264 results about "Harmonic voltages" patented technology

The invention relates to an intelligent power distribution harmonic monitoring and dynamic compensation system which comprises a monitoring unit, a correction unit and a compensation unit. The monitoring unit continuously collects high-frequency harmonic voltage and current data in a distribution line at a high sampling frequency, extracts transient harmonic components through wavelet packet transformation and empirical mode decomposition, and generates low-dimensional feature vectors based on sparse representation. And the correction unit decodes the low-dimensional feature vector, recovers harmonic time-frequency features, calculates a phase drift rate, predicts a harmonic propagation path and an accumulation node by combining real-time power distribution network topology construction and adopting a nonlinear dynamic prediction model, and generates a correction instruction when abnormality is detected. And the compensation unit adopts pulse sequence density modulation to dynamically adjust a compensation current phase according to the correction instruction, and meanwhile, an inductive coupling device is utilized to transfer harmonic energy to a low-risk node, so that harmonic voltage distortion of a target node is quickly recovered to a stable level in a fundamental wave period after early warning.

The invention discloses a new energy power grid probability harmonic load flow calculation method based on improved semi-invariant and Gram-Charlier series expansion. The new energy power grid probability harmonic load flow calculation method comprises the following steps: establishing a random variable probability model, a wind-light output model and a wind-light joint distribution model; secondly, considering the output correlation between wind and light fields, converting the wind and light combined distribution model based on a Copula function into independent variables by utilizing Rosenblatt conversion for calculation, then calculating each-order semi-invariant of load, photovoltaic output and wind power output according to the expected values of node voltage and branch power flow and a sensitivity matrix, and finally calculating the output correlation between the wind and light fields according to each order semi-invariant of the load, the photovoltaic output and the wind power output. The method comprises the following steps of: obtaining a state variable, further solving each-order semi-invariant form of the state variable and the branch power flow, and finally, obtaining a probability density function and a probability distribution function of harmonic voltage of each node by combining Gram-Charlier series expansion.

This invention discloses a method and system for suppressing capacitor voltage fluctuations in SiC MMC submodules, belonging to the field of electronic power technology. Based on the analysis results of the optimal broadband harmonic circulating current injection boundary and order for SiC MMC submodules, an optimized model for submodule capacitor voltage fluctuations is determined that simultaneously injects 2nd, 4th, and 8th harmonic circulating currents and 3rd harmonic voltages, which can fully utilize the higher control bandwidth characteristic of SiC MMC. By solving the optimized model for submodule capacitor voltage fluctuations, the amplitude and phase of the reference values ​​of the 2nd, 4th, and 8th harmonic circulating currents to be injected, as well as the amplitude and phase of the corresponding 3rd harmonic voltage, are determined. Then, by injecting 2nd, 4th, and 8th harmonic circulating currents and jointly injecting the 3rd harmonic voltage, broadband harmonic joint injection is achieved, reducing the capacitor voltage fluctuations of the submodule and realizing a method for suppressing capacitor voltage fluctuations in SiC MMC submodules with high suppression effect.

The invention discloses a model prediction control method of a high-speed permanent magnet synchronous motor and a related device, and relates to the field of control, and the method comprises the steps: building a stator current equation capable of simulating the behavior of the high-speed permanent magnet synchronous motor based on the position change of a rotor in the same control period, a high control input basic voltage value is obtained by fixing motor parameters and combining a total disturbance parameter of a current loop system and a set stator current tracking target at the next moment at the same time; on the basis of the control input basic voltage value, current loop harmonic voltage compensation is carried out through the control input harmonic compensation voltage value to obtain a control input voltage value, and voltage modulation is carried out according to the control input voltage value to control the high-speed permanent magnet synchronous motor. According to the method, when the stator current equation is constructed, rotor position change parameters in the same control period are innovatively introduced, so that the motor behavior simulation precision is remarkably improved; the defect that the switching frequency is not fixed in a traditional finite set model predictive control algorithm is effectively overcome through the voltage modulation technology.

