This paper first introduces bidirectional isolated AC-DC matrix converter working principle and the influencing factors of energy flow direction,then analyzes the realization principle of bipolar current space vector modulation method in detail,and finally designs a PI direct power controller to adjust the charging current.The unit power factor control and low harmonic distortion rate of grid current were realized,and the correctness of the design was verified by simulation.
A portable phase separation grounding wire device was propesed.Through reasonable design,the grounding soft copper wire can be wound on the winding coil,and portable storage can be achieved,which is convenient for on-site workers to save time and effort,reduce high-altitude work time,and reduce the risk of personnel working on the iron tower.
This paper discusses the change of contact resistance of silver nickel alloy in temperature controller under the protection of organic corrosion inhibitor under different assembly conditions,studies the differences of two kinds of organic corrosion inhibitors and their combinations,and through the analysis of their differences,it is selected that the PMTA+BTA combination of corrosion inhibitors has great practical value for the protection of film resistance on the surface of silver alloy.
For the line loss calculation of medium-voltage distribution networks containing DGs with high-density collection data,a continuous line loss calculation method for the distribution network was proposed,aiming at improving the accuracy compared with the traditional line loss calculation method.The proposed method makes full use of the high-density collection data on the dispatch side and DG side,distributing the supply power to each load node by power to calculate real-time power flow,thus obtaining a more credible line loss value.The effectiveness and accuracy of the proposed method were verified in the IEEE 17-node distribution system.
Aiming at the problems of low accuracy and low timeliness of photovoltaic power prediction method,an ultra short-term photovoltaic power prediction method based on the combination of Time Varying Filtering-Empirical Mode Decomposition(TVF-EMD)and Extreme Learning Machine(ELM)was proposed.First,the TVF-EMD method was used to decompose the photovoltaic power data,so as to obtain a group of relatively stable components and reduce the interaction between different power influencing factors.Then the ELM neural network model was used to construct different prediction models according to the characteristics of each component to predict the value of each component.The values of each component predicted by ELM were added to obtain the final prediction result.Example results show the effectiveness of the proposed method.Compared with the traditional model,the normalized root mean square error decreases by 25.8%,the standard mean absolute error decreases by 17.97%,and the correlation coefficient increases by 8.3%.
Four different distribution automation methods were compared and analyzed,and four different distribution automation schemes were quantitatively evaluated and compared.
This paper provides an overview of intelligent power grid technology and analyzes its application in power scheduling automation.It suggests designing an efficient power intelligent scheduling system based on intelligent power grid technology,improving the human resource management efficiency of the intelligent power dispatching system,and developing intelligent robots.
This article proposes three characteristics of data fluctuations,including mutation degree,stability degree,correlation and verifies the role of these data fluctuation characteristics in practical work,providing theoretical basis for the accuracy of oil chromatography online monitoring.
This paper describes the construction of fire closure and the mechanism of acoustic measurement technology.From the aspest of engineering,combined with acoustic emission and acoustic imaging technology,the fire closure of switchgear cable silo or cable channel was tested and studied,and the effective evaluation index was given.
Applying artificial intelligence technology to power dispatch automation systems can effectively alleviate the pressure on power supply and meet the demand for power supply in different environments,ensuring the stability and effectiveness of power supply.This research mainly explores the application of artificial intelligence technology in power dispatch automation systems,with the aim of promoting the sustainable and stable development of China's power industry.
In this paper,a balance control strategy based on DC side voltage is proposed,which adopts two layers of voltage control.The first layer is the balance control of each phase of three-phase voltage,and the second layer is the voltage balance control of each power unit.This paper uses Matlab/simulink to build a simulation model,and the results show that the static reactive power compensator can quickly achieve reactive power balance by using this method.
In order to optimize power quality,this paper proposes a line compensator consisting of two sets of capacitors.When two sets of capacitors compensate reactive power,the configuration is flexible,the compensation range is wide,and thus is economical.Based on the line compensation device,this paper proposes a capacitor bank switching control strategy based on voltage and reactive power.By collecting the information of voltage and reactive power,the working area of the power grid was divided into 17 areas,and the capacitor bank switching method was given when the power grid operates in different areas.In order to verify the line compensation device and control method,experiments were carried out.The results show that the line compensation device can improve the power factor and the quality of the power network.
The article first introduce the preparation method of porous graphitized carbon based materials derived from manganese coordination compounds and the method of making them into electrodes.It also elaborates on the structural characterization of porous graphite grounding materials,and conducts testing and analysis on two aspects:sample electrochemical performance and symmetrical full capacitor electrochemical performance.
This paper presents a high voltage direct current transmission line modeling method based on traveling wave theory and vector fitting method.In order to verify the effectiveness of the proposed method,a simulation model was built,and the simulation results show that the model established by the method are more accurate in the wide band range.
Taking the 24-slot 4-pole motor as an example to reduce the cogging torque of the surface-mounted permanent magnet motor,this research firstly analysed the mechanism of cogging torque generation based on the energy method,determined the combination of pole arc coefficient,air gap length,pole eccentricity distance,permanent magnet thickness and slot opening width as the optimisation parameters,then filtered out the parameters with greater influence on the optimisation target from the above parameters by Taguchi method and fited the relevant mathematical model by response surface,and finally the bat algorithm with Lévy's flight characteristics was applied to find the minimum value of this mathematical model.Simulation experiments using finite element software on the motor modelwith optimal solution show that the motor's cogging torque is reduced by 82.16%,efficiency is increased by 1.6%and torque pulsation is reduced by 8.2%.
Test for 220 kV oxide multi-section arrester was carried out without removing the primary lead,and the test result is consistent with test with primary lead removed and can meet relevant standards.
Based on the analysis of the definition and characteristics of transient enclosure voltage,this paper summarizes the key points of developing transient enclosure voltage measuring device.A measuring device with high safety and reliability was designed by means of impedance voltage divider,battery power supply system,shielding box and high-performance wave recorder.The results show that both the measuring time error and voltage amplitude error of the device are within the allowable range.
110 kV transmission line belongs to the category of high-voltage line,it not only has special requirements for construction technology,but also has more complex construction process.In addition,the operation is usually carried out outdoors,which will inevitably be restricted by geographical,environmental and climatic conditions and other factors.In this regard,in order to ensure the smooth construction,it is more necessary for power enterprises to strengthen the exploration of construction technology,so as to ensure the construction quality of transmission lines.
This article focuses on the impact of disorderly charging of electric vehicles on the power grid,starting from three aspects:grid load,grid loss,and voltage deviation.It comprehensively analyzes the adverse effects of disorderly charging of electric vehicles on the distribution network,providing a basis for taking relevant measures for the safe operation of the power grid in the future.
This article conducts research and analysis on the electrical system of an old extruder imported from Europe,and optimizes and upgrades the circuit of the extruder using electrical components such as servers,signal isolators,switches,and PLCs.It solves the problem of real-time remote monitoring and data analysis of the extrusion process parameters of old equipment,realizes digital upgrading and transformation of the equipment,which provides a reference for the transformation and upgrading of similar equipment.
