Distributed power grid power quality early warning method and device, terminal and storage medium

Abstract

The present application relates to the technical field of power grid operation monitoring, and particularly relates to a distributed power grid power quality early warning method, device, terminal and storage medium, the method of the present application first acquires the bus waveform of a bus; then, waveform analysis is performed on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators; next, according to the bus waveform, influence analysis is performed on a plurality of feeder waveforms to determine a plurality of pending feeder waveforms; finally, waveform analysis is performed on the plurality of pending feeder waveforms to determine a target feeder. In the present application, the influence analysis and the feeder waveform analysis for the problem point are used to replace the waveform transformation analysis of the plurality of feeders, so that the calculation cost is low, the work efficiency is high, the positioning is more accurate, and the real-time performance is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid operation monitoring, and in particular to a distributed power grid power quality early warning method, device, terminal and storage medium. Background Art

[0002] Distributed generators (DG) typically refer to small, modular, decentralized power generation units ranging from a few kilowatts to hundreds of megawatts, typically located near users. They require minimal investment, require minimal floor space, have a short construction period, are energy-efficient and environmentally friendly, and are more economical and effective than traditional methods during peak load periods.

[0003] However, grid-connected distributed generation (DGs) can cause issues such as frequency deviation, voltage fluctuation, voltage flicker, voltage imbalance, harmonic distortion, and DC injection. Accurately and comprehensively extracting and locating power quality (PQ) status factors is crucial for enabling DGs to access the grid based on power quality pricing and improving the overall PQ level of distribution networks.

[0004] The existing power quality monitoring and analysis method is to monitor the voltage, current and frequency of the monitoring point, analyze the collected data, and calculate the power quality indicators such as voltage deviation, voltage fluctuation and flicker, harmonic distortion, three-phase imbalance and frequency fluctuation at the monitoring point.

[0005] Due to the large number of nodes in the power grid, the analysis of power quality is mostly based on multiple nodes, and the collected data is analyzed in many aspects, resulting in large amount of calculation, low analysis efficiency and poor real-time performance during power quality analysis.

[0006] Based on this, it is necessary to develop and design a distributed power grid power quality early warning method. Summary of the Invention

[0007] The embodiments of the present invention provide a distributed power grid power quality early warning method, device, terminal and storage medium, which are used to solve the problem of low power quality analysis efficiency in the prior art.

[0008] In a first aspect, an embodiment of the present invention provides a distributed power grid power quality early warning method, comprising:

[0009] Get the bus waveform of the bus;

[0010] Performing waveform analysis on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators;

[0011] performing an impact analysis on a plurality of feeder waveforms based on the bus waveform to determine a plurality of feeder waveforms to be determined, wherein the plurality of feeder waveforms correspond to a plurality of feeders connected to the bus, and the plurality of feeders input and / or output electric energy to the bus;

[0012] Waveform analysis is performed on the multiple feeder waveforms to determine a target feeder, wherein the target feeder is a feeder that causes power quality degradation in the power grid.

[0013] In one possible implementation, performing waveform analysis on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators includes:

[0014] Sampling the waveform of the bus to obtain a plurality of sampling data;

[0015] Extracting a preset number of sample data from the plurality of sample data in a predetermined order to form a first sample group;

[0016] The waveform margin determination step is to determine the waveform margin according to the first sample group and a first formula, wherein the first formula is:

[0017]

[0018] Where Δα is the waveform margin, N is the number of sampled data in the first sample group, and ws(n) is the nth sampled data in the first sample group;

[0019] If the waveform margin exceeds a threshold, extracting data from the plurality of sampled data in a predetermined order and adding the data to the first sample group and jumping to the waveform margin determination step;

[0020] Performing waveform transformation on the first sample group to obtain a fundamental wave and multiple harmonics;

[0021] The plurality of power quality data are determined according to the fundamental wave and the plurality of harmonics.

