Distributed power grid dynamic frequency acquisition method and related device

Abstract

The invention belongs to the field of power system automation, and discloses a distributed power grid dynamic frequency acquisition method and a related device, and the method comprises the steps: obtaining a frequency measurement value sequence of each frequency measurement point; according to the frequency measurement value sequence of each frequency measurement point, a measurement point frequency center value sequence of each frequency measurement point is obtained based on differential operation and a preset frequency change threshold; obtaining a non-direct-current component sequence of the frequency measurement value sequence of each frequency measurement point according to the frequency measurement value sequence of each frequency measurement point, extracting a minimum direct-current component of each moment of all the frequency measurement points, and obtaining a regional frequency center value sequence according to the extracted minimum direct-current component; and performing weighted superposition on the measurement point frequency center value sequence of each frequency measurement point and the regional frequency center value sequence to obtain a dynamic frequency value sequence of each frequency measurement point. The method has the advantages of time domain change capture and global feature fusion, and greatly improves the real-time performance and accuracy of frequency measurement and the overall adaptability of the system.

Description

Technical Field

[0001] The present invention belongs to the field of power system automation and relates to a method for acquiring dynamic frequency of a distributed power grid and a related device. Background Art

[0002] With the rapid integration of high-proportion renewable energy and the accelerated advancement of large-scale DC transmission, the trend toward power electronics in power grids is becoming increasingly evident. This has led to a significant increase in disturbances such as harmonics, power oscillations, and sudden changes generated by various power electronic devices during operation and control, posing severe challenges to the safe and stable operation of the power grid. Against this backdrop, achieving high-precision and reliable measurement of power grid operating status has become a key technical issue that urgently needs to be addressed in order to strengthen the monitoring, analysis, and control of power grid dynamics and transient processes, deepen understanding of the characteristics of new power systems, and enhance understanding of the characteristics of these systems.

[0003] As a core physical quantity that reflects the supply and demand balance and operational stability of power systems, accurate measurement of grid frequency is of great significance for ensuring the safe operation of power systems, equipment protection, scientific dispatch, and market settlement. Existing grid frequency measurement methods are mostly based on signals under steady-state conditions and are primarily designed for steady-state and slowly changing signals. This makes it difficult to accurately and quickly respond to and reflect the frequency changes of synchronous quantities in distributed power grids under dynamic and transient conditions. Consequently, it is difficult to accurately and quickly reflect the actual state of the power grid under dynamic and transient conditions. Consequently, in key links such as rapid power flow analysis, wide-area synchronous perception, and real-time control, computational lags, insufficient measurement accuracy, and inaccurate determination of the system's dynamic center frequency often occur. Consequently, the applicability, accuracy, and data consistency of frequency measurement are significantly insufficient, making it difficult to meet the needs of new power systems for high-precision, real-time perception of operating status. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a method for obtaining dynamic frequency of a distributed power grid and related devices.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for acquiring dynamic frequency of a distributed power grid, comprising: acquiring a frequency measurement value sequence of each frequency measurement point of the distributed power grid; obtaining a measurement point frequency center value sequence of each frequency measurement point based on a differential operation and a preset frequency change threshold according to the frequency measurement value sequence of each frequency measurement point; obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point according to the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence according to the extracted minimum DC component; and weightedly superimposing the measurement point frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain a dynamic frequency value sequence of each frequency measurement point of the distributed power grid.

[0007] Optionally, obtaining the frequency center value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, based on a differential operation and a preset frequency change threshold, includes: performing a first-order differential operation on the frequency measurement value sequence of each frequency measurement point by the following formula to obtain the frequency change amount at each moment of each frequency measurement point:

[0008] df i (n) = f i (n)-f i (n-1)

[0009] Among them, df i (n) is the frequency change at the nth moment of frequency measurement point i; f i (n) is the frequency measurement value of the frequency measurement point i at the nth moment; f i (n-1) is the frequency measurement value at the n-1th moment of frequency measurement point i.

[0010] When the frequency variation of each frequency measurement point at the current moment satisfies the following formula, the frequency measurement value of each frequency measurement point at the current moment is taken as the time-varying center value of each frequency measurement point at the current moment:

[0011] df i (n-1)≤df i (n)≤df i (n+1) and |df i (n)|>l

[0012] Among them, df i (n-1) is the frequency change at the n-1th moment of frequency measurement point i; df i (n+1) is the frequency change at the (n+1)th moment of frequency measurement point i; l is the preset frequency change threshold.

