Study On The Condition Monitoring And Fault-indicating System For Mining Hv Distribution Equipment

The project in this thesis is one of the important parts of the project "Study on the safe state monitoring system and fault diagnosis and early warning system of underground power distribution and ventilation networks in coal mine" (2007BAK29B05), which is supported by National Science & Technology Pillar Program of China. It is aiming at high failure rate of distribution equipment in the HV side of the mobile substation and the imperfect fault monitoring device.A condition monitoring system has been developed through the analysis of the common faults of the HV distribution equipment and the features of faults characteristics. A fault-indicating means which is suitable for the HV distribution equipment has been founded by means of information fusion. The purpose of this thesis is to develop a fault-indicating system, which has perfect function, high reliability of the monitored data, and can provide the technical support of reliability of the HV distribution equipment. The main contents studied in this thesis are as follows:The common failures of the HV distribution equipment are studied, based on which, a failure tree of the HV distribution equipment has been set up. The fault characteristics to respond to the failures have been founded and analyzed. A method is given for the important characteristics parameters online extraction in the HV distribution equipment.According to the monitoring requirements, the hall current sensors and the hall voltage sensors have been used to monitor the operating coil of the breaker, which can realize an arbitrary waveforms monitoring of the coil. The non-contact angular sensor based on magnetic field measuring has been chosen to monitor the trip of circuit breaker indirectly, which solve the problem that the sensor is not easy to install in HV distribution equipment. As the vibration signal of vacuum circuit breaker is of great impact strength and short lasting time, a piezoelectric acceleration sensor has been adopted to monitor the vibration signal.According to the technical requirements for the monitoring system, the hardware circuits based on TMS320LF2812DSP chip have been designed, which mainly include the DSP system circuits, signal processing and converting circuits, and communication interface circuits. The circuits of signal processing and converting include operating coil voltage and current monitoring circuits, vibration signal monitoring circuits, temperature monitoring circuits for isolators based on the nRF905 wireless modules that are controlled by DSP2812 and MCS-51, power supply circuits based on quick-magnetic saturated current transformer, the mechanism of switch monitoring circuits and the vacuum monitoring circuits.It has been given in this paper that the important characteristics extracting methods of high voltage circuit breaker and the algorithms of signal filtering and signal analyzing. The software related to the monitoring system has been compiled, and the signal processing and analyzing in the DSP2812 has been realized. Thereby, the burden of field bus communication has been reduced and the real-time of the monitoring system has been improved.A fusion technology based on the D-S evidence theory has been given in this paper, and the evidence has been chosen to reflect the HV distribution equipment's running state from different aspects. The HV distribution equipment fault-indicating model based on D-S evidence theory has been established. The process of fault early warning has been determined, which provided the foundation of the development of fault early warning system.The platform of HV distribution equipment monitoring system has been established and debugged in laboratory. The experiments of data acquisition, data processing, data analysis and data communication have been carried out. The experimental results show that the chosen sensors work appropriately, the hardware circuits designed reasonably and the software programs compiled correctly. The system can detect the faults characteristics of the HV distribution equipment exactly, reliably and quickly.