Synchronous phasor measurement method and device under sub / super synchronous oscillation

Abstract

The invention relates to the technical field of electromagnetic measurement, in particular to a synchronous phasor measurement method and device under subsynchronous / super-synchronous oscillation, and the method comprises the steps: calculating a filter output value group at a measurement moment through a measured signal segment of a target power grid and a coefficient of a fundamental wave frequency measurement filter group under subsynchronous / super-synchronous oscillation, a target synchronous phasor measurement filter is matched in the synchronous phasor measurement filter alternative set under sub / super synchronous oscillation, a target filtering output value is calculated based on the coefficient of the target synchronous phasor measurement filter and the measured signal segment, and a synchronous phasor measurement value at the measurement moment is obtained. According to the embodiment of the invention, the method can achieve the quick and accurate measurement of the synchronous phasor under the condition that the strong sub / super synchronous oscillation is monitored in a broadband measurement process, improves the adaptability of broadband measurement to a complex-pattern oscillation signal, inhibits the impact on the measurement precision of the synchronous phasor from the sub / super synchronous oscillation, and is higher in practicality.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic measurement technology, and in particular to a synchronous phasor measurement method and device under sub- / super-synchronous oscillation. Background Art

[0002] With the rapid transformation of the power grid to a new type of power system, the frequency of wideband oscillation events has increased, affecting the safe operation of the power grid. In related technologies, wideband measurement devices can be used for monitoring, among which the phasor measurement unit (PMU) samples, analyzes and calculates the voltage and current signals of the measurement point with the world coordinated time clock, and can report the synchronous phasor, frequency and frequency change rate measurement results of the power frequency signal at high speed and low latency.

[0003] However, in the related technology, the existing PMU measurement standards lack measurement performance requirements under oscillation interference. When there are multiple unknown dynamically changing oscillation components near the fundamental frequency, it is difficult to achieve accurate measurement of the fundamental phasor and difficult to perform PMU and wideband measurement functions at the same time. As a result, when wideband oscillations occur in the power grid, the PMU algorithm may produce large measurement errors due to sub / supersynchronous oscillations adjacent to the fundamental, thereby failing to guarantee the normal operation of wideband measurements, which needs to be solved urgently. Summary of the invention

[0004] The present application provides a synchronous phasor measurement method and device under sub- / super-synchronous oscillation to solve the problems in the related art that the existing PMU measurement standard lacks measurement performance requirements under oscillation interference, it is difficult to accurately measure the fundamental phasor when there are multiple unknown dynamically changing oscillation components near the fundamental frequency, it is difficult to simultaneously perform PMU and wideband measurement functions, resulting in the PMU algorithm may produce a large measurement error due to the sub- / super-synchronous oscillation near the fundamental in the case of wideband oscillation of the power grid, thereby failing to ensure the normal operation of the wideband measurement.

[0005] A first aspect embodiment of the present application provides a synchronous phasor measurement method under sub / super synchronous oscillation, comprising the following steps: obtaining a measured signal segment of a signal sampling sequence of a target power grid, and obtaining a filter output value group of the measured signal segment at a measurement moment based on the measured signal segment and a coefficient of a pre-constructed fundamental frequency measurement filter group under sub / super synchronous oscillation; calculating a fundamental frequency estimation value according to the filter output value group, and using the fundamental frequency estimation value to match a target synchronous phasor measurement filter in a pre-constructed candidate set of synchronous phasor measurement filters under sub / super synchronous oscillation; performing calculation based on the coefficient of the target synchronous phasor measurement filter and the measured signal segment to obtain a target filter output value at the measurement moment, performing phase compensation according to the target filter output value, and obtaining a synchronous phasor measurement value at the measurement moment.

[0006] Optionally, in one embodiment of the present application, using the fundamental frequency estimate to match a target synchronized phasor measurement filter in a pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillations includes: obtaining the fundamental reference frequency of each synchronized phasor measurement filter in the pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillations; based on each fundamental reference frequency, matching a target fundamental reference frequency that satisfies a preset approximation condition with the fundamental frequency estimate, and confirming the target synchronized phasor measurement filter by the synchronized phasor measurement filter corresponding to the target fundamental reference frequency.

[0007] Optionally, in one embodiment of the present application, obtaining the measured signal segment of the signal sampling sequence of the target power grid includes: setting a data window under a preset power frequency cycle based on the measurement moment; and obtaining the measured signal segment from the target power grid signal sampling sequence within the data window.

[0008] Optionally, in one embodiment of the present application, the fundamental frequency estimation value calculation formula is:

[0009]

[0010] in, is the estimated value of the fundamental frequency, p i is the filter output value group, i=0,1, f0 is the fundamental standard power frequency.

[0011] Optionally, in one embodiment of the present application, before obtaining the filter output value group of the measured signal segment at the measurement time based on the measured signal segment and the coefficient of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation, it also includes: based on a preset fundamental standard power frequency, obtaining multiple target offsets, and confirming the normalized angular frequency and filter order of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation according to the multiple target offsets and the grid signal sampling frequency; constructing a target Fourier matrix and weighted coefficient vector of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation based on the normalized angular frequency and the filter order; constructing a target intermediate vector based on the target Fourier matrix and the weighted coefficient vector, and using the target intermediate vector to respectively confirm the two channel coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation.

