41 results about "Voltage distortion" patented technology

The invention relates to a harmonic traceability method based on an electric energy quality index monitoring cloud platform, which is realized based on the electric energy quality monitoring cloud platform of an electric power system, and comprises the following steps: S1, selecting an attention node; s2, selecting a harmonic traceability time period; s3, selecting a correlation coefficient calculation item; s4, collecting and processing harmonic data of all feeders of each concerned node, and drawing a voltage distortion rate and harmonic current trend curve contrastive analysis chart of each feeder; and S5, the electric energy quality monitoring cloud platform uses a built-in traceability algorithm to calculate correlation coefficients, screens feeder lines whose correlation coefficients are greater than K, and outputs a harmonic traceability report. According to the invention, one-key positioning and accurate identification are carried out on the system harmonic source based on the electric energy quality monitoring cloud platform by adopting synchronous electric energy quality data of multiple monitoring points according to an advanced correlation traceability algorithm, so that the harmonic traceability accuracy and working efficiency are greatly improved, and the harmonic traceability cost is reduced.

The invention belongs to the technical field of power generation and power supply, and particularly relates to a power distribution network electric energy quality monitoring and comprehensive evaluation method and system, and the method comprises the steps: obtaining an environment reference parameter, three-phase voltage data, three-phase current data, transformer harmonic current and transformer harmonic current times; calculating a transformer voltage distortion rate and a transformer total current which represent the overall level of the electric energy quality; calculating a harmonic erosion index representing the load side harmonic frequency spectrum complexity; calculating a thermal harmonic coupling degree used for judging a high temperature generation reason; calculating a power grid health score; grading the operation state of the power grid; judging the fault type; and issuing adjustment instructions to different fault types. The technical problem that the dynamic coupling relation between the harmonic form and the equipment thermal state cannot be evaluated in the prior art is effectively solved.

The invention discloses a power distribution network harmonic suppression method based on virtual admittance of a photovoltaic grid-connected inverter, and the method comprises the following steps: generating a harmonic compensation current through the photovoltaic grid-connected inverter, constructing a virtual admittance control mechanism based on the harmonic compensation current, and obtaining a mapping relation between a virtual admittance value and a phase angle on the harmonic suppression effect; modeling a photovoltaic grid-connected inverter of the power distribution network, and constructing a virtual admittance regulation mechanism of the power distribution network; and based on a virtual admittance control mechanism, taking each virtual admittance parameter as an optimization variable, and carrying out a multi-photovoltaic grid-connected inverter collaborative optimization strategy to realize graded treatment of power distribution network harmonics. According to the method, a virtual admittance control mechanism is constructed, and a photovoltaic grid-connected inverter is equivalent to earth admittance; and harmonic fractional compensation and global optimization configuration are realized by combining sensitivity analysis of voltage distortion of each node. The problem that the VDAPF only adjusts through harmonic conductance and neglects the impedance characteristic of the power distribution network and the uncertainty of the harmonic phase is solved, and the harmonic compensation capability is remarkably improved.

This application provides a DC boost grid connection method, system, device, equipment, medium, and product, relating to the field of new energy grid connection. The method employs a cascaded topology of H-bridge modules to dynamically adjust the DC voltage output of the photovoltaic array according to the light intensity to match the light conditions. Simultaneously, it dynamically adjusts the number and switching times of the H-bridge modules based on the grid voltage demand, ensuring that the peak value of the multi-level AC voltage output by the adjusted H-bridge module group matches the voltage demand. Furthermore, it actively constrains the harmonic distortion rate and amplitude fluctuation rate of the output voltage to be below preset thresholds. Without requiring a power frequency boost transformer and a large-capacity inverter, it achieves direct boost grid connection from photovoltaic DC to high-voltage AC. It also solves the voltage distortion and amplitude fluctuation problems that easily occur during the dynamic adjustment of the number of modules, improving grid-connected power quality and system operational stability, and reducing the cost of the photovoltaic DC boost grid connection system.

