Voltage flicker measurement and evaluation method and device based on DSP

Abstract

The application discloses a voltage flicker measurement and evaluation method and device based on DSP, and the method comprises the following steps: S1, sampling the fluctuating voltage signal according to the set sampling frequency and sampling interval, and calculating the root mean square value of the sampling signal by using the equal interval method to obtain the voltage fluctuation sampling point; S2, judging whether the sampling point number meets the condition of calculating the instantaneous visual sensitivity, if yes, executing step S3, otherwise returning to S1; S3, converting the voltage fluctuation sampling point into a voltage signal suitable for the measurement circuit; S4, performing the envelope line extraction operation on the voltage signal to obtain the input signal instantaneous flicker visual sensitivity value without verification; S5, after verifying the gain value K in the flicker model by using the IEC verification method, performing statistical analysis on the input signal instantaneous flicker visual sensitivity value to obtain the short-time flicker severity value and the long-time flicker severity value, so that the basic requirements of IEC are met, the resource cost is reduced, and the implementation cost is lowered.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power quality detection, more particularly, to a voltage flicker measurement and evaluation method and device based on DSP. BACKGROUND

[0002] With the continuous development of science and technology, the power load structure has changed greatly, and many nonlinear electrical equipment has entered our life, which brings us convenience in life, but also causes power grid voltage fluctuation and flicker, voltage waveform distortion and other power quality problems. In life, for example, computer, power electronics and other equipment have higher requirements for power grid, and the above problems will affect the product operation quality and service life; especially the unstable light brightness caused by flicker will cause people's eye fatigue, vision decline, lack of concentration and other situations. According to the standard published by IEC (International Electrotechnical Commission), voltage flicker is one of the important indicators for evaluating power quality.

[0003] At present, the research and implementation method of voltage flicker is generally divided into two methods: analog and digital implementation. The analog design is mainly based on hardware, but the maintenance and upgrade in the later stage is more complicated, and the instrument price is relatively expensive; with the gradual maturity of digital technology and computer technology in power system, numerical calculation is often used by digital flicker meter, which needs to consider real-time sampling, transmission, input adaptation, calculation, display and storage of voltage signal, and the overall process is more complicated, the detection error is large, the cost is high, and the storage space requirement is high, which is not easy to realize in embedded microprocessor. SUMMARY

[0004] The purpose of the present application is to provide a voltage flicker measurement and evaluation method and device based on DSP, which can reduce resource consumption and reduce implementation cost while meeting the basic requirements of IEC.

[0005] To achieve the above purpose, a voltage flicker measurement and evaluation method based on DSP, comprising:

[0006] S1, sampling the fluctuating voltage signal according to the set sampling frequency and sampling interval, and calculating the root mean square value of the sampling signal by using the equal interval method to obtain the voltage fluctuation sampling point u Rms ;

[0007] S2, judging whether the number of sampling points meets the condition of calculating instantaneous visual sensitivity, if yes, executing step S3, otherwise returning to step S1;

[0008] S3, converting the voltage fluctuation sampling point u Rms into a voltage signal u' Rms suitable for the measurement circuit.

[0009] S4, performing an envelope extraction operation on the voltage signal u' Rms to obtain an unverified input signal instantaneous flicker perceptibility value S'(t);

[0010] S5, verifying the gain value K in the flicker model using an IEC verification method to obtain an input signal instantaneous flicker perceptibility value S(t), and performing statistical analysis to obtain a short-time flicker severity value and a long-time flicker severity value.

[0011] Optionally, in step S1, the fluctuating voltage signal is directly obtained from a metering core of an electric energy meter;

[0012] The root mean square value of the sampling signal is calculated using an equal interval method to obtain a voltage fluctuation sampling point u Rms , comprising:

[0013] The sampling frequency and the sampling interval are determined according to the Nyquist theorem and the limitation of hardware resources, and sampling is performed;

[0014] The root mean square value of the sampling signal is calculated using an equal interval method:

[0015]

[0016] N=N 原始 / (f / 50)

[0017] wherein u Rms (k) is the root mean square value of the sampling signal, N 原始 is the number of points of a single cycle of a power frequency signal, N is the number of original signal points required for calculation of sampling points, u i is the instantaneous value of the sampled voltage waveform, and k represents the number of the sampling point.

