Harmonic Characteristic Analysis And Governance Research Based On ETAP For The Substation

In recent years,with the development of industrialization,more and more devices are applied to the power grid,such as power electronic devices,arc furnace and various rectification devices.At the same time,these devices also put a lot of harmonic current into the system,which has great impact on the power operation.Harmonic is an important reason of resulting in declining of power quality.In addition,the economic efficiency and safe operation of the power supply enterprise have been largely affected,which reduced the life of the service greatly.Thus,the research and suppression of harmonic is an important issue needs to be solved in order to ensure the reliability,quality and economy operation of power systems.The article takes a phenomenon as the research background what capacitor groups in10kV side of a 220kV substation under the Hanzhong Power Supply Bureau frequently appeared the damage,researching the harmonic which bring effects to the whole substation system when the transformer substation accessed the nonlinear loads.Firstly,using a portable harmonic tester to test harmonic level in the 10k V side,through switching test of the capacitor,and concluding that direct reason of amplification of giving rise to the three times harmonic and leading to the damage of capacitors.Based on the fault in this background,a detailed analysis of matching problem has been given to resolve reactive power compensation capacitor and series reactor parameters.Then,the paper analyzes the harmonic characteristics of the harmonic source.The ETAP is a integrated computing software about simulation of power system,which is used to build the single line diagram of the system.The parameters of each element are inputted,then putting the data of testing on each nonlinear load into the library of harmonic source to establish the harmonic source model and simulate.The simulation model is established to verify its correctness by comparing with the measured data.Secondly,the tolerance constraint of capacitor operation under harmonic condition is analyzed.At the same time,the influence of operating parameters such as capacitor voltage,current and power to the capacitor is discussed within harmonic factors considered.The relationship curve about the background harmonic voltage content and harmonic hazard coefficientg_n-a_nis made,which limited by various conditions of different harmonic.Then,according to the constraints,what the curve of theg_n-a_nis put into operation combining with the specific parameters and concluding the influence of the harmonic to capacitor can not be ignored.In the engineering background,the improvement scheme is proposed for the phenomenon that the harmonic voltage is seriously distorted and the harmonic current is excessive,which leads to the frequently damage of the parallel capacitor bank.The harmonic level of each bus side is analyzed.Through the ETAP simulation,the optimal filtering scheme is designed by using the passive filtering method to solve the harmonic current violation that injected into power network.Finally,this paper summarizes the content of the study and provides a reference for the study of the safety operation of the capacitor and the whole power system.