Research And Realization Of The Electric Source Technology Of Grounding Resistance Measurement Instrument

It is essential to investigate potential safety hazards in grounding resistance measurement regularly to ensure the safe operation of broadcast or television launcher.In order to avoid the inspection risk and improve the efficiency of inspection and investigation,a digital networked grounding resistance instrument with cloud data interface for broadcast or TV launcher grounding system is proposed in the thesis.The instrument can provide precise voltage and effective driving current for the measurement of ground resistance.The full-bridge inverter circuit is used as the voltage and current amplification circuit of the measuring instrument.The digital signal controller(DSC)is used to realize the closed-loop control of voltage/current excitation.The measurement results are transmitted to the communication module through the communication management control chip ATmega328 to realize the cloud of the measurement data and the visualization of the mobile data.First,the working state and mathematical model of the full-bridge inverter circuit are analyzed,the numerical calculation method of the grounding resistance is studied,the voltage/current proportional resonance PR controller and the adaptive voltage and current switching control strategy are designed.The voltage/current feedback control of the system is simulated in the MATLAB/Simulink.The simulation results show that the voltage/current excitation of the system power circuit meets the design requirements.The system hardware is designed,including the full-bridge inverter circuit,auxiliary power circuit,drive circuit,sampling conditioning circuit and communication circuit.Voltage/current closed-loop control,grounding resistance measurement,data communication including key function codes development are completed.An experimental platform is also built.The accuracy verification experiment and the field measurement experiment of ground resistance are completed.The measurement results show that the measuring system can select a reasonable measuring mode according to the resistance range of the grounding resistance,adapt to the field measuring environment,and improve the measurement accuracy of the grounding resistance.4G communication module and pass-through platform are adopted to realize the upper cloud function of grounding resistance measurement data.The measured data of ground resistance can be inquired by mobile terminal equipment in real time.The designed instrument can realize the automatic measurement of the grounding resistance,which saves the cost of manual inspection,and improves the measurement efficiency of the grounding resistance.At the same time,it also provides unmanned implementation ideas for the safe inspection of the same type of electronic and communication systems.