Multi-stage electric energy harmonic measuring and monitoring method, system, equipment and medium

Abstract

The invention discloses a multi-stage electric energy harmonic wave measuring and monitoring method, system, equipment and medium, and relates to the field of electric energy quality governance, and the method comprises the steps: generating a source signal containing a fundamental wave signal and a harmonic wave signal according to a set demand; collecting source signals for frequency domain change and extraction to obtain harmonic characteristic parameters; separating harmonic components by using the extracted harmonic characteristic parameters, and performing reconstruction to obtain pure harmonic signals; performing error evaluation and correction on the harmonic characteristic parameters to obtain corrected harmonic characteristic parameters reflecting a real harmonic state; and obtaining the real-time state of the harmonic wave based on the corrected harmonic wave characteristic parameters, and tracing the real-time state of the harmonic wave to obtain the source and the propagation path of the harmonic wave. According to the method, harmonic components superposed in a source signal can be accurately separated, the propagation path and the source of harmonic in a power grid are intelligently identified, and the comprehensive influence of multi-order harmonic on voltage, current and system energy consumption is converted into a quantifiable evaluation index.

Description

Technical Field

[0001] This invention relates to the field of power quality management, and in particular to a multi-stage power harmonic measurement and monitoring method, system, equipment and medium. Background Technology

[0002] Against the backdrop of building a new type of power system, the measurement objects are gradually shifting from traditional steady-state AC to dynamic high-frequency DC and AC. Currently, various metering instruments with harmonic measurement functions have emerged in the power system, such as harmonic energy meters and IoT meters. As is well known, harmonics not only affect power quality but also threaten the safe operation of the power grid, causing overheating, aging, and damage to power equipment, increasing energy loss, and polluting the environment. Therefore, accurate measurement and analysis of harmonics in the power grid are crucial means to improve power quality and power grid security.

[0003] Currently, the main methods for measuring and analyzing harmonics in power grids are as follows: Harmonic measurement involves using harmonic measuring instruments to measure harmonics in the power grid, obtaining parameters such as amplitude, phase, and frequency. These parameters are then used for analysis and control. The advantage of this method is its simplicity and ease of implementation. However, its disadvantages include limitations in the accuracy and range of the measuring instruments, making it unsuitable for wide-area monitoring and source tracing of harmonics, and hindering the identification of their origin and extent of influence.

[0004] The harmonic power flow method utilizes the phase relationship between harmonic voltage and current to determine the direction of harmonic flow, thereby identifying the source and range of influence of harmonics. The advantage of this method is its ability to monitor and trace harmonics over a wide area. However, its disadvantages include the need for extensive measurement data and calculations, high precision in measuring the phase of harmonic voltage and current, and susceptibility to noise and interference.

[0005] The harmonic source modeling method utilizes the impedance relationship between the voltage and current of harmonics to establish a mathematical model of the harmonic source, thereby determining the source and range of influence of the harmonics. The advantage of this method is its ability to monitor and trace harmonics over a wide area. The disadvantages are that it requires modeling various harmonic sources in the power grid, demands high precision in measuring the voltage and current impedance of harmonics, and is easily affected by noise and interference.

[0006] In summary, existing harmonic measurement methods suffer from low accuracy and poor real-time performance, making them unsuitable for the needs of modern power systems. This invention proposes a multi-stage method for measuring and monitoring power harmonics, enabling real-time and accurate measurement and analysis of harmonics in the power grid, effectively improving the efficiency and accuracy of power quality monitoring. Summary of the Invention

[0007] In view of the above-mentioned problems, the present invention provides a multi-stage method, system, device and medium for measuring and monitoring electrical harmonics.

[0008] Therefore, the problem that this invention aims to solve is that existing harmonic measurement methods suffer from low accuracy and poor real-time performance, making it difficult to meet the needs of modern power systems.

[0009] To address the aforementioned technical problems, this invention provides the following technical solution: a multi-stage method for measuring and monitoring power harmonics, comprising: generating a source signal containing a fundamental wave signal and harmonic signals according to set requirements; acquiring the source signal, performing frequency domain transformation and extraction to obtain harmonic characteristic parameters; using the extracted harmonic characteristic parameters to separate harmonic components and reconstruct them to obtain a pure harmonic signal; performing error assessment and correction on the harmonic characteristic parameters to obtain corrected harmonic characteristic parameters reflecting the true harmonic state; obtaining the real-time state of the harmonics based on the corrected harmonic characteristic parameters, tracing the real-time state of the harmonics to obtain the source and propagation path of the harmonics; and outputting the harmonic state analysis results for power quality assessment and monitoring.

