Synchronous phasor measurement method adopting CIC compensation filtering and related device

Abstract

The invention discloses a synchronous phasor measurement method adopting CIC compensation filtering and a related device, and the method comprises the steps: carrying out the equal-time-interval sampling of an AC signal, obtaining a sampling sequence, carrying out the coordinate transformation of the sampling sequence, and constructing an original phasor through the coordinate transformation result; performing cascade integrator comb filtering on the original phasor to obtain a downsampled phasor result sequence; filtering the downsampling result phasor sequence by using a compensation filter to obtain a compensation filtering result sequence; and calculating the amplitude, phase angle, frequency and frequency change rate measurement value of the synchronous phasor according to the compensation filtering result sequence. The method and the related device can accurately measure the synchronous phasor, the frequency and the frequency change rate of the power system under the steady and dynamic conditions.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology for power automation systems, and relates to a synchronous phasor measurement method and related devices using a cascaded integrator-comb filter (CIC). Background Technology

[0002] Synchronous phasor measurement technology is an important means of monitoring the operating status of power systems. IEEE std 1344-1995 first defined synchronous phasor measurements at the standard level. Through several iterations of the IEEE std C37.118 and IEC / IEEE 60255-118 standards, the definition of synchronous phasor measurements has been expanded from steady-state signals to dynamic signals. Currently, the definition of synchronous phasor measurements comprehensively covers the amplitude, phase angle, frequency, and rate of change of the symmetrical components of power frequency (rated frequency 50Hz or 60Hz) voltage, current, and their three-phase systems. Related standards comprehensively provide requirements for steady-state and dynamic measurement accuracy performance indicators and transient step response performance indicators.

[0003] Synchronization phasors are frequency domain vectors expressed in polar or rectangular coordinates. To convert time-domain sampled data of power frequency voltage or current signals into frequency domain vectors, a Directional Fourier Transform (DFT) is required. The DFT is a bandpass filter; when the signal deviates from the center frequency of the DFT, amplitude attenuation and spectral leakage occur, leading to measurement errors. To improve the accuracy of synchronization phasor measurements under frequency offset conditions, industry professionals and engineers have conducted extensive research, including calculating and correcting analytical spectral leakage terms using multi-point DFT results, recovering synchronization phasor amplitude attenuation based on DFT amplitude-frequency characteristics and signal frequency (offset) measurements, and standards such as IEEE 60255-118 (GB / T 14598.118) also provide informative algorithms for correcting synchronization phasor amplitudes based on frequency variables and amplitude-frequency characteristics. These methods have achieved good results when processing steady-state single-frequency signals. However, correcting amplitude based on the correspondence between amplitude-frequency characteristics and signal frequency has inherent flaws. For example, for amplitude-modulated signals, the amplitude varies over time while the frequency remains constant. Obviously, the correction amount corresponding to a constant frequency is constant and cannot correct for varying amplitudes. Similarly, for frequency- or phase-modulated signals, the frequency fluctuates while the amplitude remains constant. The varying frequency corresponds to a varying amplitude correction amount, introducing unwanted amplitude errors. Therefore, the problem of low accuracy in phasor and frequency measurements under dynamic conditions has been a hot research topic in the industry, but it has not yet been substantially resolved. Relevant standards have increased the error limits under dynamic conditions by 1-2 orders of magnitude compared to steady-state conditions.

[0004] Some literature has proposed methods based on Taylor series expansion, Kalman filtering, matrix bundles, and rotation invariance techniques to improve the accuracy of synchronous phasor measurement, but the effects are limited and the calculations are very complex, making it difficult to implement in embedded power measurement devices. In recent years, some literature has designed and adopted a method for extracting synchronous phasors based on real-time sampling using complex coefficient bandpass filters. The core idea is to treat the time-domain signal as two conjugate phasors with opposite rotation directions in the frequency domain based on Euler transform. By filtering out the phasor rotating in the clockwise direction, the synchronous phasor is obtained. Since complex coefficient bandpass filters can be designed to have flat passband characteristics, the measurement error introduced by the amplitude-frequency characteristics of DFT under frequency offset is avoided, thus achieving good dynamic measurement accuracy. However, this also weakens the natural anti-harmonic interference advantage of DFT. Its application in the measurement of "high-harmonic and high-frequency" power systems remains to be discussed.