[0013] All time-varying center values ​​of each frequency measurement point are obtained and a center value sequence is generated in sequence with time as the sequence order, and the center value sequence is interpolated according to a preset sequence time interval to obtain a measurement point frequency center value sequence of each frequency measurement point.

[0014] Optionally, interpolating the central value sequence according to a preset sequence time interval includes: interpolating the central value sequence according to the preset sequence time interval using a linear interpolation method or a spline interpolation method.

[0015] Optionally, the steps of obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence based on the extracted minimum DC component includes: extracting the non-DC component sequence of the frequency measurement value sequence of each frequency measurement point by the following formula:

[0016] f z,i (n) = IFFT[F i (k) × (1-δ(k))]

[0017] F i (k) = FFT[f i (n)]

[0018] Among them, f z,i (n) is the non-DC component at the nth moment of frequency measurement point i; F i (k) is f i The spectrum of (n); f i (n) is the frequency measurement value at the frequency measurement point i at the nth moment; δ(k) is the Dirac function, which is 1 when k is 0 and 0 otherwise; IFFT is the inverse fast Fourier transform; and FFT is the fast Fourier transform.

[0019] The minimum non-DC component at each moment of all frequency measurement points is extracted by the following formula:

[0020] f k (n) = min i∈{1,2,3,…,N} {f i (n)}

[0021] Where N is the number of frequency measurement points; f k (n) is the minimum non-DC component at the nth moment of all frequency measurement points.

[0022] According to the minimum DC component of all frequency measurement points at each moment, a sequence of regional frequency center values ​​is generated in sequence with the moments as the sequence.

[0023] Optionally, the step of weighting and superimposing the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid includes weighting and superimposing the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence using the following formula to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid:

[0024] f final,i (n) = a × f out,i (n)+(1-a)×f center (n)

[0025] Among them, f final,i (n) is the sequence value at the nth moment in the dynamic frequency value sequence of the frequency measurement point i; a is the preset weighting coefficient; f out,i (n) is the sequence value at the nth moment in the sequence of the frequency center value of the frequency measurement point i; f center (n) is the sequence value at the nth moment in the regional frequency center value sequence.

[0026] In a second aspect, the present invention provides a distributed power grid dynamic frequency acquisition system, comprising: a data acquisition module for acquiring a frequency measurement value sequence of each frequency measurement point of the distributed power grid; a measurement point frequency module for obtaining a measurement point frequency center value sequence of each frequency measurement point based on a differential operation and a preset frequency change threshold according to the frequency measurement value sequence of each frequency measurement point; a regional frequency module for obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point according to the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component of all frequency measurement points at each moment, and obtaining a regional frequency center value sequence based on the extracted minimum DC component; and a fusion module for weightedly superimposing the measurement point frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain a dynamic frequency value sequence of each frequency measurement point of the distributed power grid.

[0027] Optionally, obtaining the frequency center value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, based on a differential operation and a preset frequency change threshold, includes: performing a first-order differential operation on the frequency measurement value sequence of each frequency measurement point by the following formula to obtain the frequency change amount at each moment of each frequency measurement point:

[0028] df i (n) = f i (n)-f i (n-1)

[0029] Among them, df i (n) is the frequency change at the nth moment of frequency measurement point i; f i(n) is the frequency measurement value of the frequency measurement point i at the nth moment; f i (n-1) is the frequency measurement value at the n-1th moment of frequency measurement point i.

[0030] When the frequency variation of each frequency measurement point at the current moment satisfies the following formula, the frequency measurement value of each frequency measurement point at the current moment is taken as the time-varying center value of each frequency measurement point at the current moment:

[0031] df i (n-1)≤df i (n)≤df i (n+1) and |df i (n)|>l

[0032] Among them, df i (n-1) is the frequency change at the n-1th moment of frequency measurement point i; df i (n+1) is the frequency change at the (n+1)th moment of frequency measurement point i; l is the preset frequency change threshold.

[0033] All time-varying center values ​​of each frequency measurement point are obtained and a center value sequence is generated in sequence with time as the sequence order, and the center value sequence is interpolated according to a preset sequence time interval to obtain a measurement point frequency center value sequence of each frequency measurement point.