[0022] In one possible implementation, performing waveform transformation on the first sample group to obtain a fundamental wave and multiple harmonics includes:

[0023] determining the frequency of the bus waveform according to the number of sampled data and the sampling time interval in the first sample group;

[0024] The fundamental wave amplitude of the fundamental wave and the amplitudes of the multiple harmonics corresponding to the multiple harmonics are determined according to the first sample group and a second formula, wherein the second formula is:

[0025]

[0026] Where vol(k) is the amplitude of the kth wave, N is the number of sampled data in the first sample group, ws(n) is the nth sampled data in the first sample group, e is a natural constant, i is an imaginary unit, and π is the ratio of circumference to circumference.

[0027] In one possible implementation, the multiple power quality data include: a voltage waveform distortion coefficient, a current harmonic coefficient, and a voltage deviation; the bus waveform includes a voltage waveform and a current waveform; and determining the multiple power quality data based on the fundamental wave and the multiple harmonics includes:

[0028] According to the fundamental wave, the multiple harmonics, and a third formula, a plurality of harmonic ratios corresponding to the multiple harmonics are determined, wherein the harmonic ratio represents the ratio of the harmonics in the bus waveform, and the third formula is:

[0029]

[0030] Where ratio(k) is the ratio of the amplitude of the kth harmonic to the amplitude of the fundamental wave, vol(k) is the amplitude of the kth harmonic, and vol(1) is the amplitude of the fundamental wave;

[0031] The harmonic rate with the largest value among the multiple harmonic rates of the voltage waveform is used as the voltage waveform distortion coefficient, and the harmonic rate with the largest value among the multiple harmonic rates of the current waveform is used as the current harmonic coefficient;

[0032] The voltage deviation is determined according to the amplitude of the fundamental wave of the voltage waveform and a preset voltage value.

[0033] In one possible implementation, performing an impact analysis on multiple feeder waveforms based on the bus waveform to determine multiple feeder waveforms to be determined includes:

[0034] Determine a first sample group according to the waveform of the bus, wherein the first sample group includes a plurality of sample data obtained by sampling within at least one complete cycle of the bus waveform;

[0035] Acquire multiple second sample groups corresponding to the multiple feeder waveforms according to the time node at which sampling of the first sample group starts and the amount of sampled data in the first sample group, wherein the sampling time interval of the second sample groups is the same as the sampling time interval of the first sample group;

[0036] A plurality of influence coefficients are determined according to the first sample group, the plurality of second sample groups, and a fourth formula, wherein the fourth formula is:

[0037]

[0038] Where, Eff mis the influence coefficient of the waveform of the mth feeder on the bus waveform, ws(n) is the nth sampling data in the first sample group, ts m (n) is the nth sample data in the second sample group corresponding to the waveform of the mth feeder, and N is the number of sample data in the first sample group;

[0039] Selecting a preset number of undetermined feeder coefficients from the multiple influence coefficients according to the magnitudes of the multiple influence coefficients;

[0040] Feeder waveforms corresponding to the preset number of undetermined feeder coefficients are obtained as a plurality of undetermined feeder waveforms.

[0041] In one possible implementation, if the cause of the power quality degradation is voltage waveform distortion or current harmonics, performing waveform analysis on the waveforms of the multiple feeders to be determined to determine the target feeder includes:

[0042] Obtaining the period of the bus waveform;

[0043] Determining a plurality of harmonic rates included in the plurality of feeder waveforms to be determined based on the orders of the harmonics that cause the power quality data to degrade, wherein the harmonic rates represent the waveforms containing the harmonic rates that cause the power quality data to degrade;

[0044] The feeder corresponding to the harmonic rate with the largest value is selected as the target feeder.

[0045] In one possible implementation, determining the multiple harmonic rates included in the multiple pending feeder waveforms based on the orders of the harmonics that cause the power quality data to degrade includes:

[0046] Determine a plurality of harmonic rates included in the plurality of feeder waveforms to be determined based on the order of the harmonic that causes the power quality data to degrade, the fifth formula, and the plurality of feeder waveforms to be determined, wherein the fifth formula is:

[0047]

[0048] Where HR(m) is the harmonic rate of the harmonic that causes power quality degradation in the mth feeder, cos() is the cosine function, sin() is the sine function, T is the period of the bus waveform, ω is the angular frequency of the fundamental wave of the bus waveform, k is the order of the harmonic that causes power quality degradation, and ts m (t) is the waveform of the mth feeder.