[0010] As a preferred embodiment of the multi-stage power harmonic measurement and monitoring method of the present invention, the step of generating a source signal containing a fundamental wave signal and harmonic signals according to a set requirement includes: a signal generator generating a source signal containing a fundamental wave signal and harmonic signals according to a set frequency and amplitude; a power amplifier amplifying the power of the source signal output by the signal generator; and a harmonic regulator adjusting the amplitude and phase of the source signal output by the power amplifier to simulate harmonic sources of different types and characteristics.

[0011] As a preferred embodiment of the multi-stage power harmonic measurement and monitoring method of the present invention, the method for obtaining harmonic characteristic parameters includes: preprocessing the acquired source signal to remove DC components and linear trends; performing frequency domain transformation on the preprocessed source signal to present different frequency components in frequency domain form; and extracting amplitude, phase, and frequency information related to harmonic components based on the distribution of each frequency component in the frequency domain to form harmonic characteristic parameters.

[0012] As a preferred embodiment of the multi-stage power harmonic measurement and monitoring method of the present invention, the method for obtaining a pure harmonic signal includes: determining the corresponding position of each harmonic component in the frequency domain based on the extracted harmonic characteristic parameters, so that different orders of harmonics are distinguished in frequency distribution; separating the corresponding harmonic components in the source signal according to the amplitude, phase and frequency characteristics of different harmonic components, so that each harmonic component is presented in an independent form; and recombining the separated harmonic components according to the amplitude, phase and frequency relationship, so that the harmonic components are reconstructed in a form without fundamental wave and other interference components, thereby forming a pure harmonic signal.

[0013] The beneficial effects of this preferred technical solution are: separation and reconstruction avoid superposition interference between harmonics, making harmonic signals of different orders more identifiable in the time domain, and improving the accuracy of harmonic analysis and measurement.

[0014] As a preferred embodiment of the multi-stage power harmonic measurement and monitoring method of the present invention, the step of error assessment and correction of harmonic characteristic parameters includes: constructing an error relationship to characterize the measurement deviation based on the extracted harmonic characteristic parameters; obtaining error information to characterize the degree of deviation by comparing the theoretical correlation and actual performance between the amplitude, phase and frequency of different order harmonics; adjusting the harmonic characteristic parameters according to the error information; and combining the adjusted characteristic parameters to form a correction result.

[0015] The beneficial effects of this preferred technical solution are: through systematic error assessment and correction, the harmonic parameter offset caused by sampling frequency, quantization accuracy and equipment deviation can be effectively eliminated, and misjudgment caused by deviation can be avoided.

[0016] As a preferred embodiment of the multi-stage electrical harmonic measurement and monitoring method of the present invention, the method for tracing the real-time state of harmonics includes: analyzing the amplitude changes, phase differences, and energy distribution characteristics of each order harmonic at different time periods and different nodes based on the obtained real-time state of harmonics, so as to identify the propagation trend of harmonic signals in space and time; based on the propagation trend, using the amplitude flow direction, phase change direction, and frequency stability of each order harmonic as the tracing basis, inferring the transmission path of harmonic components along the electrical network; and combining the path inference results to determine the generation region of harmonic components and obtain the propagation path of harmonics in the network.

[0017] As a preferred embodiment of the multi-stage power harmonic measurement and monitoring method of the present invention, the power quality assessment and monitoring includes: quantifying the impact range of harmonics in the electrical network based on the obtained harmonic sources and propagation paths, combined with the amplitude changes, phase shifts, and frequency characteristics of each order of harmonics, to determine the potential impact of current harmonics on power quality; comprehensively analyzing the impact of harmonics on power parameters based on the potential impact of each order of harmonics to form an assessment index reflecting the current power quality status of the power grid; and continuously monitoring the operation of the power grid based on the assessment index.

[0018] To address the aforementioned technical problems, this invention provides the following technical solution: a multi-stage power harmonic measurement and monitoring system, comprising: a source signal generation module, a harmonic signal extraction module, a correction module, a source tracing module, and a monitoring module; the source signal generation module generates a source signal containing a fundamental wave signal and harmonic signals according to set requirements; the harmonic signal extraction module acquires the source signal, performs frequency domain transformation and extraction to obtain harmonic characteristic parameters, uses the extracted harmonic characteristic parameters to separate harmonic components, and reconstructs them to obtain a pure harmonic signal; the correction module performs error evaluation and correction on the harmonic characteristic parameters to obtain corrected harmonic characteristic parameters reflecting the true harmonic state; the source tracing module obtains the real-time state of the harmonics based on the corrected harmonic characteristic parameters, traces the real-time state of the harmonics, and obtains the source and propagation path of the harmonics; the monitoring module outputs harmonic state analysis results for power quality assessment and monitoring. A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of a multi-stage electrical harmonic measurement and monitoring method as described above.

