| As the backbone network of my country’s power grid,the 500kV double-circuit transmission line on the same tower is the prerequisite for the reliability of power supply of the power grid to ensure its safe and stable operation.The current autonomous online and offline live working robots need to perform equipotential at a suitable safe distance,and the transfer current generated during the potential transfer process will damage the equipotential arm,and the high-current high-frequency pulse will couple and resonate with the chassis,increasing the electromagnetic field inside the chassis.Second,the normal operation of the robot is greatly affected by the large magnetic field and large electric field of the 500kV transmission line.Therefore,it is urgent to analyze the potential transfer process,calculate the equipotential safety distance,determine the influence of the transfer current,and design the electromagnetic protection of the chassis.First of all,the thesis analyzes the working tasks and overall mechanical structure of the live working robot,including the walking mechanism,the potential transfer mechanism,the live working mechanism,etc.,and discusses the robot’s on-line and equipotential process.Then,according to the process of the robot going online and offline,the equivalent circuit model of each phase potential before and during the transfer is established,and the safety distance of the equipotential is obtained from the formula of the average breakdown field strength of each phase.On the basis of analyzing the relationship between each parameter and the transfer current The parameters are controlled to reduce the transfer current;by simulating the potential transfer process,the transfer current waveform is obtained,thereby determining the relationship between the transfer energy and the damage characteristics of the material,and obtaining the time,speed and motion trajectory of the potential transfer process.Secondly,the electromagnetic field environment of the robot is analyzed,and the influence of the robot’s control chassis material,thickness,hole size,shape,spacing,etc.on the electric field inside the chassis is studied.Taking the electric field and magnetic field strength limits as the judgment conditions,the parameters of the shielding body are determined.Calculate the electromagnetic shielding effectiveness of the chassis after taking shielding measures;perform Fourier decomposition on the potential transfer current,analyze the influence of electromagnetic fields of different frequencies on the shielding effectiveness of the shielded chassis,and determine the shielding effectiveness of the electromagnetic field inside the chassis when the hole-slot-cavity coupling resonance occurs.whether the requirements are met.Finally,the prototype of the live working robot is developed,the simulation experiment of withstand voltage and equipotential process is carried out on the robot,and the field experiment of electromagnetic compatibility and withstand voltage is carried out on the chassis.Simulation and field experiments show that the equipotential safety distance calculated in the thesis can ensure the potential transfer of the robot before arcing occurs,and the time and speed of the potential transfer can effectively protect the potential transfer arm from damage;the designed chassis shield parameters can effectively Eliminate the electromagnetic influence of 500kV transmission lines.The potential transfer model established in this thesis lays the foundation for analyzing the equipotential safety distance and transfer current.The hole-slit-cavity coupling resonance provides a basis for judging whether the chassis can still meet the shielding requirements when resonance occurs,so as to ensure the safe and stable live operation of the robot. |