[0012] A second aspect of the present application provides a synchronous phasor measurement device under sub / super synchronous oscillation, including: an acquisition module, used to acquire a measured signal segment of a signal sampling sequence of a target power grid, and obtain a filter output value group of the measured signal segment at a measurement moment based on the measured signal segment and a coefficient of a pre-constructed fundamental frequency measurement filter group under sub / super synchronous oscillation; a matching module, used to calculate a fundamental frequency estimation value according to the filter output value group, and use the fundamental frequency estimation value to match a target synchronous phasor measurement filter in a pre-constructed candidate set of synchronous phasor measurement filters under sub / super synchronous oscillation; a measurement module, used to perform calculation based on the coefficient of the target synchronous phasor measurement filter and the measured signal segment to obtain a target filter output value at the measurement moment, so as to perform phase compensation according to the target filter output value to obtain a synchronous phasor measurement value at the measurement moment.

[0013] Optionally, in one embodiment of the present application, the matching module includes: an acquisition unit, used to acquire the fundamental reference frequency of each synchronized phasor measurement filter in the pre-constructed candidate set of synchronized phasor measurement filters under sub-synchronous / super-synchronous oscillation; a matching unit, used to match, based on each fundamental reference frequency, a target fundamental reference frequency that satisfies a preset approximation condition with the fundamental frequency estimate, and the synchronized phasor measurement filter corresponding to the target fundamental reference frequency confirms the target synchronized phasor measurement filter.

[0014] Optionally, in one embodiment of the present application, the acquisition module includes: a setting unit, used to set a data window under a preset power frequency cycle based on the measurement time; and a confirmation unit, used to obtain the measured signal segment from a target power grid signal sampling sequence within the data window.

[0015] Optionally, in one embodiment of the present application, the fundamental frequency estimation value calculation formula is:

[0016]

[0017] in, is the estimated value of the fundamental frequency, p i is the filter output value group, i=0,1, f0 is the fundamental standard power frequency.

[0018] Optionally, in one embodiment of the present application, the device also includes: a confirmation module, which is used to obtain multiple target offsets based on a preset fundamental standard power frequency before obtaining the filter output value group of the measured signal segment at the measurement time based on the measured signal segment and the coefficient of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation, and confirm the normalized angular frequency and filter order of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation according to the multiple target offsets and the grid signal sampling frequency; a first construction module, which is used to construct a target Fourier matrix and a weighted coefficient vector of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation based on the normalized angular frequency and the filter order; a second construction module, which is used to construct a target intermediate vector based on the target Fourier matrix and the weighted coefficient vector, and use the target intermediate vector to respectively confirm the two channel coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation.

[0019] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the synchronous phasor measurement method under sub / super synchronous oscillation as described in the above embodiments.

[0020] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the above-mentioned synchronous phasor measurement method under sub / super synchronous oscillation.

[0021] The fifth aspect of the present application provides a computer program, which, when executed, implements the above-mentioned synchronous phasor measurement method under sub / super synchronous oscillation.

[0022] The embodiment of the present application can realize fast and accurate measurement of synchronized phasors when strong sub / supersynchronous oscillations occur during broadband measurement, improve the adaptability of broadband measurement to complex-style oscillation signals, suppress the influence of sub / supersynchronous oscillations on the accuracy of synchronized phasor measurement, and be more practical. Thus, the problems in the related art that the existing PMU measurement standard lacks measurement performance requirements under oscillation interference, and it is difficult to accurately measure the fundamental phasor when there are multiple unknown dynamically changing oscillation components near the fundamental frequency, and it is difficult to perform PMU and broadband measurement functions at the same time, resulting in that when broadband oscillations occur in the power grid, the PMU algorithm may produce large measurement errors due to sub / supersynchronous oscillations near the fundamental, thereby failing to ensure the normal operation of broadband measurement, etc.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A flowchart of a synchronous phasor measurement method under sub- / super-synchronous oscillation provided according to an embodiment of the present application;

[0026] Figure 2 A schematic diagram of the h0 coefficient of the frequency estimation filter according to an embodiment of the present application;

[0027] Figure 3 A schematic diagram of a frequency estimation filter h1 system according to an embodiment of the present application;

[0028] Figure 4 A schematic diagram of a vector measurement filter coefficient (reference frequency f1 = 50 Hz) according to an embodiment of the present application;

[0029] Figure 5 A schematic diagram of the amplitude-frequency characteristic (reference frequency f1 = 50 Hz) of a phasor measurement filter according to an embodiment of the present application;

[0030] Figure 6 A schematic diagram of a synchronized phasor measurement error under a standard sinusoidal pattern according to an embodiment of the present application;

[0031] Figure 7 A schematic diagram of synchronous phasor measurement error under an amplitude / phase modulation mode according to an embodiment of the present application;