[0019] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a multi-stage electrical harmonic measurement and monitoring method as described above.

[0020] The beneficial effects of this invention are as follows: By constructing a complete multi-stage harmonic measurement chain—"feature extraction—harmonic separation—error correction—real-time identification—source analysis—quality assessment"—this invention achieves reliable processing throughout the entire process from raw signal acquisition to power quality monitoring result output, improving the accuracy, stability, and intelligence of harmonic measurement. This invention can accurately separate the harmonic components superimposed on the source signal, correct harmonic characteristic parameters affected by noise, equipment deviation, and sampling errors, intelligently identify the propagation path and source of harmonics in the power grid, and transform the comprehensive impact of multi-order harmonics on voltage, current, and system energy consumption into quantifiable evaluation indicators. With these capabilities, this invention not only improves the accuracy of harmonic measurement and analysis but also advances harmonic management from passive monitoring to active diagnosis, providing highly reliable technical support for steady-state power quality assessment, real-time monitoring, and anomaly early warning. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of a multi-stage electrical harmonic measurement and monitoring method in Example 1. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0025] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a multi-stage method for measuring and monitoring electrical harmonics, including: S1: Generates a source signal containing fundamental and harmonic signals according to the set requirements.

[0026] S2: Acquire the source signal, perform frequency domain transformation and extraction to obtain harmonic characteristic parameters.

[0027] S3: Use the extracted harmonic feature parameters to separate the harmonic components and reconstruct them to obtain a pure harmonic signal.

[0028] S4: Perform error assessment and correction on the harmonic characteristic parameters to obtain corrected harmonic characteristic parameters that reflect the true harmonic state.

[0029] S5: Based on the corrected harmonic characteristic parameters, the real-time state of the harmonics is obtained, and the source and propagation path of the harmonics are traced.

[0030] S6: Outputs harmonic state analysis results for power quality assessment and monitoring.

[0031] It should be noted that existing technologies in the field of harmonic power measurement mainly rely on traditional Fourier transform analysis methods or harmonic detection devices based on single-point measurements. These technologies have significant limitations when facing the large number of unsteady harmonics, interharmonics, and multi-source superimposed harmonics in modern power grids. Furthermore, existing measurement devices generally lack effective error assessment and correction mechanisms, and lack the ability to dynamically correct harmonic amplitude, phase, and frequency deviations caused by sampling errors, hardware biases, and quantization noise, leading to deviations in measurement results from the actual power grid conditions. In addition, traditional harmonic monitoring systems are mostly based on local observation, lacking the ability to systematically identify harmonic propagation paths and sources, making it difficult to achieve harmonic source tracing and diffusion trend prediction in the power grid, thus keeping harmonic mitigation at a passive response level.

[0032] Therefore, in response to the above problems, such as Figure 1 As shown, through steps S1-S6, basic data suitable for in-depth analysis is obtained by acquiring and preprocessing power grid signals containing fundamental and multi-order harmonic components. Subsequently, frequency domain analysis is performed on the signals to extract key harmonic features, accurately characterizing the amplitude, phase, and frequency information of each harmonic. Based on this, the harmonic components are further separated and reconstructed to make the harmonics clearer in the time and frequency domains. Then, the extracted feature parameters are systematically error-judged and corrected to ensure that the harmonic information is closer to the actual power grid condition. Next, a dynamic behavior description of harmonics in the network is constructed based on the corrected harmonic features to identify their propagation direction and trend. Furthermore, the source and propagation path of harmonics are inferred based on these dynamic features to determine the true generation area of ​​harmonics. Finally, the above results are integrated and converted into assessment information for power quality judgment, realizing the monitoring, early warning, and analysis of power grid harmonic conditions.

[0033] Example 2, the second embodiment of the present invention, differs from the first embodiment in that: a multi-stage power harmonic measurement and monitoring method further includes, in step S1, generating a source signal containing a fundamental wave signal and harmonic signals according to set requirements, including the following steps A1-A3: A1: The signal generator produces a source signal containing fundamental and harmonic signals, such as sine wave, square wave, and triangle wave, according to the set frequency and amplitude.

[0034] A2: The power amplifier amplifies the source signal output by the signal generator so that it can have a sufficient impact on the power grid.

[0035] A3: The harmonic modulator adjusts the amplitude and phase of the source signal output by the power amplifier to simulate different types and characteristics of harmonic sources, such as linear harmonic sources, nonlinear harmonic sources, balanced harmonic sources, unbalanced harmonic sources, etc.