[0018] Optionally, in step S3, the voltage fluctuation sampling point u Rms is converted into a voltage signal u' Rms suitable for a measurement circuit through the following formula:

[0019]

[0020] wherein u' Rms (k) is the voltage signal suitable for the measurement circuit at the kth sampling point, u Rms (k) is the sampling value of the kth voltage fluctuation sampling point, M represents the number of sampling points for calculating the instantaneous flicker perceptibility once, and Q is an excitation coefficient.

[0021] Optionally, the envelope extraction operation on the voltage signal u' Rms includes:

[0022] Make the voltage signal u' Rms The unverified input signal instantaneous flicker visibility value S'(t) is obtained by sequentially passing through a 0.05HZ high-pass filter, smoothing processing, a 35HZ low-pass filter, a visual sensitivity weighting filter, and a square and first-order smoothing mean filter.

[0023] Optionally, the smoothing process includes:

[0024] The initial stage of the voltage signal after passing through the 0.05 Hz high-pass filter is smoothed, and the smoothing process is implemented by the following formula:

[0025] num up =min(round(f / 10),length(u hp ))

[0026]

[0027] Among them, the round function is a rounding function, u hp is the voltage signal after high-pass filtering, length(u hp ) is the number of voltage signal points, num up To calculate the upper limit of the number of smoothed data, k = 1, 2…num up , that is u hp (k) first num up Each data is reduced by k / num up times.

[0028] Optionally, in step S4, the 0.05 Hz high-pass filter, the 35 Hz low-pass filter, the visual sensitivity weighted filter, and the square and first-order smoothing mean filter all adopt infinite length unit impulse response digital filters.

[0029] Optionally, in step S5, the IEC verification method is used to verify the gain value K in the flicker model, including:

[0030] Obtain the instantaneous flicker visual sensitivity value S'(t) of the input signal without gain;

[0031] The short-term flicker severity value P is obtained by statistically analyzing the instantaneous flicker visual sensitivity value S(t) of the input signal after the gain value K. st , and the instantaneous flicker visual sensitivity value S'(t) of the input signal without gain is statistically analyzed to obtain the short-term flicker severity value P s ' t ,in,

[0032] The short-time flicker severity value P is set in sequence in the IEC recommended amplitude modulation frequency range st The theoretical value of the short-time flicker severity value P s ' t The correction gain K sequence under each amplitude modulation frequency is obtained, wherein:

[0033] When the amplitude modulation frequency range is 2-20Hz, K takes a fixed value;

[0034] When the amplitude modulation frequency range is out of 2-20Hz, the gain value K sequence is obtained by polynomial fitting through the least square method:

[0035]

[0036] Wherein a, b, c, d, e are coefficients, f AM is the amplitude modulation frequency.

[0037] Optionally, the step S5 further comprises:

[0038] The voltage fluctuation value d is obtained according to the power quality index, and the voltage fluctuation frequency flucFreq is indirectly recorded in the process of calculating the voltage fluctuation value d;

[0039] The waveform type of the amplitude modulation wave is judged, and the specific process is:

[0040] f AM = flucFreq / 2t

[0041]

[0042] According to the definition of the voltage fluctuation frequency, the frequency f AM of the amplitude modulation wave is calculated, t represents time (unit: second), f is the sampling frequency of the power frequency signal, round is the rounding function, and SampleDot represents the sampling point number of the power frequency signal in the corresponding flicker period;

[0043] When the difference between the data of two adjacent sampling points is less than a set threshold, the counter count starts to count, and when the counter count is greater than 30% of the sampling point number of the power frequency signal in the flicker period, the voltage signal contains a rectangular amplitude modulation wave, otherwise the voltage signal contains a sinusoidal amplitude modulation wave.

[0044] Optionally, in step S5, the statistical analysis of the input signal instantaneous flicker visual sensitivity value S(t) comprises:

[0045] All S(t) values in a set time length are obtained, and S(t) values are selected, and the short-time flicker severity P st is calculated by using the sorting method:

[0046] P st = (0.0314P 0.1 + 0.0525P 1s + 0.0657P 3s + 0.28P 10s + 0.08P 50s ) 1 / 2

[0047] Wherein, on the basis of ordering S(t) values from small to large, P 0.1 , P 1s , P 3s , P 10s , P 50s respectively represent the corresponding S(t) value after statistics of all S(t) values in the set duration more than 0.1%, 1%, 3%, 10%, 50% time ratio;

[0048] If the corresponding value cannot be found directly, it is calculated by the following linear interpolation formula:

[0049]

[0050] Wherein, S n , S n+1 represent the adjacent two values of S x to be calculated, x, n represent the index value of the corresponding input signal instantaneous flicker visual sensitivity value S(t);

[0051] Then, the long-time flicker severity value P lt is calculated based on the probability algorithm P st .