[0049] In a second aspect, an embodiment of the present invention provides a distributed power grid power quality early warning device, configured to implement the distributed power grid power quality early warning method described in the first aspect or any possible implementation of the first aspect, the distributed power grid power quality early warning device comprising:

[0050] A bus waveform acquisition module, used to obtain the bus waveform of the bus;

[0051] A bus waveform analysis module, configured to perform waveform analysis on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators;

[0052] a feeder impact analysis module, configured to perform an impact analysis on a plurality of feeder waveforms based on the bus waveform, and determine a plurality of pending feeder waveforms, wherein the plurality of feeder waveforms correspond to a plurality of feeders connected to the bus, and the plurality of feeders input and / or output electrical energy to the bus;

[0053] as well as,

[0054] A feeder positioning module is used to perform waveform analysis on the multiple feeder waveforms to be determined to determine a target feeder, wherein the target feeder is the feeder that causes the power quality of the power grid to deteriorate.

[0055] In a third aspect, an embodiment of the present invention provides a terminal comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, it implements the steps of the method described in the first aspect or any possible implementation of the first aspect.

[0056] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the method described in the first aspect or any possible implementation of the first aspect.

[0057] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0058] An embodiment of the present invention discloses an implementation method for a distributed power grid power quality early warning method, which first obtains a bus waveform of a bus; then, performs waveform analysis on the bus waveform to determine multiple power quality data corresponding to multiple power indicators; then, based on the bus waveform, performs impact analysis on multiple feeder waveforms to determine multiple pending feeder waveforms, wherein the multiple feeder waveforms correspond to multiple feeders, the multiple feeders are connected to the bus, and the multiple feeders input and / or output electric energy to the bus; finally, performs waveform analysis on the multiple pending feeder waveforms to determine a target feeder, wherein the target feeder is a feeder that causes the power quality of the power grid to deteriorate. In an embodiment of the present invention, a waveform analysis is first performed on the bus to determine the problem points of the bus waveform power quality. Then, an impact analysis is performed on multiple feeders. The impact analysis characterizes the impact of the feeder on the bus waveform, so as to select one or more suspicious feeders to be determined. The waveform analysis of the multiple feeders to be determined is performed based on the quality problem points of the bus waveform, so as to locate the feeder that causes the bus power quality to deteriorate. In an embodiment of the method of the present invention, since the waveform transformation analysis of multiple feeders is replaced by the impact analysis and the analysis of the problem points, the computational cost is low, the work efficiency is high, the positioning is more accurate, and the real-time performance is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0060] Figure 1 This is a flow chart of a distributed power grid power quality early warning method provided by an embodiment of the present invention;

[0061] Figure 2 This is a distributed power grid topology diagram provided by an embodiment of the present invention;

[0062] Figure 3 This is a functional block diagram of a distributed power grid power quality early warning device provided by an embodiment of the present invention;

[0063] Figure 4 This is a functional block diagram of a terminal provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0064] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in alternative embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0065] In order to make the objectives, technical solutions and advantages of the present invention more clear, the following will be described through specific implementation methods in conjunction with the accompanying drawings.

[0066] The following is a detailed description of an embodiment of the present invention. This example is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiment.

[0067] Figure 1 This is a flow chart of a distributed power grid power quality early warning method provided by an embodiment of the present invention.

[0068] like Figure 1 As shown, it shows a flow chart of the implementation of the distributed power grid power quality early warning method provided by the embodiment of the present invention, which is detailed as follows:

[0069] In step 101, a bus waveform of a bus is obtained.

[0070] In step 102, waveform analysis is performed on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators.

[0071] In some embodiments, step 102 includes:

[0072] Sampling the waveform of the bus to obtain a plurality of sampling data;

[0073] Extracting a preset number of sample data from the plurality of sample data in a predetermined order to form a first sample group;

[0074] The waveform margin determination step is to determine the waveform margin according to the first sample group and a first formula, wherein the first formula is:

[0075]

[0076] Where Δα is the waveform margin, N is the number of sampled data in the first sample group, and ws(n) is the nth sampled data in the first sample group;

[0077] If the waveform margin exceeds a threshold, extracting data from the plurality of sampled data in a predetermined order and adding the data to the first sample group and jumping to the waveform margin determination step;

[0078] Performing waveform transformation on the first sample group to obtain a fundamental wave and multiple harmonics;

[0079] The plurality of power quality data are determined according to the fundamental wave and the plurality of harmonics.

