A power fluctuation suppression method based on oscillation period determination and zero delay compensation

Abstract

This invention discloses a power fluctuation suppression method based on oscillation period measurement and zero-delay compensation. The method includes: acquiring voltage and current signals at the grid connection point of a renewable energy power plant; calculating instantaneous active power based on the voltage and current signals at the grid connection point of the renewable energy power plant; measuring the oscillation period of the instantaneous active power; obtaining the power value at the current moment and the historical power value half an oscillation period ago based on the measured oscillation period; and performing compensation calculations based on the power value at the current moment and the historical power value to obtain a stable power value after fluctuation suppression. This invention can effectively eliminate low-frequency oscillation components in the power signal and output a stable reference value without introducing any filtering delay, fundamentally solving the contradiction that traditional filtering methods cannot simultaneously meet the requirements of primary frequency modulation speed and low-frequency oscillation suppression.

Description

Technical Field

[0001] This invention relates to a power fluctuation suppression method based on oscillation period measurement and zero-delay compensation, belonging to the field of power system automation technology. Background Technology

[0002] The proportion of new energy power generation, such as wind power and photovoltaic power, is increasing. Numerous new energy bases have been built in Northwest my country and other regions. Due to the volatility and randomness of new energy sources, the power grid requires new energy power plants to have primary frequency regulation capabilities. This means that when the grid frequency deviates from the rated value of 50Hz, the active power can be rapidly adjusted within seconds to support grid stability. For example, it is required to see power changes within 1 second and adjust to 90% of the target value within 5 seconds.

[0003] Currently, most renewable energy power plants are equipped with primary frequency regulation systems. These systems collect electrical quantities at the grid connection point to calculate active power and system frequency. When the frequency exceeds the limit, the power generation of the entire power plant is adjusted according to a preset droop characteristic. However, renewable energy power plants are mostly located at the end of the grid, have small system short-circuit capacity, and use a large number of power electronic devices, which can easily trigger subsynchronous oscillations (frequency below 50Hz) or supersynchronous oscillations (frequency above 50Hz), resulting in periodic oscillations with large amplitudes in the active power of the transmission lines.

[0004] Existing primary frequency modulation (FM) systems often employ finite impulse response (FIR) low-pass filters to remove high-frequency noise from power signals. While FIR filters have short delays, effectively filtering low-frequency oscillations requires a very long order, resulting in significant filtering delays (typically exceeding one second), which fails to meet the speed requirements of primary FM. Therefore, current technology is often ineffective against low-frequency oscillations in power signals, causing the power reference value used by the primary FM system to fluctuate wildly during operation, severely impacting the accuracy and stability of regulation. Summary of the Invention

[0005] The purpose of this invention is to provide a power fluctuation suppression method based on oscillation period measurement and zero-delay compensation. By utilizing the periodic characteristics of oscillation, the stable component of power can be extracted through simple real-time calculation, fundamentally eliminating the phase lag and time delay caused by traditional digital filters, and fully meeting the requirements of fast control functions such as primary frequency modulation.

[0006] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution.

[0007] On one hand, the present invention provides a power fluctuation suppression method based on oscillation period measurement and zero-delay compensation, comprising:

[0008] Collect voltage and current signals at the grid connection points of new energy power plants;

[0009] Instantaneous active power is calculated based on the voltage and current signals at the grid connection point of the new energy power station;

[0010] The oscillation period of the instantaneous active power was determined by spectrum analysis;

[0011] Based on the measured oscillation period, obtain the power value at the current moment and the historical power value half an oscillation period ago;

[0012] Compensation calculations are performed based on the current power value and historical power values ​​to obtain a stable power value after suppressing fluctuations.

[0013] Furthermore, the specific method for calculating the instantaneous active power is as follows:

[0014] ;

[0015] in: Let be the instantaneous values ​​of the three-phase voltages at time t. , respectively, are the instantaneous values ​​of the three-phase current at time t.

[0016] Furthermore, the method for determining the oscillation period of the instantaneous active power is as follows:

[0017] The instantaneous active power sequence obtained by continuous sampling is preprocessed until the DC component is eliminated;

[0018] After windowing the instantaneous active power sequence, a fast Fourier transform is performed to convert the time-domain power signal to the frequency domain, thus obtaining the spectrum of the instantaneous active power sequence.

[0019] Power frequency and its harmonic components are excluded from the spectrum, and in the low-frequency band, the peak value of the spectrum with a significantly higher amplitude than the background noise is searched.