This invention discloses a predictive maintenance system for medical X-ray equipment, belonging to the field of medical equipment maintenance technology. It includes a multi-source data acquisition module, a feature construction module, a coupled degradation modeling module, a risk assessment module, and a maintenance strategy generation module. Based on voltage distortion rate, current harmonic components, and temperature field gradient, this invention extracts the standard deviation of voltage distortion rate, the total distortion coefficient of current harmonics, and the rate of change of temperature gradient after denoising using wavelet thresholding, and fuses them into a feature vector. Combining a long short-term memory network and a Bayesian network, it calculates a comprehensive degradation index of multi-parameter coupling; subsequently, it constructs a multi-parameter feature space and outputs a comprehensive risk level through unsupervised learning methods; finally, it generates targeted maintenance strategies based on the risk level and optimization algorithms. This invention achieves accurate prediction and intelligent maintenance of medical X-ray equipment faults, reduces sudden failures, lowers maintenance costs, and improves equipment operational reliability and diagnostic and treatment safety.

This invention belongs to the field of power generation and supply technology, specifically relating to a method and system for monitoring and comprehensively evaluating the power quality of distribution networks. The method includes: obtaining environmental reference parameters, three-phase voltage data, three-phase current data, transformer harmonic current, and transformer harmonic current order; calculating the transformer voltage distortion rate and total transformer current, which characterize the overall power quality level; calculating the harmonic erosion index, which characterizes the complexity of the harmonic spectrum on the load side; calculating the thermal harmonic coupling degree used to determine the cause of high temperatures; calculating the grid health score; classifying the grid operating status into levels; determining the fault type; and issuing adjustment commands for different fault types. This invention effectively solves the technical problem that existing technologies cannot assess the dynamic coupling relationship between harmonic morphology and equipment thermal state.

The invention relates to the technical field of three-phase systems, and provides a three-phase voltage state estimation method and system based on virtual coordinates, and the method comprises the steps: calculating the voltage peak value of each phase for three-phase voltages, and determining that a phase is open if the peak voltage of a certain phase is lower than a threshold value in the three peak voltages; for three-phase voltage, virtual beta-axis voltage is generated through an all-pass filter, actual beta-axis voltage is obtained through Clark transformation, the product of the virtual beta-axis voltage and the actual beta-axis voltage serves as an evaluation function, and a positive sequence and a negative sequence are distinguished according to the positive and negative of the evaluation function. The system state can be accurately and effectively judged under the conditions of three-phase imbalance and voltage distortion, the anti-noise capability and the anti-harmonic interference capability are high, and safe and stable operation of equipment under the abnormal condition is ensured.

The invention relates to the technical field of anomaly detection, in particular to a substation equipment anomaly detection method based on deep learning. Comprising the following steps: determining whether the operation of a single secondary device is qualified based on a voltage distortion rate, marking the unqualified secondary device as an abnormal device, and determining whether the operation of the secondary device is qualified based on a frequency deviation for the secondary device whose voltage distortion rate is greater than a second preset voltage distortion rate and less than or equal to a first preset voltage distortion rate, unqualified secondary equipment is marked as abnormal equipment, and the secondary equipment is a relay protection device; based on the disqualification ratio, determining that the reason for disqualification of the test process is preset matching degree abnormity or secondary equipment detection abnormity; adjustment is correspondingly carried out according to reasons for disqualification of the test process; according to the invention, the equipment abnormity detection efficiency is effectively improved.

The invention is suitable for the technical field of electric energy metering, and relates to an electric energy metering method and device of an electric energy meter. Corresponding fundamental wave voltage current components, harmonic wave voltage current components, corresponding fundamental wave phase angles and harmonic wave phase angles are extracted, and based on the data, fundamental wave positive sequence active power, reactive power, non-fundamental wave equivalent apparent power, voltage distortion power, current distortion power, harmonic wave apparent power, unbalanced apparent power and the like are obtained through calculation; various electric parameters of the electric energy meter are metered so as to guide an electric power department to charge, make economic decisions, measure main harmonic pollution sources and the like, and the quality of electric power service is greatly improved.