[0080] In some implementations, performing waveform transformation on the first sample group to obtain a fundamental wave and multiple harmonics includes:

[0081] determining the frequency of the bus waveform according to the number of sampled data and the sampling time interval in the first sample group;

[0082] The fundamental wave amplitude of the fundamental wave and the amplitudes of the multiple harmonics corresponding to the multiple harmonics are determined according to the first sample group and a second formula, wherein the second formula is:

[0083]

[0084] Where vol(k) is the amplitude of the kth wave, N is the number of sampled data in the first sample group, ws(n) is the nth sampled data in the first sample group, e is a natural constant, i is an imaginary unit, and π is the ratio of circumference to circumference.

[0085] In some embodiments, the plurality of power quality data includes: a voltage waveform distortion coefficient, a current harmonic coefficient, and a voltage deviation; the bus waveform includes a voltage waveform and a current waveform; and determining the plurality of power quality data based on the fundamental wave and the plurality of harmonics includes:

[0086] According to the fundamental wave, the multiple harmonics, and a third formula, a plurality of harmonic ratios corresponding to the multiple harmonics are determined, wherein the harmonic ratio represents the ratio of the harmonics in the bus waveform, and the third formula is:

[0087]

[0088] Where ratio(k) is the ratio of the amplitude of the kth harmonic to the amplitude of the fundamental wave, vol(k) is the amplitude of the kth harmonic, and vol(1) is the amplitude of the fundamental wave;

[0089] The harmonic rate with the largest value among the multiple harmonic rates of the voltage waveform is used as the voltage waveform distortion coefficient, and the harmonic rate with the largest value among the multiple harmonic rates of the current waveform is used as the current harmonic coefficient;

[0090] The voltage deviation is determined according to the amplitude of the fundamental wave of the voltage waveform and a preset voltage value.

[0091] For example, Figure 2As shown in the figure, the topology diagram of a distributed distribution network is shown. In the figure, the transformer 201 supplies power to multiple feeders 203 through the bus 202, or receives electric energy from the feeder 203. When the load 205 is connected to the feeder 203, it receives electric energy from the feeder 203, and the distributed power source 204, for example, a solar power generation device, is connected to the bus 202 through the feeder 203 to generate electricity.

[0092] As mentioned above, power quality includes voltage deviation, voltage fluctuation and flicker, voltage waveform distortion, three-line imbalance, frequency fluctuation, and current harmonics. Among them, voltage waveform distortion and voltage deviation are mostly caused by distributed power generation connected to the grid, while current harmonics may be caused by both distributed power generation connected to the grid and load power consumption.

[0093] Due to the complex currents in distributed distribution networks, the existing technology obtains the problems of power quality by analyzing the waveforms of the busbars and feeders. This analysis method has a large amount of calculation, which further leads to poor positioning effect and poor real-time performance.

[0094] The embodiment of the present invention adopts the method of obtaining the bus waveform. The bus waveform may be the bus voltage waveform, the bus current waveform, or both, depending on the target of the power quality to be analyzed.

[0095] For example, when analyzing the voltage waveform distortion as above, the bus voltage should be obtained, and when analyzing the current harmonics, the bus voltage and bus current should be obtained.

[0096] One method for analyzing the bus waveform is to sample the bus waveform and obtain multiple data, and determine its period according to the first formula. The first formula is:

[0097]

[0098] Where Δα is the waveform margin, N is the number of sampled data in the first sample group, and ws(n) is the nth sampled data in the first sample group;

[0099] As can be seen, this formula obtains the sum of multiple sampled data. If the multiple sampled data are close to one or more integer periods, this sum will tend to 0. In other words, if the waveform margin calculated by the above formula for multiple consecutive data is 0, then these consecutive data are data of one or more waveform periods.

[0100] Based on the data of the waveform period, transformation can be performed to obtain the fundamental wave and multiple harmonics. Generally speaking, the number of multiple harmonics is not less than 20.