[0036] In this way, the output parameters of the harmonic power source can be adjusted according to different testing requirements, simulating harmonic sources of different types and characteristics, thus enhancing the flexibility and controllability of the harmonic power source.

[0037] Furthermore, in step S2, obtaining the harmonic characteristic parameters includes the following steps B1-B3: B1: Preprocess the acquired source signal to remove DC components and linear trends.

[0038] B2: Perform frequency domain transformation on the preprocessed source signal so that different frequency components are presented in frequency domain form.

[0039] B3: Based on the distribution of each frequency component in the frequency domain, extract the amplitude, phase and frequency information related to the harmonic components to form harmonic characteristic parameters.

[0040] In this embodiment of the application, in step B3, the harmonic characteristic parameters are obtained using the FFT (Fast Fourier Transform) + wavelet method, including the following steps B311-B313: B313: Perform FFT transformation on the preprocessed source signal to obtain the energy distribution of each frequency component in the signal, so that the fundamental wave and each level of harmonics can be separated in the frequency domain.

[0041] B313: Perform wavelet transform on the FFT results to analyze the local variation characteristics of different frequency bands at multiple scales, so as to enhance the ability to identify non-steady harmonics and interharmonics.

[0042] B313: Based on the comprehensive frequency domain information obtained from FFT and wavelet analysis, the amplitude peak, phase change and frequency shift of the corresponding harmonic are located, thereby forming the harmonic characteristic parameters.

[0043] Specifically, continuous signals are segmented into overlapping segments to reduce the frequency resolution limitations of the FFT.

[0044] Fast Fourier Transform (FFT): Performing an FFT on each segment yields a frequency domain representation. The transform module performs an FFT on the filtered signal output from the filtering module to obtain the transformed signal representation. in, To transform the signal, For filtered signals, The number of sampling points. For frequency index, For sampling point index, It is the imaginary unit.

[0045] The transformation module extracts characteristic parameters of harmonics such as amplitude, phase, and frequency based on the complex form of the transformed signal. , , ,in The amplitude of the harmonic. For the phase of the harmonic, For the frequency of harmonics, The sampling frequency.

[0046] In an optional implementation, the harmonic characteristic parameters can also be obtained using the Hilbert transform, including the following steps B321-B323: B321: Perform empirical mode decomposition on the preprocessed source signal to split the signal into multiple intrinsic mode functions with different frequency band characteristics.

[0047] B322: Perform Hilbert transform on each intrinsic mode function to obtain instantaneous frequency and instantaneous amplitude representations, so that the harmonic components form distinguishable trajectories in the time-frequency plane.

[0048] B323: Based on the instantaneous frequency and instantaneous energy distribution of each mode, identify the corresponding harmonic order, and extract the amplitude, phase and frequency parameters of the harmonics to form a set of harmonic characteristic parameters.

[0049] In another alternative implementation, the harmonic characteristic parameters can also be obtained using a short-time Fourier transform (STFT), including the following steps B331-B333: B331: Perform a short-time Fourier transform on the preprocessed source signal to obtain the time-frequency distribution of the signal within a sliding time window, so that different frequency components appear in each local window.

[0050] B332: Based on the amplitude and phase spectra obtained from STFT, the frequency intensity and phase changes of the signal within different time windows are tracked to identify the changing trend of harmonic components.

[0051] B333: By analyzing the stable and strong frequency trajectories in the STFT time-frequency matrix, the amplitude, phase and frequency of the corresponding harmonic components are extracted to form harmonic characteristic parameters for subsequent processing.

[0052] It should be noted that after the source signal is preprocessed and frequency domain transformed, different frequency components are effectively separated, so that harmonic features are no longer mixed with the fundamental wave or noise, thereby significantly improving the accuracy of harmonic feature extraction. By analyzing the local features of the signal in the frequency domain, non-steady-state components such as frequency drift and interharmonics can be identified, providing a stable basis for harmonic analysis in complex power grid environments.

[0053] Furthermore, in step S3, obtaining a pure harmonic signal includes the following steps C1-C3: C1: Determine the corresponding position of each harmonic component in the frequency domain based on the extracted harmonic characteristic parameters, so that harmonics of different orders can be distinguished in frequency distribution.

[0054] C2: Based on the amplitude, phase and frequency characteristics of different harmonic components, the corresponding harmonic components in the source signal are separated and processed so that each harmonic component is presented in an independent form.

[0055] C3: The separated harmonic components are recombined according to the relationship between amplitude, phase and frequency, so that the harmonic components are reconstructed in a form without fundamental wave and other interference components, forming a pure harmonic signal.

