

[0090] Smoothing exit mechanism: When the frequency enters the safe zone, the frequency regulation power of new energy smoothly returns to zero, avoiding secondary disturbances caused by power mutations, and at the same time releasing frequency regulation resources for subsequent needs.

[0091] 3. Enhance the adaptability of the power grid to a high proportion of new energy

[0092] Flexible configuration of virtual inertia: New energy controls through inverters to simulate the inertia characteristics of synchronous machines, making up for the defect that the inertia of traditional power sources decreases with the increase in the new energy penetration rate, and enhancing the anti-disturbance ability of the power grid.

[0093] Adaptive parameter adjustment: Dynamically update the critical trajectory ( f c ) and the planned trajectory ( f p ) based on the time-domain inversion model to adapt to complex working conditions such as new energy output fluctuations and load changes.

[0094] 4. Optimize the collaborative efficiency of multiple power sources

[0095] Complementary frequency regulation strategy: The division of labor between new energy and conventional power sources is clear. New energy is responsible for quickly tracking the planned trajectory ( f p ), and conventional power sources provide steady-state support, reducing conflicts in frequency regulation resources.

[0096] Reduce dependence on traditional frequency regulation resources: Through precise frequency regulation of new energy, reduce the frequency and amplitude of the frequency regulation output of synchronous machines, and extend the service life of traditional units.

[0097] 5. High reliability and scalability

[0098] Closed-loop verification mechanism: Verify the effectiveness of the frequency regulation strategy through the simulation module, and dynamically optimize control parameters (such as K p , K d ), ensuring that the theoretical design is consistent with the actual scenario.

[0099] Compatible with multiple power types: applicable to power systems hybridized with wind power, photovoltaic power, energy storage, and synchronous machines, supporting the integration of a high proportion of renewable energy in the future. Description of the Drawings

[0100] Figure 1 is the frequency trajectory under the time-varying inertia damping model of the present invention.

[0101] Figure 2 is the trajectory planning control block diagram of complementary and collaborative frequency modulation between new energy and conventional power sources of the present invention.

[0102] Figure 3 is the flow chart of the trajectory planning of complementary and collaborative frequency modulation between new energy and conventional power sources of the present invention.

[0103] Figure 4 is the simulation model of the trajectory planning of complementary and collaborative frequency modulation between new energy and conventional power sources of the present invention.

[0104] Figure 5(a) is the frequency change curve when the converter does not participate in frequency modulation.

[0105] Figure 5(b) is the frequency change curve of complementary and collaborative frequency modulation of various power sources of the present invention.

[0106] Figure 6(a) is the output curve of the converter when the converter does not participate in frequency modulation.

[0107] Figure 6(b) is the output curve of the converter during complementary and collaborative frequency modulation of various power sources of the present invention. Detailed Description of the Invention

[0108] The technical solution of the present invention will be further described in detail below in conjunction with the drawings in the specification.

[0109] Example 1:

[0110] A frequency modulation method for multi-scale coordination between new energy and conventional power sources includes the following steps:

[0111] S1: Real-time detection

[0112] The voltage signal at the point of common coupling (PCC) is collected in real time through the converter frequency detection algorithm, and the phase-locked loop (PLL) is used to track the system frequency to generate the measured frequency time-domain curve f g ( t ), with a sampling frequency of 1 kHz to ensure data real-time.

[0113] S2: Determine the trajectory

[0114] 1. Critical trajectory calculation: According to the maximum frequency deviation specified in the grid guide F c and the maximum frequency change rateR c , generate the critical frequency trajectory through the time-domain inversion model f c ( t )

[0115] 2. Trajectory correction planning: On the basis of f c ( t ), superimpose 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 )

[0116] f p ( t ) = f c ( t ) ± δ (The dynamic adjustment direction is determined by sign( R ))

[0117] S3: Safety judgment and time-domain inversion

[0118] 1. Model construction: Dynamically invert the equivalent inertia of the system based on the second-order frequency response equation M and damping D :

[0119]

[0120] The input parameters include the initial frequency f 0, the frequency deviation direction sign( R ), F c and R c .

[0121] 2. Safety domain determination:

[0122] If f g ( t ) is always within the planned domain , it is determined to be safe and the new energy does not participate in frequency regulation;

[0123] If f g ( t ) exceeds the planned domain, trigger the frequency regulation signal and update M and D(The update period is 100 ms).