The utility model discloses a kind of electric energy quality DNV voltage distortion rate elimination stabilizer and sampling circuit, including load equipment and for the DVA voltage stabilizer on the load equipment, still including with the DVA voltage stabilizer and the load equipment electric connection A circuit, B circuit, C circuit and N circuit.The beneficial effect of the utility model is: through filter current transformer, voltage stabilizer current transformer and DVA voltage stabilizer, realize the process in the use of load equipment, inhibit load equipment dynamic and steady-state voltage drop and voltage variable, eliminate surge, eliminate voltage flicker, with good dynamic voltage stability capacity, output voltage reaches precision ±1% -5% adjustable, can effectively filter each harmonic, three-phase unbalance, improve power factor, improve power supply electric energy quality, and harmonic elimination stabilizer has ideal energy-saving effect, between 1-8% in different field energy-saving effect.

The embodiment of the invention provides a direct-current boost grid connection method, system, device, equipment, medium and product, and relates to the field of new energy grid connection, the method adopts an H-bridge module group cascade topology structure to dynamically adjust the direct-current voltage output by a photovoltaic array according to the illumination intensity so as to enable the direct-current voltage to be matched with the illumination condition, and the direct-current boost grid connection is realized. Meanwhile, the input number and the switching time of the H-bridge modules are dynamically adjusted according to the voltage requirement of the power grid, so that the multi-level alternating-current voltage peak value output by the adjusted H-bridge module group is matched with the voltage requirement, and the harmonic distortion rate and the amplitude fluctuation rate of the output voltage are actively restrained to be lower than preset threshold values; on the premise that a power frequency boosting transformer and a large-capacity inverter do not need to be configured, direct boosting grid connection from photovoltaic direct current to high-voltage alternating current is achieved, meanwhile, the problems of voltage distortion and amplitude fluctuation which are prone to occurring in the dynamic adjustment process of the number of modules are solved, the grid-connected electric energy quality and the system operation stability are improved, and the system reliability is improved. And the cost of the photovoltaic direct-current boost grid-connected system is reduced.

The invention provides an SVG self-synchronization control system and method based on active disturbance rejection control. The system comprises an active power reference value calculation module, a power calculation module, an active power synchronization loop module, a reactive power-AC voltage outer loop module, a positive sequence current component control loop module, a negative sequence current component control loop module and a pulse generation module. By adopting modules such as an active power synchronous ring for active disturbance rejection control, internal and external disturbances under complex working conditions such as power grid faults and voltage distortion are effectively suppressed, and the stability and dynamic response performance of the system in a transient process are improved. The synchronization performance of the SVG under the fault working condition can be improved, and the safety and stability of a power grid are improved.

This invention relates to the field of motor control technology, particularly to applications requiring low vibration and high efficiency in underwater propulsion motors. Specifically, it provides a method for suppressing low-order harmonic torque and high-frequency harmonic current in underwater propulsion motors. This invention switches control modes according to changes in the motor's operating frequency, meeting not only the low-noise requirements for low-speed navigation but also improving controller efficiency for high-speed navigation. When the underwater propulsion motor operates at low speed, harmonic compensation of the line current suppresses low-order harmonics generated by the motor body and controller, thereby reducing electromagnetic force pulsation caused by harmonics. Furthermore, by significantly increasing the switching frequency using silicon carbide power devices, it suppresses phase voltage distortion caused by pulse width modulation technology, improves the sinusoidal nature of the output voltage, and reduces harmonic torque. When the underwater propulsion motor operates at high speed, the output current is large; by reducing the switching frequency, the switching losses of the power devices are reduced, improving the efficiency of the controller in the propulsion system.