[0056] In this embodiment of the application, step C2, the separation process employs harmonic component separation based on frequency domain filtering and inverse transform, including the following steps C211-C213: C211: Based on the harmonic frequency positions obtained from C1, construct a selection mask for the corresponding frequency band in the frequency domain so that the frequency region belonging to the target harmonic order is preserved separately.

[0057] C212: Apply frequency band selection operation to the frequency domain signal to extract the frequency components of the corresponding order from the overall frequency domain, so that the amplitude and phase information of the harmonic order exist separately in the frequency domain expression.

[0058] C213: Perform inverse Fourier transform on the extracted frequency domain components to obtain the independent signal of the harmonic in the time domain, thereby achieving the separation of the target harmonic components.

[0059] In an optional implementation, the separation process may also employ harmonic component decomposition based on Empirical Mode Decomposition (EMD), including the following steps C221-C223: C221: Perform empirical mode decomposition on the source signal, decomposing the signal into multiple intrinsic mode functions (IMFs) with different frequency characteristics.

[0060] C222: Based on the obtained harmonic frequency positions, match the main frequency distribution of each IMF, and select the IMF corresponding to the target harmonic order as the target component.

[0061] C223: Select the output of the chosen IMF as the corresponding harmonic component, so that the component exists independently in the time domain, achieving a mode-based harmonic separation effect.

[0062] In another alternative implementation, the separation process can also employ harmonic trajectory identification and extraction based on the STFT time-frequency matrix, including the following steps C231-C233: C231: Perform a short-time Fourier transform (STFT) on the source signal to generate a time-frequency matrix, so that each harmonic forms a trajectory with continuous characteristics in the time-frequency surface.

[0063] C232: Based on the identified harmonic frequency positions, cluster analysis is performed on the energy clusters near the corresponding frequencies in the time-frequency matrix to select continuous frequency trajectories belonging to the target harmonic order.

[0064] C233: Reconstruct the time-frequency region corresponding to the trajectory in reverse, obtain the independent time-domain signal of the harmonic through inverse STFT operation, and realize harmonic component separation based on time-frequency clustering.

[0065] It should be noted that separation and reconstruction avoid the superposition interference between harmonics, making the harmonic signals of different orders more identifiable in the time domain. The reconstructed harmonic signal components are independent and are not affected by fundamental frequency, voltage fluctuations or noise, thus improving the accuracy of harmonic analysis and measurement.

[0066] Furthermore, in step S4, the error assessment and correction of the harmonic characteristic parameters includes the following steps D1-D3: D1: Based on the extracted harmonic characteristic parameters, construct the error relationship to characterize the measurement deviation. By comparing the theoretical correlation and actual performance between the amplitude, phase and frequency of different order harmonics, obtain error information to characterize the degree of deviation.

[0067] D2: Adjust the harmonic characteristic parameters based on the error information so that the harmonic amplitude deviation, phase drift and frequency shift meet the expected harmonic physical characteristic relationship after correction.

[0068] D3: Combine the adjusted feature parameters to form a correction result, so that it can reflect the true harmonic state and serve as the input for subsequent harmonic identification and source tracing.

[0069] In this embodiment of the application, step D2, which adjusts the harmonic characteristic parameters using the least squares method combined with Newton's iterative correction, includes the following steps D211-D213: D211: Construct a least squares error model based on the obtained error information, and use the least squares method to calculate the overall deviation of harmonic amplitude error, phase error and frequency error.

[0070] D212: Using the deviation obtained by least squares as the initial correction direction, construct the error correction function, and use Newton's iteration method to iteratively solve the correction function to obtain the correction parameters after the error converges.

[0071] D213: Update the amplitude, phase, and frequency based on the Newton iteration results to ensure that the corrected harmonic characteristic parameters satisfy the theoretical harmonic characteristic relationship, which is the final correction result.

[0072] Specifically, the least squares method is used to perform error analysis on the characteristic parameters of the transformed signal, and the error value is expressed as follows: in, This is the error value. The order of the harmonic is denoted by . To transform the characteristic parameters of the signal, This is the theoretical value. This is the harmonic order index.

[0073] The error value is corrected using Newton's iteration method, and the corrected characteristic parameters are expressed as follows: in, These are the corrected feature parameters. These are the characteristic parameters before correction. It is a function of the error value. The derivative of the function of the error value.

[0074] In an optional implementation, the harmonic characteristic parameters can also be adjusted using a gradient descent correction method, including the following steps D221-D223: D221: Construct an error loss function based on the error information generated in step D1, incorporating amplitude deviation, phase deviation, and frequency deviation into a unified loss expression.

