Study On Power Frequency Electromagnetic Field Distribution Around Inspection Robot In 500kV Substation

With the rapid development of smart grid in China,a large number of substation inspection robots are put into operation.At present,the research on inspection robot of substation is mainly focused on the structure design and software design of inspection robots.The distribution of induced potential and electric field around the equipment is seldom studied when the inspection robot works in the substation and the distribution of induced potential and electric field around the inspection robot and the substation operator is seldom studied when the inspection robot is close to the substation operator in the station.This is not conducive to the development of smart grid in China.Study on the distribution of induced potential and electric field around the equipment of inspection robot and the distribution of induced potential and electric field around inspection robot and substation operator when inspection robot is close to substation operator which can provide numerical and theoretical references for operators in stations about the matters needing attention in close proximity to inspection robots,matters needing attention in operation of inspection robots and the design of electromagnetic protection,thus promoting the development of smart grid in China.The main contents of this paper are as follows:(1)The calculation method of space electric field based on the combination of point charge and line charge is deduced and discussed.The calculation procedure and flow chart of the method of combining Charge Simulation Method with Finite Element Method are deduced.Based on Biosavart's law,the calculation method of 3D power frequency magnetic field in substation is discussed.A three-dimensional simplified calculation model of main large power equipment in 500 kV substation is established,including switching field,transformer,reactor group,etc.The distribution of power frequency electromagnetic field in the above-mentioned power equipment area is calculated and studied.(2)A simplified 3D computational model of inspection robot is established.Potential errors on the boundary of the finite element computational region are analyzed.The appropriate boundary of the finite element computational region is established.Potential on the boundary of the finite element region calculated by the Charge Simulation Method is used as the boundary condition of the finite element computations.Inspection robot patrol operation in power equipment area of substation whether the inspection robot is grounded or not will reduce the distribution of induced potential around it,but the electric field around the top equipment will be greatly distorted.Grounding of inspection robot equipment can improve the electric field distribution around the equipment under the inspection robot,but it will deteriorate the electric field distribution around the whole inspection robot.The use of high permeability material in the outer shell of inspection robot equipment can effectively reduce the distribution of power frequency magnetic field in the equipment.(3)When the inspection robot close to the substation operator,the induced potential of the inspection robot and the human body decreases,but the induced current density of the human body increases.There is a potential difference between the inspection robot and the human body when they are close to each other,and there is a risk of electric shock effect on the human body.If the inspection robot fails in the work,the human body should bend down close to it and then squat down to inspect it.