[0005] Finite Impulse Response (FIR) filters, also known as non-recursive filters, are fundamental components in digital signal processing systems. They can guarantee arbitrary amplitude-frequency characteristics while maintaining strictly linear phase-frequency characteristics. Furthermore, their unit sample response is finite, making the filter a stable system. FIR filters have wide applications in communication, image processing, and pattern recognition. FIR filters are also essential components for synchronous phasor measurement processing. The DFT transform and complex coefficient bandpass filters mentioned above are essentially FIR filters. Even when using algorithms based on Taylor series expansion, Kalman filtering, matrix beaming, and rotation invariance techniques for synchronous phasor measurement processing, FIR digital filters are still required to reduce computational load and ensure linear phase. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and related device for measuring synchronous phasors using CIC compensation filtering. This method and related device can accurately measure the synchronous phasors, frequency, and frequency change rate of a power system.

[0007] To achieve the above objectives, this invention discloses a synchronous phasor measurement method employing CIC compensation filtering, comprising: The AC signal is sampled at equal time intervals to obtain a sampling sequence. The sampling sequence is then subjected to coordinate transformation, and the original phasor is constructed using the result of the coordinate transformation. The original phasors are subjected to cascaded integral comb filtering to obtain a downsampled phasor result sequence; The downsampled phasor result sequence is then subjected to a compensation filter to obtain the compensated filtered result sequence. The amplitude, phase angle, frequency, and frequency change rate of the synchronous phasor are calculated based on the result sequence of the compensation filtering.

[0008] Furthermore, the coefficient sequence of the coordinate transformation for:

[0009] The original phasor The sampling sequence and Multiplying yields a phasor transformed to a coordinate system rotating at the rated frequency of the power system, where the phasor includes... and They are respectively:

[0010]

[0011] in, , and , Based on the sampling sequences of phases A, B, and C , , , , and The calculated d and q component sequences of voltage and current are as follows:

[0012]

[0013]

[0014]

[0015] in, The rated frequency of the power system, serial number The sampling time is aligned with the Coordinated Universal Time (UTC) integer second. , This represents the number of sampling points per second, and its value is equal to the sampling frequency. .

[0016] Furthermore, the process of performing cascaded integral comb filtering on the original phasor to obtain the downsampled result sequence is as follows: For the original phasor A cascaded integral comb filter is performed to obtain the downsampled result sequence.

[0017] Furthermore, the downsampled result sequence is subjected to a compensation filter to obtain the compensation filter result. In this process, the compensation filter is a compensation filter matched with the cascaded integrator-comb filter. The passband characteristics satisfy:

[0018] The result of the compensation filtering for:

[0019] in, This is the frequency offset. For the cascaded integral comb filter, The number of phasor sequence points in the integral comb filter data window. To compensate for the filter bandwidth control parameters, To compensate for the unit impulse response of the filter, This represents the number of points in the sequence.

[0020] Furthermore, the calculation method for the synchronization phasor is as follows:

[0021]

[0022] in, Phasor amplitude; The phase angle is the phasor angle.

[0023] Furthermore, the frequency measurement value for:

[0024]

[0025] in, for and The time interval, for and The phase angle difference, The rated frequency of the power system.

[0026] Furthermore, the frequency change rate for:

[0027] Compensation filter The passband characteristics are:

[0028] in, Indicates the length of the compensation filter. The sequence of cascaded comb filter results representing the rate of frequency change. The oscillation frequency, representing the phase angle or frequency, The number of points in the frequency change rate integral comb filter data window. for Bandwidth control parameters.