[0075] D222: Use gradient descent to calculate the gradient direction and magnitude of the loss function with respect to each feature parameter, and then gradually correct the feature parameters according to the gradient direction.

[0076] D223: Through multiple rounds of gradient iteration, the corrected amplitude, phase, and frequency gradually approach the true harmonic characteristics, achieving dynamic error correction.

[0077] In another alternative implementation, the harmonic characteristic parameters can also be adjusted using a statistical correction method based on deviation distribution fitting, including the following steps D231-D233: D231: Perform statistical analysis on the error information obtained in step D1, and use probability density estimation to obtain the error distribution model, thereby grasping the overall trend of the characteristic parameter deviation.

[0078] D232: Based on the error distribution model, a deviation compensation function is constructed, and different compensation coefficients are used for different amplitude, phase and frequency ranges to achieve differentiated correction of characteristic parameters.

[0079] D233: The amplitude, phase and frequency are corrected according to the compensation function to make them closer to the true harmonic state in a statistical sense, forming the corrected characteristic parameters.

[0080] It should be noted that through systematic error assessment and correction, the offset of harmonic parameters caused by sampling frequency, quantization accuracy and equipment deviation can be effectively eliminated; the corrected parameters can more accurately reflect the real harmonic situation of the power grid and avoid misjudgment caused by deviation.

[0081] Furthermore, in step S5, obtaining the real-time state of the harmonics based on the corrected harmonic characteristic parameters includes: monitoring the corrected characteristic parameters using the harmonic energy flow method to obtain the real-time state of the harmonics, expressed as follows: in, This represents the real-time state of harmonics. The voltage for harmonics, For harmonic currents, This is a conjugate operation.

[0082] Furthermore, tracing the real-time state of harmonics involves the following steps E1-E3: E1: Based on the obtained real-time harmonic status, analyze the amplitude changes, phase differences, and energy distribution characteristics of each harmonic at different time periods and nodes to identify the propagation trend of harmonic signals in space and time.

[0083] E2: Based on the propagation trend, the amplitude flow direction, phase change direction and frequency stability of each harmonic are used as the basis for tracing the source, and the propagation path of the harmonic components along the electrical network is inferred.

[0084] E3: Based on the comprehensive path inference results, determine the generation region of harmonic components and obtain the propagation path of harmonics in the network.

[0085] In this embodiment of the application, step E2, which involves inferring the transmission path using the harmonic power flow method, includes the following steps E211-E213: E213: Based on the obtained real-time harmonic state, calculate the phase relationship between the voltage and current of a specific order harmonic, and determine the direction of the harmonic power through the phase difference between the harmonic voltage and the harmonic current.

[0086] E213: Based on the positive or negative determination of the harmonic power direction, identify the energy inflow and outflow nodes of the harmonic, thereby inferring the propagation direction of the harmonic in the network.

[0087] E213: Based on the harmonic power flow results of multiple nodes, the propagation directions of each order of harmonics are connected in series to form the propagation path of that order of harmonic in the electrical network.

[0088] Specifically, the source of harmonics can be represented as follows: in, As a source of harmonics, The voltage for harmonics, The current is a harmonic current.

[0089] In an alternative implementation, the transmission path can also be inferred using a source tracing method based on harmonic impedance analysis, including the following steps E221-E223: E221: Based on the obtained real-time harmonic status, measure the equivalent impedance change characteristics of each node at the harmonic frequency, and infer the node impedance level by the ratio of the amplitude of the harmonic voltage to the harmonic current.

[0090] E222: Based on the relative high and low impedance trends of each node, identify the nodes where harmonic energy is more likely to flow to the nodes with lower impedance, and thus infer the possible propagation direction of harmonic energy.

[0091] E223: Combine the correspondence between the impedance change trend of each node and the harmonic flow direction to construct the propagation path of the harmonic signal in the network.

[0092] In another alternative implementation, the transmission path can be inferred using a source tracing method based on harmonic impedance analysis, including the following steps E231-E233: E231: Based on the obtained real-time state of harmonics, continuously observe the time-frequency distribution of harmonic signals and record the intensity changes of specific order harmonic trajectories at different locations or time periods.

[0093] E232: Based on the direction of change in the intensity of the harmonic trajectory, identify the possible propagation area of ​​the harmonic signal, and use the direction in which the harmonic intensity gradually increases as the basis for inferring energy transmission.

[0094] E233: Perform reverse tracing according to the direction of trajectory enhancement, connect the energy change trends of each time band in series, and form the propagation path and possible source location of the harmonic.