[0124] Based on the time-domain inversion model, using the measured frequency time-domain curve f g and the critical frequency time-domain trajectory f c to judge the power grid frequency safety situation according to their positional relationship. If f g leaves the planning domain, then new energy frequency modulation is triggered;

[0125] In the power system, it is difficult to obtain the system critical inertia damping parameters, but the initial frequency f 0, and the positive and negative signs of the frequency deviation sign( R ) can be directly measured. The maximum frequency deviation F c and the maximum frequency change rate R c specified in the guidelines can be directly queried. According to the above parameters, the time-domain inversion model describing the process can be inversely deduced.

[0126] Using f g and f c to intuitively reflect the current frequency safety situation of the power grid according to their positional relationship. According to f g whether it is within the f p determined planning domain, intuitively judge whether new energy needs frequency modulation:

[0127] If f g is always within the planning domain, then the power grid frequency is safe and new energy does not require frequency modulation to reduce the frequency modulation cost;

[0128] If f g leaves the planning domain, then new energy must be frequency modulated to ensure that f g is always within the f c determined safety domain and as close as possible to f p to maintain the necessary safety margin until f g exits the frequency modulation when entering the planning domain to minimize the frequency modulation cost.

[0129] The time-domain inversion model is a mathematical model that reversely deduces the dynamic characteristics (such as inertia and damping) of the power system through real-time frequency data. Its core goal is to dynamically evaluate the frequency safety state of the power grid based on the measured frequency trajectory and the preset safety threshold, and trigger the decision-making of new energy frequency modulation. The following is the specific description of this model:

[0130] 1. Basis for constructing the time-domain inversion model

[0131] Input parameters:

[0132] Initial frequency f 0: The steady-state frequency value before the disturbance occurs.

[0133] Frequency deviation direction sign(R): The positive and negative sign of the rate of change of frequency (RoCoF), reflecting the rising or falling trend of frequency.

[0134] Maximum allowable frequency deviation F c : The upper limit of frequency deviation specified in the power grid guidelines (such as ±0.5 Hz).

[0135] Maximum allowable rate of change of frequency R c : The upper limit of the rate of change of frequency specified in the power grid guidelines (such as ±1 Hz / s).

[0136] Output targets:

[0137] Critical frequency trajectory f c : The theoretical frequency time-domain curve when the frequency deviation and the rate of change exactly reach F c and R c .

[0138] Planned frequency trajectory f p : On the basis of f c superimposed with a safety margin (such as 90% F c ), the actual frequency modulation target trajectory after measurement error compensation and control delay.

[0139] 2. Mathematical expression and inversion logic

[0140] The time-domain inversion model deduces the dynamic relationship between the frequency trajectory and system parameters through the following steps:

[0141] Step 1: Establish the system frequency response equation

[0142] Assume that after the power grid disturbance, the frequency dynamic response satisfies the second-order differential equation:

[0143]

[0144] Wherein:

[0145] M : The system equivalent inertia (including the inertia of conventional power sources and the virtual inertia of new energy);

[0146] D : The system equivalent damping coefficient;

[0147] K : The frequency-power regulation coefficient;

[0148] Δ P : The power deficit or surplus.

[0149] Step 2: Inverse solution of the critical inertia damping parameters

[0150] According to the grid security constraints ( F c , R c ), inversely deduce the critical inertia ( M c ) and critical damping ( D c ) required by the system:

[0151] When the frequency deviation reaches F c , the critical frequency trajectory satisfies:

[0152] Through numerical methods (such as the Newton-Raphson method) or analytical solutions, solve for M c and D c .

[0153] Step 3: Generate the critical frequency trajectory ( f c )

[0154] Substitute the critical parameters ( M c , D c ) into the frequency response equation to simulate and obtain the theoretical critical trajectory f c ( t ), which represents the frequency change process of the system in the limit safety state.

[0155] 3. Safety judgment logic

[0156] Definition of the planning domain: On the critical trajectory f c ( t) Based on this, considering the engineering safety margin (such as 10% F c ), define the planned frequency trajectory f p ( t ):

[0157] Real-time safety assessment: Compare the measured frequency trajectory f g ( t ) with the planned domain :

[0158] If f g ( t ) is always within the planned domain, it is determined to be safe and the new energy does not participate in frequency regulation;

[0159] If f g ( t ) exceeds the planned domain, it is determined to be out of limit and the new energy is triggered to participate in frequency regulation.