[0032] Figure 8 A schematic diagram of frequency measurement error under a frequency ramp signal pattern according to an embodiment of the present application;

[0033] Fig. 9 A schematic diagram of a current recording data waveform according to an embodiment of the present application;

[0034] Fig.10 A schematic diagram of an amplitude spectrum of recorded wave data according to an embodiment of the present application;

[0035] Fig.11 A schematic diagram of a synchronous phasor amplitude measurement value of current recording data according to an embodiment of the present application;

[0036] Fig.12 A schematic diagram of a synchronous phasor phase measurement value of current recording data according to an embodiment of the present application;

[0037] Fig.13 A schematic diagram of a synchronous phasor measurement error of current recording data according to an embodiment of the present application;

[0038] Fig.14 A schematic diagram of the control principle of synchronized phasor measurement under sub- / super-synchronous oscillation according to an embodiment of the present application;

[0039] Fig.15 Schematic diagram of the structure of a synchronous phasor measurement device under sub-synchronous / super-synchronous oscillation according to an embodiment of the present application;

[0040] Fig.16 Schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0042] The following describes the synchronous phasor measurement method and device under sub / super synchronous oscillation of the embodiment of the present application with reference to the accompanying drawings. In view of the related technologies mentioned in the above background technology, the existing PMU measurement standard lacks measurement performance requirements under oscillation interference. When there are multiple unknown dynamically changing oscillation components near the fundamental frequency, it is difficult to achieve accurate measurement of the fundamental phasor, and it is difficult to perform PMU and broadband measurement functions at the same time, resulting in the PMU algorithm may produce a large measurement error due to the sub / super synchronous oscillation adjacent to the fundamental in the case of broadband oscillation in the power grid, thereby failing to ensure the normal operation of broadband measurement. The present application provides a synchronous phasor measurement method under sub / super synchronous oscillation, in which the method can realize fast and accurate measurement of the synchronous phasor when strong sub / super synchronous oscillation occurs during broadband measurement, improve the adaptability of broadband measurement to complex style oscillation signals, suppress the influence of sub / super synchronous oscillation on the accuracy of synchronous phasor measurement, and be more practical. As a result, the problems in the related art are solved, such as the existing PMU measurement standards lack requirements for measurement performance under oscillation interference, it is difficult to achieve accurate measurement of the fundamental phasor when there are multiple unknown dynamically changing oscillation components near the fundamental frequency, and it is difficult to simultaneously execute the PMU and wideband measurement functions, resulting in the PMU algorithm causing large measurement errors due to sub / super synchronous oscillations near the fundamental in the case of wideband oscillations in the power grid, thereby failing to ensure the normal operation of wideband measurements.

[0043] Specifically, Figure 1 A schematic flow chart of a synchronous phasor measurement method under sub-synchronous / super-synchronous oscillation provided in an embodiment of the present application.

[0044] like Figure 1 As shown, the synchronous phasor measurement method under sub-synchronous / super-synchronous oscillation includes the following steps:

[0045] In step S101, a measured signal segment of a signal sampling sequence of a target power grid is obtained, and a filter output value group of the measured signal segment at the measurement time is obtained based on the measured signal segment and coefficients of a pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation.

[0046] It can be understood that in the embodiments of the present application, the measured signal segments are flipped, multiplied and summed with the coefficients of a two-channel FIR filter group that is pre-optimized and designed with a length of 6 standard power frequency cycles to achieve fundamental frequency estimation under sub / super synchronous oscillation, to obtain the output of the power grid signal filtered by the filter group at the measurement time, that is, the filter output value group.

[0047] Optionally, in one embodiment of the present application, before obtaining the filter output value group of the measured signal segment at the measurement time based on the measured signal segment and the coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation, it also includes: obtaining multiple target offsets based on a preset fundamental standard power frequency, and confirming the normalized angular frequency and filter order of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation according to the multiple target offsets and the grid signal sampling frequency; constructing a target Fourier matrix and weighted coefficient vector of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation based on the normalized angular frequency and the filter order; constructing a target intermediate vector based on the target Fourier matrix and the weighted coefficient vector, and using the target intermediate vector to respectively confirm the two-channel coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation.

[0048] In the actual implementation process, for the pre-constructed sub- / super-synchronous oscillation fundamental frequency measurement filter group, the sub- / super-synchronous oscillation fundamental frequency measurement filter group {h0[k], h1[k]} can be generated according to the preferred parameters, by recording the fundamental standard power frequency as f0=50Hz, and obtaining multiple target offsets, recording v1=f0-7.5, v2=f0+7.5, v3=f0-11.8, v4=f0+11.8, v5=f0-19.8, v6=f0+19.8, v7=f0-28.8, v8=f0+28.8, and setting v 8+i =-v i ,i=1,2,…,8. Let the sampling frequency of the power grid signal be f s (such as f s =4000Hz), then the normalized angular frequency ω i =2πf i / f s , i = 1, 2, ..., M (M = 16), and let the filter order in It means that x is rounded down, and the target Fourier matrix Ψ and the weight coefficient vector W are recorded as:

[0049]

[0050] Among them, w k , k = 0, 1, ..., N-1 is the coefficient of the second-order Kaiser window function with a length of N. Define the target intermediate vector:

[0051] Π=[(WΨ) H (WΨ)] -1 (WΨ) H W,

[0052] And remember π i is the i-th row vector of Π, and the two-channel coefficients are defined as:

[0053]

[0054] Thus, the two-channel filter groups {h0[k], h1[k], k = -(N-1) / 2, ..., (N+1) / 2} are:

[0055] h0[k]=g0[-k], h1[k]=g1[-k], k=-(N-1) / 2,…,(N-1) / 2

[0056] Thus, a two-channel FIR (Finite Impulse Response) filter group with a length of 6 standard power frequency cycles and optimized in advance for realizing fundamental frequency estimation under sub / super synchronous oscillation is obtained, that is, a pre-constructed fundamental frequency measurement filter group under sub / super synchronous oscillation.

[0057] Optionally, in one embodiment of the present application, obtaining a measured signal segment of a signal sampling sequence of a target power grid includes: setting a data window under a preset power frequency cycle based on a measurement moment; and obtaining the measured signal segment from the target power grid signal sampling sequence within the data window.

[0058] It should be noted that the preset power frequency period can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0059] In the actual implementation process, a data window with a length of 6 standard power frequency cycles (120ms) can be set with the measurement time as the center, and the power grid sampling sequence in the data window can be selected as the measured signal segment to obtain the measured signal segment. For example, a measured signal segment with a length of 6 cycles centered at time t is selected, and the measured sequence can be recorded as s t [k], k = -(N-1) / 2,…,(N-1) / 2, where s t [k] = s(t + k / f s) is the power grid signal s(t) at t+k / f s The sampling value at the moment, f s is the sampling frequency.

[0060] In step S102, a fundamental frequency estimation value is calculated according to the filter output value group, and the fundamental frequency estimation value is used to match a target synchronized phasor measurement filter in a pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillation.

[0061] It can be understood that, in the embodiment of the present application, for the pre-constructed sub- / super-synchronous oscillation synchronized phasor measurement filter candidate set, a sub- / super-synchronous oscillation synchronized phasor measurement filter {h (q) [k],q=1,…,Q}, we can write f1 (q) =48+(q-0.5)Δv, q=1,…,Q, take Δv=0.25Hz, Q=16, and define {f1 (q)} is the reference frequency set of the fundamental wave. Take f1=f1 (q) is the fundamental reference frequency, let v1 = f1-0.25, v2 = f1+0.25, v3 = f1-10.6, v4 = f1+10.6, v5 = f1-16.8, v6 = f1+16.8, v 6+i =-v i ,i=1,2,…,6. Note ω i =2πf i / f s , i=1,2,…,M(M=12), and remember:

[0062]

[0063] where w k , k = 0, 1, ..., N-1 is the coefficient of the 0.5-order Kaiser window function with a length of N. Definition:

[0064] Π=[(WΨ) H (WΨ)] -1 (WΨ) H W,

[0065] And remember π i is the i-th row vector of Π, which is defined as:

[0066]

[0067] The reference frequency is f1=f1 (q) , filter h for synchronized phasor measurement (q) [k] is:

[0068] h (q)[k]=g0[-k],k=-(N-1) / 2,…,(N-1) / 2,

[0069] where h (q) [k], k = -(N-1) / 2, ..., (N-1) / 2, q = 1, ..., Q is Q (= 16) candidate FIR filters for realizing synchronized phasor measurement under sub- / super-synchronous oscillation, that is, a pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillation is obtained.

[0070] Optionally, in one embodiment of the present application, the fundamental frequency estimation value calculation formula is:

[0071]

[0072] in, is the estimated value of fundamental frequency, p i is the filter output value group, i=0,1, f0 is the fundamental standard industrial frequency.

[0073] In the actual execution process, the fundamental frequency estimation value can be calculated from the two filter output values ​​in the filter output value group, and the fundamental frequency at time t can be estimated by filtering {h0[k], h1[k]}. The specific calculation process is:

[0074]

[0075] The estimated fundamental frequency at time t is:

[0076]

[0077] Optionally, in one embodiment of the present application, a target synchronized phasor measurement filter is matched in a pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillations using a fundamental frequency estimate, including: obtaining a fundamental reference frequency of each synchronized phasor measurement filter in a pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillations; based on each fundamental reference frequency, matching a target fundamental reference frequency that satisfies a preset approximate condition with the fundamental frequency estimate, and confirming the target synchronized phasor measurement filter by the synchronized phasor measurement filter corresponding to the target fundamental reference frequency.

[0078] It should be noted that the preset approximate conditions can be set by those skilled in the art according to actual conditions and are not specifically limited here.