[0052] The second aspect, the present application proposes a kind of voltage flicker measurement and evaluation device based on DSP, including embedded microprocessor with DSP function, the embedded microprocessor is used to execute the voltage flicker measurement and evaluation method based on DSP of any one of the first aspect.

[0053] The beneficial effects of the present application are:

[0054] The present application realizes the calculation process in microprocessor, is based on IEC square detection method, considers processor resource consumption and so on, improves its algorithm, including the sampling mode and standardization processing of input signal, adds data smoothing processing process in the envelope extraction process, selects suitable digital filter, finally carries out statistical analysis to flicker value.Satisfy the basic requirement of IEC at the same time, reduce resource consumption, reduce implementation cost.

[0055] The DSP-based voltage flicker measurement and evaluation algorithm of the application directly obtains the fluctuating voltage signal from the metering core of the electric energy meter, saves the digital processing process of the signal, and obtains the flicker value with good precision through calculation, and the implementation process is relatively simple and can be implemented in an embedded microprocessor.

[0056] The system of the application has other characteristics and advantages that will be apparent from and / or set forth in the accompanying drawings and the detailed description that follows, which together serve to explain certain principles of the application. BRIEF DESCRIPTION OF DRAWINGS

[0057] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures.

[0058] Figure 1 is a flow chart of a DSP-based voltage flicker measurement and evaluation method according to an embodiment of the application.

[0059] Figure 2 is a flow chart of the sampling mode and processing process of the voltage signal in a DSP-based voltage flicker measurement and evaluation method according to an embodiment of the application.

[0060] Figure 3 is a flow chart of the calculation of the gain K value in a DSP-based voltage flicker measurement and evaluation method according to an embodiment of the application.

[0061] Figure 4 is a flow chart of the judgment of the waveform type of the amplitude-modulated wave in a DSP-based voltage flicker measurement and evaluation method according to an embodiment of the application. DETAILED DESCRIPTION

[0062] The application will be described in more detail with reference to the drawings, in which the preferred embodiments of the application are shown. It should be understood, however, that the application can be practiced in various forms other than those illustrated and described, and should not be considered limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0063] Example 1

[0064] As shown in Figure 1 , a DSP-based voltage flicker measurement and evaluation method comprises:

[0065] S1, sampling the fluctuation voltage signal according to a set sampling frequency and sampling interval, and calculating the root mean square value of the sampling signal by using an equal interval method to obtain a voltage fluctuation sampling point u Rms ;

[0066] Specifically, the voltage signal with fluctuation is sampled and calculated to obtain a signal u Rms . In this embodiment, the embedded microprocessor is used to complete the collection and operation. Preferably, the single-chip microcomputer uses Cortex-M4 kernel, and the DSP function is self-contained in the kernel, supporting single-precision floating-point operation, and containing high-speed embedded memory (1Mbyte of Flash and 256Kbyte of SRAM). Considering the portability of the design scheme and the stability of the filter, the power grid voltage collection is designed as follows, and the specific process is shown in Figure 2 :

[0067] The maximum frequency of the voltage signal to be analyzed is 50Hz. According to the Nyquist theorem, the sampling frequency needs to be greater than twice the frequency of the analyzed signal. The theoretical value of the sampling frequency is 100Hz. According to the simulation under different sampling frequencies and the limitation of hardware resources, the sampling frequency f is selected. Considering the influence of phase on the sampling point and improving the flicker precision, the root mean square value of the signal is calculated by using the equal interval method to obtain the sampling point u Rms :

[0068]

[0069] N = N 原始 / (f / 50)

[0070] Wherein, N 原始 is the number of points of a single cycle of the power frequency signal, N is the number of original signal points required for calculating the sampling point, u i is the instantaneous value of the sampled voltage waveform, and k represents the number of the sampling point.

[0071] S2, judging whether the number of sampling points meets the condition for calculating the instantaneous visual sensitivity, if yes, executing step S3, otherwise returning to step S1;

[0072] Specifically, the above sampling method is repeated in sequence until the number of points meets the condition for calculating the instantaneous visual sensitivity.

