Multi-band filtering and power safety domain self-protection damping methods

Abstract

This invention discloses a method for smoothing out multi-band filtering and power safety domain self-protection, relating to the field of large-scale power grid security technology. The specific steps of the method are: operating condition identification step, switching buffer step, safety domain matching step, control execution step, and signal constraint output step. This invention distinguishes different operating states of GWh-level energy storage power stations and matches corresponding control strategies. When switching states, it adopts a continuous and smooth parameter transition method, combined with control logic that combines frequency band processing and full-band processing, so that the control method fully conforms to the inherent characteristics of power fluctuations at the grid connection point of the energy storage power station. This technology can avoid grid connection point disturbances caused by sudden changes in control parameters, allowing the control action to adaptively adjust with the operating state of the energy storage power station. It achieves fine-grained fluctuation suppression under steady-state charging and discharging, and achieves rapid fluctuation smoothing under scheduling command switching or grid connection point disturbances, ensuring the continuity and adaptability of the control process.

Description

Technical Field

[0001] This invention relates to the field of large-scale power grid security technology, specifically to a method for mitigation through multi-band filtering and power safety domain self-protection. Background Technology

[0002] GWh-level energy storage power stations are core regulation resources for new power systems and key carriers supporting high-proportion renewable energy consumption, grid peak-valley regulation, and system frequency stability. Their operational safety and control reliability are core guarantees for the development of the power system. With the large-scale development of the energy storage industry, the number of large-capacity energy storage power stations connected to the grid continues to grow, and the frequency of dynamic switching of power station operating conditions has increased significantly. Under scenarios such as charging and discharging state switching, dispatch command adjustment, and grid connection point disturbances, the form and amplitude of power fluctuations exhibit diverse characteristics. The power fluctuation patterns and grid connection control requirements of energy storage power stations under different operating conditions are significantly different. How to adapt to dynamic changes in operating conditions and effectively suppress power fluctuations at the grid connection point has become a key issue in ensuring the reliable grid connection operation of large-capacity energy storage power stations and a key technological direction that needs to be broken through in the field of energy storage grid connection control.

[0003] However, existing power fluctuation mitigation technologies for GWh-level energy storage power stations generally employ fixed control parameters and a single filtering logic, failing to develop differentiated control schemes for different operating conditions. This results in poor adaptability to operating conditions, with control parameters undergoing abrupt changes during condition switching, easily triggering power oscillations and frequency fluctuations at the grid connection point, making a smooth transition impossible. Furthermore, existing technologies lack power safety constraint mechanisms that match operating conditions and do not form a dynamic and fixed safety boundary judgment logic, resulting in a lack of effective protection during the control process. In addition, each control link is independent of the others, and the control signals lack boundary verification and correction links, easily generating over-limit control commands. This makes it difficult to cope with power fluctuations under complex operating conditions and fails to meet the refined and safe grid connection mitigation control requirements of large-capacity energy storage power stations. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for smoothing out power fluctuations through multi-band filtering and power safety domain self-protection. This invention distinguishes different operating states of GWh-level energy storage power stations and matches corresponding control strategies. When switching states, it adopts a continuous and smooth parameter transition method. Combining frequency-band processing and full-band processing control logic, the control method fully conforms to the inherent characteristics of power fluctuations at the grid connection point of the energy storage power station. This technology can avoid grid connection point disturbances caused by sudden changes in control parameters, allowing the control action to adaptively adjust with the operating state of the energy storage power station. It achieves fine-grained fluctuation suppression under steady-state charging and discharging, and achieves rapid fluctuation smoothing under scheduling command switching or grid connection point disturbances, ensuring the continuity and adaptability of the control process, and ensuring that the power fluctuation smoothing action always remains consistent with the actual operating state of the energy storage power station.

[0005] To solve the above-mentioned technical problems, this invention provides the following technical solution: a method for smoothing out multi-band filtering and power safety domain self-protection, the specific steps of which are as follows:

[0006] Operating condition identification steps: Collect real-time operating power data of the grid-connected point of the GWh-level energy storage power station, perform preprocessing, extract power fluctuation characteristic parameters, and output the operating condition classification results and operating condition indicator signals of the GWh-level energy storage power station.

