Analysis Of Harmonic Transmission And Amplification Of Power System Based On ETAP

The importance of electricity as a foundation to support all industries is selfevident.High-quality electrical energy should be a sinusoidal waveform with a constant frequency and standard voltage,but the widespread use of modern equipment,a large number of harmonics are injected into the grid.The power network is a unified whole formed by the connection of various voltage levels.Harmonics will be widely transmitted through the power components in the system,and even harmonics will be amplified during the transmission process,which seriously reduces the power quality of the power grid.Therefore,exploring the transmission law of harmonics in the power network and the causes of harmonic amplification phenomena are of great significance for solving power quality problems.In this paper,the harmonic transmission model of the main components of the power network is established.The harmonic transmission coefficient is used to qualitatively and quantitatively analyze the transmission of harmonics and the cause of amplification in the network.The network component model and the actual distribution network model are built using ETAP software for further analysis and verification.First,the harmonic transmission between the same voltage level and the amplification phenomenon are considered.The harmonic transmission between the same voltage level mainly passes through the transmission line,including the overhead line and the cable line,according to the distributed parameter model of the overhead line and the centralized parameter model of the cable line,Theoretically deduce the transmission coefficient of the harmonic voltage and harmonic current of the transmission line,and analyze the influence of different harmonic order,line length and terminal load type on the transmission line harmonic transmission coefficient.After that,the harmonic transmission and amplification phenomena between different voltage levels are analyzed,and the influence of the harmonic transmission model of the transformer,different harmonic orders,load size,and transformer wiring method on the harmonic transmission coefficient of the transformer is considered.Based on the actual distribution network structure,the equivalent impedance parameter model and the ETAP simulation model are built.The theoretical analysis and simulation verification of the transmission characteristics of harmonic currents in different voltage levels of the power grid are carried out.The parallel resonance at the load side bus with no-load line is considered.Harmonic current amplification phenomenon,and the main factors affecting harmonic current amplification.And further explore the transmission law of harmonic voltage in the power grid,considering the influence of load power factor and voltage loss coefficient on the harmonic voltage transfer coefficient of different orders,considering the harmonic voltage amplification when the reactive power compensation device and the system occur series resonance,theoretical analysis of the compensation device capacitance reactance value,system impedance value and load parameters on the harmonic voltage amplification factor,and through the establishment of simulation models to analyze the background harmonic voltage amplification phenomenon.Finally,the harmonic voltage amplification cases that actually occur in the distribution network,this thesis conducts theoretical analysis and calculations on the examples through the power quality test results,and based on actual network data modeling and simulation,explores the causes of harmonic voltage amplification and proposes an effective harmonic suppression scheme.The paper has 85 pictures,18 tables,and 91 references.