[0073] S3, converting the voltage fluctuation sampling point u Rms into a voltage signal u' Rms suitable for the measurement circuit;

[0074] Specifically, u Rms is converted into a voltage signal suitable for the measurement circuit to obtain u' Rms , and the process is as follows:

[0075]

[0076] Wherein, M represents the number of sampling points for calculating the instantaneous flicker visual sensitivity, Q represents the excitation coefficient, and the value is determined according to the processing effect of the software on the amplitude modulation wave.

[0077] After repeated research, the essence of the calculation process of the fluctuation and flicker of the power grid voltage is to estimate and extract the envelope waveform of the voltage signal, and the effect of envelope extraction will directly affect the final instantaneous flicker visual sensitivity calculation result. The above processing purpose is to make the fluctuation change of the power grid voltage more prominent, ensure the accuracy of the output data of the subsequent filter, and obtain good voltage flicker detection precision.

[0078] S4, extracting an envelope of the voltage signal u Rms to obtain an unverified input signal instantaneous flicker visual sensitivity value S'(t);

[0079] Specifically, the flicker model of the embodiment is composed of a signal collection processor, a 0.05HZ high-pass filter, a smoothing process, a 35HZ low-pass filter, a visual sensitivity weighted filter, a square and first-order smoothing mean filter, a gain K, and a statistical evaluation, etc. The envelope of the processed fluctuation sampling signal u Rms is extracted through the flicker model, specifically including: making the signal pass through the 0.05HZ high-pass filter, the smoothing process, the 35HZ low-pass filter, the visual sensitivity weighted filter, and the square and first-order smoothing mean filter in sequence to obtain the unverified input signal instantaneous flicker visual sensitivity value (curve) S'(t).

[0080] It is found through simulation that the input signal has a relatively large amplitude of oscillation at the starting stage after passing through the 0.05Hz high-pass filter, which greatly affects the flicker precision, and therefore the starting stage of the signal after high-pass filtering needs to be smoothed, and the processing process is as follows:

[0081] num up =min(round(f / 10),length(u hp ))

[0082]

[0083] Wherein, the round function is a rounding function, u hp is the voltage signal after high-pass filtering, length(u hp ) is the number of voltage signal points, num up is the upper limit number of the calculated smoothed data. k=1,2…num up , that is, the first num hp of u upEach data is reduced by k / num up By smoothing, the oscillation amplitude of the high-pass filter output signal in the initial stage can be reduced, and the flicker accuracy can be improved.

[0084] Further, the above filters used in this step are all infinite-length unit impulse response digital filters. In the case of a known transfer function, the digital method is selected to be the bilinear transformation method, and the digitalization process can be completed with the bilinear function in the software, and the function format is:

[0085] [numd,dend] = bilinear(num, den, f s )

[0086] Where f s is the signal sampling frequency, (num, den) is the coefficient matrix of the numerator and denominator of the analog transfer function arranged in descending power, and (numd, dend) is the coefficient matrix after bilinear transformation. According to the above method, the digital filter coefficients are generated by digitizing each filter, and the digital filter function is realized by software programming.

[0087] S5, the gain value K in the flicker model is verified by using the IEC verification method, the input signal instantaneous flicker visual sensitivity value S(t) is obtained, and statistical analysis is performed to obtain the short-time flicker severity value and the long-time flicker severity value.

[0088] Specifically, the gain and flicker statistical process are calculated, and the details are as follows:

[0089] The instantaneous flicker value S(t) of the input signal can be obtained through the gain K (the recommended value is 2). Since this method has a great improvement on the IEC recommended algorithm, in order to improve the flicker accuracy, the K value is verified within the frequency range of the IEC recommended amplitude modulation wave (rectangular wave, sine wave), and the details are as follows:

[0090] The input signal instantaneous flicker visual sensitivity value S(t) and the input signal instantaneous flicker visual sensitivity value S'(t) without gain are respectively statistically obtained. The short-time flicker P st , P s ' t , and the theoretical relationship between the two is Within the frequency range of the IEC recommended amplitude modulation wave, the P st theoretical value is sequentially set, and according to P s ' t The correction gain K sequence under each frequency can be obtained, such as Figure 3K value changes little in the frequency range of 2-20 Hz, and K takes a fixed value under the premise of meeting the accuracy; the least square method is used for fitting in the high and low frequency bands of the amplitude modulation wave respectively, and the fitting polynomial result of the high frequency band of 20-33.33 Hz is:

[0091]

[0092] Wherein a = 0.0001608, b = -0.015967, c = 0.5862591, d = -9.454812, e = 58.6000893, f AM represents the frequency of the amplitude modulation wave.