[0101] As for the waveform transformation method, in one method, first, the frequency of the bus waveform is determined by the total amount of sampling data and the sampling time interval. For example, the total amount of sampling data is A and the interval is B. Obviously, the period of the bus waveform is (A-1)B, and the frequency of the bus waveform is the inverse of the period of the bus waveform.

[0102] After knowing the frequency of the bus waveform, it can be transformed according to its frequency, as shown in the second formula:

[0103]

[0104] Where vol(k) is the amplitude of the kth wave, N is the number of sampled data in the first sample group, ws(n) is the nth sampled data in the first sample group, e is a natural constant, i is an imaginary unit, and π is the ratio of circumference to circumference.

[0105] The amplitude of the corresponding wave can be obtained through the above formula.

[0106] Furthermore, we can perform power quality analysis of the bus waveform based on the amplitude of each wave. For example, the voltage waveform distortion coefficient (the principle of current harmonic coefficient is the same as that of voltage waveform distortion coefficient) can be analyzed and determined according to the third formula to determine the ratio of harmonics to fundamental wave:

[0107]

[0108] Where ratio(k) is the ratio of the amplitude of the kth harmonic to the amplitude of the fundamental wave, vol(k) is the amplitude of the kth harmonic, and vol(1) is the amplitude of the fundamental wave;

[0109] If one or more of the highest harmonic ratios exceeds the specification, it is obvious that the bus waveform has a voltage waveform distortion problem.

[0110] For another example, the voltage deviation problem is generally determined by the amplitude of the fundamental wave and the amplitude of the target voltage.

[0111] In step 103, based on the bus waveform, an impact analysis is performed on multiple feeder waveforms to determine multiple feeder waveforms to be determined, wherein the multiple feeder waveforms correspond to multiple feeders, the multiple feeders are connected to the bus, and the multiple feeders input and / or output electric energy to the bus.

[0112] In some embodiments, step 103 includes:

[0113] Determine a first sample group according to the waveform of the bus, wherein the first sample group includes a plurality of sample data obtained by sampling within at least one complete cycle of the bus waveform;

[0114] Acquire multiple second sample groups corresponding to the multiple feeder waveforms according to the time node at which sampling of the first sample group starts and the amount of sampled data in the first sample group, wherein the sampling time interval of the second sample groups is the same as the sampling time interval of the first sample group;

[0115] A plurality of influence coefficients are determined according to the first sample group, the plurality of second sample groups, and a fourth formula, wherein the fourth formula is:

[0116]

[0117] Where, Eff m is the influence coefficient of the waveform of the mth feeder on the bus waveform, ws(n) is the nth sampling data in the first sample group, ts m (n) is the nth sample data in the second sample group corresponding to the waveform of the mth feeder, and N is the number of sample data in the first sample group;

[0118] Selecting a preset number of undetermined feeder coefficients from the multiple influence coefficients according to the magnitudes of the multiple influence coefficients;

[0119] Feeder waveforms corresponding to the preset number of undetermined feeder coefficients are obtained as a plurality of undetermined feeder waveforms.

[0120] Illustratively, in an embodiment of the present invention, an attempt is made to find one or more suspicious feeders from multiple feeders and conduct targeted and in-depth analysis, thereby reducing the amount of calculation and achieving the purpose of accurate positioning.

[0121] Therefore, a plurality of feeder sample groups are obtained according to the bus waveform sample group, and the number of samples in the feeder sample group is the same as that of the bus waveform sample group and is contemporaneous.

[0122] According to the fourth formula, multiple influence coefficients are obtained:

[0123]

[0124] Where, Eff m is the influence coefficient of the waveform of the mth feeder on the bus waveform, ws(n) is the nth sampling data in the first sample group, ts m (n) is the nth sample data in the second sample group corresponding to the waveform of the mth feeder, and N is the number of sample data in the first sample group.

[0125] Multiple influence coefficients represent the coefficients of multiple feeders affecting the busbar waveform shape. According to the size of the coefficient value, one or more largest influence coefficients are selected, and the waveforms of multiple feeders are determined based on the influence coefficients. These waveforms are used as key waveforms for waveform analysis.