[0034] Optionally, the steps of obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence based on the extracted minimum DC component includes: extracting the non-DC component sequence of the frequency measurement value sequence of each frequency measurement point by the following formula:

[0035] f z,i (n) = IFFT[F i (k) × (1-δ(k))]

[0036] F i (k) = FFT[f i (n)]

[0037] Among them, f z,i (n) is the non-DC component at the nth moment of frequency measurement point i; F i (k) is f i The spectrum of (n); f i (n) is the frequency measurement value at the frequency measurement point i at the nth moment; δ(k) is the Dirac function, which is 1 when k is 0 and 0 otherwise; IFFT is the inverse fast Fourier transform; and FFT is the fast Fourier transform.

[0038] The minimum non-DC component at each moment of all frequency measurement points is extracted by the following formula:

[0039] f k (n) = min i∈{1,2,3,…,N} {f i (n)}

[0040] Where N is the number of frequency measurement points; f k (n) is the minimum non-DC component at the nth moment of all frequency measurement points.

[0041] According to the minimum DC component of all frequency measurement points at each moment, a sequence of regional frequency center values ​​is generated in sequence with the moments as the sequence.

[0042] According to a third aspect of the present invention, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for acquiring the dynamic frequency of a distributed power grid when executing the computer program.

[0043] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method for acquiring the dynamic frequency of a distributed power grid are implemented.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The distributed power grid dynamic frequency acquisition method of the present invention first obtains a frequency center value sequence of each frequency measurement point based on a differential operation and a preset frequency change threshold based on the frequency measurement value sequence of each frequency measurement point. This method can track subtle frequency changes in real time and identify and determine the time-varying center value of the power grid under dynamic and sudden operating conditions based on the set frequency change threshold. This effectively avoids the reliance of traditional frequency measurement methods on steady-state and slowly changing signals, and improves the response speed and determination accuracy of frequency anomalies under rapid disturbances and complex power grid operation. At the same time, based on the frequency measurement value sequence of each frequency measurement point, a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point is obtained, and the minimum DC component at each moment of all frequency measurement points is extracted. A regional frequency center value sequence is obtained based on the extracted minimum DC component. By searching the entire region for the minimum value as the regional frequency center value, the dynamic frequency characteristics of the entire power grid can be more comprehensively reflected, avoiding the one-sidedness and local anomaly effects brought about by single-point measurement. Compared with previous frequency detection methods that mainly rely on single-point measurement or steady-state averaging, the method of the present invention combines the advantages of time domain change capture and global feature fusion, greatly improving the real-time performance, accuracy and overall adaptability of frequency measurement, and providing more reliable and refined data support for the operation monitoring, dynamic control and abnormal warning of new power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart of a method for acquiring dynamic frequency of a distributed power grid according to an embodiment of the present invention.

[0047] Figure 2 This is a structural block diagram of a distributed power grid dynamic frequency acquisition system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0049] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0050] The present invention is described in further detail below with reference to the accompanying drawings:

[0051] See also Figure 1 In one embodiment of the present invention, a method for obtaining the dynamic frequency of a distributed power grid is provided, specifically a dynamic frequency fusion method suitable for synchronous measurement of a distributed power grid. By coordinating the frequency center value of the measurement point and the regional frequency center value, high-precision and high-reliability measurement of the power grid frequency is achieved.

[0052] Specifically, the distributed power grid dynamic frequency acquisition method of the present invention includes the following steps:

[0053] S1: Obtain a frequency measurement value sequence of each frequency measurement point of the distributed power grid.

[0054] S2: According to the frequency measurement value sequence of each frequency measurement point, based on a differential operation and a preset frequency change threshold, a measurement point frequency center value sequence of each frequency measurement point is obtained.

[0055] S3: According to the frequency measurement value sequence of each frequency measurement point, a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point is obtained, and the minimum DC component of all frequency measurement points at each moment is extracted, and a regional frequency center value sequence is obtained according to the extracted minimum DC component.

[0056] S4: performing weighted superposition of the frequency center value sequence of each frequency measurement point and the regional frequency center value sequence to obtain a dynamic frequency value sequence of each frequency measurement point of the distributed power grid.