The invention belongs to the technical field of power electronics, and provides a method and a system for improving harmonic transient stability of a grid-forming type active power filter, droop control is performed on a deviation value of an active power reference instruction and an actually measured active power value, integration is performed to obtain a power angle, and the power angle and a grid-side harmonic phase are added to generate a harmonic voltage phase instruction; pI control is carried out on a deviation value between the reactive power reference instruction and an actually measured reactive power value to obtain a voltage deviation value, and the voltage deviation value and a network side specified subharmonic voltage amplitude are summed to generate a harmonic voltage amplitude instruction; taking a harmonic voltage amplitude instruction as a d-axis reference, taking 0 as a q-axis reference, respectively subtracting the d-axis reference and the q-axis reference from the harmonic voltage on the d-axis and the q-axis to obtain deviation values, and obtaining a dq component of the harmonic voltage reference through PI control. The operation safety of the power grid can be improved.

The invention discloses a specific grid-connected current harmonic suppression method and device for an energy storage converter, and belongs to the technical field of power systems, and the method comprises the steps: obtaining a given current value of a fundamental current loop, and carrying out the dq / abc conversion to obtain a three-phase current reference value; acquiring a three-phase current value of a power grid side, and subtracting the three-phase current value from the three-phase current reference value to obtain a harmonic current value; converting the harmonic current value to a target subharmonic synchronous rotating coordinate system to obtain a target subharmonic current value; extracting the target sub-harmonic current value in a direct current form through a low-pass filter, and sending the target sub-harmonic current value to a PI regulator for regulation to obtain a harmonic voltage compensation amount; and injecting the harmonic voltage compensation amount into a modulation wave to realize suppression of the target subharmonic current. According to the invention, the grid-connected side current harmonic of the energy storage converter can be effectively suppressed, and the grid-side current quality is improved.

The invention discloses an electric power system harmonic propagation analysis method and device and a storage medium, and belongs to the technical field of electric power system harmonic analysis, and the method comprises the steps: inputting a to-be-predicted operation condition parameter and a harmonic voltage parameter into a trained regression prediction model, obtaining a corresponding prediction cross admittance matrix, and obtaining a prediction cross admittance matrix; the predicted cross admittance matrix is applied to harmonic propagation analysis of the power system; wherein the regression prediction model is integrated with Bagging based on a decision tree; according to the method, by improving the data set quality and optimizing the model hyper-parameters, the harmonic source cross admittance matrix which is self-adaptive to the operation condition and is established by adopting the decision tree-based regression device and the Bagging element regression device can meet the harmonic analysis precision requirements under different operation conditions, and harmonic propagation of the power system can be analyzed more accurately; the analysis efficiency is improved, and a feasible technical path is provided for online monitoring or rapid evaluation.

The invention discloses a harmonic suppression method and system based on feedforward control and virtual impedance, and belongs to the field of electric energy quality control, and the method comprises the steps: constructing a harmonic extraction model based on the cascading of double third-order generalized integrators, and obtaining a voltage harmonic component based on the harmonic extraction model and real-time power grid data; based on a preset power outer loop control strategy, a preset voltage and current double closed loop control strategy, a preset harmonic voltage feed-forward control strategy and the voltage harmonic component, constructing a network construction type charging pile control model, and obtaining an initial output current; obtaining each virtual impedance based on the initial output current, the harmonic extraction model and the voltage harmonic component; and obtaining a harmonic suppression model based on each virtual impedance and the network construction type charging pile control model, so as to obtain a harmonic suppression output current based on the harmonic suppression model and the real-time power grid data. According to the harmonic suppression method and system based on feedforward control and virtual impedance provided by the invention, grid-connected output current harmonics controlled by a network-forming type charging pile are effectively suppressed.