[0093] Further, the waveform type judgment of the amplitude modulation wave signal is based on the voltage fluctuation value d known from the power quality index, and the voltage fluctuation frequency flucFreq is indirectly recorded in the process of calculating d, so as to judge the waveform type of the amplitude modulation wave, such as Figure 4 as shown, and the specific process is as follows:

[0094] f AM = flucFreq / 2t

[0095]

[0096] According to the definition of the voltage fluctuation frequency, the frequency f AM of the amplitude modulation wave is calculated, t represents time (unit: second), f is the sampling frequency of the power frequency signal, round is the rounding function, and SampleDot represents the sampling point number of the power frequency signal in the corresponding flicker period. When the difference between adjacent two sampling point data is less than the set threshold, the count starts to count, and when the count is greater than 30% of the sampling point number of the power frequency signal in the flicker period, it is considered that the voltage signal contains rectangular amplitude modulation wave, otherwise it is considered that the voltage signal contains sinusoidal amplitude modulation wave.

[0097] When Freq is greater than 20 Hz, the count value is relatively small, which corresponds to the high-frequency flicker signal: the judgment method is similar to that of the low-frequency flicker signal, and the difference lies in the number of sampling points. The number of sampling points SampleDot is 10 times of the low-frequency signal.

[0098] Further, statistical analysis is performed on the input signal flicker S(t), and in principle, all S(t) values in 10 minutes are calculated. Considering that the data amount is large and the present application is implemented in a microprocessor, the S(t) value needs to be selected: in principle, the larger the proportion factor f scale , the less the resource consumption (small data amount), and for the amplitude modulation wave frequency greater than 3 Hz or so, because the S(t) value distribution is relatively uniform, the f scale value size has little effect on the final calculation Pst On the contrary, for small amplitude modulation wave frequencies (such as 0.5Hz, 1Hz, etc.), the calculated values ​​of S(t) are relatively scattered, and f scale P st The calculation result has a large error, so when considering the microprocessor resources, the accuracy of the flicker value must also be considered. st , the process is as follows:

[0099] P st =(0.0314P 0.1 +0.0525P 1s +0.0657P 3s +0.28P 10s +0.08P 50s ) 12

[0100] Among them, on the basis of sorting the S(t) values ​​from small to large, P 0.1 ,P 1s ,P 3s ,P 10s ,P 50s They represent the S(t) values ​​corresponding to the time ratios exceeding 0.1%, 1%, 3%, 10%, and 50% after counting all S(t) values ​​within 10 minutes. If the corresponding values ​​cannot be found directly, they can be calculated using the following linear interpolation:

[0101]

[0102] Among them, S n 、S n+1 Indicates S to be calculated x Two adjacent values, x and n, represent the index values ​​of S(t). Finally, based on the probability statistics algorithm, P st Calculate the long-term flicker severity P lt :

[0103]

[0104] Among them, N = 12 means calculating P within 2 hours lt value.

[0105] In specific implementation:

[0106] like Figure 2 As shown, the specific steps of the signal sampling method and processing process of this embodiment are:

[0107] (1) Input fluctuating voltage u i Obtained from the metering core of the energy meter and generated by an external standard flicker meter;

[0108] (2) Sampling: the root mean square value of the fluctuation signal is calculated according to the equal interval method to obtain a sampling point u Rms ;

[0109] (3) The sampling quantity is incremented by index++, and it is judged whether the sampling quantity satisfies the condition for calculating the flicker. If not, the data pointer points to the next data area to be sampled, and the process is repeated according to the sampling method until the point quantity satisfies the condition for calculating the instantaneous visual perception.

[0110] (4) The sampling signal with fluctuation is converted into a voltage signal u' suitable for the measurement circuit Rms ;

[0111] (5) The envelope line is extracted from the processed fluctuation sampling signal, and the flicker statistics of the input signal are completed.