[0057] The distributed power grid dynamic frequency acquisition method of the present invention first obtains a frequency center value sequence of each frequency measurement point based on a differential operation and a preset frequency change threshold based on the frequency measurement value sequence of each frequency measurement point. This method can track subtle frequency changes in real time and identify and determine the time-varying center value of the power grid under dynamic and sudden operating conditions based on the set frequency change threshold. This effectively avoids the reliance of traditional frequency measurement methods on steady-state and slowly changing signals, and improves the response speed and determination accuracy of frequency anomalies under rapid disturbances and complex power grid operation. At the same time, based on the frequency measurement value sequence of each frequency measurement point, a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point is obtained, and the minimum DC component at each moment of all frequency measurement points is extracted. A regional frequency center value sequence is obtained based on the extracted minimum DC component. By searching the entire region for the minimum value as the regional frequency center value, the dynamic frequency characteristics of the entire power grid can be more comprehensively reflected, avoiding the one-sidedness and local anomaly effects brought about by single-point measurement. Compared with previous frequency detection methods that mainly rely on single-point measurement or steady-state averaging, the method of the present invention combines the advantages of time domain change capture and global feature fusion, greatly improving the real-time performance, accuracy and overall adaptability of frequency measurement, and providing more reliable and refined data support for the operation monitoring, dynamic control and abnormal warning of new power systems.

[0058] In one possible implementation, obtaining a sequence of measurement point frequency center values ​​of each frequency measurement point based on a difference operation and a preset frequency change threshold according to a sequence of frequency measurement values ​​of each frequency measurement point includes performing a first-order difference operation on the sequence of frequency measurement values ​​of each frequency measurement point using the following formula to obtain a frequency change at each moment of each frequency measurement point:

[0059] df i (n) = f i (n)-f i (n-1)

[0060] Among them, df i (n) is the frequency change at the nth moment of frequency measurement point i; f i(n) is the frequency measurement value of the frequency measurement point i at the nth moment; f i (n-1) is the frequency measurement value at the n-1th moment of frequency measurement point i.

[0061] When the frequency variation of each frequency measurement point at the current moment satisfies the following formula, the frequency measurement value of each frequency measurement point at the current moment is taken as the time-varying center value of each frequency measurement point at the current moment:

[0062] df i (n-1)≤df i (n)≤df i (n+1) and |df i (n)|>l

[0063] Among them, df i (n-1) is the frequency change at the n-1th moment of frequency measurement point i; df i (n+1) is the frequency change at the (n+1)th moment of frequency measurement point i; l is the preset frequency change threshold.

[0064] All time-varying center values ​​of each frequency measurement point are obtained and a center value sequence is generated in sequence with time as the sequence order, and the center value sequence is interpolated according to a preset sequence time interval to obtain a measurement point frequency center value sequence of each frequency measurement point.

[0065] Interpretatively, frequency change inflection points are identified by tracking the frequency change trend in real time. A preset frequency change threshold is used to filter out minor fluctuations, ensuring that only significant frequency change points are captured. Once a frequency change point is identified, the frequency measurement value at that point is recorded as the time-varying center value.

[0066] Obtain all time-varying center values ​​at each frequency measurement point and generate a center value sequence using time as a sequence order. Then, interpolate the center value sequence according to a preset sequence time interval. The preset sequence time interval can be the same sequence time interval for the entire center value sequence, or it can be designed to have multiple sequence time intervals for the entire center value sequence, such as designing a separate interval time for each sequence interval as the sequence time interval.

[0067] In a possible implementation, interpolating the central value sequence according to a preset sequence time interval includes: interpolating the central value sequence using a linear interpolation method or a spline interpolation method according to the preset sequence time interval.

[0068] Explanatory, linear interpolation fills in data by constructing straight line segments between adjacent center values. For any point to be interpolated, the position and value of the two nearest known center values ​​are used to proportionally calculate the interpolation result. This process is simple and intuitive, with minimal computational effort. Spline interpolation divides the entire sequence of center values ​​into multiple small intervals, constructing a low-degree polynomial within each interval. The polynomial coefficients are determined by satisfying conditions such as continuity and smoothness at the endpoints of the interval, resulting in an interpolation result with a smooth interpolation curve.

[0069] Interpolation based on preset sequence time intervals can unify the data time scale, so that the central values ​​at different times can be arranged in order at fixed intervals, meeting the requirements of data standardization for subsequent analysis; linear interpolation calculation is efficient and suitable for scenarios with high real-time requirements and general accuracy requirements; spline interpolation can better fit data change trends, reduce interpolation errors, and provide a more accurate data basis for algorithms that need to restore the dynamic changes of central values ​​with high precision.