The invention discloses a resonance identification method and system based on cross-voltage-level harmonic monitoring data. The method comprises the following steps: synchronously sampling cross-voltage-level monitoring amplitude data of a high-voltage side and a low-voltage side of a main transformer; calculating a first correlation coefficient of concerned frequency harmonic voltage and harmonic current of the low-voltage side of the main transformer, and judging whether the power grid generates resonance or not based on the first correlation coefficient; when resonance occurs, according to the cross-voltage level monitoring amplitude data, calculating the concerned frequency harmonic voltage content ratios of the high and low voltage sides; calculating a harmonic voltage transfer coefficient according to the concerned frequency harmonic voltage content ratios of the high and low voltage sides; calculating a second correlation coefficient between the harmonic voltage transfer coefficient and the load rate of the main transformer, and identifying the position of the resonance source based on the second correlation coefficient; identifying the resonance type based on the harmonic voltage transfer coefficient when the resonance source is located at the power grid side; the resonance type is identified based on a third correlation coefficient between the low-voltage-side frequency-of-interest harmonic voltage content and the main transformer load rate when the resonance source is located on the load side.

The invention discloses a harmonic analysis method, system and device for a flexible direct current converter and a medium, and relates to the technical field of flexible direct current transmission, and the method comprises the steps: obtaining key electrical parameters of a to-be-tested flexible direct current converter; constructing a high-frequency equivalent circuit corresponding to each target device according to the key electrical parameters; calculating a harmonic voltage component of a single bridge arm of a converter valve in the to-be-tested flexible DC converter according to the key electrical parameters so as to generate a harmonic voltage source; integrating the high-frequency equivalent circuit and the harmonic voltage source into simulation software for transient simulation; and determining harmonic voltage distribution and harmonic current distribution of the to-be-tested flexible direct current converter according to the simulation result, thereby effectively avoiding the equipment operation risk and reducing the fault rate of the flexible power transmission equipment.

The invention relates to the technical field of grid connection of new energy units, in particular to a control parameter identification method and system for a grid-connected converter of a new energy unit, a storage medium and a processor. The method comprises the following steps: establishing a high-frequency impedance model of a new energy unit grid-connected system, and determining to-be-identified parameters including a proportionality coefficient of a current inner ring of a converter, an integral coefficient of the current inner ring of the converter and control delay of the converter; harmonic voltage disturbance under different frequencies is applied, harmonic currents of a unit under different frequencies are measured, then impedance values under three different frequencies are obtained, the impedance values under the three different frequencies are input into a high-frequency impedance model of the new energy unit grid-connected system, and the high-frequency impedance model of the new energy unit grid-connected system is obtained. And solving the high-frequency impedance model of the new energy unit grid-connected system to obtain a to-be-identified parameter. The model involved in the method is low in order, the control parameters of the current inner loop of the converter can be obtained only through a small number of impedance tests and equation set calculation, and the method has the advantages of being high in identification efficiency and accuracy.

The invention relates to an AC motor synchronous modulation method based on a phase-locked loop and a PWM generator, and belongs to the technical field of motor control, and the method comprises the steps: determining a voltage phase angle outputted by an AC motor based on an output voltage of vector control of the AC motor, and converting the voltage phase angle into a synchronous phase angle of a carrier wave based on a carrier wave ratio; the synchronous phase angle is used for determining a sine input signal of the phase-locked loop; determining a cycle count increment adjustment value of the carrier based on the sinusoidal input signal; and correcting the cycle count increment value of the carrier based on the cycle count increment adjustment value. According to the alternating current motor synchronous modulation method based on the phase-locked loop, the period ratio and the phase relation of the carrier wave and the modulation wave are fixed, so that the harmonic content of the output voltage and the harmonic content of the output current are kept consistent in the synchronous modulation process, extra harmonic voltage and current cannot be generated, and overall harmonic treatment of a system is facilitated.