[0126] In step 104, waveform analysis is performed on the multiple feeder waveforms to be determined to determine a target feeder, wherein the target feeder is a feeder that causes power quality degradation in the power grid.

[0127] In some embodiments, if the cause of power quality degradation is voltage waveform distortion or current harmonics, step 104 includes:

[0128] Obtaining the period of the bus waveform;

[0129] Determining a plurality of harmonic rates included in the plurality of feeder waveforms to be determined based on the orders of the harmonics that cause the power quality data to degrade, wherein the harmonic rates represent the waveforms containing the harmonic rates that cause the power quality data to degrade;

[0130] The feeder corresponding to the harmonic rate with the largest value is selected as the target feeder.

[0131] In some embodiments, determining a plurality of harmonic rates included in the plurality of pending feeder waveforms based on the orders of harmonics causing power quality data degradation comprises:

[0132] Determine a plurality of harmonic rates included in the plurality of feeder waveforms to be determined based on the order of the harmonic that causes the power quality data to degrade, the fifth formula, and the plurality of feeder waveforms to be determined, wherein the fifth formula is:

[0133]

[0134] Where HR(m) is the harmonic rate of the harmonic that causes power quality degradation in the mth feeder, cos() is the cosine function, sin() is the sine function, T is the period of the bus waveform, ω is the angular frequency of the fundamental wave of the bus waveform, k is the order of the harmonic that causes power quality degradation, and ts m (t) is the waveform of the mth feeder.

[0135] For example, waveform analysis is a targeted analysis of problems that arise in the bus waveform power quality.

[0136] For example, if the quality analysis of the busbar waveform determines that the voltage waveform is distorted, and the harmonic frequency that mainly causes the waveform distortion is the kth, then a harmonic analysis should be performed on the kth harmonic of the feeder.

[0137] Specifically, the harmonic ratios of multiple suspicious feeders are obtained, and the feeder with the largest harmonic ratio is selected as the target feeder, thereby locating the feeder.

[0138] The harmonic rate is determined by the fifth formula:

[0139]

[0140] Where HR(m) is the harmonic rate of the harmonic that causes power quality degradation in the mth feeder, cos() is the cosine function, sin() is the sine function, T is the period of the bus waveform, ω is the angular frequency of the fundamental wave of the bus waveform, k is the order of the harmonic that causes power quality degradation, and ts m (t) is the waveform of the mth feeder

[0141] The present invention provides an implementation method for a distributed power grid power quality early warning method, which first obtains a bus waveform of a bus; then, performs waveform analysis on the bus waveform to determine multiple power quality data corresponding to multiple power indicators; then, based on the bus waveform, performs impact analysis on multiple feeder waveforms to determine multiple pending feeder waveforms, wherein the multiple feeder waveforms correspond to multiple feeders, the multiple feeders are connected to the bus, and the multiple feeders input and / or output power to the bus; finally, performs waveform analysis on the multiple pending feeder waveforms to determine a target feeder, wherein the target feeder is a feeder that causes a decrease in power quality in the power grid. In an embodiment of the present invention, a waveform analysis is first performed on the bus to determine the problem points of the bus waveform power quality. Then, an impact analysis is performed on multiple feeders. The impact analysis characterizes the impact of the feeder on the bus waveform, so as to select one or more suspicious feeders to be determined. The waveform analysis of the multiple feeders to be determined is performed based on the quality problem points of the bus waveform, so as to locate the feeder that causes the bus power quality to deteriorate. In an embodiment of the method of the present invention, since the waveform transformation analysis of multiple feeders is replaced by the impact analysis and the analysis of the problem points, the computational cost is low, the work efficiency is high, the positioning is more accurate, and the real-time performance is higher.

[0142] It should be understood that the size of the serial numbers of each step in the above embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0143] The following is an embodiment of the device of the present invention. For details not described in detail, please refer to the corresponding method embodiment described above.