[0070] In one possible implementation, obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence based on the extracted minimum DC component includes: extracting the non-DC component sequence of the frequency measurement value sequence of each frequency measurement point using the following formula:

[0071] f z,i (n) = IFFT[F i (k) × (1-δ(k))]

[0072] F i (k) = FFT[f i (n)]

[0073] Among them, f z,i (n) is the non-DC component at the nth moment of frequency measurement point i; F i (k) is f i The spectrum of (n); f i (n) is the frequency measurement value at the frequency measurement point i at the nth moment; δ(k) is the Dirac function, which is 1 when k is 0 and 0 otherwise; IFFT is the inverse fast Fourier transform; and FFT is the fast Fourier transform.

[0074] The minimum non-DC component at each moment of all frequency measurement points is extracted by the following formula:

[0075] f k (n) = min i∈{1,2,3,…,N} {f i (n)}

[0076] Where N is the number of frequency measurement points; f k (n) is the minimum non-DC component at the nth moment of all frequency measurement points.

[0077] According to the minimum DC component of all frequency measurement points at each moment, a sequence of regional frequency center values ​​is generated in sequence with the moments as the sequence.

[0078] Explanatory, the DC component is removed by using the Dirac function. In addition, by comprehensively searching for the minimum value of the non-DC component at each moment as the regional frequency center value, the dynamic frequency characteristics of the entire power grid can be more comprehensively reflected, avoiding the one-sidedness and local anomaly caused by single measurement point measurement.

[0079] In one possible implementation, weighted superposition of the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid includes weighted superposition of the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence using the following formula to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid:

[0080] f final,i (n) = a × f out,i (n)+(1-a)×f center (n)

[0081] Among them, f final,i (n) is the sequence value at the nth moment in the dynamic frequency value sequence of the frequency measurement point i; a is the preset weighting coefficient; f out,i (n) is the sequence value at the nth moment in the sequence of the frequency center value of the frequency measurement point i; f center (n) is the sequence value at the nth moment in the regional frequency center value sequence.

[0082] Explanatory, preset weighting coefficients can be dynamically adjusted based on actual application scenarios and data quality to optimize the accuracy and responsiveness of dynamic frequency values. Based on the dynamic frequency value sequence obtained above, it can effectively capture the dynamic changes in grid frequency, and improve response speed while ensuring measurement accuracy, providing strong data support for the operation monitoring, dynamic control, and abnormal warning of distributed complex power grids.

[0083] In one possible implementation, a distributed power grid consists of eight 500kV substations, each equipped with a measurement and control device capable of time synchronization and frequency measurement. Each device collects local frequency data in real time and reports the current frequency measurement value to the dispatch master station via the dispatch data network every 10ms. Each station can collect 100 precise measurement messages per second. For statistical analysis purposes, all measurement messages are time-stamped at the top of each second and numbered in the order of arrival.

[0084] At the dispatching master station, based on the distributed power grid dynamic frequency acquisition method of the present invention, firstly, a first-order difference is performed on the frequency measurement value sequence uploaded by each substation to identify significant mutation points, and a more delicate continuous wide-area frequency change trend, i.e., a sequence of frequency center values ​​of the measurement points, is obtained through time interpolation. At the same time, a fast Fourier transform is performed on the frequency measurement value sequence of each frequency measurement point, and the non-DC components in the frequency measurement value sequence of each frequency measurement point are extracted in sequence, and then the minimum component is selected along the column (i.e., different stations at the same time) as the regional frequency center value. For example, all reported frequency measurement values ​​can be differentiated from the current dynamic frequency value in real time. If the difference is greater than ±0.005Hz, an alarm prompt of the central platform is automatically triggered, prompting the power grid monitoring personnel to pay attention to the abnormal frequency distribution. For example, each substation data communication gateway can also monitor the local frequency change rate in real time. If the frequency change rate exceeds the specified threshold or the measured frequency measurement value deviates from the dynamic frequency value by more than 0.1Hz, the device will issue an abnormal alarm locally and send it to the dispatching master station.

[0085] This monitoring and calculation method ensures the accuracy of global frequency perception under complex operation and high-fluctuation conditions, and improves the dynamic stability and emergency response capabilities of the power grid.

[0086] The following are device embodiments of the present invention, which can be used to perform the method embodiments of the present invention. For details not disclosed in the device embodiments, please refer to the method embodiments of the present invention.

[0087] See also Figure 2 In another embodiment of the present invention, a distributed power grid dynamic frequency acquisition system is provided, which can be used to implement the above-mentioned distributed power grid dynamic frequency acquisition method. Specifically, the distributed power grid dynamic frequency acquisition system includes a data acquisition module, a measurement point frequency module, a regional frequency module and a fusion module.

