| The maintenance of disconnect circuit breakers?DCB?in 110 kV Substations is currently carried out by outage maintenance or manual hot-line operation.Power outage will cause economic losses and reduce the reliability of power supply,while manual hot-line operation has risks in the safety of personnel and reliability of operation.Therefore,it is necessary to develop a hot-line working robot,which can automatically assemble and disassemble the connect fittings of disconnect circuit breakers without power outage.In order to meet this demand,this paper deeply studies the hot-line working robot of disconnect circuit breaker in 110 kV substation,and carries out field operation in 110 kV substation,which verifies that the robot can complete the task safely,reliably and efficiently.The main contents and achievements of this paper include:A workflow and constraint model of hot-line operation robot for 110kV substation is proposed.The constraints of robot design are analyzed,including the constraints of phase-to-ground and phase-to-phase safe distances under electrical safety constraints;the constraints of vision system under weak rigid state due to the deterioration of positioning points surface and the requirements of high precision positioning under the condition of outdoor variable illumination;and the control method of compliant assembly with complex structure and positioning errors of L-shaped connect fittings.According to the above constraints,the dynamic model of the robot is established.The influence of positioning errors of each degree of freedom on the final assembly results is analyzed.According to the principle and task requirement of hot-line work,the first form of hot-line work overhaul and operation specifications is proposed.A draft for approval is formed,which provides the basis for the national standard of hot-line work in high voltage environment for robots.Safety analysis and calculation of safe working space for hot-line working robot in high voltage environment.The electric field distribution of robot during hot-line working is analyzed.The electric field strength and distribution between phase and ground,phase and phase under different postures of DCBot are calculated.The finite element analysis model is established to verify the calculation results.Then,the electric field between the working platform and the connect fittings of the phase to be operated is analyzed and calculated.A safe distance determination method based on the safe definition condition that the electric field intensity around the ACSR of the adjacent phase is less than the corona electric field intensity is proposed.According to this method,the safe distance of hot-line operation of the robot in this paper is determined.The calculation method of safe working space of hot-line working robot is introduced in detail.The theoretical and experimental validation of the safe working space is carried out,and an equivalent experimental platform is built.By measuring 50%operating impulse discharge voltage,the danger rate of hot-line working robot is less than 10-5,which ensures the safety of hot-line working and verifies the reliability of the calculation results.It establishes the basis for path planning of the manipulator.A high-precision visual positioning method for objects with worn surfaces in outdoor environment is proposed.A monocular machine vision positioning method is designed for outdoor substations in various illumination conditions,complex imaging background,interference of induction arc discharge and wear of object surface.Regarding to the edge confusion caused by metal wear,a sub-pixel fuzzy smoothing edge location method is proposed,which can make the edge extraction smoother and ensure the positioning accuracy and success.Iterative approximation is used to solve the instability of shooting position,and the ideal shooting position is approached from the initial position to the set position.The searching hole strategy in the assembly process of complex contact surface is studied.The force acting on the axle holes in the process of assembling the connect fittings is analyzed,and the coordinate system transformation chain with visual positioning results as the core is established for the control system.The key variables in the feedback information of the force sensor are determined,which greatly improves the accuracy of the follow-up control.Based on this,an active compliance control drilling strategy based on force sensor is proposed and the geometric structure of the shaft hole in the phase of posture adjustment is analyzed.The validity and feasibility of the assembly strategy and control algorithm are proved by laboratory functional test and equal scale simulation test.The current pulse characteristics of AC induction corona and arc at power frequency in equipotential time between robot end-effector and fittings are studied.The similarities and differences between them and ESD current characteristics are analyzed.On the basis of retaining the key characteristics,the discharge model is simplified.The radiation field is calculated and compared by finite element method.The coupling law and shielding effectiveness of radiation field and metal shielding box with holes on equipotential working platform are analyzed.The optimal solution of depth and size of hole in shielding body of safety monitoring camera on working platform are obtained.This paper presents a system design of DCBot,which can assembly and disassembly the connect fittings of disconnect circuit breaker without shutting down the power in substations.The overall mechanism,mobile carrier and working platform of the scheme are designed in detail.A communication and control system architecture suitable for robot operation in substation system is proposed,in which the upper and lower parts are at different potentials.A redundant remote control method under the unexpected fault of the robot is designed.An electromagnetic shielding method for electrical components on equipotential working platform is proposed and verified by EMC test.According to the design scheme,the prototype is manufactured,and the relevant indicators are achieved through field test and verification of intelligent substation.It provides a reference for the design and manufacture of hot-line working robots in substation system in the future. |
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