[0007] Switching buffer steps: Receive the working condition classification result and working condition flag signal. When the working condition has not changed, directly output the fixed control reference parameters of the corresponding working condition. When the working condition changes, perform a smooth transition. After the transition is completed, lock and output the fixed control reference parameters of the new working condition.

[0008] Safety domain matching steps: Receive the operating condition classification results, generate a dynamic narrow threshold power safety domain for steady-state operating conditions, generate a fixed wide threshold power safety domain for disturbed operating conditions, and output the corresponding power safety domain;

[0009] Control execution steps: Receive the operating condition classification results, the fixed control reference parameters and the corresponding power safety domain for the corresponding operating condition, match the filter control logic for the corresponding operating condition, set the filter strength according to the fixed control reference parameters for the corresponding operating condition, generate the initial filter control signal for the corresponding operating condition and output it.

[0010] Signal constraint output steps: Receive the initial filter control signal and the corresponding power safety domain for the corresponding operating condition, perform boundary verification and limit correction of the initial filter control signal, and output the smoothing control signal.

[0011] Further, in the operating condition identification step, real-time operating power data of the GWh-level energy storage power station grid connection point is collected by the power measurement unit at the GWh-level energy storage power station grid connection point. A set of real-time operating power data is output for each sampling period, and a 100ms moving average filtering process is performed to obtain preprocessed power data. The preprocessed power data enters a sliding time window of 150-200ms. Every 10ms, the preprocessed power data within the window is updated, and power fluctuation characteristic parameters are extracted, including power fluctuation amplitude and spectral characteristic parameters. The power fluctuation amplitude is the average power of all sampling points of the preprocessed power data within the window and the average power of the sliding time window. The maximum absolute deviation is determined by the spectral characteristic parameter, which is the ratio of fluctuation energy in the 0.1-10Hz frequency band to the total fluctuation energy after performing a fast Fourier transform on the preprocessed power data within the window. Based on the power fluctuation amplitude and spectral characteristic parameter, the comprehensive operating condition judgment index is calculated using the formula. The operating condition classification result of the GWh-level energy storage power station is obtained based on the comprehensive operating condition judgment index. At the same time, it is compared with the operating condition classification result of the previous period, and an operating condition flag signal is output. There are two types of operating condition flag signals: operating condition change flag signal and operating condition same flag signal. When the operating condition classification results are different, the operating condition change flag signal is output; when the operating condition classification results are the same, the operating condition same flag signal is output.

[0012] Furthermore, in the operating condition identification step, the formula for calculating the comprehensive operating condition judgment index is as follows: ,in, This is a comprehensive working condition assessment index. This refers to the power fluctuation amplitude. The rated charge and discharge power of a GWh-level energy storage power station The amplitude weighting coefficient, with a value of 0.7, is determined based on historical statistical results of the power stability impact factors of GWh-level energy storage power stations. For spectral characteristic parameters, The spectral weighting coefficient, with a value of 0.3, is determined by the proportion of the impact of fluctuations in different frequency bands on the grid connection stability of energy storage power stations.

[0013] The judgment threshold was determined by statistical analysis of historical operating data from GWh-level energy storage power stations. ,when When, it is determined to be a steady-state operating condition, when When the condition is determined to be a disturbance condition, the condition classification result is output when the results of three consecutive determinations are consistent.

[0014] Furthermore, in the switching buffer step, the operating condition classification result and the operating condition flag signal are received. When the operating condition flag signal is the same as the operating condition flag signal, the fixed control reference parameter corresponding to the current operating condition is directly output. The fixed control reference parameters for steady-state operating condition and disturbance operating condition are set separately through the grid-connected operation control standard of GWh-level energy storage power station, respectively corresponding to the standard filter control parameters under the two operating conditions. When the operating condition flag signal is the operating condition change flag signal, a transition process with a duration of 10s is started. During the transition, the transition control reference parameter is calculated through the S-shaped smooth transition formula for operating condition switching. After the transition process is completed, the fixed control reference parameter corresponding to the new operating condition is locked and output.

