| The project in this thesis is one important part of the major project "Study on the Condition Monitoring and Fault-indicating System for Mining HV Distribution Equipment", which is the sub-project of "Mine Ventilation and Power System Security Condition Monitoring and Fault Diagnosis of the Early warning syste"(No:2007BAK29B05) sponsored by the National Key Technology R&D Program of China during the Eleventh Five-year Plan Period. In addition, being one of main parts of condition monitoring and fault early-waring system for mining HV distribution equipment, this work is proposed based on the tough condition such as the lack of comprehensive and effective fault detection for mining high-voltage vacuum distribution equipment, as well as failure to predict failures and eliminate hidden dangers.With the development of fully mechanized mining face in production technology, as well as total installed power increases in shearers and armored-face conveyors, more and more coal mines adopt lOkV voltage as power supply directly. With the increase of voltage level, mine power system has posed a serious challenge. The number of mining voltage vacuum distribution equipments are in dominate of mining high-voltage equipments, whose overall performance and operational status directly affects the security and reliability of coal mine power system. However, working conditions of mining high-voltage vacuum distribution equipments is poor, with large load changes and work status being instability. The fault detection and assessment of the state of its own devices only relies on traditional planned maintenance. The mining high-voltage distribution equipment causes widespread concern in the community for safety accidents frequently occurrence caused by its own fault. Thus, the fault detection of mining high voltage vacuum distribution equipment has a very important practical significance for the safety of coal mine production and increasing of the economic efficiently.The existing mining high-voltage power distribution equipments cannot conduct a comprehensive inspection and judgment of its own state, let alone taking the fault self-diagnosis and early warning. In order to compensate for this deficiency, this paper develops mine-line monitoring of HV electrical installations and fault warning system. The main content in this thesis is as follows:Based on the in-depth field research and a large number of domestic and overseas relevant literatures, the study of the common faults of mining high-voltage vacuum distribution equipment, and the analysis of the characteristics of the various feature faults were studied. The operating status and various faults parameters of mining detection voltage vacuum distribution equipment, which includes the vacuum breaker vibration signal and the action signal, the coil current and the energy storage capacitor voltage of closing the secondary circuit, the three-phase contact current, the vacuum of vacuum interrupter, the isolated contact temperature, were determined. Based on the characteristic parameter of each failure characteristics, the advantages and disadvantages of fault detection method for the existing high-voltage vacuum distribution equipment was analyzed. The online extraction method of characteristic parameters of each fault and the appropriate sensor and installation of detection points were determined.The overall program of fault detection system was proposed for mining high-voltage vacuum distribution equipment in-connection with requirements of fault detection system. Wireless detecting sub-circuit of high-voltage and the main circuit of low voltage detection system were designed, with C8051F020MCU and TMS320F2812DSP being their CPU. Hardware circuit mainly includes power supply circuit, the minimum system circuit, the signal conditioning circuit, the communication circuits, etc.. The detection isolation of high voltage and low voltage was achieved by nRF905wireless communication module. An infrared temperature sensor and one vacuum sensor were developed, a temperature compensation method was proposed, which meets testing requirements isolation temperature of the high voltage side and vacuum interrupter contacts of vacuum.On the basis of the hardware circuit and the principles of software design requirements, the lower machine software program was compiled, which includes data collection program, data processing program and communications program. The data acquisition during switching period was achieved by data collection procedure. The data processing procedure achieves temperature compensation calculation operation and signal filtering and short-term energy computing. The nRF905wireless communication protocol and RS-485main communications protocol were developed to by a data transfer module.Under laboratory conditions, a hardware circuit debugging regarding infrared temperature sensors, the vacuum sensor and fault detection system were conducted. Software design for data acquisition, pre-processing and communications were developed. By the whole industrial test results showed that the system design was reasonable with comprehensive detecting parameters. The hardware performance was reliable, and the software features were improved that could quickly and accurately detect the fault feature. The work in this thesis laid a solid foundation for life assessment of high voltage vacuum distribution devices. |
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