[0079] In the actual implementation process, from multiple FIR filters that are pre-optimized and designed with a length of 6 standard power frequency cycles and realize synchronous phasor measurement under sub / super synchronous oscillation, a filter with a reference frequency closest to the fundamental frequency estimate can be selected, that is, a filter whose target fundamental reference frequency and fundamental frequency estimate meet the preset approximate conditions, to obtain the target synchronous phasor measurement filter.

[0080] Specifically, the fundamental reference frequency and the corresponding measurement filter can be selected by converting the fundamental frequency estimate With the fundamental reference frequency set {f1 (q) ,q=1,...,Q}, and record The reference frequency with the closest value is f1 (m) , then the selected filter is

[0081] In step S103, a target filter output value at the measurement time is obtained by calculation based on the coefficient of the target synchronized phasor measurement filter and the measured signal segment, and phase compensation is performed according to the target filter output value to obtain the synchronized phasor measurement value at the measurement time.

[0082] It can be understood that in the embodiment of the present application, the measured signal segment and the coefficient of the selected target synchronous phasor measurement filter are flipped, multiplied and summed to obtain the output of the power grid signal filtered by the phasor measurement filter at the measurement time, and the filtered output value is phase compensated to obtain the synchronous phasor measurement value at the measurement time. Among them, the synchronous phasor measurement value at time t is obtained by filtering and phase compensation of the phasor measurement filter, and the specific calculation formula is:

[0083]

[0084] in, That is the synchronous phasor measurement value at time t.

[0085] The following is a detailed description of the working content of the embodiment of the present application with a specific embodiment. Based on the above steps, the signal sampling frequency f is set s =4.0kHz, the standard frequency of the power grid f0 =50Hz, and the FIR filter group {h0[k],h1[k]} for fundamental frequency measurement under sub / super synchronous oscillation and multiple FIR filters {h (q) [k],q=1,…,Q}. The coefficients of filters h0[k] and h1[k] are as follows: Figure 2 and Figure 3 As shown, the filter h corresponding to the reference frequency f1 = 50Hz (q) The coefficient of [k] is Figure 4 As shown, the reference frequencies are f1 = 48 Hz, 50 Hz and 52 Hz.(q) The amplitude-frequency response characteristic curve of [k] is as follows Figure 5 shown.

[0086] The embodiment of the present invention refers to the technical specification Q / GDW 12214-2022 of the broadband measurement device of the power system and the international standard IEC / IEEE 60255-118-1 2018 of the PMU measurement, and sets the test conditions to verify the accuracy performance of the synchronized phasor measurement algorithm proposed in the present invention. The accuracy of synchronized phasor measurement is characterized by the total vector error (TVE), which is specifically defined as:

[0087]

[0088] Among them, X(t) and are the true value and measured value of the synchronized phasor at time t, respectively. Usually, in order to evaluate the measurement accuracy of a measurement algorithm for a certain style of deterministic signal, it is necessary to measure the signal for a sufficiently long period of time and calculate the maximum value of the measurement error, that is:

[0089]

[0090] The test conditions are set as follows: when sub / supersynchronous oscillation occurs, according to the waveform characteristics of the power grid in static and dynamic operation, the test waveforms of tests a), b) and c) respectively consider the fundamental wave and oscillation signal as three typical signal styles of single-frequency sine, amplitude / phase modulation and frequency ramp; the test waveform of test d) comes from the on-site current recording data, which is the actual working condition of sub / supersynchronous oscillation occurring in the power grid.

[0091] a) Standard sine: The signal frequency band contains fundamental wave, subsynchronous oscillation and supersynchronous oscillation. Each component is an ideal sine wave. Its frequency and normalized effective value are shown in Table 1, which is the signal parameter table of simulation experiment a). The fundamental wave static frequency deviation Δf is within -2Hz to 2Hz, and the interval Δv between subsynchronous / supersynchronous oscillation and fundamental wave frequency is 10Hz to 35Hz. In addition, Gaussian white noise with a standard deviation of 0.01 is added to the signal.

[0092] Table 1

[0093]

[0094] b) AM / FM: The signal components, center frequency and average power of each signal are the same as those of test waveform 1, but the amplitude and phase of the fundamental wave, harmonics and sub / supersynchronous oscillation signals are modulated by a low-frequency sinusoidal signal at the same time. The amplitude and phase modulation depth are set to 10%, and the sinusoidal modulation frequency f m 0~2Hz.

[0095] c) Frequency ramp: The signal components and the center frequency and average power of each signal are basically the same as those of test waveform 1, but the frequencies of the fundamental, subsynchronous and supersynchronous oscillation signals change uniformly within 0.5 to 4.5 seconds (i.e., frequency ramp style), with the ranges of 48 to 52 Hz, 38 to 42 Hz and 58 to 62 Hz respectively.

[0096] d) On-site recording: The current recording signal of a transmission line in a certain area. The recording data contains a strong oscillation component in the low-frequency band, mainly distributed in the 80-120Hz and 5-25Hz frequency bands. The total distortion rate of the harmonics between these two frequency bands is close to 10%.

