338 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.

A system-side harmonic impedance estimation method and apparatus, and a storage medium and an electronic device. The method comprises: acquiring an h-th harmonic parameter equivalent circuit simplified on the basis of power grid characteristics, h being a positive integer greater than or equal to 2 (S1); on the basis of the h-th harmonic parameter equivalent circuit, establishing a system-side harmonic impedance estimation mathematical model (S2); acquiring amplitude and phase data of a harmonic voltage and a harmonic current at a PCC (S3); dividing the amplitude data of the harmonic voltage at the PCC into several stable intervals (S4); on the basis of the amplitude and phase data of the harmonic voltage and the harmonic current in the several stable intervals, establishing a variable coefficient regression model between a harmonic voltage phasor and a harmonic current phasor (S5); selecting an optimal window width of a kernel function of the variable coefficient regression model (S6); and calculating a system harmonic impedance on the basis of the variable coefficient regression model and the optimal window width (S7).

The invention discloses an island detection method based on harmonic dynamic characteristics and reactive slip collaborative identification and a detection system thereof, and relates to the field of new energy island detection. In order to solve the defects of low feature extraction precision, threshold stiffness and insufficient response speed of existing island detection, an operation data set of a micro-grid system is acquired according to a topological structure of the micro-grid system; dynamic characteristic data fusion processing is implemented, and harmonic voltage is calculated; a harmonic voltage break variable is used as a starting criterion of island detection; sequentially judging whether the harmonic voltage break variable, the fundamental voltage amplitude and the offset of each harmonic voltage are out of limit or not so as to judge whether the micro-grid is in an island state or not; and constructing a virtual orthogonal signal to calculate a three-phase reactive slip ratio, judging whether the three-phase reactive slip ratio is out of limit, if not, determining that the microgrid is in a non-islanding state, and if yes, determining that the microgrid is in an islanding state. The method is mainly used for judging whether the microgrid is in the island state or not.

The invention relates to the technical field of cable line power distribution network harmonic resonance treatment, in particular to a global and local cooperative partition cooperative resonance suppression method and device. The method comprises the steps of determining a harmonic conductance sensitivity index of each node in a power distribution network according to a target power distribution network admittance matrix parameter, and performing node region division; performing modal analysis on the admittance matrix parameters to obtain modal impedance and participation factors; determining a global optimal virtual admittance instruction value according to the modal impedance, the participation factor and the voltage distortion rate; according to the global optimal virtual admittance instruction value and the voltage distortion rate, determining a regional optimal virtual admittance instruction value in the region; and determining a harmonic compensation current value according to the regional optimal virtual admittance instruction value and the harmonic voltage. According to the method, harmonic suppression is realized for the whole power distribution network by adopting a partition and cooperation mode, and meanwhile, for background harmonic injection change, external interference such as resonance center offset and the like can be effectively overcome, so that the optimal harmonic suppression effect is realized.

The invention discloses a power supply reliability analysis method and system based on operation and maintenance characteristics of a power distribution network, and particularly relates to the technical field of power supply analysis of the power distribution network. Harmonic data, including harmonic current, harmonic voltage and frequency components, of each node in a power distribution network system are collected in real time; in combination with the topological structure of the power distribution network, the sparse linear equation set is solved through L1 norm optimization, and the main source of harmonic waves is identified; the contribution degree of each nonlinear load to the harmonic distortion of a power distribution network system is calculated, a list of key harmonic sources is screened out through Pareto analysis, a filter configuration optimization model is constructed based on the identified key harmonic sources, and the harmonic distortion level and the filter installation cost are used as constraint functions to optimize the filter configuration. The installation position and the parameter configuration of the filter serve as decision variables, an optimization algorithm is adopted for solving, and the recommended installation position and the parameter configuration of the filter are output; the harmonic suppression effects under different load conditions are evaluated, and the problem that the power supply reliability is reduced due to harmonic distortion is effectively solved.

The invention discloses a distributed photovoltaic power quality monitoring method. The method comprises the following steps: acquiring original waveform data of the Internet of Things in real time through a serial peripheral interface; calculating cyclic wave voltage amplitude, cyclic wave harmonic voltage and / or current amplitude, inter-harmonic voltage and / or current amplitude, harmonic active power, positive sequence, negative sequence and zero sequence components of voltage and / or current and unbalance degree according to the original waveform data; and calculating an instantaneous flicker value through a filter according to the original waveform data, and carrying out transient rise, transient drop and interruption event monitoring according to the original waveform data. According to the invention, the technical problems of how to monitor the electric energy quality quickly in real time and how to calculate the frequency deviation in real time are solved.