[0112] As shown in Figure 3 , the steps for calculating the gain K in the embodiment are as follows:

[0113] (1) According to the amplitude modulation wave information recommended by IEC, the fluctuation frequency and fluctuation amplitude of the amplitude modulation wave signal are set respectively;

[0114] (2) The amplitude modulation wave signal passes through the envelope extraction model (i.e. passes through steps S1-S4, and the gain is not set), to obtain the sequence S'(t) without gain K correction;

[0115] (3) According to the obtained S'(t) sequence, the statistical calculation is performed to obtain the short-time flicker value P' st ;

[0116] (4) According to the set short-time flicker theoretical value of the amplitude modulation wave signal, the gain K value of the signal is obtained according to the calculation formula ;

[0117] (5) The above steps (1-4) are repeated, and the IEC recommended amplitude modulation wave signal is set in turn to obtain the corresponding gain K(f) sequence.

[0118] As shown in Figure 4 , the specific steps for judging the waveform type of the amplitude modulation wave in the embodiment are as follows:

[0119] (1) Based on the voltage fluctuation frequency flucFreq, the amplitude modulation wave frequency Freq and the sampling point number SampleDot of the power frequency signal in the corresponding flicker period are calculated;

[0120] (2) According to the size of the amplitude modulation wave frequency Freq, the sampling point number required in the process of judging the waveform type of the amplitude modulation wave is determined;

[0121] (3) The difference between two adjacent sampling points is calculated, and when the result is less than a set threshold, the count starts to count, and the above operation process is sequentially cycled, and the cycle number is SampleDot times.

[0122] (4) When the count is greater than 30% of the sampling point number of the power frequency signal in the flicker period, it is considered that the voltage signal contains a rectangular amplitude modulation wave, otherwise it is considered that the voltage signal contains a sinusoidal amplitude modulation wave.

[0123] Embodiment 2

[0124] The embodiment provides a voltage flicker measurement and evaluation device based on a DSP, which comprises an embedded microprocessor with a DSP function, and the embedded microprocessor is used for executing the voltage flicker measurement and evaluation method based on the DSP shown in the embodiment 1.

[0125] Preferably, the embedded microprocessor of the embodiment is a single-chip microcomputer with a Cortex-M4 core, the single-chip microcomputer core is self-provided with a DSP function, supports single-precision floating point operation, and comprises high-speed embedded memory (1Mbyte of Flash and 256Kbyte of SRAM).

[0126] To sum up, the input fluctuation voltage is obtained from a metering core of an electric energy meter, is generated through an external standard flicker meter, and then is sampled and processed, envelope line extraction work is performed, the input signal instantaneous flicker visual sensitivity value is obtained through calculation, and statistical analysis is performed on the flicker value. The above series of flicker calculation processes are realized through the embedded microprocessor, so that the problems of complicated calculation process, high storage space requirement and difficulty in realizing the embedded microprocessor are solved.

[0127] The above has described the embodiments of the application, and the above description is exemplary, is not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A DSP-based voltage flicker measurement and evaluation method, characterized by, Comprise: S1, sampling the fluctuation voltage signal according to a set sampling frequency and sampling interval, and calculating the root mean square value of the sampling signal using an equal interval method to obtain voltage fluctuation sampling points ; S2, judge whether the sampling point number satisfies the condition of calculating instantaneous visual sensitivity, if yes, execute step S3, otherwise return to step S1; S3, converting the voltage fluctuation sampling points to a voltage signal suitable for the measurement circuit ; S4, performing an envelope extraction operation on the voltage signal to obtain an unverified input signal instantaneous flicker perceptibility value ; S5, the gain value K in the flicker model is checked by using the IEC checking method, and the input signal instantaneous flicker visual sensitivity value is obtained And the short-time flicker severity value and the long-time flicker severity value are obtained by statistical analysis.

2. The voltage flicker measurement and evaluation method according to claim 1, characterized in that, In step S1, the fluctuation voltage signal is directly obtained from the metering core of the electric energy meter; The root mean square value of the sampling signal is calculated by using the equal interval method to obtain the voltage fluctuation sampling point , comprising: The sampling frequency and the sampling interval are determined according to the Nyquist theorem and the limitation of hardware resources, and sampling is performed; The equal interval method is adopted to calculate the root mean square value of the sampling signal: ， wherein, is the root mean square value of the sampled signal, is the number of points of the single cycle power frequency signal, is the number of original signal points required to calculate the sampling points, is the instantaneous value of the sampled voltage waveform, k represents the kth sampling point, is the sampling frequency of the power frequency signal.