[0160] 4. Application of the model in frequency regulation control

[0161] Dynamic parameter update: According to the real-time frequency data f g ( t ) and the type of disturbance (such as load mutation, new energy output fluctuation), periodically update the inversion model parameters ( M , D ), to ensure the accuracy of trajectory prediction.

[0162] Calculation of frequency regulation output: When frequency regulation is triggered, calculate the power Δ Preq that the new energy needs to supplement, so that the measured trajectory f g ( t ) tracks the planned trajectory f p ( t ):

[0163]

[0164] Among them, K p , K d are the proportional-derivative control coefficients.

[0165] 5. Differences from traditional methods

[0166]

[0167] 6. Practical application examples

[0168] Scenario: The sudden increase in grid load causes the frequency to drop.

[0169] Inversion process:

[0170] Detect f g ( t ) Deviate from the planned domain, triggering model update;

[0171] Invert and calculate the current system inertia M Insufficient, new energy is required to provide virtual inertia;

[0172] Generate a frequency modulation command to increase the output of new energy and promote f g ( t ) Approach f p ( t );

[0173] The synchronous machine gradually increases its output, the new energy smoothly exits, and the system returns to a steady state.

[0174] S4: Cooperative frequency modulation and exit control:

[0175] 1. Fast response of the converter:

[0176] The new energy converter adopts frequency trajectory tracking control and generates a power compensation command Δ req according to the deviation P :

[0177]

[0178] ( K p = 0.8, K d = 0.2, and adjust the output of the converter through PWM modulation).

[0179] Gradual frequency modulation of the synchronous machine: The synchronous machine gradually increases its output at a rate of 20% of the rated power per second to avoid mechanical shock.

[0180] 2. Smooth power exit:

[0181] When f g ( t ) enters the safe domain (satisfies ≤ 0.05 Hz for 3 consecutive cycles), the new energy frequency modulation power decays to zero according to an exponential curve;

[0182] The synchronous machine completely takes over the frequency modulation task, and the new energy switches to the constant power standby mode.

[0183] During the new energy frequency modulation process, according to the measured frequency time-domain curvef g The deviation information from the planned frequency trajectory, through the complementary and collaborative operation of new energy power sources and conventional power sources, synchronously adjusts the frequency regulation output of new energy to make f p it closely follow f g operation, ensuring the safety of the grid frequency and minimizing the frequency regulation cost; f p Specifically: As

[0184] shown in 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, within the interception section of primary frequency regulation, the frequency index is the worst and frequency accidents are most likely to occur. Therefore, it is crucial to ensure the frequency safety in primary frequency regulation, and the converter must actively participate in frequency regulation to ensure the stable and safe operation of the power system frequency. The processes after primary frequency regulation (such as secondary frequency regulation and tertiary frequency regulation) are all droop-free controls, which restore the system frequency to the rated value, and the frequency quality safety level is relatively high. To sum up, in view of the frequency safety problem in the primary frequency regulation stage, this embodiment 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 and prevent the system frequency from becoming unstable, resulting in frequency safety accidents such as generator tripping and load shedding.

[0185] As Figure 2 shown in Figure 3 , this embodiment mainly consists of new energy power sources, conventional power sources, load parts, etc. Among them, the power system composed of new energy converters and synchronous machines delivers power to the load and can reduce the frequency regulation output of the converter while ensuring that the frequency does not exceed the limit, thereby reducing costs. The converter control determines whether the converter participates in frequency regulation according to the