[0144] Figure 3 This is a functional block diagram of a distributed power grid power quality early warning device provided by an embodiment of the present invention, referring to Figure 3 The distributed power grid power quality early warning device 3 includes: a bus waveform acquisition module 301, a bus waveform analysis module 302, a feeder impact analysis module 303 and a feeder positioning module 304, wherein:

[0145] A bus waveform acquisition module 301 is used to acquire the bus waveform of a bus;

[0146] A bus waveform analysis module 302 is configured to perform waveform analysis on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators;

[0147] a feeder impact analysis module 303 configured to perform an impact analysis on a plurality of feeder waveforms based on the bus waveform to determine a plurality of pending feeder waveforms, wherein the plurality of feeder waveforms correspond to a plurality of feeders connected to the bus and inputting and / or outputting electrical energy to the bus;

[0148] The feeder locating module 304 is configured to perform waveform analysis on the plurality of feeder waveforms to be determined, and determine a target feeder, wherein the target feeder is a feeder that causes power quality degradation in the power grid.

[0149] Figure 4 This is a functional block diagram of a terminal provided by an embodiment of the present invention. Figure 4 As shown, the terminal 4 of this embodiment includes: a processor 400 and a memory 401, wherein the memory 401 stores a computer program 402 that can be run on the processor 400. When the processor 400 executes the computer program 402, the steps in the above-mentioned distributed power grid power quality early warning method and embodiment are implemented, such as Figure 1 Steps 101 to 104 are shown.

[0150] Illustratively, the computer program 402 may be divided into one or more modules / units, and the one or more modules / units are stored in the memory 401 and executed by the processor 400 to implement the present invention.

[0151] The terminal 4 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The terminal 4 may include, but is not limited to, a processor 400 and a memory 401. Those skilled in the art will understand that Figure 4 It is only an example of terminal 4 and does not constitute a limitation on terminal 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal 4 may also include input and output devices, network access devices, buses, etc.

[0152] The processor 400 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0153] The memory 401 may be an internal storage unit of the terminal 4, such as a hard disk or memory of the terminal 4. The memory 401 may also be an external storage device of the terminal 4, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the terminal 4. Furthermore, the memory 401 may include both an internal storage unit of the terminal 4 and an external storage device. The memory 401 is used to store the computer program 402 and other programs and data required by the terminal 4. The memory 401 may also be used to temporarily store data that has been output or is about to be output.

[0154] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the implementation method can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method implementation method, and will not be repeated here.

[0155] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0156] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0157] In the embodiments provided herein, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of modules or units is merely a logical functional division. In actual implementation, there may be other division methods, such as multiple units or components being combined or integrated into another system, or some features being ignored or not implemented. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interface, or the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0158] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of this embodiment.

[0159] In addition, the functional units in various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0160] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned implementation method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of the above-mentioned various methods and device implementation methods. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0161] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A distributed power grid power quality early warning method, characterized in that: include: Get the bus waveform of the bus; Performing waveform analysis on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators; Based on the bus waveform, an impact analysis is performed on multiple feeder waveforms to determine multiple feeder waveforms to be determined, including: Determine a first sample group according to the waveform of the bus, wherein the first sample group includes a plurality of sample data obtained by sampling within at least one complete cycle of the bus waveform; Acquire, based on a sampling start time of the first sample group and a quantity of sampled data in the first sample group, a plurality of second sample groups corresponding to the plurality of feeder waveforms, wherein a sampling time interval of the second sample groups is the same as a sampling time interval of the first sample group, wherein the plurality of feeder waveforms correspond to a plurality of feeders, the plurality of feeders are connected to the bus, and the plurality of feeders input and / or output electric energy to the bus; A plurality of influence coefficients are determined according to the first sample group, the plurality of second sample groups, and a fourth formula, wherein the fourth formula is: Where, For the The influence coefficient of the waveform of the feeder on the bus waveform, The first sample group Sampling data, For the corresponding The second sample group of the waveform of the feeder Sampling data, is the number of sample data in the first sample group; Selecting a preset number of undetermined feeder coefficients from the multiple influence coefficients according to the magnitudes of the multiple influence coefficients; Acquire feeder waveforms corresponding to the preset number of undetermined feeder coefficients as a plurality of undetermined feeder waveforms; Performing waveform analysis on the multiple feeder waveforms to be determined to determine the target feeder includes: Obtaining the period of the bus waveform; Determine a plurality of first harmonic rates included in the plurality of feeder waveforms to be determined based on the order of the harmonic that causes the power quality data to degrade, the fifth formula, and the plurality of feeder waveforms to be determined, wherein the first harmonic rates represent the waveform containing the harmonic rate that causes the power quality data to degrade, and the fifth formula is: Where, For the The first harmonic rate of the harmonics that cause the power quality data to degrade in the feeder, is the cosine function, is a sine function, is the period of the bus waveform, is the angular frequency of the fundamental wave of the busbar waveform, The number of harmonics that cause the power quality data to degrade. For the The waveform of the feeder; A feeder corresponding to a first harmonic rate having a maximum value is selected as a target feeder, wherein the target feeder is a feeder that causes power quality of the power grid to deteriorate.