[0015] Furthermore, in the switching buffer step, the formula for the S-shaped smooth transition of the operating condition switching is: ,in, for Transition control reference parameters at time points, The fixed control reference parameters are those corresponding to the operating conditions before the switch. These are the fixed control reference parameters corresponding to the operating conditions after the switch. To buffer the total transition time, the grid-connected inertia constant of the GWh-level energy storage power station and the allowable fluctuation range of the grid connection point frequency are used. The runtime within the transition process, with a value range of [value missing]. .

[0016] Furthermore, in the safety domain matching step, when the operating condition classification result is a steady-state operating condition, the one-sided threshold of the steady-state power safety domain is calculated using the steady-state dynamic power safety domain threshold formula to generate a dynamic narrow threshold power safety domain. The upper limit of the safety domain is the sum of the average power of the current sliding time window and the one-sided threshold of the steady-state power safety domain, and the lower limit of the safety domain is the difference between the average power of the current sliding time window and the one-sided threshold of the steady-state power safety domain. When the operating condition classification result is a disturbance operating condition, a fixed wide threshold power safety domain is generated. The lower limit of the safety domain is 85% of the rated charge and discharge power of the GWh-level energy storage power station, and the upper limit of the safety domain is 115% of the rated charge and discharge power of the GWh-level energy storage power station.

[0017] Furthermore, in the safety domain matching step, the steady-state dynamic power safety domain threshold formula is: ,in, The one-sided threshold of the steady-state power safety region. This is the load factor correction factor, which is the ratio of the average power of the current sliding time window to the rated charge and discharge power of the GWh-level energy storage power station. The steady-state fluctuation allowable factor is set to 0.02, determined by the power deviation requirements of the grid-connected steady-state operation procedure for GWh-level energy storage power stations. This refers to the rated charging and discharging power of a GWh-level energy storage power station.

[0018] Furthermore, in the control execution step, when the operating condition classification result is a steady-state operating condition, the power fluctuation signal at the grid connection point of the energy storage power station is divided into three independent frequency bands: 0.1-1Hz, 1-5Hz, and 5-10Hz. The filtering coefficients of each frequency band are set according to the fixed control reference parameters, and the power fluctuation is filtered band by band in order from high frequency to low frequency. When the operating condition classification result is a disturbance operating condition, a parallel full-pass filtering architecture is used to process the power fluctuation signal in the 0.01-100Hz full-band. The full-band filtering gain is set according to the fixed control reference parameters, and the fluctuation components of all frequency bands are filtered synchronously. Finally, the initial filtering control signal corresponding to the operating condition is generated, including the target power value after control and the filtering execution parameters.

[0019] Furthermore, in the signal constraint output step, the adjusted power target value corresponding to the initial filter control signal is compared one by one with the upper and lower limits of the corresponding power safety domain. When the adjusted power target value is within the upper and lower limit range of the power safety domain, the initial filter control signal is directly retained. When the adjusted power target value exceeds the upper limit of the power safety domain, it is corrected to the upper limit of the corresponding safety domain. When the adjusted power target value is lower than the lower limit of the power safety domain, it is corrected to the lower limit of the corresponding safety domain. After completing the boundary verification and over-limit correction, the smoothing control signal is output.

[0020] Compared with existing technologies, this multi-band filtering and power safety domain self-protection method has the following advantages:

[0021] I. This invention distinguishes different operating states of a GWh-level energy storage power station and matches corresponding control strategies. During state switching, it adopts a continuous and smooth parameter transition method, combined with a control logic that integrates frequency band processing and full frequency band processing. This makes the control method fully conform to the inherent characteristics of power fluctuations at the grid connection point of the energy storage power station. This technology can avoid grid connection point disturbances caused by sudden changes in control parameters, allowing the control action to adaptively adjust with the operating state of the energy storage power station. It achieves fine-grained fluctuation suppression under steady-state charging and discharging, and achieves rapid fluctuation smoothing under scheduling command switching or grid connection point disturbances. This ensures the continuity and adaptability of the control process, and makes the power fluctuation smoothing action always consistent with the actual operating state of the energy storage power station.