[0095] It should be noted that this step, by inferring the direction of harmonic energy flow, phase distribution, and propagation trend, can determine whether the harmonic originates from user-side equipment, internal nodes of the power grid, or external interference sources. It can also clarify the transmission lines of harmonics in the power grid and the affected areas, thereby improving the targeted nature of harmonic mitigation.

[0096] Furthermore, in step S6, the power quality assessment and monitoring includes the following steps F1-F3: F1: Based on the obtained harmonic sources and propagation paths, and combined with the amplitude changes, phase shifts and frequency characteristics of each order of harmonics, the influence range of harmonics in the electrical network is quantitatively assessed to determine the potential impact of the current harmonics on power quality.

[0097] F2: Based on the potential impact of each harmonic, the impact of harmonics on power parameters is comprehensively analyzed to form an assessment index reflecting the current power quality status of the power grid.

[0098] F3: Continuously monitor the power grid operation based on the evaluation indicators.

[0099] It should be noted that the potential impact can be comprehensively judged based on the amplitude, phase, and frequency characteristics of each harmonic. Specifically, statistical analysis of harmonic amplitude can be performed to obtain the trend of amplitude changes in historical intervals, the maximum value offset, and the distance from the standard limit, which can be used to quantify the strength of harmonic energy. Simultaneously, a phase offset tracking method can be used to determine whether the harmonic may cause superposition effects or local resonance by calculating the direction and amplitude of phase changes over time. Furthermore, a frequency drift detection method can be used to continuously calculate the degree of harmonic frequency shift and stability interval to determine the risk of interharmonics or unsteady harmonics. Combining amplitude deviation indicators, phase drift indicators, and frequency stability indicators according to preset rules or weighting methods yields the potential impact level reflecting the disturbance intensity, diffusion capability, and instability of the harmonic in the power grid, which can be categorized as mild impact, moderate impact, significant impact, or risk of impact.

[0100] To further explain, assessment indicators can be generated based on the potential impact level to achieve a quantitative evaluation of power quality. Specifically, the potential impact level can first be used as the weighting basis for each harmonic order, ensuring that harmonic orders with higher impact levels contribute more in subsequent assessments. Subsequently, basic indicators for single-order harmonics are calculated based on the amplitude, phase, and frequency characteristics of each harmonic, including harmonic energy proportion, voltage deviation contribution, and current distortion contribution. Furthermore, the basic indicators for multiple orders can be weighted and combined according to their potential impact level to obtain comprehensive indicators such as total voltage distortion, total node harmonic energy, and system energy consumption trends. In addition, trend-based indicators, including harmonic growth rate, propagation path changes, and source stability, can be introduced to determine whether there is a risk of power quality deterioration or spread. Finally, the basic indicators, comprehensive indicators, and trend indicators can be normalized or graded according to a preset model to form assessment indicators such as comprehensive power quality scores, node harmonic risk levels, or equipment health indices, for real-time monitoring and early warning output.

[0101] Example 3, the third embodiment of the present invention, differs from the previous two embodiments in that it is a multi-stage power harmonic measurement and monitoring system, including a source signal generation module, a harmonic signal extraction module, a correction module, a source tracing module, and a monitoring module. The source signal generation module generates a source signal containing a fundamental signal and harmonic signals according to set requirements. The harmonic signal extraction module acquires the source signal, performs frequency domain transformation and extraction to obtain harmonic characteristic parameters, uses the extracted harmonic characteristic parameters to separate harmonic components, and reconstructs them to obtain a pure harmonic signal. The correction module performs error evaluation and correction on the harmonic characteristic parameters to obtain corrected harmonic characteristic parameters that reflect the true harmonic state. The source tracing module obtains the real-time state of the harmonics based on the corrected harmonic characteristic parameters, traces the real-time state of the harmonics, and obtains the source and propagation path of the harmonics. The monitoring module outputs harmonic state analysis results for power quality assessment and monitoring.

[0102] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0103] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0104] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0105] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented in combination with any of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-stage method for measuring and monitoring electrical energy harmonics, characterized in that: include, Generate a source signal containing both fundamental and harmonic signals according to the set requirements; The source signal is acquired and subjected to frequency domain transformation and extraction to obtain harmonic characteristic parameters; Harmonic components are separated using the extracted harmonic feature parameters and reconstructed to obtain a pure harmonic signal. Error assessment and correction are performed on the harmonic characteristic parameters to obtain corrected harmonic characteristic parameters that reflect the true harmonic state. Based on the corrected harmonic characteristic parameters, the real-time state of the harmonics is obtained, and the source and propagation path of the harmonics are traced. Output harmonic state analysis results for power quality assessment and monitoring.