The invention discloses a self-adaptive dead zone compensation method for a servo driver. The method comprises the following steps: step 1, building a motor three-phase current acquisition circuit and acquiring three-phase current in real time; step 2, current polarity discrimination based on hysteresis comparison; 3, reconstructing a dead-zone voltage error vector in real time; 4, dynamically adjusting the self-adaptive compensation coefficient; 5, direct correction and compensation injection of a PWM duty ratio instruction are carried out; and step 6, loop iterative optimization and full-working-condition real-time compensation are carried out. The method has the advantages that the non-ideal voltage deviation caused by the inherent switching dead time of the voltage source type inverter is accurately offset. The dead-zone effect comes from physical characteristics of power electronic devices, and aims to prevent straight-through short circuit of power tubes of upper and lower bridge arms of an inverter and unexpected voltage distortion of motor end voltage in an actual process. The objective of the invention is to recover the ideal waveform of the motor terminal voltage and improve the current tracking precision, the torque stability and the low-speed performance.

This invention provides a method and apparatus for selecting the location of an active harmonic mitigation device for radial distribution networks, belonging to the field of power quality management technology. The method includes: acquiring equipment parameters of each branch of the distribution network; determining the harmonic impedance of each branch based on the equipment parameters, and calculating the influence coefficient of each nonlinear load branch's harmonics on the distribution network's harmonic voltage; calculating the contribution rate of each nonlinear load branch's harmonics to the voltage distortion of the distribution network based on the influence coefficients of all nonlinear load branches; determining the numerical distribution characteristics of the voltage distortion contribution rate corresponding to all nonlinear load branches based on the coefficient of variation and a threshold; and determining the optimal location of the active harmonic mitigation device based on the numerical distribution characteristics, the expected minimum target for harmonic mitigation, and the voltage distortion contribution rate corresponding to each nonlinear load branch. This invention can solve the problem of difficult location selection for harmonic mitigation devices in radial distribution networks where harmonic sources are dispersed.

The invention relates to a cable insulation fault positioning method and system, and the method comprises the following steps: collecting a three-phase voltage traveling wave signal when a cable has a single-phase insulation damage grounding fault, and carrying out the signal decoupling, and obtaining an independent line mode component and a zero mode component; a Db45 wavelet basis is used as a mother wavelet, multi-scale wavelet decomposition and reconstruction are carried out on the decoupled line mode component so as to extract fault traveling wave head features, and the number of layers of multi-scale wavelet decomposition is determined according to the sampling frequency and the power grid fundamental wave frequency; and according to a wavelet reconstruction result, detecting the moment when a fault traveling wave head arrives at monitoring points at two ends of the line, thereby calculating the distance from a fault point to one end of the line. Compared with the prior art, the method has the advantages that inter-phase coupling interference is eliminated through phase-mode transformation, and serious voltage distortion and harmonic interference in a power grid are effectively suppressed by using the excellent time-frequency localization characteristic of the Db45 wavelet basis, so that the accuracy and reliability of cable insulation fault positioning are greatly improved.

The invention discloses a three-phase four-bridge-arm inverter control method and device based on multi-quasi-PR parallel resonance, terminal equipment and a storage medium, and relates to the field of inverter control, and the method comprises the steps: carrying out the proportional scaling of a three-phase voltage error of a three-phase load voltage and a three-phase reference voltage, obtaining a proportional control signal, and carrying out the control of the proportional control signal; carrying out resonance gain amplification on the fundamental wave, the first harmonic wave and the second harmonic wave to obtain corresponding resonance control signals, and carrying out parallel superposition to obtain a current inner loop reference value; determining a three-phase bridge arm output voltage according to the deviation between the current inner ring reference value and the three-phase inductive current in combination with the compensation of the three-phase load current; and according to the three-phase bridge arm output voltage, determining a neutral line bridge arm voltage, further generating a switch control pulse signal of a bridge arm, and controlling the three-phase four-bridge arm inverter. Through the implementation of the invention, the problem of output voltage distortion caused by the fact that PI control is difficult to adapt to a nonlinear load in the prior art is solved, and the output voltage distortion rate under the nonlinear load is reduced.