[0022] Second, this invention establishes dual safety boundary constraint rules that match the operating status of a GWh-level energy storage power station, providing a fixed operating threshold and a dynamic adjustment boundary for power regulation. At the same time, it performs boundary comparison and violation correction on the regulation output signal, forming a complete self-protection control logic. This technology can dynamically define the safe regulation range according to the operating status of the energy storage power station, ensure regulation accuracy under normal operating conditions, reserve sufficient regulation margin under abnormal disturbance conditions, and eliminate over-limit regulation behavior through closed-loop verification. It avoids the grid-connected operation risk of the energy storage power station from the regulation execution level, ensuring that the power regulation is within the grid-connected safe and compliant operating range under all operating conditions.

[0023] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0025] Figure 1 A flowchart of a multi-band filtering and power safety domain self-protection damping method;

[0026] Figure 2 A framework diagram of the switching buffer step in a suppression method for multi-band filtering and power safety domain self-protection;

[0027] Figure 3 This is a framework diagram of the safety domain matching step in a suppression method for multi-band filtering and power safety domain self-protection. Detailed Implementation

[0028] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0029] Example:

[0030] This embodiment is applied to the scenario of power fluctuation smoothing at the grid connection point of a 1GWh grid-side shared energy storage power station. The power station mainly undertakes the core tasks of new energy consumption, grid peak-valley regulation and auxiliary frequency regulation. During operation, there are small power fluctuations during steady-state charging and discharging, as well as large power fluctuations due to grid dispatch command switching and grid connection point voltage disturbances. It is necessary to adapt to dual operating conditions to achieve smooth power fluctuation smoothing and grid connection safety self-protection.

[0031] Operating condition identification steps: Real-time operating power data of a 1GWh-level energy storage power station grid-connected point is collected using a power measurement unit at the grid connection point. This power measurement unit completes sampling at a fixed period, outputting a set of real-time operating power data for each sampling period. To eliminate noise interference such as electromagnetic interference and sampling spikes, a 100ms sliding mean filtering process is performed on the collected real-time operating power data. The arithmetic mean of the sampling data within 100ms is taken, and high-frequency noise components are removed to obtain the preprocessed power data. The preprocessed power data is then input into a 170ms sliding time window, with the window being processed at 10ms intervals. The sliding update of data within the window ensures the real-time and continuous nature of the analysis. Two power fluctuation characteristic parameters are extracted within the sliding time window: one is the power fluctuation amplitude, which is the maximum absolute deviation between all preprocessed power data sampling points within the window and the average power of the sliding time window, used to characterize the magnitude of the power fluctuation; the other is a spectral characteristic parameter, which is the ratio of the fluctuation energy in the 0.1-10Hz frequency band to the total fluctuation energy after performing a Fast Fourier Transform on the preprocessed power data within the window, used to characterize the frequency characteristics of the power fluctuation. Based on these two power fluctuation characteristic parameters, the comprehensive operating condition judgment index is calculated using the following formula: ,in, This is a comprehensive working condition assessment index. This refers to the power fluctuation amplitude. The rated charge and discharge power of a GWh-level energy storage power station The amplitude weighting coefficient, with a value of 0.7, is determined based on historical statistical results of the power stability impact factors of GWh-level energy storage power stations. For spectral characteristic parameters, The spectral weighting coefficient, with a value of 0.3, is determined by the proportion of the impact of fluctuations in different frequency bands on the grid-connected stability of energy storage power stations; and the judgment threshold is determined by statistical analysis of historical operating data of GWh-level energy storage power stations. ,when When, it is determined to be a steady-state operating condition, when When a condition is identified as a disturbance, to avoid errors from a single judgment, three consecutive judgments must yield consistent results before the final condition classification result is output. Simultaneously, the current condition classification result is compared with the result from the previous cycle. If the results differ, a condition change flag signal is output; if the results are the same, a condition same flag signal is output, completing the entire condition identification process. Figure 1 As shown.