3. The voltage flicker measurement and evaluation method according to claim 2, characterized in that In step S3, the voltage fluctuation sampling point is converted into a voltage signal suitable for the measuring circuit by the following equation: ， wherein, V(k) is the voltage signal of the suitable measurement circuit for the kth sampling point, V(k) is the sampling value of the kth voltage fluctuation sampling point, and M represents the number of sampling points for calculating the instantaneous flicker visual sensitivity once, is the excitation coefficient.

4. The voltage flicker measurement and evaluation method according to claim 1, characterized in that, The voltage signal is analyzed by a flicker model The envelope extraction operations include: voltage signal in succession high-pass filter, smoothing process, low-pass filter, a visibility weighted filter and a sum-of-squares first-order smoothing mean filter, to obtain an unverified input signal instantaneous flicker visibility value .

5. The voltage flicker measurement and evaluation method according to claim 4, characterized in that, The smoothing processing comprises: Regarding the The high-pass filter performs smoothing at the initial stage of the voltage signal. The smoothing process is achieved by the following formula: ， wherein, The function is a rounding function, is a high-pass filtered voltage signal, is the number of voltage signal points, is the number of upper limit points of the smoothed data, , is the sampling frequency of the power frequency signal.

6. The voltage flicker measurement and evaluation method according to claim 4, characterized in that, In step S4, the The high-pass filter, the The low-pass filter, the visibility weighting filter, and the square and first-order smoothing mean filter employ infinite-length unit impulse response digital filters.

7. The voltage flicker measurement and evaluation method according to claim 1, characterized in that, In step S5, the gain value K in the flicker model is checked by adopting the IEC checking method, comprising: Acquiring an input signal instantaneous flicker perceptibility value without gain ; the input signal transient flicker perceptibility value the short term flicker value severity value the input signal transient flicker perceptibility value the short term flicker value severity value wherein ; The short-time flicker severity values are set in order in the IEC recommended range of the amplitude modulation wave frequency The theoretical value of the short-time flicker severity value The correction gain K sequence at each amplitude modulation wave frequency is obtained according to the short-time flicker severity value When the amplitude modulation wave frequency range is 2-20Hz, K takes a fixed value; When the amplitude modulation wave frequency range is out of 2-20Hz, the gain value K sequence polynomial is obtained by least square fitting: ， wherein is a coefficient, is the amplitude modulation wave frequency.

8. The voltage flicker measurement and evaluation method according to claim 7, characterized in that, The step S5 further comprises: The voltage fluctuation value is obtained according to the power quality index, and the voltage variation frequency is indirectly recorded in the process of calculating the voltage fluctuation value ; The waveform type of the amplitude modulation wave is judged, and the specific process is: ， According to the definition of the frequency of the voltage variation, the frequency of the amplitude-modulated wave is calculated t is time, in seconds, is the sampling frequency of the power frequency signal, is the rounding function, represents the number of sampling points of the power frequency signal within the corresponding flicker period; When the data of two adjacent sampling points is subtracted and is less than a set threshold, a counter starts counting, and when the counter is greater than 30% of the number of sampling points of the power frequency signal in the flicker cycle, then the voltage signal contains a rectangular amplitude modulation wave, and otherwise, the voltage signal contains a sinusoidal amplitude modulation wave.

9. The voltage flicker measurement and evaluation method according to claim 1, characterized in that, In step S5, the input signal instantaneous flicker perceptibility value The statistical analysis comprises: Obtaining all of the values within a set time length and selecting the values, calculating the short-time flicker severity using the ranking method : ， Wherein, in the process of setting values are sorted from small to large basis, respectively, the set duration within all value statistics after more than time corresponding to the value; If the corresponding value cannot be directly found, it is calculated by the following linear interpolation formula: ， wherein, denotes the value to be calculated the two values adjacent to denotes the index value of the corresponding input signal instantaneous flicker perceptibility value ; Thereafter, the long-time flicker severity value is calculated based on the probabilistic algorithm from calculating long-time flicker severity values .

10. A DSP-based voltage flicker measurement and evaluation device, characterized by Comprise an embedded microprocessor with DSP function, the embedded microprocessor is used for executing the voltage flicker measurement and evaluation method based on DSP in any one of claims 1-9.

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