The invention discloses a potential energy recovery system and method for a ship unloader of a coal wharf, and relates to the technical field of energy-saving technologies of large loading and unloading equipment of coal ports, and the system comprises a multi-motor cooperation module, a central electric energy conversion module, a system main control unit and a hybrid energy storage system. The method comprises the steps of multi-motor cooperative power generation and priority division, electric energy preprocessing and input, direct current bus voltage stabilization and power grid state perception, reactive compensation and harmonic filtering, energy scheduling and path selection, hybrid energy storage system hierarchical control and the like. Through the technical scheme of combining multi-motor cooperative control, power grid state real-time sensing and intelligent compensation, the problems of multi-motor energy scheduling imbalance, power grid voltage distortion and the like are effectively solved, and efficient recovery and safe utilization of potential energy of the ship unloader are achieved.

The invention discloses an SOGI parameter self-tuning SiC motor speed-sensorless control method, and aims to solve the problems of fixed injection frequency and SOGI parameter mismatch in the prior art. The method comprises five links of working condition identification and injection frequency dynamic switching, SOGI parameter adaptive tuning, dead zone time cooperative compensation, rotor position estimation and error feedback and system integration optimization. Working conditions are divided through two-dimensional fuzzy clustering, differential injection frequencies are adapted, SOGI parameter self-tuning is achieved by combining fuzzy control and PI adjustment, a dead-time voltage distortion model is established, cooperative compensation is carried out, and rotor position estimation precision is improved by adopting a weighted fusion algorithm. According to the method, the sixth harmonic suppression rate can be increased to 95% or above, the rotating speed estimation error is reduced to be within 10 r / min, the full-working-condition adaptability and stability of the system are enhanced, engineering practicability is achieved, and the method is suitable for the fields of industrial transmission, new energy power generation and the like.

This invention relates to the field of microgrid control technology, and discloses a distributed harmonic control method, device, and multi-inverter system for multi-inverter systems. In this invention, adjacent inverter control units are connected to form a ring network. During harmonic control, the output voltage and output current of the inverter in the inverter control unit are used to separate the fundamental and harmonic components. Based on the obtained fundamental component, the fundamental component of the outer loop reference voltage is calculated. The harmonic power is calculated based on the harmonic current component. Combined with the harmonic power of other interconnected units, a harmonic power sharing controller is calculated to determine the harmonic voltage gain coefficient. Based on this coefficient and the harmonic current component, the harmonic component of the outer loop reference voltage is obtained. The outer loop reference voltage is then calculated, and the control voltage for the corresponding three-phase inverter bridge is obtained from this reference voltage. This invention is unaffected by grid interference and feeder impedance mismatch, compensates for voltage distortion caused by nonlinear loads, and achieves precise harmonic power distribution between the DG (Distributed Generator and Controller).

The application discloses a new energy photovoltaic inverter energy conversion control system and relates to the technical field of new energy power generation grid connection. The system comprises the following modules: a signal acquisition module, which acquires grid-connected current instructions, grid voltage and current feedback signals; a virtual impedance generation module, which generates synchronous virtual impedance reference signals based on the grid voltage, wherein the virtual resistance component is negative to provide active damping; a grid working condition monitoring module, which monitors the voltage distortion rate and the frequency fluctuation rate to determine the grid working condition; a dynamic instruction generation module, which dynamically increases the inductance component weight in the virtual impedance signal according to the disturbance amplitude when the grid is in a non-ideal working condition, performs enhancement processing on the dominant disturbance type, and then superimposes the current negative feedback to the current instruction to generate a dynamic grid-connected current instruction; and a closed-loop control and driving module, which generates a switching driving signal based on the dynamic instruction and the feedback signal. The application can adapt to grid impedance changes and severe working conditions, and can improve grid stability and current control quality.