[0032] Switching buffer step: Receive the operating condition classification result and operating condition flag signal output from the operating condition identification step, and establish the corresponding relationship between operating conditions and control parameters; when a flag signal indicating the same operating condition is received, directly output the fixed control reference parameter corresponding to the current operating condition. This fixed control reference parameter is pre-set according to the grid-connected operation control standard for GWh-level energy storage power stations. Steady-state operating conditions and disturbance operating conditions each correspond to dedicated standard filter control parameters; when an operating condition change flag signal is received, immediately initiate a 10-second transition process. During the transition, the transition control reference parameter is calculated using the S-shaped smooth transition formula for operating condition switching. The S-shaped smooth transition formula for operating condition switching is: ,in, for Transition control reference parameters at time points, The fixed control reference parameters are those corresponding to the operating conditions before the switch. These are the fixed control reference parameters corresponding to the operating conditions after the switch. To buffer the total transition time, the grid-connected inertia constant of the GWh-level energy storage power station and the allowable fluctuation range of the grid connection point frequency are used. The runtime within the transition process, with a value range of [value missing]. The total buffer transition time is fixed at 10 seconds. This smooth transition method avoids grid-connected power oscillations caused by sudden changes in control parameters. After the transition process is completed, the fixed control reference parameters corresponding to the new operating condition are locked and output, such as... Figure 2 As shown; and the entire update frequency is once every 100ms, keeping the timing synchronized with the working condition identification step.

[0033] Safety Domain Matching Step: Receive the operating condition classification result output from the operating condition identification step, generate the corresponding power safety domain based on the operating condition type, and provide safety boundary constraints for subsequent regulation; when the operating condition classification result is a steady-state operating condition, calculate the unilateral threshold using the steady-state dynamic power safety domain threshold formula. The steady-state dynamic power safety domain threshold formula is: ,in, The one-sided threshold of the steady-state power safety region. This is the load factor correction factor, which is the ratio of the average power of the current sliding time window to the rated charge and discharge power of the GWh-level energy storage power station. The steady-state fluctuation allowable factor is set to 0.02, determined by the power deviation requirements of the grid-connected steady-state operation procedure for GWh-level energy storage power stations. This represents the rated charge and discharge power of a GWh-level energy storage power station; based on the average power of the current sliding time window, a dynamic narrow threshold power safety domain is generated, such as... Figure 3 As shown; the upper limit of the safety domain is the sum of the average power of the current sliding time window and the one-sided threshold of the steady-state power safety domain, and the lower limit of the safety domain is the difference between the average power of the current sliding time window and the one-sided threshold of the steady-state power safety domain, which is adapted to the fine control requirements of small steady-state fluctuations; when the operating condition classification result is a disturbance operating condition, a fixed wide threshold power safety domain is directly generated, with the lower limit being 85% of the rated charge and discharge power of the GWh-level energy storage power station and the upper limit being 115% of the rated charge and discharge power of the GWh-level energy storage power station, providing sufficient control margin for smoothing large fluctuations; the power safety domain parameters are also updated at a frequency of 100ms every time to ensure that the constraint parameters are effective in real time.

[0034] Control execution steps: Receive the operating condition classification results, the corresponding fixed control reference parameters, and the corresponding power safety domain; match the operating condition with appropriate filtering control logic. When the operating condition is steady-state, divide the grid-connected power fluctuation signal into three independent frequency bands: 0.1-1Hz, 1-5Hz, and 5-10Hz. Set the filter coefficients for each frequency band according to the fixed control reference parameters, and complete the filtering process band by band in order from high frequency to low frequency to achieve refined suppression of small steady-state fluctuations. When the operating condition is a disturbance, use a parallel full-pass filtering architecture to process the 0.01-100Hz full-band power fluctuation signal. Set the full-band filtering gain according to the fixed control reference parameters, and simultaneously complete the filtering process for all frequency band fluctuation components to achieve rapid smoothing of large disturbance fluctuations. After filtering, generate and output an initial filtering control signal containing the controlled power target value and filtering execution parameters to provide a data basis for subsequent constraint verification.