[0020] The frequency corresponding to the peak value with the largest amplitude is defined as the main oscillation frequency of the power oscillation. ;

[0021] Based on the main oscillation frequency The corresponding oscillation period T can be calculated using the following expression:

[0022] ;

[0023] in: For the oscillation period, The main oscillation frequency.

[0024] Furthermore, the calculation expression for the compensation is as follows:

[0025] ;

[0026] in: To stabilize the power value, The power value at the current moment. This represents the historical power value half a oscillation cycle ago.

[0027] Secondly, the present invention provides a power fluctuation suppression device based on oscillation period measurement and zero-delay compensation, comprising:

[0028] The current and voltage acquisition module is used to acquire voltage and current signals at the grid connection point of new energy power plants;

[0029] The instantaneous active power calculation module is used to calculate the instantaneous active power based on the voltage and current signals at the grid connection point of the new energy power station;

[0030] An oscillation period module is used to determine the oscillation period of the instantaneous active power through spectrum analysis;

[0031] The fluctuation suppression module is used to obtain the power value at the current moment and the historical power value half a oscillation period ago based on the measured oscillation period; and to perform compensation calculations based on the power value at the current moment and the historical power value to obtain a stable power value after fluctuation suppression.

[0032] Furthermore, the power fluctuation suppression device employs shared memory, and the instantaneous active power calculation module and the fluctuation suppression module interact with each other through the shared memory.

[0033] The shared memory defines structures for storing instantaneous active power data and status, with each structure stored sequentially within it; the access pointer of each structure points to the address of the first address of the shared memory plus the sum of the sizes of all structures preceding that structure.

[0034] Furthermore, the instantaneous active power calculation module reads the voltage and current sampling values ​​in real time, calculates the instantaneous active power value, and packages the instantaneous active power value with its timestamp and writes it into a structure in a predefined structured storage area in shared memory.

[0035] After being triggered at a set time, the fluctuation suppression module accesses the shared memory, locates and reads the historical power value from the storage area according to the number of sampling points corresponding to half an oscillation cycle, and performs compensation calculations to obtain the stable power value after fluctuation suppression.

[0036] Thirdly, the present invention provides a power fluctuation suppression system based on oscillation period measurement and zero-delay compensation, comprising:

[0037] Memory, used to store computer programs / instructions;

[0038] A processor is configured to execute the computer program / instructions to implement the steps of the power fluctuation suppression method based on oscillation period determination and zero delay compensation described above.

[0039] Fourthly, the present invention provides a computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, when the computer program / instructions are executed by a processor, they implement the steps of the above-described power fluctuation suppression method based on oscillation period determination and zero delay compensation.

[0040] Fifthly, the present invention provides a computer program product, including a computer program / instruction, characterized in that, when the computer program / instruction is executed by a processor, it implements the steps of the above-described power fluctuation suppression method based on oscillation period determination and zero delay compensation.

[0041] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0042] This invention extracts the stable power component by measuring and utilizing the periodic characteristics of oscillation in real time and using a "measurement period - real-time compensation" algorithm. It only needs to obtain the current value and the historical value half a cycle ago and perform an average calculation once. The process does not rely on future data and the calculation delay is extremely short. It fundamentally eliminates the inherent phase lag and time delay of traditional digital filters and fully meets the requirements of fast control functions such as primary frequency modulation.

[0043] This invention is applicable to scenarios with fixed oscillation frequencies caused by devices with fixed parameters. By accurately determining the period T through spectrum analysis and using the mathematical principle of averaging the half-cycle antiphase points, it can accurately cancel the oscillation components of that specific frequency and output a smooth and stable power reference.

[0044] The compensation algorithm of this invention only involves basic arithmetic operations, has a small computational load, and is easy to implement in embedded systems. Combined with a multi-core architecture that uses shared memory and structure pointer access, it achieves efficient and deterministic data interaction between the calculation module and the suppression module, ensuring the reliability of the system under high real-time requirements. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the process of the present invention;

[0046] Figure 2 This is a typical application architecture diagram of the present invention in a new energy power station;

[0047] Figure 3 This is a schematic diagram illustrating the data structure and management of shared memory in this invention;

[0048] Figure 4 This is a schematic diagram comparing the power reference values ​​of a primary frequency modulation system before and after using the method of the present invention. Detailed Implementation

[0049] It should be noted that:

[0050] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0051] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0052] Example 1

[0053] like Figure 1 One embodiment of the above provides a power fluctuation suppression method based on oscillation period measurement and zero-delay compensation, comprising:

[0054] Voltage and current signals at the grid connection point of new energy power plants are collected by connecting to an external PT / CT.