[0029] This invention discloses a synchronous phasor measurement system employing CIC compensation filtering, characterized in that it comprises: The phasor construction module is used to sample the AC signal at equal time intervals to obtain a sampling sequence, perform coordinate transformation on the sampling sequence, and use the result of the coordinate transformation to construct the original phasor. A cascaded integral comb filter module is used to perform cascaded integral comb filtering on the original phasors to obtain a downsampled phasor result sequence; The compensation filtering module is used to perform compensation filtering on the downsampled phasor result sequence using a cascaded integral comb filter matched with a compensation filter, to obtain the compensation filtered result sequence. The calculation module is used to calculate the amplitude and phase angle, frequency, and frequency change rate measurement of the synchronization phasor based on the result sequence of the compensation filtering.

[0030] The present invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the synchronous phasor measurement method using CIC compensation filtering.

[0031] The present invention discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the synchronous phasor measurement method using CIC compensation filtering.

[0032] The present invention has the following beneficial effects: The synchronous phasor measurement method and related device using CIC compensation filtering described in this invention, in specific operation, performs equal-interval sampling of AC signals to obtain a sampling sequence, performs coordinate transformation on the sampling sequence, constructs the original phasor using the result of the coordinate transformation, and then performs cascaded integral comb filtering and compensation filtering. The compensation filtering solves the mechanistic error problem of synchronous phasor amplitude in signals with no or weak correlation between amplitude fluctuation and frequency fluctuation based on frequency measurement values. The accuracy of amplitude, phase angle, frequency and frequency change rate of dynamic time-varying signals is improved by 1 to 2 orders of magnitude compared with the standard requirements. At the same time, it eliminates the influence of DFT spectrum leakage on frequency measurement accuracy under non-positive periodic sampling conditions, thereby accurately measuring the phasor, frequency and frequency change rate of power systems, and is extremely practical. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a system structure diagram of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0037] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0038] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0039] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0040] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0042] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0043] Example 1 refer to Figure 1 The synchronous phasor measurement method using CIC compensation filtering described in this invention includes the following steps: 1) Perform coordinate transformation on the sampled values ​​to construct the original phasor; The specific operation of step 1) is as follows: 11) Set the sampling frequency to The AC signal is sampled at equal intervals, with a sampling time interval of . , The sampling sequences of the three-phase voltages and three-phase currents Ua, Ub, Uc, Ia, Ib, and Ic are obtained as follows: Serial Number The sampling time is aligned with the Coordinated Universal Time (UTC) whole second. , The number of sampling points per second, the value is equal to .

[0044] 12) Calculate the coordinate transformation coefficient sequence for:

[0045] in, The rated frequency for the power system is 50Hz or 60Hz.

[0046] 13) Take the sampling sequences of the three-phase voltages and three-phase currents Ua, Ub, Uc, Ia, Ib, and Ic obtained in step 1). respectively with the coordinate transformation coefficient sequence Multiplying them yields the original phasor sequence. for:

[0047] Where Y represents phase.

[0048] 14) For a three-phase system, utilize the original phasor sequence of voltage and current. , , , , , Calculate the original phasor sequence of positive sequence voltage and current. and for:

[0049]

[0050] 15) Based on the sampling sequences of phases A, B, and C , , , , and Calculate the d and q component sequences of voltage and current. , and , And use this to construct the original phasor , Including d and q components and ;

[0051]

[0052]

[0053]

[0054]

[0055]

[0056] 2) For the original phasor Perform cascaded integral comb filtering; The specific process of step 2) is as follows: 21) Select the data window length for integral comb filtering. Synchronous phasor decimation (calculation and output) frequency Typical values ​​for m are 2, 1, and 0.5. m can also take the value 0.25, that is:

[0057] 22) Calculate the original phasor sequence The first integral comb filter result sequence In this context, the subscript "Y" represents "Ua", "Ub", "Uc", "Ia", "Ib", "Ic", "U1", "I1", "Udq", and "Idq". for:

[0058] Calculation using a recursive formula:

[0059] 23) Perform the 2nd to pth integral comb filtering. Given the sequence of results from the previous integral comb filter, p is based on harmonics, interharmonics, and out-of-band frequency components (frequency greater than or equal to...). The suppression design parameters and the downsampling frequency setting of the integral comb filter result sequence were selected.