[0035] Signal constraint output steps: The initial filtered control signal output from the regulation execution step and the corresponding power safety domain output from the safety domain matching step are received. Boundary verification and over-limit correction are performed on the initial filtered control signal. Specifically, the regulated power target value is extracted from the initial filtered control signal and compared with the upper and lower limits of the power safety domain one by one. If the regulated power target value is within the upper and lower limits of the safety domain, the initial filtered control signal is directly retained. If it exceeds the upper limit of the safety domain, the signal is corrected to the upper limit value of the safety domain. If it is lower than the lower limit of the safety domain, the signal is corrected to the lower limit value of the safety domain. After completing all boundary verification and over-limit correction, a smoothing control signal is output. The verification and output frequency is also once every 100ms, realizing the safety constraint and accurate output of the regulation signal.

[0036] In summary, in the scenario of a 1GWh grid-side shared energy storage power station, the system accurately distinguishes between steady-state and disturbance conditions through operating condition identification, achieves smooth transition of control parameters by relying on switching buffers, provides dual-mode safety boundary constraints by combining safety domain matching, generates a filter signal adapted to the operating condition through control execution, and finally completes over-limit correction through signal constraint output. This effectively realizes the adaptive smoothing and safety self-protection of power fluctuations at the grid connection point of a large-capacity energy storage power station.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for mitigating multi-band filtering and power safety domain self-protection, characterized in that, The specific steps of this method are as follows: Operating condition identification steps: Collect real-time operating power data of the grid-connected point of the GWh-level energy storage power station, perform preprocessing, extract power fluctuation characteristic parameters, and output the operating condition classification results and operating condition indicator signals of the GWh-level energy storage power station. Switching buffer steps: Receive the working condition classification result and working condition flag signal. When the working condition has not changed, directly output the fixed control reference parameters of the corresponding working condition. When the working condition changes, perform a smooth transition. After the transition is completed, lock and output the fixed control reference parameters of the new working condition. Safety domain matching steps: Receive the operating condition classification results, generate a dynamic narrow threshold power safety domain for steady-state operating conditions, generate a fixed wide threshold power safety domain for disturbed operating conditions, and output the corresponding power safety domain; Control execution steps: Receive the operating condition classification results, the fixed control reference parameters and the corresponding power safety domain for the corresponding operating condition, match the filter control logic for the corresponding operating condition, set the filter strength according to the fixed control reference parameters for the corresponding operating condition, generate the initial filter control signal for the corresponding operating condition and output it. Signal constraint output steps: Receive the initial filter control signal and the corresponding power safety domain for the corresponding operating condition, perform boundary verification and limit correction of the initial filter control signal, and output the smoothing control signal.

2. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 1, characterized in that, In the operating condition identification step, real-time operating power data of the grid-connected point of the GWh-level energy storage power station is collected by the power measurement unit of the grid-connected point of the GWh-level energy storage power station. A set of real-time operating power data is output in each sampling period and subjected to a 100ms sliding mean filtering process to obtain preprocessed power data. The preprocessed power data enters a sliding time window with a length of 150~200ms. The preprocessed power data within the window is updated every 10ms, and power fluctuation characteristic parameters, including power fluctuation amplitude and spectral characteristic parameters, are extracted. Based on the power fluctuation amplitude and spectral characteristic parameters, the comprehensive operating condition judgment index is calculated using the formula for the comprehensive operating condition judgment index. Based on the comprehensive operating condition judgment index, the operating condition classification result of the GWh-level energy storage power station is obtained. At the same time, it is compared with the operating condition classification result of the previous period, and an operating condition flag signal is output. The operating condition flag signal is of two types: operating condition change flag signal and operating condition same flag signal. When the operating condition classification results are different, the operating condition change flag signal is output; when the operating condition classification results are the same, the operating condition same flag signal is output.

3. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 2, characterized in that, In the operating condition identification step, the formula for calculating the comprehensive operating condition judgment index is as follows: ,in, This is a comprehensive working condition assessment index. This refers to the power fluctuation amplitude. The rated charge and discharge power of a GWh-level energy storage power station The amplitude weighting coefficient, with a value of 0.7, is determined based on historical statistical results of the power stability impact factors of GWh-level energy storage power stations. For spectral characteristic parameters, The spectral weighting coefficient, with a value of 0.3, is determined by the proportion of the impact of fluctuations in different frequency bands on the grid connection stability of energy storage power stations. The judgment threshold was determined by statistical analysis of historical operating data from GWh-level energy storage power stations. ,when When, it is determined to be a steady-state operating condition, when When the condition is determined to be a disturbance condition, the condition classification result is output when the results of three consecutive determinations are consistent.

4. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 1, characterized in that, In the switching buffer step, the operating condition classification result and the operating condition flag signal are received. When the operating condition flag signal is the same as the operating condition flag signal, the fixed control reference parameter corresponding to the current operating condition is directly output. The fixed control reference parameters for steady-state operating condition and disturbance operating condition are set separately through the grid-connected operation control standard of GWh-level energy storage power station. When the operating condition flag signal is the operating condition change flag signal, a transition process with a duration of 10s is started. During the transition, the transition control reference parameter is calculated by the S-shaped smooth transition formula for operating condition switching. After the transition process is completed, the fixed control reference parameter corresponding to the new operating condition is locked and output.

5. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 4, characterized in that, In the switching buffer step, the formula for the S-shaped smooth transition of the operating condition switching is: ,in, for Transition control reference parameters at time points, The fixed control reference parameters are those corresponding to the operating conditions before the switch. These are the fixed control reference parameters corresponding to the operating conditions after the switch. To buffer the total transition time, the grid-connected inertia constant of the GWh-level energy storage power station and the allowable fluctuation range of the grid connection point frequency are used. The runtime within the transition process, with a value range of [value missing]. .

6. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 1, characterized in that, In the safety domain matching step, when the operating condition classification result is a steady-state operating condition, the one-sided threshold of the steady-state power safety domain is calculated by the steady-state dynamic power safety domain threshold formula to generate a dynamic narrow threshold power safety domain. The upper limit of the safety domain is the sum of the average power of the current sliding time window and the one-sided threshold of the steady-state power safety domain, and the lower limit of the safety domain is the difference between the average power of the current sliding time window and the one-sided threshold of the steady-state power safety domain. When the operating condition classification result is a disturbance operating condition, a fixed wide threshold power safety domain is generated. The lower limit of the safety domain is 85% of the rated charge and discharge power of the GWh-level energy storage power station, and the upper limit of the safety domain is 115% of the rated charge and discharge power of the GWh-level energy storage power station.

7. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 6, characterized in that, In the security domain matching step, the steady-state dynamic power security domain threshold formula is: ,in, The one-sided threshold of the steady-state power safety region. This is the load factor correction factor, which is the ratio of the average power of the current sliding time window to the rated charge and discharge power of the GWh-level energy storage power station. The steady-state fluctuation allowable factor is set to 0.02, determined by the power deviation requirements of the grid-connected steady-state operation procedure for GWh-level energy storage power stations. This refers to the rated charging and discharging power of a GWh-level energy storage power station.

8. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 1, characterized in that, In the control execution steps, when the operating condition classification result is a steady-state operating condition, the power fluctuation signal at the grid connection point of the energy storage power station is divided into three independent frequency bands: 0.1-1Hz, 1-5Hz, and 5-10Hz. The filter coefficients for each frequency band are set according to the fixed control reference parameters, and the power fluctuation is filtered band by band in order from high frequency to low frequency. When the operating condition classification result is a disturbance operating condition, a parallel full-pass filter architecture is used to process the power fluctuation signal in the 0.01-100Hz full-band. The full-band filter gain is set according to the fixed control reference parameters, and the fluctuation components of all frequency bands are filtered synchronously. Finally, the initial filter control signal corresponding to the operating condition is generated, including the target power value after control and the filter execution parameters.

9. The method for smoothing out multi-band filtering and power safety domain self-protection according to claim 1, characterized in that, In the signal constraint output step, the adjusted power target value corresponding to the initial filter control signal is compared one by one with the upper and lower limits of the corresponding power safety domain. When the adjusted power target value is within the upper and lower limit range of the power safety domain, the initial filter control signal is directly retained. When the adjusted power target value exceeds the upper limit of the power safety domain, it is corrected to the upper limit of the corresponding safety domain. When the adjusted power target value is lower than the lower limit of the power safety domain, it is corrected to the lower limit of the corresponding safety domain. After completing the boundary verification and over-limit correction, the smoothing control signal is output.

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