The invention discloses a current coordinated distribution and voltage optimization control method of a multi-network converter considering nonlinearity and negative sequence load. The method comprises the following steps: carrying out harmonic separation on three-phase load side current and three-phase capacitor voltage through feedforward compensation to obtain a fundamental wave positive sequence component, a fundamental wave negative sequence component and an h-order harmonic component; fundamental wave positive sequence active and reactive power are solved, and angular frequency and output voltage are respectively obtained through an active frequency regulator and a reactive voltage regulator; virtual impedance of a fundamental wave positive sequence, a fundamental wave negative sequence and a harmonic component is set, a multi-frequency-point virtual impedance voltage drop instruction is calculated, and a voltage reference instruction value is obtained by subtracting the multi-frequency-point virtual impedance voltage drop instruction value from the output voltage of the constructed network type converter; calculating a three-phase modulation wave signal based on the voltage reference instruction value, the capacitor voltage, the load side current, the inductor current and the DC voltage; and calculating a pulse signal of the switching device based on the three-phase modulated wave signal. The virtual impedance of the networking converter is set to be a negative value, the harmonic voltage drop on a common coupling point can be reduced, the sum of the virtual impedance and the actual impedance is adjusted to be a certain proportion, and the harmonic current of each order of the multi-networking converter can be distributed according to the proportion.

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.

The invention relates to the field of power distribution network bearing capacity analysis, in particular to a multi-dimension-based power distribution network photovoltaic bearing capacity evaluation method and system, and aims to solve the problems that HC evaluation is inaccurate and the real-time requirement is difficult to meet in the prior art. According to the method, firstly, a multi-dimensional voltage quality index measurement space including voltage deviation, voltage unbalance degree and voltage fluctuation amplitude is constructed, and a comprehensive operation constraint model is established in combination with a total harmonic voltage distortion rate and an individual harmonic voltage distortion rate; thirdly, learning a complex nonlinear time sequence mapping relation between a time sequence of a power grid multi-dimensional state in historical operation data and the maximum allowable photovoltaic bearing capacity meeting the strict constraint conditions by using a BILSTM network; by comprehensively considering the key power quality and the harmonic constraint and applying the strong time sequence information processing capability of the BILSTM, the accuracy and robustness of HC evaluation are remarkably improved.

The invention discloses a converter harmonic impedance modeling method and related equipment, and belongs to the technical field of converters, firstly, space vectors of voltage and current of a grid-connected point are obtained, the space vectors can accurately reflect the magnitude and direction of the voltage and current in real time, and compared with traditional scalar modeling, more comprehensive information is provided. Based on the space vector, harmonic power under the influence of positive and negative sequence harmonic waves, reference voltage passing through a power control loop and harmonic voltage output by an inverter are obtained through sequential calculation, and modeling of a harmonic impedance model is carried out based on positive sequence harmonic voltage and negative sequence harmonic voltage of an inverter side and a grid-connected point and a power grid main circuit. A harmonic model in a coupling frequency impedance matrix form is adopted, the interaction relation between harmonic voltage and harmonic current and the coupling relation of harmonic waves with different frequencies after passing through a converter can be described more accurately, and therefore the accuracy and reliability of an analysis result are improved, and a solid model foundation is provided for harmonic power flow research.

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 relates to a fusion power supply harmonic suppression method based on an energy storage type STATCOM. The method comprises the following steps: determining a harmonic amplification factor K value; selecting and designing a proper discrete digital band-pass filter, and detecting a target frequency band and filtering characteristic sub-harmonics; the detected harmonic voltage amplitude and phase are used as references, an energy storage type STATCOM is adopted to output same-frequency and same-phase harmonic current, virtual damping is formed at a grid-connected point, a K value is used as a damping coefficient, the output harmonic current reference amplitude is determined, virtual harmonic damping is controlled, and harmonic resonance is suppressed. The virtual harmonic damping method for the energy storage type STATCOM is provided for accurate tracking of low-frequency harmonic and inter-harmonic voltage amplitudes and phases, the chain type STATCOM has the advantages of being high in high-voltage direct-hanging efficiency, high in redundancy fault-tolerant capability and the like and is suitable for high-voltage large-capacity scenes, virtual damping control achieves harmonic suppression by adjusting virtual damping at the harmonic frequency of a control structure, and the energy storage type STATCOM can be applied to high-voltage large-capacity scenes. And the system stability can be effectively improved while harmonic waves are treated.