[0088] Among them, the data acquisition module is used to obtain the frequency measurement value sequence of each frequency measurement point of the distributed power grid; the measurement point frequency module is used to obtain the measurement point frequency center value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, based on differential operation and a preset frequency change threshold; the regional frequency module is used to obtain the non-DC component sequence of the frequency measurement value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, and extract the minimum DC component of all frequency measurement points at each moment, and obtain the regional frequency center value sequence based on the extracted minimum DC component; the fusion module is used to weightedly superimpose the measurement point frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid.

[0089] In one possible implementation, obtaining a sequence of measurement point frequency center values ​​of each frequency measurement point based on a difference operation and a preset frequency change threshold according to a sequence of frequency measurement values ​​of each frequency measurement point includes performing a first-order difference operation on the sequence of frequency measurement values ​​of each frequency measurement point using the following formula to obtain a frequency change at each moment of each frequency measurement point:

[0090] df i (n) = f i (n)-f i (n-1)

[0091] Among them, df i (n) is the frequency change at the nth moment of frequency measurement point i; f i (n) is the frequency measurement value of the frequency measurement point i at the nth moment; f i (n-1) is the frequency measurement value at the n-1th moment of frequency measurement point i.

[0092] When the frequency variation of each frequency measurement point at the current moment satisfies the following formula, the frequency measurement value of each frequency measurement point at the current moment is taken as the time-varying center value of each frequency measurement point at the current moment:

[0093] df i (n-1)≤df i (n)≤df i (n+1) and |df i (n)|>l

[0094] Among them, df i (n-1) is the frequency change at the n-1th moment of frequency measurement point i; df i (n+1) is the frequency change at the (n+1)th moment of frequency measurement point i; l is the preset frequency change threshold.

[0095] All time-varying center values ​​of each frequency measurement point are obtained and a center value sequence is generated in sequence with time as the sequence order, and the center value sequence is interpolated according to a preset sequence time interval to obtain a measurement point frequency center value sequence of each frequency measurement point.

[0096] In a possible implementation, interpolating the central value sequence according to a preset sequence time interval includes: interpolating the central value sequence using a linear interpolation method or a spline interpolation method according to the preset sequence time interval.

[0097] In one possible implementation, obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence based on the extracted minimum DC component includes: extracting the non-DC component sequence of the frequency measurement value sequence of each frequency measurement point using the following formula:

[0098] f z,i (n) = IFFT[F i (k) × (1-δ(k))]

[0099] F i (k) = FFT[f i (n)]

[0100] Among them, f z,i (n) is the non-DC component at the nth moment of frequency measurement point i; F i (k) is f i The spectrum of (n); f i (n) is the frequency measurement value at the frequency measurement point i at the nth moment; δ(k) is the Dirac function, which is 1 when k is 0 and 0 otherwise; IFFT is the inverse fast Fourier transform; and FFT is the fast Fourier transform.

[0101] The minimum non-DC component at each moment of all frequency measurement points is extracted by the following formula:

[0102] f k (n) = min i∈{1,2,3,…,N} {f i (n)}

[0103] Where N is the number of frequency measurement points; f k (n) is the minimum non-DC component at the nth moment of all frequency measurement points.

[0104] According to the minimum DC component of all frequency measurement points at each moment, a sequence of regional frequency center values ​​is generated in sequence with the moments as the sequence.

[0105] In one possible implementation, weighted superposition of the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid includes weighted superposition of the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence using the following formula to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid:

[0106] f final,i (n) = a × f out,i (n)+(1-a)×f center (n)

[0107] Among them, f final,i (n) is the sequence value at the nth moment in the dynamic frequency value sequence of the frequency measurement point i; a is the preset weighting coefficient; f out,i (n) is the sequence value at the nth moment in the sequence of the frequency center value of the frequency measurement point i; f center (n) is the sequence value at the nth moment in the regional frequency center value sequence.

[0108] All relevant contents of each step involved in the embodiment of the above-mentioned distributed power grid dynamic frequency acquisition method can be referred to the functional description of the corresponding functional modules of the distributed power grid dynamic frequency acquisition system in the embodiment of the present invention, and will not be repeated here.