The application provides a new energy grid-connected system harmonic risk evaluation method, comprising the following steps: calculating the grid-connected point harmonic voltage of the new energy grid-connected system and the key outgoing line harmonic current after setting the background harmonic through the harmonic node voltage equation; obtaining the harmonic voltage constraint of the grid-connected point and the harmonic current constraint of the key outgoing line; calculating the first deviation factor according to the grid-connected point harmonic voltage and the harmonic voltage constraint, calculating the second deviation factor according to the key outgoing line harmonic current and the harmonic current constraint, and comparing to obtain the maximum value of the deviation factor; calculating the harmonic risk comprehensive evaluation index according to the maximum value of the deviation factor and the harmonic weight factor actual value and judging the harmonic risk of the current operation condition of the new energy grid-connected system. The evaluation method provided by the application can effectively measure the harmonic risk degree under different operation conditions, draw the safe operation area and the risk operation area, and guarantee the safe and stable operation of the new energy grid-connected system.

The embodiment of the invention provides a power quality processing method, electronic equipment, a storage medium and a program product. The method comprises the following steps: constructing a multi-target optimization model according to collected power quality data of a to-be-optimized power distribution network, and configuring constraint conditions for the multi-target optimization model; wherein the multi-objective optimization model is determined according to power grid loss, total voltage deviation and total harmonic voltage distortion rate, and the constraint conditions are used for limiting current, voltage, power and harmonic waves in the multi-objective optimization model; solving the multi-objective optimization model according to an improved whale algorithm to obtain power quality optimization data; and regulating and controlling the power distribution network to be optimized according to the power quality optimization data. The method is used for achieving the technical effect of effectively regulating and controlling the power quality of the power distribution network.

The invention provides a power distribution network resonance key element identification method and device based on harmonic monitoring data, and the method comprises the steps: collecting the harmonic voltage and branch harmonic current data of a key node through the deployment of an online harmonic monitoring device, converting a time domain signal to a frequency domain through band-pass filtering for a preset harmonic number set, and extracting a complex amplitude value, carrying out normalization processing to obtain standardized data; secondly, constructing a node admittance matrix in a frequency domain in combination with the newest power grid topology and equipment static parameters, identifying a feature root closest to zero and a corresponding resonant frequency thereof through eigenvalue decomposition, and obtaining a modal vector; tiny disturbance is applied to inductive reactance / capacitive reactance element parameters, and the sensitivity of the inductive reactance / capacitive reactance element parameters to modal admittance is calculated and normalized into dimensionless indexes; and screening and sorting according to the sensitivity threshold, and outputting a group of resonance key elements. The method does not need off-line simulation, has the advantages of high real-time performance, high engineering adaptability, low implementation cost and the like, and provides efficient technical support for active treatment of harmonic waves of the power distribution network.

The invention discloses a method and a system for designing parameters of a cross-voltage-level active damping device for suppressing system resonance. The method comprises the following steps of: collecting resonance system parameters, determining a resonance frequency band range of a system according to a system impedance model, determining a resonance frequency and a corresponding initial harmonic voltage content ratio, and setting a target harmonic voltage content ratio; calculating harmonic current generated by the nonlinear load, and solving a damping value of system suppression resonance; determining the capacity of the active damping device according to the equivalent harmonic impedance, the harmonic current generated by the nonlinear load and the damping value of system suppression resonance, and carrying out cross-voltage grade transformer type selection; and designing a virtual resistance-capacitance value of the active damping device according to the parameters of the selected transformer and the damping value of the system for suppressing resonance. The insulation performance requirement of the active damping device is lowered, and the equipment treatment investment and the occupied area are reduced; and the influence of the cross-voltage level on the resistance-capacitance parameters of the device is fully considered, so that the parameter design result is more accurate, and the resonance suppression effect is further enhanced.

