Study On The Measurement And Conttrol System Of LV Vacuum Feeder Switchgear For Mining Mobile Transformer Substation Based On Intel 80C196KB

Mobile Transformer substations(MTS) are widely used in underground modern mechanized mining face, which transform HV energy to LV energy and supply them for the niotors driving working machines. Mining flameproof mobile transformer substation consists of high voltage load switchgear, dry type transformer and low voltage feeder switchgear. Because the MTS is the power supply for underground machinery, its operating properties are the key facts which do directly affect the reliability and continuity of underground distribution networks, which could further result in the reduction of coal production and the drop of worker's safety. It is because of the terrible condition in underground faces that the electrical faults occur frequently in underground distribution networks, such as earth leakage, short circuit and so on. However, traditional feeder switchgear cannot satisfy the requirements of safety and reliability in power supply system due to complicated protective circuits and various pluggable units. It is hence important to develop a new measurement and control system with high properties and large capacity for MTS.A novel measurement and control system has been developed in detail based on Intel 80C196KB in this thesis as following:Fist of all, the present situation and the trend of development on the field of MTS at home and abroad are reviewed, and the problems existed in the present MTS are also introduced. At the same time, the necessity to develop the new measurement and control system is analyzed. Based on the rules of'Safety Regulation of Underground Coal Mines' and the demand for underground distribution networks, the function specifications and technical requirements are put forward in the thesis.According to the technical requirements of the measurement and control system, the fault characteristics and protective principle in underground LV distribution networks are analyzed in the second chapter, such as earth leakage, short circuit, over-load, over voltage, under voltage and so on. At the same time, the signal-sampling circuits are designed. The tests have been done in our laboratory and it has been shown that the circuits sample accurately, act sensitively, and detect the faults of the networks reliably and quickly.Central processing unit is introduced in the fourth chapter. In terms of the requirements of the measurement and control system, a proper central controller is selected, I/O unit and human-computer interface are designed. The experiment results show that the controller used in this system is powerful, the internal A/D converter is precise and quick in sampling, and the human-computer interface is friendly. All of these make the whole system to work more stably.The structured programming design method is applied in the whole system software, which make debug and compile program very easily and conveniently. The monitoring program and function subprograms of the measurement and control system are designed.According to the actual environment in underground electrical distribution networks, the sources and the features of interference signals are discussed. With the exception of this, anti-interference measures by use of hardware and software are taken to eliminate interference singles in this thesis. Experiment results show that anti-interference measures can nearly eliminate all interference.It has been proved by the results of tests in the intelligent apparatus laboratory that the system can detect all the faults exactly, reliably and quickly,and execute the corresponding protection. At the same time, the friendly human-computer interface can save the time to identify the types of fault and get rid of the fault, which may improve the production efficiency.