[0060]

[0061] Alternatively, a recursive calculation formula can be used:

[0062] 24) To The sequence is downsampled to obtain the downsampled result. .

[0063] The specific process of step 24) is as follows: 241) Based on the measurement frequency range, error limit, and output delay specifications, design an equal-ripple FIR low-pass downsampling filter. Generally, the stopband start frequency of a downsampling filter is less than half the downsampling decimation frequency. When the total attenuation of the stopband and integral comb filter is greater than 60dB, and the attenuation of the p-th integral comb filter is greater than 60dB, directly... Perform downsampling.

[0064] 242) Press Using a downsampling filter right Filtering calculations for the sequence , This is the ratio of the original sampling frequency to the downsampling decimation frequency. This is a preset non-negative integer used to adjust the sampling time deviation.

[0065] downsampling results for:

[0066] 3) Design a compensation filter and perform... Perform compensation filtering; The specific process of step 3) is as follows: 31) Design a compensation filter for a p-level sequential comb filter. ; Step 31) is as follows: 311) Amplitude-frequency response characteristics of a compensation filter for a p-class cascaded integrator comb filter. for:

[0067] For signal frequency deviating from rated frequency The absolute value, .

[0068] 312) Output total delay based on synchronous phasor measurement Determine the compensation filter for the p-order chain integral comb filter. Allowable delay This allows for the determination of the compensation filter length. , The total delay is generated by the p-order continuous integral comb filtering. The sampling time interval of the phasor sequence of the input compensation filter is used without a downsampling filter. Then ignore .

[0069]

[0070]

[0071] 313) For the compensation filter The frequency characteristics are sampled, specifically as follows: Set cutoff frequency ,right Sampling is performed to generate a passband amplitude-frequency characteristic sampling sequence. The stopband attenuation is set to -60dB for sampling to generate a stopband amplitude-frequency response sampling sequence. ,and The overall amplitude-frequency response sampling sequence of the compensation filter is spliced ​​together. The number of sequence points is ;right Phase angles are sampled at equal intervals to generate phase angle sequences. The number of sequence points is , The sampling sequence of the frequency characteristics is:

[0072] 314) Find The inverse Fourier transform (IDFT) is then normalized to obtain the coefficients of the compensation filter. .

[0073] 315) Adjustment , The overall response characteristics of p-level joint integral comb filtering, downsampling filtering, and compensation filtering are then analyzed. The amplitude error within the measurement frequency range must be less than the limit required by the design or standard, where * represents the convolution operator.

[0074] 32) Take advantage of right Perform compensation filtering and calculate the result of the compensation filtering. for:

[0075] 4) Calculate the sequence of synchronization phasors and frequency measurement results; The specific process of step 4) is as follows: 41) Calculation The phasor amplitude and phase angle measurements, i.e.: Phasor amplitude:

[0076] Phasor phase angle:

[0077] 42) Calculate the frequency measurement value , for and The time interval.

[0078]

[0079]

[0080] 5) Calculate the measured value of the rate of change of frequency. ; The specific process of step 5) is as follows: 51) Calculate the instantaneous rate of change of frequency. for:

[0081] 52) Calculate the frequency change rate integral comb filter result sequence. for:

[0082] in, This represents the number of data window points for the integral comb filter.

[0083] Alternatively, it can be calculated using a recursive formula:

[0084] 52) Design a filter to compensate for the rate of change of frequency. ,right Filtering is performed to obtain a sequence of frequency change rate measurement results. ; The specific process of step 52) is as follows: 521) Determine the amplitude-frequency response characteristics of the p-th order integral comb filter. , The oscillation frequency is the amplitude or phase angle.

[0085]

[0086] 522) Determined and the length of the compensation filter By setting the cutoff frequency and stopband attenuation, sampling the frequency response of the rate of change compensation filter, performing inverse Fourier transform (IDFT), and then normalizing the results, the compensation filter is obtained. By adjusting , Until the oscillation frequency Within the monitoring range, the error of the frequency change rate measurement is less than the error limit required by the design or standard.