2. The distributed power grid power quality early warning method according to claim 1, characterized in that: The performing waveform analysis on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators includes: Sampling the waveform of the bus to obtain a plurality of sampling data; Extracting a preset number of sample data from the plurality of sample data in a predetermined order to form a first sample group; The waveform margin determination step is to determine the waveform margin according to the first sample group and a first formula, wherein the first formula is: Where, is the waveform margin, is the number of sample data in the first sample group, The first sample group Sampling data; If the waveform margin exceeds a threshold, extracting data from the plurality of sampled data in a predetermined order and adding the data to the first sample group and jumping to the waveform margin determination step; Performing waveform transformation on the first sample group to obtain a fundamental wave and multiple harmonics; The plurality of power quality data are determined according to the fundamental wave and the plurality of harmonics.

3. The distributed power grid power quality early warning method according to claim 2, characterized in that: The performing waveform transformation on the first sample group to obtain a fundamental wave and multiple harmonics includes: determining the frequency of the bus waveform according to the number of sampled data and the sampling time interval in the first sample group; The fundamental wave amplitude of the fundamental wave and the amplitudes of the multiple harmonics corresponding to the multiple harmonics are determined according to the first sample group and a second formula, wherein the second formula is: Where, For the The amplitude of the secondary wave, is the number of sample data in the first sample group, The first sample group Sampling data, is a natural constant, is the imaginary unit, is pi.

4. The distributed power grid power quality early warning method according to claim 3, characterized in that: The plurality of power quality data includes: a voltage waveform distortion coefficient, a current harmonic coefficient, and a voltage deviation; the bus waveform includes a voltage waveform and a current waveform; and determining the plurality of power quality data based on the fundamental wave and the plurality of harmonics includes: A plurality of second harmonic rates corresponding to the plurality of harmonics are determined according to the fundamental wave, the plurality of harmonics, and a third formula, wherein the second harmonic rate represents a ratio of the harmonics in the bus waveform, and the third formula is: Where, For the The ratio of the amplitude of the subharmonic to the amplitude of the fundamental, For the The amplitude of the subharmonics, is the amplitude of the fundamental wave; The harmonic rate with the largest value among the multiple second harmonic rates of the voltage waveform is used as the voltage waveform distortion coefficient, and the harmonic rate with the largest value among the multiple second harmonic rates of the current waveform is used as the current harmonic coefficient; The voltage deviation is determined according to the amplitude of the fundamental wave of the voltage waveform and a preset voltage value.

5. A distributed power grid power quality early warning device, characterized in that: For implementing the distributed power grid power quality early warning method according to any one of claims 1 to 4, the distributed power grid power quality early warning device comprises: A bus waveform acquisition module, used to obtain the bus waveform of the bus; A bus waveform analysis module, configured to perform waveform analysis on the bus waveform to determine a plurality of power quality data corresponding to a plurality of power indicators; a feeder impact analysis module, configured to perform an impact analysis on a plurality of feeder waveforms based on the bus waveform, and determine a plurality of pending feeder waveforms, wherein the plurality of feeder waveforms correspond to a plurality of feeders connected to the bus, and the plurality of feeders input and / or output electrical energy to the bus; as well as, A feeder positioning module is used to perform waveform analysis on the multiple feeder waveforms to be determined to determine a target feeder, wherein the target feeder is the feeder that causes the power quality of the power grid to deteriorate.

6. A terminal comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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