[0109] The module division in the embodiments of the present invention is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in various embodiments of the present invention may be integrated into a single processor, exist physically as separate modules, or two or more modules may be integrated into a single module. The integrated modules may be implemented in either hardware or software functional modules.

[0110] In another embodiment of the present invention, a computer device is provided, comprising a processor and a memory, wherein the memory is configured to store a computer program, the computer program including program instructions, and the processor is configured to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions, specifically for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function. The processor described in the embodiment of the present invention can be used for the operation of the distributed power grid dynamic frequency acquisition method.

[0111] In another embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in a computer device, used to store programs and data. It is understood that the computer-readable storage medium herein may include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides storage space, which stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for being loaded and executed by a processor. These instructions may be one or more computer programs (including program code). It should be noted that the computer-readable storage medium herein may be a high-speed RAM memory or a non-volatile memory, such as at least one disk storage device. The processor may load and execute the one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the distributed power grid dynamic frequency acquisition method in the above-mentioned embodiment.

[0112] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0113] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0114] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0115] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for obtaining dynamic frequency of a distributed power grid, characterized in that: include: Obtaining a frequency measurement value sequence of each frequency measurement point of the distributed power grid; According to the frequency measurement value sequence of each frequency measurement point, based on the differential operation and the preset frequency change threshold, a measurement point frequency center value sequence of each frequency measurement point is obtained; Obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point according to the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence according to the extracted minimum DC component; The frequency center value sequence of each frequency measurement point is weightedly superimposed with the regional frequency center value sequence to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid.

2. The method for obtaining dynamic frequency of a distributed power grid according to claim 1, wherein: The step of obtaining a frequency center value sequence of each frequency measurement point based on a frequency measurement value sequence of each frequency measurement point and a differential operation and a preset frequency change threshold comprises: Perform the first-order difference operation on the frequency measurement value sequence of each frequency measurement point through the following formula to obtain the frequency change at each time of each frequency measurement point: df i (n)=f i (n)-f i (n-1) Among them, df i (n) is the frequency change at the nth moment of frequency measurement point i; f i (n) is the frequency measurement value of the frequency measurement point i at the nth moment; f i (n-1) is the frequency measurement value of frequency measurement point i at the n-1th moment; When the frequency variation of each frequency measurement point at the current moment satisfies the following formula, the frequency measurement value of each frequency measurement point at the current moment is taken as the time-varying center value of each frequency measurement point at the current moment: df i (n - 1) ≤ df i (n) ≤ df i (n + 1) and |df i (n)| > l Among them, df i (n-1) is the frequency change at the n-1th moment of frequency measurement point i; df i (n+1) is the frequency change at the n+1th moment of frequency measurement point i; l is the preset frequency change threshold; All time-varying center values ​​of each frequency measurement point are obtained and a center value sequence is generated in sequence with time as the sequence order, and the center value sequence is interpolated according to a preset sequence time interval to obtain a measurement point frequency center value sequence of each frequency measurement point.

3. The method for obtaining dynamic frequency of a distributed power grid according to claim 2, characterized in that: The interpolating the central value sequence according to the preset sequence time interval includes: interpolating the central value sequence according to the preset sequence time interval using a linear interpolation method or a spline interpolation method.

4. The method for obtaining dynamic frequency of a distributed power grid according to claim 1, wherein: The steps of obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point according to the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence according to the extracted minimum DC component include: The non-DC component sequence of the frequency measurement value sequence at each frequency measurement point is extracted by the following formula: f z,i (n)=IFFT[F i (k)×(1-δ(k))] F i (k)=FFT[f i (n)] Among them, f z,i (n) is the non-DC component at the nth moment of frequency measurement point i; F i (k) is f i The spectrum of (n); f i (n) is the frequency measurement value at the frequency measurement point i at the nth moment; δ(k) is the Dirac function, which is 1 when k is 0 and 0 otherwise; IFFT is the inverse fast Fourier transform; FFT is the fast Fourier transform; The minimum non-DC component at each moment of all frequency measurement points is extracted by the following formula: f k (n)=min i∈{1,2,3,…,N} {f i (n)} Where N is the number of frequency measurement points; f k (n) is the minimum non-DC component at the nth moment of all frequency measurement points; According to the minimum DC component of all frequency measurement points at each moment, a sequence of regional frequency center values ​​is generated in sequence with the moments as the sequence.