[0087] 523) Exploit right Perform compensation filtering to obtain for:

[0088] Example 2 The specific process of this embodiment is as follows: 1) Construct the original phasor using the sampled values; 11) Set the sampling frequency to The AC signal is sampled at equal intervals, with a sampling time interval of . , The sampling sequence is Serial Number The sampling time is aligned with the Coordinated Universal Time (UTC) whole second. , The number of sampling points per second, the value is equal to .

[0089] 12) Generate the coordinate transformation coefficient sequence , Set to 50Hz.

[0090]

[0091] 13) Sample sequences of Ua, Ub, Uc, Ia, Ib, and Ic and Calculate the original phasor sequence of Ua, Ub, Uc, Ia, Ib, and Ic point by point. ,Right now:

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] 14) For a three-phase system, use the calculated original phasor sequences of voltage and current. , , , , , Calculate the original phasor sequence of positive-sequence voltage and current. and for:

[0098]

[0099] 15) Using the sampling sequences of phases A, B, and C , , , , , Calculate the d and q components of the voltage and current respectively. , , , And construct the original phasor and :

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] 2) Perform a two-stage comb filter on the original phasor sequence; 21) Set the reporting or uploading frequency of synchronized phasor measurement data to 100 times / second, i.e. , DFT transform data window length ,Right now:

[0106] 22) Calculate the original phasor sequence The first integral comb filter result sequence for:

[0107] Alternatively, a recursive calculation formula can be used:

[0108] 23) Take Perform a second integral comb filter:

[0109] Alternatively, a recursive calculation formula can be used:

[0110] 24) To The sequence is downsampled to obtain : 241) Set the downsampling decimation frequency to 1600Hz, passband bandwidth to 40Hz, passband ripple to 0.001dB, stopband start frequency to 650Hz, and stopband attenuation to 40dB. Design... FIR low-pass filter of order 1 ; 242) Settings ,Right now , Used to compensate for the synchronization deviation of the original sampling points. right The sequence is downsampled and filtered to obtain a phasor sequence with a sampling frequency of 1600Hz. :

[0111] 3) Design compensation filters and their corresponding... Perform filtering; 31) Design a compensation filter for a two-stage cascaded integrator comb filter. ; 311) Determine the amplitude-frequency response characteristics :

[0112] in, For signal frequency Deviation from rated frequency The absolute value. Setting. .

[0113] 312) Determine the length of the compensation filter according to the total delay requirement of the output of the synchronization phasor measurement value: Total delay Delay of 2-order joint integral comb filter downsampling filter Delay Compensation filter Allowable delay .

[0114] Compensation filter length for:

[0115] in, The sampling time interval of the phasor sequence of the input compensation filter, i.e. .

[0116] 313) For the compensation filter The frequency characteristics are sampled; Set cutoff frequency ,right Perform sampling generation Passband amplitude-frequency characteristic sampling sequence ;set up Sampling is performed with a stopband attenuation of -60dB to generate Stopband amplitude-frequency response sampling sequence ,and spliced ​​together Overall amplitude-frequency response sampling sequence of the compensation filter ; Generate based on linear phase Phase frequency characteristic sampling sequence , The sampling sequence of the frequency characteristics is:

[0117] 314) Find The inverse Fourier transform (IDFT) is normalized to obtain the compensation filter. The coefficient; 315) Adjustment , The overall response characteristics of two-stage comb filtering, downsampling filtering, and compensation filtering are then analyzed. The error within the measurement frequency range is less than the limit specified in the design or standard.

[0118] 32) Take advantage of right Compensation filtering calculations are performed to obtain ;

[0119] 4) Calculate the synchronization phasor sequence ; 41) Calculate the phasor magnitude and phase angle; Phasor amplitude:

[0120] Phasor phase angle:

[0121] 42) Calculate the frequency of the phasor ;

[0122]

[0123] 5) Calculate the measured value of the rate of change of frequency. ; 51) Calculate the instantaneous rate of change of frequency. for:

[0124] 52) Calculate the results of the integral comb filter based on the rate of change of frequency. The data window for integral comb filtering has 80 points.