[0186] process shown in Figure 3 . If the converter does not participate in frequency regulation, a constant power control strategy is adopted, using the power outer loop and the converter inner loop to generate PWM signals and control the operation mode of the converter. If the converter participates in frequency regulation, a frequency trajectory planning strategy is adopted, taking the power adjustment and the dispatching instruction as the power command, and using the power outer loop and the converter inner loop to generate PWM signals, thereby changing the operation mode of the converter. f g As f g shown inF act and R act , it indicates that f g is always within the safety domain: It shows that the new - energy non - frequency - regulating power grid can also ensure frequency safety. If the new energy still participates in frequency regulation, then f g will continue to move away from f c this safety boundary, the frequency safety margin increases, but it consumes the new - energy frequency - regulation resources and generates unnecessary frequency - regulation costs. From the perspective of reducing the new - energy frequency - regulation costs, the new energy does not need to participate in the power - grid frequency regulation at this time. This mode is both safe and economical; if the disturbance is large, making f g the frequency deviation or the rate of change of frequency is greater than the specified action value F act and R act , then an action signal is triggered. The control of the present invention determines the critical frequency trajectory according to the specified maximum rate of change of frequency and the maximum frequency deviation f c , and plans a certain safety margin to obtain the planned frequency trajectory f p , f g leaves the safety domain, indicating 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 must participate in frequency regulation to ensure that f g is still within the safety domain. After frequency regulation f g is significantly away from the safety boundary f c , indicating that the safety margin is large, but the new - energy frequency - regulation cost also increases. Therefore, when the new energy participates in frequency regulation, ensure that f g close to f p is sufficient. When the frequency - regulation effect of the power grid itself can make f g cross f c , the new energy can immediately withdraw from frequency regulation. Therefore, the new energy synchronously changes the frequency - regulation output according to the deviation information between f g and f c , so that f g exactly runs along the critical trajectory that is both safe and economical, offsetting the out - of - limit frequency components caused by the time - variation of the power - supply structure / operation parameters, and the power grid can always be maintained in the critical inertia - damping state that is both safe and economical.

[0187] 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.

[0188] 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.

[0189] The multi-scale complementary frequency modulation characteristics of the converter and synchronous machine are shown in the following table:

[0190]

[0191] S5: Simulation verification and parameter optimization

[0192] 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.

[0193] In this embodiment, a simulation model built in MATLAB environment is used, such as Figure 4As shown in the figure, a synchronous machine model with adjustable system parameters is used to simulate the conventional power source in reality. The grid-connected converter is a typical inverter. The control scheme in the figure adopts frequency trajectory planning control. Through dq transformation, the voltage and current in the three-phase stationary abc coordinate system are transformed into the voltage and current in the two-phase rotating dq coordinate system. The converter is controlled by a phase-locked loop to track the grid frequency. Since the frequency trajectory planning control needs to judge whether the converter participates in frequency modulation based on the system frequency deviation and RoCoF, it is necessary to sample the system frequency to obtain the frequency change rate. If the converter needs to participate in frequency modulation, the converter outputs a response power to provide power support for the system. If the converter does not need to participate in frequency modulation, it still operates according to the working conditions of the initial operating point. After passing through the control of the power outer loop and current inner loop, a PWM control signal is output to regulate the operating conditions of the converter.

[0194] The effectiveness of the frequency modulation method for multi-scale coordination of new energy and conventional power sources in the present invention is verified through simulation waveforms: after the system frequency index (such as frequency deviation or frequency change rate) exceeds the given action value, the converter quickly participates in frequency modulation, making the system frequency close to the planned frequency trajectory and always remaining within the frequency safety domain, avoiding frequency safety accidents in the system that lead to generator tripping and load shedding in the power system; the red line in Figure 5(a) represents the planned frequency curve. f tp The blue line represents the frequency change curve when the converter does not participate in frequency modulation. The red line in Figure 5(b) represents the planned frequency curve. f tp The blue line represents the frequency change curve when the converter participates in frequency modulation. It can be seen from the comparison of the two frequency change curves 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 disturbances (as shown in Figure 5(b)). In Figure 5(a), the frequency change curve without participating in frequency modulation shows greater volatility and instability.

[0195] By observing the comparison of the output curves of the converter when it does not participate in frequency modulation and when various power sources are complementary and coordinated for frequency modulation, the effectiveness of the frequency modulation method for 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, changes its operating point, increases the frequency modulation power, and ensures the system frequency safety. When the system frequency enters the safety domain, the frequency modulation power significantly decreases and smoothly decreases to 0, reducing the frequency modulation cost of the converter and ensuring the economy of system frequency modulation. Figure 6(a) is the output curve of the converter when it 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 for frequency modulation. Combining with the frequency curve of the converter without 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:

[0196] When the converter does not participate in frequency regulation (Figure 6(a)), the output power curve shows relatively stable characteristics. The output power of the converter basically maintains a certain set value, lacking dynamic response to grid frequency fluctuations. This indicates that when the converter does not participate in frequency regulation, 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 quickly adjusted to compensate for the frequency deviation.

