Study Of Online Insulation Monitoring System For Mining Main Ventilator Motor

The research topic in this thesis is an important part of the project “Studyon the safety state monitoring system and fault diagnosis and early warningsystem of underground power distribution and ventilation networks in coalmine”(No.2007BAK29B05). It is sponsored by National Science&Tech-nology Pillar Program of China for the purpose of reducing minal accidents，diminishing the high rate of insulation aging and making online monitoringperfection.The mine main ventilator is one of mine-used essential equipment toguarantee safety production，which is drived by motor, is responsible forreplacement of fresh air to the coal mine, dilution and discharge explosivegas and dust underground. Because of the harsh environment，the insulationsystems suffer TEAM stress and lead to insulation faults. As a weak link ofmotor insulation system, winding insulation system online monitoring candetect insulation defects, catch online characteristic, evaluate aging state andjudge fault position. Non-invasion online monitoring plays an important rolefor safety production and lower maintenance cost.In this thesis, the stator winding insulation materials, insulation structureand insulation processing technology are investigated, and the material agingphenomenonand and feather are analyzed based on working condition.Considering the requirement and the feasibility of online measurement，the aging parameters and scheme were determined. Per-embedded Pt100wasselected as temperature sensor on the basis of actual situation. By buildingthe online model，the formula of insulation resistance and dielectric loss onthe condition of non-aging condition, phase to ground aging condition andphase to phase aging condition had been deduced. While the insulation parameter of above condition had been extracted and compared. The vectorof parameter can show the aging state and the aging part.Taking part in the design of system hardware， which includetemperature part, insulation resistance and dielectric loss part, partialdischarge part, core control part and upper computer part. By improvingtemperature monitoring circuit, determining sensor installing method anddebugging hardware, the system hardware circuits pass the test in laboratory.Lower computer software based on C8051F020has been compiled withthe consider of hardware circuit, which including main program, temperaturepart, insulation resistance and dielectric loss part and partial discharge triggerpart. In the LabVIEW environment, G language program has been written,which including main program, data processing part, real time database andhuman machine interaction program. Finally, it achieves data collection andtransportation, signal processing, picking up and data displaying and storage.A motor simulation model has been put up in MATLAB and the onlinemonitoring system has been completed in laboratory. The result shows thatinsulation online measurement can reflect aging state and the aging part,while the hardware and software of insulation online system runs well andcan reach the design requirements.