5. The method for obtaining dynamic frequency of a distributed power grid according to claim 1, wherein: The step of weighting and superimposing the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain the dynamic frequency value sequence of each frequency measurement point in the distributed power grid includes: The frequency center value sequence of each frequency measurement point is weightedly superimposed with the regional frequency center value sequence using the following formula to obtain the dynamic frequency value sequence of each frequency measurement point in the distributed power grid: f final,i (n)=a×f out,i (n)+(1-a)×f center (n) Among them, f final,i (n) is the sequence value at the nth moment in the dynamic frequency value sequence of the frequency measurement point i; a is the preset weighting coefficient; f out,i (n) is the sequence value at the nth moment in the sequence of the frequency center value of the frequency measurement point i; f center (n) is the sequence value at the nth moment in the regional frequency center value sequence.

6. A distributed power grid dynamic frequency acquisition system, characterized in that: include: A data acquisition module, used to obtain a frequency measurement value sequence of each frequency measurement point of the distributed power grid; The measurement point frequency module is used to obtain the measurement point frequency center value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, based on the differential operation and the preset frequency change threshold; A regional frequency module is used to obtain a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point based on the frequency measurement value sequence of each frequency measurement point, extract the minimum DC component at each moment of all frequency measurement points, and obtain a regional frequency center value sequence based on the extracted minimum DC component; The fusion module is used to weightedly superimpose the frequency center value sequence of each frequency measurement point with the regional frequency center value sequence to obtain the dynamic frequency value sequence of each frequency measurement point of the distributed power grid.

7. The distributed power grid dynamic frequency acquisition system according to claim 6, characterized in that: The step of obtaining a frequency center value sequence of each frequency measurement point based on a frequency measurement value sequence of each frequency measurement point and a differential operation and a preset frequency change threshold comprises: Perform the first-order difference operation on the frequency measurement value sequence of each frequency measurement point through the following formula to obtain the frequency change at each time of each frequency measurement point: df i (n)=f i (n)-f i (n-1) Among them, df i (n) is the frequency change at the nth moment of frequency measurement point i; f i (n) is the frequency measurement value of the frequency measurement point i at the nth moment; f i (n-1) is the frequency measurement value of frequency measurement point i at the n-1th moment; When the frequency variation of each frequency measurement point at the current moment satisfies the following formula, the frequency measurement value of each frequency measurement point at the current moment is taken as the time-varying center value of each frequency measurement point at the current moment: df i (n - 1) ≤ df i (n) ≤ df i (n + 1) and |df i (n)| > l Among them, df i (n-1) is the frequency change at the n-1th moment of frequency measurement point i; df i (n+1) is the frequency change at the n+1th moment of frequency measurement point i; l is the preset frequency change threshold; All time-varying center values ​​of each frequency measurement point are obtained and a center value sequence is generated in sequence with time as the sequence order, and the center value sequence is interpolated according to a preset sequence time interval to obtain a measurement point frequency center value sequence of each frequency measurement point.

8. The distributed power grid dynamic frequency acquisition system according to claim 6, characterized in that: The steps of obtaining a non-DC component sequence of the frequency measurement value sequence of each frequency measurement point according to the frequency measurement value sequence of each frequency measurement point, extracting the minimum DC component at each moment of all frequency measurement points, and obtaining a regional frequency center value sequence according to the extracted minimum DC component include: The non-DC component sequence of the frequency measurement value sequence at each frequency measurement point is extracted by the following formula: f z,i (n)=IFFT[F i (k)×(1-δ(k))] F i (k)=FFT[f i (n)] Among them, f z,i (n) is the non-DC component at the nth moment of frequency measurement point i; F i (k) is f i The spectrum of (n); f i (n) is the frequency measurement value at the frequency measurement point i at the nth moment; δ(k) is the Dirac function, which is 1 when k is 0 and 0 otherwise; IFFT is the inverse fast Fourier transform; FFT is the fast Fourier transform; The minimum non-DC component at each moment of all frequency measurement points is extracted by the following formula: f k (n)=min i∈{1,2,3,…,N} {f i (n)} Where N is the number of frequency measurement points; f k (n) is the minimum non-DC component at the nth moment of all frequency measurement points; According to the minimum DC component of all frequency measurement points at each moment, a sequence of regional frequency center values ​​is generated in sequence with the moments as the sequence.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method for acquiring dynamic frequency of a distributed power grid as claimed in any one of claims 1 to 5 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for acquiring dynamic frequency of a distributed power grid as claimed in any one of claims 1 to 5 are implemented.

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