2. The multi-stage electrical energy harmonic measurement and monitoring method as described in claim 1, characterized in that: The process of generating a source signal containing both fundamental and harmonic signals according to set requirements includes: The signal generator produces a source signal containing fundamental and harmonic signals according to the set frequency and amplitude. The power amplifier amplifies the power of the source signal output from the signal generator; The harmonic modulator adjusts the amplitude and phase of the source signal output by the power amplifier to simulate harmonic sources of different types and characteristics.

3. The multi-stage electrical energy harmonic measurement and monitoring method as described in claim 2, characterized in that: The obtained harmonic characteristic parameters include, The acquired source signal is preprocessed to remove DC components and linear trends; The preprocessed source signal is subjected to frequency domain transformation so that different frequency components are presented in frequency domain form; Based on the distribution of each frequency component in the frequency domain, the amplitude, phase, and frequency information related to the harmonic components are extracted to form harmonic characteristic parameters.

4. The multi-stage electrical energy harmonic measurement and monitoring method as described in claim 3, characterized in that: The obtained pure harmonic signal includes, Based on the extracted harmonic characteristic parameters, the corresponding positions of each harmonic component in the frequency domain are determined, so that harmonics of different orders can be distinguished in terms of frequency distribution. Based on the amplitude, phase and frequency characteristics of different harmonic components, the corresponding harmonic components in the source signal are separated and processed so that each harmonic component is presented in an independent form. The separated harmonic components are recombined according to the relationship between amplitude, phase and frequency, so that the harmonic components are reconstructed in a form without fundamental wave and other interference components, forming a pure harmonic signal.

5. The multi-stage electrical harmonic measurement and monitoring method as described in claim 4, characterized in that: The error assessment and correction of harmonic characteristic parameters includes... Based on the extracted harmonic characteristic parameters, an error relationship is constructed to characterize the measurement deviation. By comparing the theoretical correlation and actual performance between the amplitude, phase and frequency of different order harmonics, error information is obtained to characterize the degree of deviation. The harmonic characteristic parameters are adjusted based on the error information. The adjusted feature parameters are combined to form the corrected result.

6. The multi-stage electrical energy harmonic measurement and monitoring method as described in claim 5, characterized in that: The real-time source tracing of harmonic states includes, Based on the obtained real-time harmonic status, the amplitude changes, phase differences and energy distribution characteristics of each order harmonic at different time periods and different nodes are analyzed to identify the propagation trend of harmonic signals in space and time. Based on the propagation trend, the amplitude flow direction, phase change direction, and frequency stability of each harmonic are used as the basis for tracing the source, and the propagation path of the harmonic components along the electrical network is inferred. Based on the comprehensive path inference results, the generation region of harmonic components is determined, and the propagation path of harmonics in the network is obtained.

7. The multi-stage electrical energy harmonic measurement and monitoring method as described in claim 6, characterized in that: The power quality assessment and monitoring includes, Based on the obtained harmonic sources and propagation paths, and combined with the amplitude changes, phase shifts and frequency characteristics of each order of harmonics, the influence range of harmonics in the electrical network is quantitatively assessed to determine the potential impact of the current harmonics on power quality. Based on the potential impact of each harmonic, the influence of harmonics on power parameters is comprehensively analyzed to form an assessment index that reflects the current power quality status of the power grid. The power grid operation is continuously monitored based on the aforementioned evaluation indicators.

8. A multi-stage power harmonic measurement and monitoring system, employing the multi-stage power harmonic measurement and monitoring method as described in any one of claims 1 to 7, characterized in that: It includes a source signal generation module, a harmonic signal extraction module, a correction module, a source tracing module, and a monitoring module; The source signal generation module generates a source signal containing fundamental and harmonic signals according to the set requirements. The harmonic signal extraction module acquires the source signal, performs frequency domain transformation and extraction to obtain harmonic characteristic parameters, uses the extracted harmonic characteristic parameters to separate the harmonic components, and reconstructs them to obtain a pure harmonic signal. The correction module performs error assessment and correction on the harmonic characteristic parameters to obtain corrected harmonic characteristic parameters that reflect the true harmonic state. The source tracing module obtains the real-time state of the harmonics based on the corrected harmonic characteristic parameters, and traces the source and propagation path of the harmonics based on the real-time state of the harmonics. The monitoring module outputs harmonic state analysis results for power quality assessment and monitoring.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the multi-stage power harmonic measurement and monitoring method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the multi-stage electrical harmonic measurement and monitoring method according to any one of claims 1 to 7.

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