[0197] When the converter participates in frequency regulation (Figure 6(b)), the output power curve shows obvious fluctuations, which is closely related to the converter's rapid adjustment of output power to respond to grid frequency changes during frequency fluctuations. Combining Figure 5(b), it can be seen that after the converter participates in frequency regulation, the frequency fluctuation amplitude decreases significantly and the frequency recovery speed increases. Although there are fluctuations in the output power curve, these fluctuations correspond to the real-time response of the converter during frequency regulation, and the final effect is to greatly improve the grid frequency stability.

[0198] The following further explains the simulation verification and parameter optimization.

[0199] 1. Simulation model construction:

[0200] Build a test system including a synchronous machine (rated power 100 MW), a new energy converter (50 MW), and a load (120 MW) in MATLAB / Simulink.

[0201] Set the disturbance scenario: The load suddenly increases by 20 MW to simulate frequency drop.

[0202] 2. Performance index verification:

[0203] Scenario 1: When there is no new energy frequency regulation, the frequency deviation reaches -0.8 Hz, triggering generator tripping;

[0204] Scenario 2: After enabling this method, the frequency deviation is limited within -0.1 Hz, the new energy frequency regulation duration is shortened to 8 s, and the frequency regulation cost is reduced.

[0205] 3. Dynamic parameter adjustment:

[0206] If the simulation shows that the tracking error > 0.05 Hz, automatically optimize K p and K d (The genetic algorithm iterates 10 times);

[0207] If the response time > 50 ms, adjust the PWM switching frequency to 5 kHz.

[0208] Example 2:

[0209] The frequency regulation system includes:

[0210] 1. Frequency detection module, used to obtain the measured frequency time-domain curve at the common connection point in real time f g ;

[0211] Hardware: High-precision voltage sensor (accuracy ±0.01%) + FPGA phase-locked loop (response time < 1 ms).

[0212] Output: f g ( t ) Data stream (sampling rate 1 kHz).

[0213] 2. Trajectory planning module, used to determine the critical frequency time-domain trajectory according to the threshold specified in the grid guide ( f c ), and determine the planned frequency trajectory based on the safety margin, measurement error and control error f p ;

[0214] It can be calculated in real time based on a time-domain inversion solver such as C++ f c ( t ) and f p ( t ).

[0215] Adaptive setting according to the new energy penetration rate (20% - 80%) δ Realize dynamic adjustment of the safety margin.

[0216] 3. Time-domain inversion module, used to establish a time-domain inversion model, and use the measured frequency time-domain curve f g and the critical frequency time-domain trajectory f c to judge the grid frequency safety situation; if f g leaves the planned domain, generate a frequency modulation trigger signal;

[0217] The model construction of the time-domain inversion module is based on the following parameters: initial frequency f 0, the positive and negative of the frequency deviation sign(R), the maximum frequency deviation specified in the guide F c and the maximum frequency change rate R c .

[0218] 4. Cooperative frequency modulation module, used to respond to the frequency modulation trigger signal, and according to the measured frequency time-domain curve f g and the planned frequency trajectory f pThe deviation information, through the complementary and collaborative operation of new energy power sources and conventional power sources, synchronously adjusts the frequency regulation output of new energy to make f g Closely attached to f p Operate;

[0219] The coordinated frequency regulation module includes:

[0220] 1. A converter control unit, which is used to generate a PWM signal according to the frequency regulation demand and control the operation mode of the new energy converter;

[0221] Working mode switching: Constant power (PQ mode) ↔ Frequency regulation mode (droop control + virtual inertia).

[0222] PWM generation: Space vector modulation (SV PWM), switching frequency 4 kHz.

[0223] 2. A coordinated scheduling unit, which is used to coordinate the frequency regulation output allocation of new energy power sources and conventional power sources;

[0224] Output allocation logic:

[0225] New energy = min(Δ P req, P max), P Synchronous machine = Δ P req − P New energy

[0226] ( P max is the maximum frequency regulation capacity of new energy).

[0227] 3. A synchronous machine frequency regulation unit, which is used to gradually increase the frequency regulation output of the synchronous machine in the conventional power source during the new energy frequency regulation process;

[0228] 4. A power smoothing unit, which is used to smoothly reduce the new energy frequency regulation power to zero when the grid frequency enters the safe area, and the synchronous machine undertakes the subsequent frequency regulation task; The new energy exits the frequency regulation and switches to the standby state.

[0229] Exit algorithm: First-order inertia link ( τ = 5s), ensuring no sudden change in power.