The invention discloses a loss optimization control method for a cascaded multilevel permanent magnet synchronous motor driving system, and the method comprises the steps: building an equivalent resistance circuit model considering motor loss, and constructing a motor broadband domain loss equivalent circuit model through linear superposition; and obtaining a dq-axis lower converter loss model according to a cascade multi-level carrier phase-shifting modulation strategy. According to the input and output power of the motor driving system before and after the LC filter is added under the working conditions of different rotating speeds and different loads and the dual Fourier series, calculating and outputting the harmonic voltage amplitude of each frequency, and identifying the equivalent resistance under the motor loss model by using a least square method; and a hysteresis component and an eddy current component are separated according to the fundamental frequency equivalent loss resistance, a motor system integrated loss model is constructed in conclusion, and optimal control is performed by applying a golden section algorithm. According to the method, the cascaded multi-level permanent magnet synchronous motor system loss model is established, efficiency optimization is realized by combining the golden section algorithm and applying the motor system loss model, and system-level loss optimization is realized.

The invention provides a power distribution network node harmonic exceeding main cause identification method, device and system and a medium, and the method comprises the steps: building a node admittance matrix based on the node harmonic voltage and branch current monitoring data of a power distribution network, building a related equation of the harmonic voltage and an injection current, and employing a compressed sampling matching pursuit algorithm to identify the harmonic exceeding main cause of the power distribution network; solving a sparse harmonic injection current vector, and calculating a node harmonic voltage distortion rate according to a harmonic current injection value so as to judge a standard exceeding condition; through a modal analysis method, harmonic current threshold comparison and multi-frequency superposition effect analysis, identifying main factors exceeding the standard, including harmonic injection standard exceeding, multi-frequency superposition and resonance phenomena; and quantizing contribution degrees of resonance and harmonic injection, and distinguishing composite causes of harmonic exceeding. According to the method, the problem that the harmonic cause is unknown in the harmonic exceeding scene is solved, and the accuracy of the harmonic exceeding cause is remarkably improved. Through simulation and actual measurement verification, the accuracy of the method provided by the invention is verified.

The invention provides a harmonic detection method and device based on moving average filtering. The actual voltage and the actual current of a node in a power grid can be converted to obtain first harmonic spectrum data. Wherein the first harmonic frequency spectrum data comprises harmonic voltage and harmonic current. And performing moving average filtering on the first harmonic spectrum data to obtain second harmonic spectrum data. And grouping the second harmonic spectrum data, and detecting the center frequency of the harmonic according to a plurality of grouping results. The moving average filtering is carried out on the first harmonic spectrum data, so that the problem of discontinuous spectrum groups in groups caused by low amplitude of partial frequencies is avoided, the reliability of a grouping result is improved, and the accuracy of harmonic detection is further improved.

The invention discloses a broadband harmonic voltage measuring system and method based on an improved CVT, and the system comprises a first current sensor which is used for measuring the first current of a high-voltage capacitor of the CVT; the broadband harmonic wave acquisition device is used for sampling the first current to obtain first current sampling data; and the broadband harmonic analysis device is used for determining an amplitude frequency spectrum of the first current based on the first current sampling data and determining each frequency component of the system voltage based on the amplitude frequency spectrum of the first current. On the basis of a large number of CVTs used in a power system, the broadband harmonic voltage measurement function within the range of hundreds of kHz is achieved by improving the CVT, the original power frequency measurement function of the CVT is not changed, the operation reliability of the CVT is not reduced, and effective broadband, high-precision and low-cost harmonic voltage measurement can be achieved.

A voltage-controlled bridge is coupled to the line voltage and the transformer primary harmonic voltage, while a current-controlled bridge is coupled to the line current and the transformer secondary harmonic voltage. A synchronous average harmonic current compensator synchronously integrates the error between the measured bridge current and the command current every half-switch cycle and samples the compensator output to control the line current and linearize the harmonic coupling between the isolation bridges. A synchronous pulse-width modulation process tracks the commanded line voltage. One or more of the primary and secondary harmonic command circuits regulate the harmonic coupling voltages of the voltage-controlled and current-controlled bridges, respectively. The line voltage, line current, and primary and secondary harmonic commands provide generalized line and isolation voltage bus regulation freedom within a single stage.