The application discloses a power converter, a system, a control method and related devices. The power converter comprises a controller and a three-phase power conversion circuit. Each phase of the three-phase power conversion circuit comprises a four-switch Buck-Boost circuit. The direct current side of the three-phase power conversion circuit is connected with a direct current source. The alternating current side of the three-phase power conversion circuit is connected with a load. The neutral point of the load is adapted to be connected with the positive pole of the direct current source. The controller controls the bias voltage to be equal to the voltage of the direct current source when the power converter works in a three-phase four-wire system. Alternatively, the controller controls the bias voltage to be equal to the voltage of the direct current source and controls the phase voltage amplitude of the alternating current side of the three-phase alternating current conversion circuit to be less than or equal to the voltage of the direct current source. The scheme can reduce the risk of phase voltage distortion in the three-phase four-wire system.

The invention discloses a grid-connected inverter control method and system based on composite PCC voltage feedforward, and the method comprises the steps: constructing a composite feedforward function which is formed by superposing a unit item, a multi-resonance compensation item and a secondary differential item with a second-order Butterworth low-pass filter, and applying the composite feedforward function to a PCC voltage feedforward channel of a grid-connected inverter. According to the multi-resonance compensation item, for fundamental waves and specific low-order harmonic frequencies, damping coefficients are set in a layered mode, low-frequency admittance phase mutation caused by resonance characteristics of a controller is accurately compensated, and low-frequency passivity is recovered; frequency selective weighting is achieved through filtered secondary differential terms, the harmonic suppression capacity is enhanced in the middle and low frequency bands, and meanwhile attenuation is conducted in the high frequency band so as to guarantee passivity. According to the method, on the premise that hardware cost is not increased, the problem that harmonic suppression and full-band stability are difficult to consider at the same time is effectively solved, and the operation robustness and the electric energy quality of the grid-connected inverter under the working conditions of a weak power grid and voltage distortion are remarkably improved.

The invention provides a power distribution network harmonic suppression method and device and a controller, and relates to the technical field of urban power distribution network harmonic resonance suppression. The method comprises the following steps: acquiring an admittance matrix of a target power distribution network, parameters of each harmonic suppression device and voltage distortion rates of each node; establishing a time domain differential state model of each module of each harmonic suppression device according to the parameters of each harmonic suppression device, converting the time domain differential state model into a frequency domain differential state model, and constructing a frequency coupling model of each harmonic suppression device about input and output according to the frequency domain differential state model; and performing optimal planning solution based on the frequency coupling model, the admittance matrix and the voltage distortion rate of each node to obtain optimal operation parameters of each harmonic suppression device. According to the method, the frequency coupling model can be integrated into harmonic treatment optimization of the target power distribution network, and compared with a traditional ideal harmonic source model, the method is more accurate, and the treatment effect is more excellent.

The invention provides a control method for a single-pole isolation DC-AC converter, and the method comprises the steps: carrying out the drive control of switching tubes Q1, Q2, Q3 and Q4 on a primary rectifier bridge of the single-pole isolation DC-AC converter through high-frequency single-pole modulation waves, and carrying out the drive control of switching tubes S1, S2, S3 and S4 on a secondary rectifier bridge through high-frequency square waves with the duty ratio of 50%; and the switching tubes J1 and J2 on the secondary rectifier bridge are driven and controlled by sine waves with the frequency as the target power frequency. According to the invention, the duty ratios of the primary side switch tubes Q1, Q2, Q3 and Q4 are selected as the output AC voltage distortion rate control freedom degree, the external phase shift is selected as the power transmission control freedom degree, and the above two control freedom degrees are combined to realize the inversion modulation under the topological structure. The topological structure can work normally under the conditions of no load, small load and capacitive load in an inversion state.

The invention discloses a self-adaptive phase locking method, device and equipment and a storage medium, and relates to the technical field of power systems. The method comprises the following steps: acquiring common coupling point voltage of a current power grid; outputting a phase-locked loop parameter by using a neural network according to the common coupling point voltage; and outputting the phase reference of the common coupling point through a phase-locked loop by using the phase-locked loop parameter. According to the technical scheme, the problem that the phase locking precision is reduced due to voltage distortion of the common coupling point is effectively solved, and the stability of a power system under broadband disturbance is remarkably improved.