[0055] Instantaneous active power is calculated based on the voltage and current signals at the grid connection point of the new energy power station;

[0056] The oscillation period of the instantaneous active power was determined by spectrum analysis;

[0057] Based on the measured oscillation period, obtain the power value at the current moment and the historical power value half an oscillation period ago;

[0058] Compensation calculations are performed based on the current power value and historical power values ​​to obtain a stable power value after suppressing fluctuations.

[0059] The specific method for calculating the instantaneous active power is as follows:

[0060] ;

[0061] in: Let be the instantaneous values ​​of the three-phase voltages at time t. , respectively, are the instantaneous values ​​of the three-phase current at time t.

[0062] The method for determining the oscillation period of the instantaneous active power is as follows:

[0063] The instantaneous active power sequence obtained by continuous sampling is preprocessed to eliminate the DC component;

[0064] After windowing the instantaneous active power sequence, a fast Fourier transform is performed to convert the time-domain power signal to the frequency domain, thus obtaining the spectrum of the instantaneous active power sequence.

[0065] Power frequency and its harmonic components are excluded from the spectrum, and in the low-frequency band, the peak value of the spectrum with a significantly higher amplitude than the background noise is searched.

[0066] The frequency corresponding to the peak value with the largest amplitude is defined as the main oscillation frequency of the power oscillation. ;

[0067] Based on the main oscillation frequency The corresponding oscillation period T can be calculated using the following expression:

[0068] ;

[0069] in: For the oscillation period, The main oscillation frequency.

[0070] The calculation expression for the compensation is as follows:

[0071] ;

[0072] in: To stabilize the power value, The power value at the current moment. This represents the historical power value half a oscillation cycle ago.

[0073] Example 2

[0074] like Figure 2 The diagram shown illustrates a typical application architecture in a renewable energy power station. This embodiment provides a power fluctuation suppression device based on oscillation period measurement and zero-delay compensation, comprising:

[0075] The current and voltage acquisition module is used to acquire voltage and current signals at the grid connection point of new energy power plants by connecting to an external PT / CT.

[0076] The instantaneous active power calculation module is used to calculate the instantaneous active power based on the voltage and current signals at the grid connection point of the new energy power station;

[0077] An oscillation period module is used to determine the oscillation period of the instantaneous active power through spectrum analysis;

[0078] The fluctuation suppression module is used to obtain the power value at the current moment and the historical power value half a oscillation period ago based on the measured oscillation period; and to perform compensation calculations based on the power value at the current moment and the historical power value to obtain a stable power value after fluctuation suppression.

[0079] like Figure 3As shown, the power fluctuation suppression device uses shared memory, and the instantaneous active power calculation module and the fluctuation suppression module interact with each other through the shared memory;

[0080] The shared memory defines structures for storing instantaneous active power data and status. Each structure is stored in the shared memory in the order of sampling time. The access pointer of each structure points to the address of the first address of the shared memory plus the sum of the sizes of all the structures preceding it.

[0081] The instantaneous active power calculation module reads the voltage and current sampling values ​​in real time and calculates the instantaneous active power value. Instantaneous active power value It is packaged with its timestamp and written into a structure in a predefined structured storage area in shared memory;

[0082] The fluctuation suppression module accesses the shared memory after being triggered at a time, and locates and reads the historical power value from the storage area according to the number of sampling points corresponding to half an oscillation cycle. Then, compensation calculations are performed to obtain the stable power value after suppressing fluctuations.

[0083] like Figure 4 The waveform comparison shown illustrates that, without the method of this invention, the power reference value received by the primary frequency regulation system itself contains oscillations, causing fluctuations in both the regulation command and the actual power at the final grid connection point, resulting in poor control performance; while the stable power value obtained by applying this invention... This will serve as an accurate power reference, which will be sent to the primary frequency regulation system. This allows the primary frequency regulation system to issue adjustment commands based on a stable reference value, thereby significantly improving the control quality of the actual power at the grid connection point. This enables the system to quickly and smoothly track the target value, enhancing the stability and accuracy of the grid frequency support.

[0084] Example 3

[0085] This embodiment provides a power fluctuation suppression system based on oscillation period measurement and zero-delay compensation, including:

[0086] Memory, used to store computer programs / instructions;

[0087] A processor for executing the computer program / instructions to implement the steps of Embodiment 1.

[0088] Example 4

[0089] This embodiment provides a computer-readable storage medium storing a computer program / instructions thereon, characterized in that, when the computer program / instructions are executed by a processor, they implement the steps of Embodiment 1.