The invention discloses a permanent magnet synchronous motor high-frequency mode identification method based on common-mode voltage injection, and the method comprises the steps: calculating a sideband common-mode voltage injection range and a sideband harmonic voltage frequency component under the injection according to a sideband harmonic voltage model; a sideband harmonic current frequency component with the maximum amplitude after injection is calculated within the common-mode voltage injection range, and an electromagnetic force wave generated by the sideband harmonic current under the condition serves as a vibration excitation source; increasing the switching frequency according to a specific step length, and carrying out a frequency sweeping experiment; and analyzing the collected data, and correcting a frequency response curve according to a high-frequency electromagnetic force calculation function to obtain modal parameters of the motor. According to the method, the common-mode voltage which has no influence on the fundamental frequency current is injected into the closed-winding permanent magnet synchronous motor, and the sideband harmonic current component with the maximum amplitude after injection is selected as the vibration excitation source for frequency sweeping, so that the identification of the high-frequency mode of the motor is effectively realized. The method can be widely applied to the field of motor mode identification.

The application discloses a high-frequency injection positionless control method for a cascade H-bridge power supply permanent magnet motor, which separately configures one H-bridge module of each phase of a cascade H-bridge converter into a square wave output mode, configures the remaining H-bridge modules of each phase of the cascade H-bridge converter into a conventional modulation mode of carrier phase shift, uses rotation transformation to extract motor rotor position information and position bias information, designs a moving average filtering algorithm based on the characteristics of high sampling rate of the cascade H-bridge to eliminate the influence of harmonic voltage in the injected square wave signal, and then uses a phase-locked loop technology to obtain motor rotor position observation results, so as to realize positionless control. The application raises the upper limit of the signal injection frequency of the cascade H-bridge motor system from half of the switching frequency to the switching frequency, is helpful for the signal separation link involved in the positionless control, can reduce the disturbance caused by the injected high-frequency signal, improve the signal-to-noise ratio and accuracy of the motor rotor position observation, and improve the operation performance of the positionless control.

The application discloses a kind of interval harmonic power flow calculation method using relative distance measure, first input the parameter of power grid and network fluctuation, construct the node admittance matrix of fundamental wave and harmonic, set the RDM initial value of node voltage and carry out fundamental wave power flow iteration calculation, in the process of fundamental wave power flow iteration, the correction of reactive power injection and voltage is carried out to PV node, after meeting convergence condition, the RDM number of the fundamental wave voltage and injection current of whole network is output. After that, the harmonic power flow iteration part in decoupling method is further simplified by using simple solution method. The harmonic current is calculated at harmonic source node in combination with harmonic spectrum, and then the harmonic admittance matrix in RDM form is established based on the harmonic model of each element in the whole network, and the harmonic voltage RDM value of each node is obtained through the harmonic voltage equation. Finally, the interval number is converted through the conversion principle of RDM number, and the harmonic voltage interval range of the whole network is obtained, which can be applied to harmonic analysis and treatment.

The application provides a harmonic source modeling method based on time-frequency feature extraction, first determines harmonic principal component frequencies of a harmonic source; then extracts harmonic voltage amplitude and phase angle corresponding to the harmonic principal component frequencies of the harmonic source, obtains a frequency domain feature set of the harmonic source, reconstructs the frequency domain feature set through IDFT to form a harmonic source frequency domain feature component matrix, and splices the frequency domain feature component matrix with an original voltage sequence collected by a synchronous phasor measurement device to obtain a time-frequency feature component matrix; the component matrix is converted into a gray scale image by using a matrix normalization method, and is converted into a three-channel time-frequency feature component color image by using a pseudo-color coding technology; finally, the collected harmonic source voltage data and the time-frequency feature component color image are taken as inputs of the model, the collected corresponding harmonic source current data are taken as outputs of the model, the network model is continuously trained through the measured data until accurate mapping of a relationship between harmonic voltage and harmonic current of the harmonic source is realized, and a harmonic source data-driven model is obtained.