[0097] The simulation curves of the synchronous phasor measurement error (TVE maximum value) of experiments a) and b) are respectively Figure 6 and Figure 7 Given. Figure 6 The curve of TVE changing with Δv when Δf is fixed (0 and ±2Hz) shows that the total measurement error caused by static frequency deviation and oscillation interference is basically limited to less than 1%. Figure 7 The curve of TVE changing with the sinusoidal modulation frequency when the fundamental wave static frequency deviation is 0 shows that the measurement error increases with the increase of modulation frequency, but at f m =2Hz, the maximum value of TVE is within 2%, which meets the normal dynamic measurement error requirements. Test c) Synchronous phasor measurement error curves at each measurement time of the signal sample Figure 8 The maximum value of TVE does not exceed 1%. Test d) The waveform of the recorded signal and its low-frequency amplitude spectrum are respectively Fig. 9 and Fig.10 It is given in , that there are oscillating components in the frequency bands of 80~120Hz and 5~25Hz. Fig.11 and Fig.12 The amplitude and phase curves of the synchronized phasor measurements are given respectively. In order to effectively evaluate the measurement accuracy, the measurement results of a high-precision algorithm (called the calibration algorithm) with a data window length of 15 cycles are given in the figure. Fig.12 The measurement error curve using the high-precision algorithm synchronized phasor measurement value as the true value calculation is given, and the TVE can be less than 1%. The above measurement errors all meet the requirements of IEC / IEEE 60255-118-1 2018 for the maximum allowable error of synchronized phasor measurement under static and dynamic conditions.

[0098] The control principle implemented in the above embodiment is as follows: Fig.14 As shown, it is a schematic diagram of the control principle of synchronized phasor measurement under sub- / super-synchronous oscillation according to an embodiment of the present application, wherein: according to the preferred parameters, a fundamental frequency measurement filter group {h0[k], h1[k]} under sub- / super-synchronous oscillation is generated, and according to the fundamental reference frequency set and the preferred parameters, a synchronized phasor measurement filter {h0[k], h1[k]} under sub- / super-synchronous oscillation is generated.(q) [k], q=1,…, Q}. A 6-cycle signal segment to be measured centered at time t is selected, and the fundamental frequency at time t is estimated by filtering {h0[k], h1[k]}. The fundamental reference frequency and the corresponding measurement filter are selected, and the synchronous phasor measurement value at time t is obtained by filtering with a phasor measurement filter and phase compensation.

[0099] According to the synchronous phasor measurement method under sub / super synchronous oscillation proposed in the embodiment of the present application, when strong sub / super synchronous oscillation occurs during broadband measurement, rapid and accurate measurement of the synchronous phasor can be achieved, thereby improving the adaptability of broadband measurement to complex pattern oscillation signals, suppressing the influence of sub / super synchronous oscillation on the accuracy of synchronous phasor measurement, and being more practical. Thus, the problems in the related art such as the lack of measurement performance requirements under oscillation interference in the existing PMU measurement standard, the difficulty in achieving accurate measurement of the fundamental phasor when there are multiple unknown dynamically changing oscillation components near the fundamental frequency, and the difficulty in simultaneously executing the PMU and broadband measurement functions are solved, resulting in the PMU algorithm possibly generating large measurement errors due to sub / super synchronous oscillations adjacent to the fundamental frequency when broadband oscillation occurs in the power grid, thereby failing to ensure the normal operation of broadband measurement, etc.

[0100] Next, a synchronous phasor measurement device under sub-synchronous / super-synchronous oscillation proposed in an embodiment of the present application is described with reference to the accompanying drawings.

[0101] Fig.15 It is a schematic diagram of the structure of a synchronous phasor measurement device under sub-synchronous / super-synchronous oscillation according to an embodiment of the present application.

[0102] like Fig.15 As shown, the synchronous phasor measurement device 10 under sub-synchronous / super-synchronous oscillation includes: an acquisition module 100, a matching module 200 and a measurement module 300.

[0103] Among them, the acquisition module 100 is used to obtain the measured signal segment of the signal sampling sequence of the target power grid, and obtain the filter output value group of the measured signal segment at the measurement time based on the measured signal segment and the coefficients of the fundamental frequency measurement filter group under the pre-constructed sub / super synchronous oscillation.

[0104] The matching module 200 is used to calculate a fundamental frequency estimation value according to the filter output value group, and use the fundamental frequency estimation value to match a target synchronized phasor measurement filter in a pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillation.

[0105] The measurement module 300 is used to calculate based on the coefficients of the target synchronized phasor measurement filter and the measured signal segment to obtain the target filter output value at the measurement time, so as to perform phase compensation according to the target filter output value to obtain the synchronized phasor measurement value at the measurement time.

[0106] Optionally, in one embodiment of the present application, the matching module 200 includes: an acquisition unit and a matching unit.

[0107] The acquisition unit is used to acquire the fundamental reference frequency of each synchronized phasor measurement filter in the pre-constructed candidate set of synchronized phasor measurement filters under sub-synchronous / super-synchronous oscillation.