[0230] V. The simulation verification module is used to conduct simulation verification on the system. When the simulation results show that the response time of the new energy converter exceeds 50 ms or the frequency trajectory tracking error exceeds ±0.05 Hz, it indicates to re-formulate or adjust the time-domain inversion model.

[0231] Function:

[0232] Pre - deployment test: Simulate 12 scenarios with new - energy penetration rates ranging from 30% to 70%;

[0233] Parameter self - healing: When K p / K d exceeds the limit, call the historical optimal parameter library to automatically roll back;

[0234] Report generation: Output indicators such as frequency deviation, frequency - modulation cost, and equipment loss rate.

[0235] VI. Data storage module, used to store the measured frequency time - domain curve f g , critical - frequency time - domain trajectory f c and planned frequency trajectory f p ;

[0236] VII. Communication module, used for real - time data interaction with new - energy power sources, conventional power sources, and grid dispatching centers.

[0237] This technical solution obtains the measured frequency time - domain curve of the common connection point in real - time through the frequency detection module f g , ensuring that the grid frequency change situation can be grasped in real - time and providing accurate data support for subsequent frequency - modulation decisions.

[0238] The trajectory planning module accurately determines the planned frequency trajectory according to the thresholds specified in the grid guide, as well as safety margins, measurement errors, and control errors f p , and formulates the critical - frequency time - domain trajectory f c , providing a clear reference path for grid frequency control and effectively ensuring grid frequency safety.

[0239] The time - domain inversion module judges the safety state of the grid frequency according to the relationship between the measured frequency time - domain curve f g and the critical - frequency time - domain trajectory f c , and generates a frequency - modulation trigger signal in a timely manner. Once the grid frequency deviates from the planned trajectory, it can quickly respond and initiate frequency - modulation to reduce the impact of system frequency deviation.

[0240] The coordinated frequency - modulation module can respond to the frequency - modulation trigger signal and optimize the frequency - modulation process through the coordinated operation of new - energy power sources and conventional power sources. By synchronously adjusting the new - energy frequency - modulation output, ensure that the grid frequency closely follows the planned trajectory f p , ensuring grid frequency safety, stability, and reducing the system regulation pressure.

[0241] After the grid frequency returns to the safe range, the coordinated frequency modulation module promptly controls the new energy to withdraw from 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 new energy, and ensures the economy and sustainability of the frequency modulation process.

[0242] The automatic control mechanism of this technical solution can automatically perform frequency modulation response and frequency control based on real-time data and algorithms, reducing human intervention and improving the efficiency and accuracy of grid frequency regulation.

[0243] Through the multi-scale coordination of new energy and conventional power sources, the burden of a single power source is reduced, the power output during frequency modulation is optimized, and the frequency modulation duration is shortened. As a result, the cost of frequency modulation is effectively reduced, and the safety and stability of the power grid are improved.

[0244] The data storage module can effectively store the measured frequency time-domain curve f g , the critical frequency time-domain trajectory f c and the planned frequency trajectory f p , ensuring that the historical data during the frequency modulation process is archived in a timely manner, facilitating subsequent analysis, optimization, and fault diagnosis. This provides a solid data foundation for the system's dispatching decision-making and fault recovery.

[0245] The communication module enables the system to perform real-time data interaction with new energy power sources, conventional power sources, and the power grid dispatching center, ensuring that each device and system can promptly obtain grid frequency information and frequency modulation requirements. Real-time data exchange helps all parties' devices quickly respond to frequency changes, ensuring the real-time nature and accuracy of frequency modulation operations, thereby enhancing the overall coordination and response speed of the system.

[0246] Through the connection with the power grid dispatching center via the communication module, the system can monitor the changes in grid frequency in real time and adjust strategies promptly. In addition, the dispatching center can remotely control and adjust the frequency modulation strategy, increasing the flexibility and adaptability of the system and ensuring the stable operation of the power grid.

[0247] The data storage module not only ensures the backup and secure storage of frequency data but also, in cooperation with the communication module, can ensure the accurate transmission of real-time data, reducing frequency modulation errors caused by data loss or transmission delays. Precise data support further enhances the reliability of frequency safety control.

[0248] The data storage module provides complete historical data for subsequent analysis, research, and optimization. Through retrospective analysis of the frequency time-domain curve, it can help power grid dispatching personnel identify potential risks, optimize frequency modulation strategies, reduce energy consumption, and further improve the cost-effectiveness of power grid frequency modulation.