[0125]

[0126] Alternatively, a recursive formula can be used for calculation:

[0127] 53) Design a filter to compensate for the rate of change of frequency. ,right Filtering is performed to obtain a sequence of frequency change rate measurement results. ; 531) Determine the amplitude-frequency response characteristics of a first-order integral comb filter. , This refers to the amplitude or phase angle oscillation frequency.

[0128]

[0129] 532) Take Filter length Referring to step 31), the cutoff frequency and stopband attenuation are set, the frequency characteristics of the rate of change compensation filter are sampled, and the results are normalized using inverse Fourier transform (IDFT) to obtain the compensation filter. By adjusting , Until the monitored oscillation frequency Within the specified range, the error in the measured rate of frequency change is less than the design or standard error limit.

[0130] 533) Exploit right Filtering is performed to obtain a sequence of frequency change rate measurement results. for:

[0131] It should be noted that the present invention has the following characteristics: This invention solves the problem of high-precision measurement of synchronous phasors under dynamic time-varying conditions. By using cascaded integral comb filtering and its compensation filtering, consistent synchronous phasor passband frequency response characteristics are achieved. This avoids the mechanistic error in the synchronous phasor amplitude of signals with unrelated or weakly related amplitude and frequency fluctuations (such as amplitude modulation or simultaneous amplitude and frequency modulation signals defined by standards such as IEC / IEEE 60255-118 and Q / GDW 10131) when correcting based on frequency measurement values. The accuracy of synchronous phasor amplitude, phase angle, frequency and frequency change rate measurement under dynamic time-varying conditions is improved by 1 to 2 orders of magnitude compared with the standard requirements.

[0132] This invention exhibits excellent performance in suppressing harmonic and out-of-band interference. It employs a cascaded integral comb filter to replace the DFT, simultaneously achieving harmonic and interharmonic filtering and downsampling; and a compensation filter to simultaneously achieve frequency response compensation and synchronous phasor decimation output. Based on the Park transform, it utilizes the symmetry of the three-phase system to eliminate the impact of spectral leakage on frequency measurement accuracy under non-integer period sampling conditions.

[0133] This invention has good adaptability to various application scenarios. By adjusting the order of the cascaded integral comb filter and the passband bandwidth and stopband attenuation parameters of the compensation filter, the P-class and M-class measurement algorithm models specified in the IEC / IEEE 60255-118 standard can be cascaded to flexibly adapt to the accuracy and real-time requirements of synchronous phasor, frequency, and rate of change measurement in application scenarios such as power system protection, new energy grid connection control, primary frequency regulation, and power grid monitoring and analysis.

[0134] The method proposed in this invention possesses strict determinism and reliability. The entire measurement processing flow consists of cascaded integral comb filtering and its compensation filtering, which can be equivalent to a single FIR filter. It exhibits strict linear phase characteristics and eliminates the need for additional error correction mechanisms such as mutual correction of measured values. The stability of the FIR filter is equivalent to the stability of the algorithm, thus achieving highly reliable measurement.

[0135] This invention is simple to implement and has good technical and economic efficiency. The cascaded integral comb filter can be calculated recursively, with each calculation involving only one addition, one subtraction, and one multiplication operation (compared to the conventional N-point DFT which requires N multiplications and N additions per operation, and the matrix bundle algorithm which requires N). 3 Even with multi-order integral comb filtering, the computational cost is extremely low, and since downsampling is achieved through multi-order integral comb filtering, a dedicated downsampling filter can be further omitted. Therefore, the method proposed in this invention is easily implemented using FPGA or extremely low-cost hardware and software.