[0108] The matching unit is used to match the target fundamental reference frequency that meets the preset approximation condition with the fundamental frequency estimation value based on each fundamental reference frequency, and the target synchronized phasor measurement filter is confirmed by the synchronized phasor measurement filter corresponding to the target fundamental reference frequency.

[0109] Optionally, in one embodiment of the present application, the acquisition module 100 includes: a setting unit and a confirmation unit.

[0110] Wherein, the setting unit is used to set the data window under the preset power frequency period based on the measurement time.

[0111] The confirmation unit is used to obtain the measured signal segment from the target power grid signal sampling sequence in the data window.

[0112] Optionally, in one embodiment of the present application, the fundamental frequency estimation value calculation formula is:

[0113]

[0114] in, is the estimated value of fundamental frequency, p i is the filter output value group, i=0,1, f0 is the fundamental standard industrial frequency.

[0115] Optionally, in one embodiment of the present application, the device 10 further includes: a confirmation module, a first construction module and a second construction module.

[0116] Among them, the confirmation module is used to obtain multiple target offsets based on the preset fundamental standard power frequency before obtaining the filter output value group of the measured signal segment at the measurement time based on the measured signal segment and the coefficients of the fundamental frequency measurement filter group under sub / super synchronous oscillation constructed in advance, and confirm the normalized angular frequency and filter order of the fundamental frequency measurement filter group under sub / super synchronous oscillation constructed in advance according to the multiple target offsets and the grid signal sampling frequency.

[0117] The first construction module is used to construct a target Fourier matrix and a weight coefficient vector of a pre-constructed fundamental frequency measurement filter bank under sub- / super-synchronous oscillation based on the normalized angular frequency and the filter order.

[0118] The second construction module is used to construct a target intermediate vector based on the target Fourier matrix and the weighted coefficient vector, and use the target intermediate vector to respectively confirm the two channel coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation.

[0119] It should be noted that the above explanation of the embodiment of the synchronized phasor measurement method under sub- / super-synchronous oscillation is also applicable to the synchronized phasor measurement device under sub- / super-synchronous oscillation of this embodiment, which will not be repeated here.

[0120] According to the synchronous phasor measurement device under sub / super synchronous oscillation proposed in the embodiment of the present application, when strong sub / super synchronous oscillation occurs during broadband measurement, rapid and accurate measurement of the synchronous phasor can be achieved, thereby improving the adaptability of broadband measurement to complex pattern oscillation signals, suppressing the influence of sub / super synchronous oscillation on the accuracy of synchronous phasor measurement, and being more practical. Thus, the problems in the related art that the existing PMU measurement standard lacks measurement performance requirements under oscillation interference, and it is difficult to achieve accurate measurement of the fundamental phasor when there are multiple unknown dynamically changing oscillation components near the fundamental frequency, and it is difficult to perform PMU and broadband measurement functions at the same time, resulting in the PMU algorithm may produce large measurement errors due to sub / super synchronous oscillations adjacent to the fundamental in the case of broadband oscillation in the power grid, thereby failing to ensure the normal operation of broadband measurement, etc.

[0121] Fig.16 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0122] A memory 1601 , a processor 1602 , and a computer program stored in the memory 1601 and executable on the processor 1602 .

[0123] When the processor 1602 executes the program, the synchronized phasor measurement method under sub-synchronous / super-synchronous oscillation provided in the above embodiment is implemented.

[0124] Furthermore, the electronic device further comprises:

[0125] The communication interface 1603 is used for communication between the memory 1601 and the processor 1602 .

[0126] The memory 1601 is used to store computer programs that can be executed on the processor 1602 .

[0127] The memory 1601 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0128] If the memory 1601, the processor 1602 and the communication interface 1603 are implemented independently, the communication interface 1603, the memory 1601 and the processor 1602 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.16 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0129] Optionally, in a specific implementation, if the memory 1601, the processor 1602 and the communication interface 1603 are integrated on a chip, the memory 1601, the processor 1602 and the communication interface 1603 can communicate with each other through an internal interface.

[0130] The processor 1602 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0131] This embodiment also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the synchronized phasor measurement method under sub-synchronous / super-synchronous oscillation is implemented as described above.

[0132] This embodiment also provides a computer program, which implements the above-mentioned synchronous phasor measurement method under sub-synchronous / super-synchronous oscillation when the computer program is executed.

[0133] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0134] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0135] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0136] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0137] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0138] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0139] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0140] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A synchronous phasor measurement method under sub- / super-synchronous oscillation, characterized in that: The following steps are involved: Acquire a measured signal segment of a signal sampling sequence of a target power grid, and obtain a filter output value group of the measured signal segment at a measurement time based on the measured signal segment and coefficients of a pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation; Calculating a fundamental frequency estimation value according to the filter output value group, and matching a target synchronized phasor measurement filter in a pre-constructed candidate set of synchronized phasor measurement filters under sub-synchronous / super-synchronous oscillation by using the fundamental frequency estimation value; A calculation is performed based on the coefficient of the target synchronized phasor measurement filter and the measured signal segment to obtain a target filter output value at the measurement moment, so as to perform phase compensation according to the target filter output value to obtain a synchronized phasor measurement value at the measurement moment.

