Research On Section Power Supply And Measurement Method Of The Electrified Railway Traction Network

Because that the traction network in the electrified railway traction power system is a huge, complicated power supply device whose working conditions are very poor and it is placed directly in the nature environment and has no standby power. So most traction power system faults occur in the traction network. Therefore it is very important to find and separate the traction network faults in time and accurately for furthest guaranteeing the normal power supply of the traction network no-faults section. This thesis analyze the traction network section power supply and measurement system by sectioning the traction network reasonably, which can separate the faults section quickly meanwhile furthest guarantee the normal power supply of the no-faults section. Besides, this measurement system uses the fault power flow symbol value based distributed measurement system as the main protection, uses the fault power flow symbol value based centralized measurement system as the standby protection. The two protection cooperates with each other to improve the reliability of the measurement system.Firstly, this thesis describes the traction network section scheme and the structure, working theory of the measurement system in detail. The power supply section, the fault power flow direction and the fault power flow symbol value is defined. The advantage of the fault power flow symbol value based identifying the traction network short circuit fault is introduced. According to the working theory of the whole measurement system, every component of the measurement system is modelled in the Matlab/Simukink. Then the traction network measurement models of single track direct supply, two tracks direct supply with terminal in parallel, single track direct supply with two sides supply, two tracks direct supply with two sides supply are established. The T-R short circuit fault is deduced. The perpetual and instantaneous short circuit faults are simulated in the built models. The feasibility and accuracy of the measurement system is verified by analyzing the fault power flow symbol value of each terminal, the commands of the breaker and the voltage between the two sides in the fault section before and after the fault. In the end, the fault location method is proposed combining with the distance protection to guarantee that the traction network can be repaired in time when thetraction network short circuit occurs.Secondly, on the basis of the theory and tested model, the disposure of the measurement information is discussed, which contains the collection and transmissionof the information, the synchronization method. The method of fault recording and data extracting is also introduced, which can help the research and development of the measurement system device.Finally, the assessment model of power supply reliability is built for the existing traction power supply system and the section traction power supply system, which quantitatively assessesthe impact of measurement system’s application on the reliability of the power supply system.