The invention discloses a harmonic voltage determination method of a permanent magnet synchronous motor and a related device, and relates to the field of motor control, and the method comprises the steps: simplifying a stator fundamental current differential equation of the permanent magnet synchronous motor through fixing motor parameters in combination with system disturbance, and obtaining a stator fundamental current simplified differential equation of the permanent magnet synchronous motor; processing based on the harmonic current and a method for constructing an augmented state variable to obtain a state-space equation containing the harmonic current, and correcting errors existing in the state-space equation and a fundamental wave current sensor measurement system at the same time according to a Kalman optimal estimation principle; and obtaining a real harmonic current estimation value in the operation process of the permanent magnet synchronous motor so as to determine the harmonic voltage of the permanent magnet synchronous motor. According to the method, the harmonic voltage of the permanent magnet synchronous motor is obtained based on the Kalman optimal estimation principle by simplifying the stator fundamental current differential equation of the permanent magnet synchronous motor, considering the harmonic current and constructing the augmented state variable.

The invention relates to a dual three-phase permanent magnet motor fault-tolerant prediction control method based on virtual vectors and common-mode rejection, and belongs to the technical field of permanent magnet synchronous motor control. In order to solve the problems of fundamental frequency offset and high harmonic content of common-mode voltage after a T-type three-level dual three-phase electric drive system has a single-phase open-circuit fault, a symmetric prediction current model is established by constructing a reduced-order decoupling matrix, a zero-harmonic voltage virtual vector set is generated, and the vector set is alternately input in combination with real-time common-mode voltage offset detection, so that the zero-harmonic voltage is obtained. And a weight-free series-parallel multi-objective optimization cost function is adopted to carry out vector preferential optimization. According to the method, the abc phase common-mode voltage is reduced to Udc / 6 in a high-speed interval, the full-speed domain of the def phase is lower than Udc / 8, the current distortion rate is smaller than 10%, meanwhile, neutral-point potential balance and low switching frequency are considered, and the fault-tolerant capability and the operation efficiency of the system are remarkably improved.

The invention provides a power distribution network harmonic instability critical damping dynamic early warning method and system. The method comprises the steps that harmonic voltage and harmonic current of key nodes of a target power distribution network are acquired every first preset time; identifying the harmonic voltage and the harmonic current according to a first preset rule so as to obtain equivalent harmonic impedance under a preset harmonic frequency according to an identification result; calculating a system damping ratio corresponding to a preset harmonic frequency according to the equivalent harmonic impedance; judging whether the system damping ratio is smaller than or equal to a preset damping ratio threshold value; and if the system damping ratio is smaller than or equal to the preset damping ratio threshold value, generating a harmonic instability early warning signal. According to the invention, the accuracy and practicability of early warning can be effectively improved.

The invention relates to the technical field of electric energy quality analysis and the technical field of artificial intelligence, and discloses a harmonic traceability method and device based on an electrified railway and a new energy inverter, and the method comprises the steps: obtaining the voltage spectrum amplitude of each harmonic of the new energy inverter through a trained deep belief network model, according to the voltage frequency spectrum amplitude of each harmonic wave of the electrified railway and the voltage frequency spectrum amplitude of each harmonic wave of the new energy inverter, generating a root-mean-square value of a harmonic voltage frequency spectrum of the electrified railway and a root-mean-square value of a harmonic voltage frequency spectrum of the new energy inverter; when the root-mean-square value of the harmonic voltage frequency spectrum of the electrified railway is greater than the harmonic threshold value of the electrified railway, marking the dominant equipment type of the harmonic source as the electrified railway, and when the root-mean-square value of the harmonic voltage frequency spectrum of the new energy inverter is greater than the harmonic threshold value of the new energy inverter, marking the dominant equipment type of the harmonic source as the electrified railway; and marking the dominant equipment type of the harmonic source as a new energy inverter. According to the invention, the acquisition efficiency of the dominant equipment type of the harmonic source can be improved.