[0136] Example 3 refer to Figure 2 The synchronous phasor measurement system employing CIC compensation filtering described in this invention includes: The phasor construction module is used to sample AC signals at equal intervals to obtain a sampling sequence, perform coordinate transformation on the sampling sequence, and construct the original phasor using the result of the coordinate transformation. A cascaded integral comb filter module is used to perform cascaded integral comb filtering on the original phasors to obtain a downsampled phasor result sequence; The compensation filtering module is used to perform compensation filtering on the downsampled phasor result sequence using a cascaded integral comb filter matched with a compensation filter, to obtain the compensation filtered result sequence. The calculation module is used to calculate the synchronous phasor amplitude, phase angle, frequency, and frequency change rate measurement value based on the phasor result sequence of the compensation filter.

[0137] In this embodiment, the coefficient sequence of the coordinate transformation for:

[0138] The original phasor From the original sampling and Multiplying yields a phasor transformed to a coordinate system rotating at the rated frequency of the power system, where the phasor includes... and They are respectively:

[0139]

[0140] in, , and , Based on the sampling sequences of phases A, B, and C , , , , and The calculated d and q component sequences of voltage and current are as follows:

[0141]

[0142]

[0143]

[0144] in, The rated frequency of the power system, serial number The sampling time is aligned with the Coordinated Universal Time (UTC) integer second. , This represents the number of sampling points per second, and its value is equal to the sampling frequency. .

[0145] In this embodiment, the process of performing cascaded integral comb filtering on the original phasors to obtain the downsampled phasor result sequence is as follows: For the original phasor Multiple integral comb filtering and downsampling filtering processes are performed to obtain the downsampled result sequence.

[0146] In this embodiment, the downsampled result sequence is subjected to a compensation filter. During the process of obtaining the compensation filter result, the compensation filter is a compensation filter matched with a cascaded integrator-comb filter. The passband characteristics are:

[0147] The result of the compensation filtering for:

[0148] in, This is the frequency offset. For the cascaded integral comb filter, The number of phasor sequence points in the integral comb filter data window. To compensate for the filter bandwidth control parameters, To compensate for the unit impulse response of the filter, This represents the number of points in the sequence.

[0149] In this embodiment, the synchronization phasor is represented as:

[0150]

[0151] in, Phasor amplitude; For phasor phase angle, This is the result of the compensation filtering.

[0152] In this embodiment, the frequency measurement value for:

[0153]

[0154] in, for and The time interval, For intermediate parameters, The rated frequency of the power system.

[0155] In this embodiment, the frequency change rate for:

[0156] Compensation filter The passband characteristics are:

[0157] in, Indicates the length of the compensation filter. The sequence of cascaded comb filter results representing the rate of frequency change. The oscillation frequency, representing the phase angle or frequency, The number of points in the frequency change rate integral comb filter data window. for Bandwidth control parameters.

[0158] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0159] Example 4 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the synchronous phasor measurement method using CIC compensation filtering. For example, the steps include: sampling an AC signal at equal time intervals to obtain a sampling sequence; performing coordinate transformation on the sampling sequence; constructing an original phasor using the result of the coordinate transformation; performing cascaded integral comb filtering on the original phasor to obtain a downsampled phasor result sequence; performing compensation filtering on the downsampled phasor result sequence using a compensation filter to obtain a compensated filtering result sequence; and calculating the synchronous phasor amplitude, phase angle, frequency, and frequency change rate measurement values ​​based on the compensated filtering result sequence. The memory may include main memory, such as high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which may be an industry standard architecture bus, a peripheral component interconnection standard bus, an extended industry standard architecture bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. The memory stores the program; specifically, the program may include program code, which includes computer operation instructions. Memory can include main memory and non-volatile memory, and provides instructions and data to the processor.

[0160] Example 5 A computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the synchronous phasor measurement method using CIC compensation filtering. For example, the method includes: sampling an AC signal at equal time intervals to obtain a sampling sequence; performing coordinate transformation on the sampling sequence; constructing an original phasor using the result of the coordinate transformation; performing cascaded integral comb filtering on the original phasor to obtain a downsampled phasor result sequence; performing compensation filtering on the downsampled phasor result sequence using a compensation filter to obtain a compensated filtering result sequence; and calculating the synchronous phasor amplitude, phase angle, frequency, and frequency change rate measurement values ​​based on the compensated filtering result sequence. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0161] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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.