[0249] The communication module can achieve real-time linkage among new energy power sources, conventional power sources, and the power grid dispatching center, promoting the reasonable allocation and common regulation of multiple resources. When the power grid frequency fluctuates, it can ensure that the dispatching center can quickly obtain and respond to the frequency modulation requirements, realizing the overall coordinated control of the system and improving the stability and reliability of the system.

[0250] Through continuous data collection and interaction, the system can generate frequency modulation reports and status monitoring in real time, supporting the decision-making analysis of the power grid dispatching center. Combining real-time data and historical data, the system can perform intelligent prediction and early warning, identify potential frequency fluctuation problems in advance, achieve preventive dispatching, and reduce the risk of faults.

[0251] 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, timely discover potential problems and make corrections, thereby improving the reliability and accuracy of the system.

[0252] When the simulation results show that the response time of the new energy converter exceeds 50 ms or the frequency trajectory tracking error exceeds ±0.05 Hz, the system can automatically identify and send an adjustment signal, requiring the re-formulation or adjustment of the time-domain inversion model. This can ensure that the system can be adjusted in a timely manner during actual operation, avoid the instability of the power grid frequency caused by the failure of the control strategy or excessive error, and ensure that the system has good responsiveness and flexibility.

[0253] The simulation verification module can identify potential risks or performance bottlenecks in advance by simulating various possible system states and fault scenarios, thereby making necessary adjustments and optimizations to the time-domain inversion model, continuously improving the frequency modulation strategy of the system, making it more accurate, economical, and efficient, and ensuring the safety and stability of the power grid frequency.

[0254] 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.

[0255] Through simulation verification, problems can be identified and solved before the system is actually put into use, avoiding the debugging delay and unnecessary downtime during the troubleshooting process that may occur in traditional methods. Simulation verification discovers and corrects potential design defects in advance, helping to save resources and time in actual deployment.

[0256] The simulation verification module supports simulating and adjusting the system behavior under different working conditions, facilitating multiple verifications and optimizations. It not only improves the stability of the existing system but also provides strong support for subsequent system expansion and upgrade. Through continuous simulation and adjustment, the system can maintain a high adaptability when facing new technical requirements or complex environments.

[0257] The simulation verification module can not only conduct verification in the initial stage, but also continuously perform simulation and evaluation during the operation of the system. This enables the system to continuously optimize according to its actual operation performance, avoid long-term performance degradation or failure, and ensure stability and efficiency during long-term operation.

[0258] The above-described frequency modulation method for multi-scale coordination of new energy and conventional power sources is a specific embodiment of the present invention, which has already reflected the substantial features and progress of the present invention. According to actual usage needs, equivalent modifications can be made to its shape, structure, etc. under the inspiration of the present invention, and all are within the protection scope of this solution.

Claims

1. A frequency modulation method for multi-scale coordination of new energy and conventional power sources, characterized in that It includes the following steps: Real-time detection: Obtain 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 ; f p = f c ± δ ; In the formula, δ is the safety margin; Safety judgment: Based on the time-domain inversion model, using the measured frequency time-domain curve f g and the critical frequency time-domain trajectory f c to judge the grid frequency safety situation according to their positional relationship. If f g it leaves the planning domain, new energy frequency modulation is triggered; Coordinated frequency regulation: During the new energy frequency regulation process, based on the measured frequency time-domain curve f g and the deviation information from the planned frequency trajectory f p through the complementary coordination of new energy power sources and conventional power sources, synchronously adjust the new energy frequency regulation output to make f g closely follow f p operation to ensure the grid frequency safety and minimize the frequency regulation cost; When the grid frequency enters the safe region, the new energy exits frequency regulation and re-enters the standby state; In the safety judgment step: The time-domain inversion model is constructed to dynamically invert the equivalent inertia of the system based on the second-order frequency response equation M and damping D : The input parameters include the initial frequency f 0, the positive or negative sign of the frequency deviation sign( R ), the maximum frequency deviation specified by the guidelines F c and the maximum frequency change rate R c ; If f g always remains within the planned domain it is determined to be safe, and the new energy does not participate in frequency regulation; If f g exceeds the planned domain, trigger a frequency modulation signal and update in real time M and D ; When the new energy power source and the conventional power source are complementary and coordinated: The converter of the new energy and the synchronous machine of the conventional power source cooperate in frequency regulation to ensure frequency safety; When the new energy is used for frequency regulation, the frequency regulation 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 safe region, the frequency regulation power of the new energy smoothly decreases to zero, and the synchronous machine undertakes the subsequent frequency regulation task, shortening the frequency regulation duration and reducing the frequency regulation cost.