2. The method according to claim 1, characterized in that The method of matching a target synchronized phasor measurement filter in a pre-constructed candidate set of synchronized phasor measurement filters under sub-synchronous / super-synchronous oscillation by using the fundamental frequency estimation value comprises: Acquire the fundamental reference frequency of each synchronized phasor measurement filter in the pre-constructed candidate set of synchronized phasor measurement filters under sub-synchronous / super-synchronous oscillation; Based on each fundamental wave reference frequency, a target fundamental wave reference frequency that satisfies a preset approximation condition with the fundamental wave frequency estimation value is matched, and the target synchronized phasor measurement filter is confirmed by the synchronized phasor measurement filter corresponding to the target fundamental wave reference frequency.

3. The method according to claim 1, characterized in that The step of obtaining a measured signal segment of a signal sampling sequence of a target power grid includes: Setting a data window under a preset power frequency period based on the measurement time; The measured signal segment is obtained from the target power grid signal sampling sequence in the data window.

4. The method according to claim 1, characterized in that: The fundamental frequency estimation value calculation formula is: in, is the estimated value of the fundamental frequency, p i is the filter output value group, i=0,1, f0 is the fundamental standard power frequency.

5. The method according to claim 1, characterized in that Before obtaining the filter output value group of the measured signal segment at the measurement time based on the measured signal segment and the pre-constructed fundamental frequency of the sub- / super-synchronous oscillation, the method further includes: Based on a preset fundamental standard power frequency, a plurality of target offsets are obtained, and according to the plurality of target offsets and the grid signal sampling frequency, a normalized angular frequency and a filter order of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation are confirmed; Based on the normalized angular frequency and the filter order, constructing a target Fourier matrix and a weighting coefficient vector of the pre-constructed fundamental frequency measurement filter bank under sub- / super-synchronous oscillation; A target intermediate vector is constructed based on the target Fourier matrix and the weighted coefficient vector, and the two-channel coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation are respectively confirmed by using the target intermediate vector.

6. A synchronous phasor measurement device under sub- / super-synchronous oscillation, characterized in that: include: An acquisition module is used to acquire a measured signal segment of a signal sampling sequence of a target power grid, and obtain a filter output value group of the measured signal segment at a measurement time based on the measured signal segment and coefficients of a pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation; A matching module, configured to calculate a fundamental frequency estimation value according to the filter output value group, and use the fundamental frequency estimation value to match a target synchronized phasor measurement filter in a pre-constructed candidate set of synchronized phasor measurement filters under sub- / super-synchronous oscillation; The measuring module is used to calculate based on the coefficient of the target synchronized phasor measurement filter and the measured signal segment to obtain the target filter output value at the measurement moment, so as to perform phase compensation according to the target filter output value to obtain the synchronized phasor measurement value at the measurement moment.

7. The device according to claim 6, characterized in that The matching module comprises: An acquisition unit, used for acquiring a fundamental reference frequency of each synchronized phasor measurement filter in the pre-constructed candidate set of synchronized phasor measurement filters under sub-synchronous / super-synchronous oscillation; A matching unit is used to match a target fundamental wave reference frequency that satisfies a preset approximation condition with the fundamental wave frequency estimation value based on each fundamental wave reference frequency, and the target synchronized phasor measurement filter is confirmed by the synchronized phasor measurement filter corresponding to the target fundamental wave reference frequency.

8. The device according to claim 6, characterized in that The acquisition module comprises: A setting unit, used for setting a data window under a preset power frequency period based on the measurement time; A confirmation unit is used to obtain the measured signal segment from the target power grid signal sampling sequence in the data window.

9. The device according to claim 6, characterized in that The fundamental frequency estimation value calculation formula is: in, is the estimated value of the fundamental frequency, p i is the filter output value group, i=0,1, f0 is the fundamental standard power frequency.

10. The device according to claim 6, characterized in that Also includes: A confirmation module is used to obtain a plurality of target offsets based on a preset fundamental standard power frequency before obtaining a filter output value group of the measured signal segment at the measurement time based on the measured signal segment and the coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation, and confirm the normalized angular frequency and filter order of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation according to the plurality of target offsets and the grid signal sampling frequency; A first construction module is used to construct a target Fourier matrix and a weight coefficient vector of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation based on the normalized angular frequency and the filter order; The second construction module is used to construct a target intermediate vector based on the target Fourier matrix and the weighted coefficient vector, and use the target intermediate vector to respectively confirm the two channel coefficients of the pre-constructed fundamental frequency measurement filter group under sub- / super-synchronous oscillation.

11. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the synchronous phasor measurement method under sub- / super-synchronous oscillation as described in any one of claims 1 to 5.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the synchronous phasor measurement method under sub-synchronous / super-synchronous oscillation as described in any one of claims 1 to 5.

13. A computer program product, comprising a computer program, characterized in that The computer program is executed to implement the synchronized phasor measurement method under sub / super synchronous oscillation as described in any one of claims 1-5.

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