[0162] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0163] 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.

[0164] 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.

[0165] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0166] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0167] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for synchronous phasor measurement using CIC compensated filtering, characterized in that, include: The AC signal is sampled at equal time intervals to obtain a sampling sequence. The sampling sequence is then subjected to coordinate transformation, and the original phasor is constructed using the result of the coordinate transformation. The original phasors are subjected to cascaded integral comb filtering to obtain a downsampled phasor result sequence; The downsampled phasor result sequence is then subjected to a compensation filter to obtain the compensated filtered result sequence. The amplitude, phase angle, frequency, and frequency change rate of the synchronous phasor are calculated based on the result sequence of the compensation filtering.

2. The synchronous phasor measurement method using CIC compensation filtering according to claim 1, characterized in that, The coefficient sequence of the coordinate transformation for: The original phasor The sampling sequence and Multiplying yields a phasor transformed to a coordinate system rotating at the rated frequency of the power system, where the phasor includes... and They are respectively: in, , and , Based on the sampling sequences of phases A, B, and C , , , , and The calculated d and q component sequences of voltage and current are as follows: in, The rated frequency of the power system, serial number The sampling time is aligned with the Coordinated Universal Time (UTC) integer second. , This represents the number of sampling points per second, and its value is equal to the sampling frequency. .

3. The synchronous phasor measurement method using CIC compensation filtering according to claim 1, characterized in that, The process of performing cascaded integral comb filtering on the original phasors to obtain the downsampled phasor result sequence is as follows: For the original phasor Multiple integral comb filtering and downsampling filtering processes are performed to obtain the downsampled result sequence.

4. The synchronous phasor measurement method using CIC compensation filtering according to claim 3, characterized in that, The downsampled result sequence is then subjected to a compensation filter to obtain the compensation filter result. This compensation filter is matched to the cascaded integrator-comb filter. The passband characteristics are: The result of the compensation filtering for: in, This is the frequency offset. For the cascaded integral comb filter, The number of phasor sequence points in the integral comb filter data window. To compensate for the filter bandwidth control parameters, The unit impulse response sequence of the compensation filter. This represents the number of points in the sequence.

5. The synchronous phasor measurement method using CIC compensated filtering according to claim 4, characterized in that, The synchronization phasor is represented as: in, Phasor amplitude; The phase angle is the phasor angle.

6. The synchronous phasor measurement method using CIC compensated filtering according to claim 1, characterized in that, The frequency measurement value for: in, for and The time interval, for and The phase angle difference, The rated frequency of the power system.

7. The synchronous phasor measurement method using CIC compensated filtering according to claim 1, characterized in that, The rate of change of frequency for: Compensation filter The passband characteristics are: in, Indicates the length of the compensation filter. The sequence of cascaded comb filter results representing the rate of frequency change. The oscillation frequency, representing the phase angle or frequency, The number of points in the frequency change rate integral comb filter data window. for Bandwidth control parameters.

8. A synchronous phasor measurement system employing CIC compensated filtering, characterized in that, include: The phasor construction module is used to sample AC signals at equal intervals to obtain a sampling sequence, perform coordinate transformation on the sampling sequence, and construct the original phasor using the result of the coordinate transformation. A cascaded integral comb filter module is used to perform cascaded integral comb filtering on the original phasors to obtain a downsampled phasor result sequence; The compensation filtering module is used to perform compensation filtering on the downsampled phasor result sequence using a cascaded integral comb filter matched with a compensation filter, to obtain the compensation filtered result sequence. The calculation module is used to calculate the amplitude and phase angle, frequency, and frequency change rate measurement of the synchronization phasor based on the result sequence of the compensation filtering.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the synchronous phasor measurement method using CIC compensation filtering as described in any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the synchronous phasor measurement method using CIC compensation filtering as described in any one of claims 1-7.

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