[0090] Example 5

[0091] This embodiment provides a computer program product, including a computer program / instructions, characterized in that the computer program / instructions, when executed by a processor, implement the steps of Embodiment 1.

[0092] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0093] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0094] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0095] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0096] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A power fluctuation suppression method based on oscillation period measurement and zero-delay compensation, characterized in that, include: Collect voltage and current signals at the grid connection points of new energy power plants; Instantaneous active power is calculated based on the voltage and current signals at the grid connection point of the new energy power station; The oscillation period of the instantaneous active power was determined by spectrum analysis; Based on the measured oscillation period, obtain the power value at the current moment and the historical power value half an oscillation period ago; Compensation calculations are performed based on the current power value and historical power values ​​to obtain a stable power value after suppressing fluctuations.

2. The power fluctuation suppression method based on oscillation period measurement and zero-delay compensation according to claim 1, characterized in that, The specific method for calculating the instantaneous active power is as follows: ； in: Let be the instantaneous values ​​of the three-phase voltages at time t. , respectively, are the instantaneous values ​​of the three-phase current at time t.

3. The power fluctuation suppression method based on oscillation period measurement and zero-delay compensation according to claim 1, characterized in that, The method for determining the oscillation period of the instantaneous active power is as follows: Preprocess the instantaneous active power sequence obtained by continuous sampling; After windowing the instantaneous active power sequence, a fast Fourier transform is performed to convert the time-domain power signal to the frequency domain, thus obtaining the spectrum of the instantaneous active power sequence. Power frequency and its harmonic components are excluded from the spectrum, and in the low-frequency band, the peak value of the spectrum with a significantly higher amplitude than the background noise is searched. The frequency corresponding to the peak value with the largest amplitude is defined as the main oscillation frequency of the power oscillation. ; Based on the main oscillation frequency The corresponding oscillation period T can be calculated using the following expression: ； in: For the oscillation period, The main oscillation frequency.

4. The power fluctuation suppression method based on oscillation period measurement and zero-delay compensation according to claim 1, characterized in that, The calculation expression for the compensation is as follows: ； in: To stabilize the power value, The power value at the current moment. This represents the historical power value half a oscillation cycle ago.

5. A power fluctuation suppression device based on oscillation period measurement and zero-delay compensation, characterized in that, include: The current and voltage acquisition module is used to acquire voltage and current signals at the grid connection point of new energy power plants; The instantaneous active power calculation module is used to calculate the instantaneous active power based on the voltage and current signals at the grid connection point of the new energy power station; An oscillation period module is used to determine the oscillation period of the instantaneous active power through spectrum analysis; The fluctuation suppression module is used to obtain the power value at the current moment and the historical power value half a oscillation period ago based on the measured oscillation period; and to perform compensation calculations based on the power value at the current moment and the historical power value to obtain a stable power value after fluctuation suppression.

6. The power fluctuation suppression device based on oscillation period measurement and zero-delay compensation according to claim 5, characterized in that, The power fluctuation suppression device uses shared memory, and the instantaneous active power calculation module and the fluctuation suppression module interact with each other through the shared memory. The shared memory defines structures for storing instantaneous active power data and status. Each structure is stored sequentially in the shared memory, and the access pointer of each structure points to the address of the first address of the shared memory plus the sum of the sizes of all the structures preceding that structure.

7. The power fluctuation suppression device based on oscillation period measurement and zero-delay compensation according to claim 6, characterized in that, The instantaneous active power calculation module reads the voltage and current sampling values ​​in real time and calculates the instantaneous active power value. Instantaneous active power value It is packaged with its timestamp and written into a structure in a predefined structured storage area in shared memory; After being triggered at a set time, the fluctuation suppression module accesses the shared memory, locates and reads the historical power value from the storage area according to the number of sampling points corresponding to half an oscillation cycle, and performs compensation calculations to obtain the stable power value after fluctuation suppression.

8. A power fluctuation suppression system based on oscillation period measurement and zero-delay compensation, characterized in that, include: Memory, used to store computer programs / instructions; A processor for executing the computer program / instructions to implement the steps of the power fluctuation suppression method based on oscillation period determination and zero delay compensation as described in any one of claims 1-4.

9. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the power fluctuation suppression method based on oscillation period determination and zero delay compensation as described in any one of claims 1-4.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the power fluctuation suppression method based on oscillation period determination and zero delay compensation as described in any one of claims 1-4.

Images