2. A frequency modulation method for multi-scale coordination of new energy and conventional power sources according to claim 1, characterized in that: The new energy frequency regulation is achieved through converter control. The converter generates a PWM signal according to the frequency regulation demand to control the operation mode of the converter.

3. A frequency modulation method for multi-scale coordination of new energy and conventional power sources according to claim 2, characterized in that: The converter judges whether to start frequency regulation according to the preset thresholds of frequency deviation and rate of change of frequency; when both the measured frequency deviation and rate of change of frequency do not exceed the thresholds, the converter maintains constant power control.

4. A frequency modulation system for multi-scale coordination of new energy and conventional power sources, characterized in that, Applying a frequency regulation method for multi-scale cooperation between new energy and conventional power sources according to any one of claims 1-3, the system includes: A frequency detection module, which is used to obtain the measured frequency time-domain curve at the common connection point in real time f g ; A trajectory planning module, configured to determine a critical frequency time-domain trajectory according to the threshold specified in the grid code f c ), and determine a planned frequency trajectory based on a safety margin, a measurement error, and a control error f p ; f p = f c ± δ ; where δ is the safety margin; A time-domain inversion module for establishing a time-domain inversion model and using the measured frequency time-domain curve f g and the critical frequency time-domain trajectory f c to determine the power grid frequency safety condition based on their positional relationship; if f g it leaves the planning domain, a frequency modulation trigger signal is generated; The construction of the time-domain inversion model is based on the dynamic inversion of the equivalent inertia of the system using the second-order frequency response equation M and damping D : The input parameters include the initial frequency f 0, the positive or negative sign of the frequency deviation sign( R ), the maximum frequency deviation specified by the guidelines F c and the maximum frequency change rate R c ; If f g always lies within the planned domain it is determined to be safe and the new energy does not participate in frequency regulation; If f g exceeds the planned domain, trigger a frequency modulation signal and update it in real time M and D ; A coordinated frequency modulation module, which is used to respond to the frequency modulation trigger signal and, according to the measured frequency time-domain curve f g and the deviation information from the planned frequency trajectory f p , through the complementary coordination of new energy power sources and conventional power sources, synchronously adjusts the new energy frequency modulation output so that f g it closely adheres to f p operation; and when the grid frequency enters the safe area, controls the new energy to withdraw from frequency modulation and switch to the standby state; When the new energy power source and the conventional power source are complementary and coordinated: The converter of the new energy and the synchronous machine of the conventional power source cooperate in frequency regulation to ensure frequency safety; When the new energy is used for frequency regulation, the frequency regulation 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 safe region, the frequency regulation power of the new energy smoothly decreases to zero, and the synchronous machine undertakes the subsequent frequency regulation task, shortening the frequency regulation duration and reducing the frequency regulation cost.

5. A frequency modulation system for multi-scale coordination of new energy and conventional power supplies according to claim 4, characterized in that: The cooperative frequency regulation module includes: A converter control unit for generating a PWM signal according to the frequency regulation demand and controlling the operation mode of the new energy converter; A cooperative scheduling unit for coordinating the distribution of frequency regulation output of the new energy power source and the conventional power source; A synchronous machine frequency regulation unit for gradually increasing the frequency regulation output of the synchronous machine in the conventional power source during the new energy frequency regulation process; A power smoothing unit for smoothly reducing the new energy frequency regulation power to zero when the grid frequency enters the safe region, and the synchronous machine undertakes the subsequent frequency regulation task.

6. A frequency modulation system for multi-scale coordination of new energy and conventional power supplies according to claim 5, characterized in that: The system further includes: A data storage module for storing the measured frequency time-domain curve f g , the critical frequency time-domain trajectory f c and the planned frequency trajectory f p ; A communication module for real-time data interaction with the new energy power source, the conventional power source, and the grid dispatching center.

7. A frequency modulation system for multi-scale coordination of new energy and conventional power sources according to claim 6, characterized in that: The system further includes a simulation verification module for simulating and verifying the system. When the simulation result shows that the response time of the new energy converter exceeds 50 ms or the frequency trajectory tracking error exceeds ±0.05 Hz, it indicates to re-formulate or adjust the time-domain inversion model.

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