Based On The Wavelet Transform And Power Electronic Technology Of Application And Research Of High Voltage Power Supply Quick Switching System

For load power supply security problem of large enterprise power grid, this paper depends on high voltage power supply quick switching project of tianjin petrochemical company, do the relevant research and analysis about power supply security problems which petrochemical power grid are facing at present. Tianjin petrochemical company power grid is now using two groups of power supply mode, and the two groups of power supply are standby each other. It use automatic throw-in equipment of emergency power supply to ensure continuous and reliable operation of the enterprise power grid. This topic analyses the existing problems of current petrochemical power grid when it apply automatic throw-in equipment of emergency power supply. Based on the microcomputer type high voltage power supply quick switching device research, a new kind of power supply quick switching system which is on the base of power electronic switch is proposed. Because the on-off time of power electronic switch is far less than mechanical switch, the switching time of power electronic type high voltage power supply quick switching system will decrease, thus the impact of impulse voltage and impulse current of the switching process is effectively reduced.Firstly, this paper studies composition and working principle of power electronic type high voltage power supply quick switching system. Thyristor reverse parallel structure was selected as the main circuit of power electronic switch and it use to instead of high voltage circuit breaker switch. Thyristor valve technology parameters are analyzed and its type is selected, the signal conditioning circuit is designed, the zero trigger way of power electronic switch main circuit are analyzed in detail, the circuit which detect thyristor normal conduction and turn off is designed. According to the working principle of the characteristics and requirements of the work, the software flow chart is given.After the power electronic type high voltage power supply quick switching system is designed, wavelet transform theory is put forward as power system fault detection method. Analyzing and discussing the common faults of the power system, then the contact between wavelet signal singularity and power system fault is introduced, the basic criterion of electric power system fault detection is given. Db6wavelet and Sym5wavelet was choose as the mother wavelet for single-phase fault signal wavelet analysis in three-phase power system. The results of the simulation experiment prove that wavelet transform power system fault detection method is rapidly.Finally, the power electronic type high voltage power supply quick switching system is applied to petrochemical power grid and some relevant analysis and research have been done. According to the tianjin petrochemical power grid of the actual structure and real data, the petrochemical grid simulation model is established, the best position of application of power electronic type high voltage power supply quick switching system is determined. After the power supply quick switching system is applied to tianjin petrochemical power grid, the transient analysis and analysis of the influence of the relay protection are completed. From the simulation result, the application of power electronic type high voltage power supply quick switching system to petrochemical power grid does not affect relay protection.