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 ground fault positioning and multi-solution screening method for a stator winding of a pumped storage unit, and belongs to the field of relay protection. The method is combined with a special structure of a stator winding of a variable-speed pumped storage unit, and a function relationship between a fault winding potential and a fault position is established by taking a slot potential as an analysis unit. In a phasor plane, by drawing a three-phase ground voltage phasor and a neutral point voltage phasor, an included angle relation between a fault point voltage phasor and the neutral point voltage phasor and a phasor triangle relation are utilized to determine an alternative fault point. And then, an optimization model for fault positioning is established, and a homonuclear molecule optimization algorithm is adopted for solving, so that accurate positioning of a plurality of alternative fault points is realized. And finally, third harmonic voltage information is introduced as auxiliary information, and a unique solution is screened out from the plurality of alternative fault points. The method is high in reliability, small in positioning result error and suitable for the positioning requirement of the variable-speed pumped storage unit stator grounding fault.

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 belongs to the technical field of power distribution, and particularly relates to a selective over-current limitation-based active filtering method for a network-forming converter, which comprises the following steps of: S1, performing state space modeling on a VSC: (i) VSC; (ii) a main controller of the VSC (Virtual Synchronous Generator), which is realized by a virtual synchronous generator (VSG); (iii) an AHF function implemented by direct harmonic voltage control; (iv) selective harmonic overcurrent protection; s2, performing preliminary calculation on the gain of the controller; s3, linearizing the nonlinear state space model of the system provided in the step S1 near a balance point, and evaluating a characteristic value; and S4, determining a stable range of each control parameter so as to set a final control gain. According to the invention, the current component can be selectively limited under the condition that the VSC is overloaded, so that a stable AHF function is provided for the VSC.

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.

A method for suppressing current harmonics of a permanent magnet synchronous motor relates to the field of permanent magnet synchronous motor control, and comprises the following steps: Step 1: designing a model reference adaptive system, including three parts: a reference model, an adjustable model and an adaptive module, to realize online identification of time-varying parameters of resistance and inductance. Step 2: designing a harmonic injection system, extracting 6x±1 times current harmonics (x is a natural number), and calculating harmonic voltage compensation. Step 3: injecting the harmonic voltage compensation calculated in step 2 into a permanent magnet synchronous motor vector control model to suppress 6x±1 times current harmonics. The present invention can identify key time-varying parameters of the harmonic injection link online during the operation of the permanent magnet synchronous motor, improve the harmonic suppression effect under time-varying motor parameters, reduce the vibration and noise of the permanent magnet synchronous motor, and realize it through software optimization, without adding additional hardware and cost, and is easy to realize.

The invention relates to the technical field of harmonic electric energy metering, and particularly discloses a harmonic electric energy metering control system based on artificial intelligence. Comprising a harmonic data acquisition module, a harmonic data preprocessing module, a harmonic electric energy data analysis module, a harmonic data error analysis module, a harmonic electric energy comprehensive analysis module, a metering error evaluation module and a management early warning module. According to the method, the harmonic data are collected from the power grid and preprocessed, the harmonic voltage error index, the harmonic current error index and the harmonic active power error index are obtained through analysis, and then the harmonic electric energy metering error evaluation index is obtained through analysis; accurate detection and real-time error metering analysis for monitoring harmonic waves of a power system are realized, electric energy metering errors are evaluated and controlled, accuracy and reliability of electric energy metering are improved, and safe and stable operation of a power grid is guaranteed.

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 invention discloses a grid-forming inverter output electric energy quality optimization control system and control method, and the method comprises the steps: replacing a PWM modulation module with model prediction control in a grid-forming inverter, extracting the voltage of a point of common coupling (PCC) and the harmonic component of a power grid current through the orthogonal characteristic of a sine function, predicting and calculating the harmonic voltage of a power grid, and carrying out the optimization of the output electric energy quality of the grid-forming inverter. The harmonic voltage obtained through calculation is multiplied by a coefficient and added into reference voltage, and model prediction control is used for modulation. The harmonic voltage amplitude on the power grid impedance is controlled by controlling the harmonic voltage multiplication coefficient, and flexible suppression of the network access current harmonic and the PCC voltage harmonic is achieved. The method is simple in structure and convenient to implement, the grid-connected inverter based on the method can achieve higher-quality electric energy output, and the method is suitable for various grid-forming type grid-connected inverters.

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.