The invention discloses a micro inverter and a grid-connected output control method thereof, and relates to the technical field of photovoltaic power generation, the micro inverter comprises a photovoltaic input port, a single-stage power conversion circuit, an output filter and a control unit, the single-stage power conversion circuit forms a full-bridge inversion topology through a silicon carbide (SiC) metal-oxide-semiconductor field effect transistor (MOSFET), and the output filter is connected with the output filter. And the switching frequency is not lower than 80kHz. According to the micro inverter and the grid-connected output control method thereof, a power grid voltage sensor is canceled, the power grid impedance is identified on line only based on the inverter side inductive current and the capacitor voltage, and the virtual power grid voltage is reconstructed to extract the synchronous phase, so that the problem of phase locking failure caused by power grid voltage distortion or a weak power grid is fundamentally avoided; even under the working condition that the power grid impedance fluctuates severely or the voltage waveform is distorted severely, stable and high-quality grid-connected current output can still be achieved, and the adaptive capacity and the operation continuity of the system in a complex power grid environment are remarkably improved.

The invention belongs to the technical field of power electronics, and relates to a low-harmonic air conditioner compressor converter and a control method and system thereof. The control method comprises the following steps: generating a three-phase original modulation wave of the grid-side converter based on a three-phase voltage of a power grid, a phase angle of the voltage of the power grid, a direct-current bus voltage and a three-phase input current of the grid-side converter, and generating a modulation wave of a switch in the grid-side converter based on the three-phase original modulation wave of the grid-side converter, a modulation wave of a switch in the compressor-side converter is generated based on a set three-phase original modulation wave of the compressor-side converter, three different carrier waves are generated based on a set isosceles triangle carrier wave, and a driving signal of a grid-side converter switch is generated according to the modulation wave of the switch in the grid-side converter and the three different carrier waves. And generating a driving signal of the switch of the compressor side converter according to the modulation wave of the switch in the compressor side converter and the three different carrier waves. The voltage distortion rate of the input current of the grid-side converter can be reduced, and the power supply quality of the power grid is high.

The application relates to the technical field of smart power grids, and provides a low-voltage power distribution network transparent fusion perception visualization scene construction method and system, which comprises the following steps: collecting voltage, current and device state data by using power line carrier communication, smart power meters and power distribution terminals synchronously, and establishing a time scale aligned ring queue; constructing a tree-shaped topological structure based on three-phase attributes and generating a connection matrix, dividing users into different transparency visualization levels through electrical distance calculation, and realizing gradual coloration and special effect warning of overload lines by combining current saturation mapping; fusing physical positions and electrical parameters through polar coordinate system conversion, generating dynamic particle flow to intuitively display current distribution; when voltage sag occurs, backtracking voltage distortion propagation path through waveform similarity, locating the disturbance source and triggering pulse diffusion animation. The method realizes transparent fusion perception of the operation state of the low-voltage power distribution network, real-time early warning of line overload and second-level positioning of the disturbance source, and improves the intelligent operation and maintenance efficiency.

Embodiments of the present application provide a kind of power grid harmonic control method, device, equipment and storage medium, involve power system technical field.The method comprises: according to the network architecture information of power system, the load distribution node matrix of power grid is determined;According to the distribution node information of load indicated by the load distribution node matrix, the first voltage distortion rate of the power grid is determined;If it is determined that the first voltage distortion rate does not satisfy the requirement of pre-set limit value, the distribution node information of load included in the load distribution node matrix is optimized, and the updated load distribution node matrix is obtained;According to the updated load distribution node matrix, after the node that the load of the power grid is accessed, power supply is carried out for the load of the power grid, to restrain the harmonic generated by the power grid.The method of the present application can flexibly, efficiently and low cost control the harmonic of power grid, improve the stability and reliability of power system.