Research Of Over Voltage Of UHV Half-wavelength AC Transmission Lines

As everyone knows, our country with a vast territory, the area is vast, but the resource distribution of extreme imbalance; in recent years, although our country electric power industry swift and violent development, but in order to better solve the energy problem of uneven distribution, long distance, large capacity transmission technical problems need to be solved urgently. While the 1000kV AC UHV transmission technology has a series of transmission characteristics, such as large capacity,ultra long-distance,low loss, can realize remote energy source allocation; at the same time, the AC transmission technology, when an electric power transmission line length reaches a certain amount of time, along the transmission lines some of the electrical quantity will change, and will appear with the conventional middle or long line,short line obviously different characteristics, according to these characteristics, based on the multi conductor transmission line theory, as 1000kV AC UHV power transmission demonstration project as the background, is an ultra long distance three-phase AC power transmission technology of UHV AC power transmission -- half wavelength technology related issues were studied, analyzed its transmission line over voltage problem (mainly the power frequency overvoltage and switching overvoltage ). Given the cycle transposition case of UHV AC transmission line unit of half wavelength long parameter matrix calculations, including wire in the two arrangement in triangular and arranged horizontally, the calculation results including the admittance matrix, impedance matrix and their symmetry matrix; after the analysis and the research, by use of electromagnetic transient simulation software EMTP, UHV AC transmission lines on half wave overvoltage condition is given, including a variety of power frequency overvoltage ( no-load line voltage, load rejection steady-state overvoltage, single-phase grounding sound phase voltage ) and a variety of switching over voltage ( line-energizing over-voltage, single-phase automatic reclosing operation over voltage, swing load operation over voltage ), discusses the UHV AC half wavelength along the transmission line overvoltage distribution trend and characteristics, for further study of UHV AC transmission technique of half wavelength provides accurate and reliable data. At the same time, simply discusses the use of surge arresters, and closing resistor and inhibition of UHV AC transmission line overvoltage of half wavelength of the advantages and disadvantages of the installation, before and after the improvement the line-energizing over-voltage in operation results are compared, some conclusions were obtained, for UHV AC transmission technique of half wavelength and practice implementation provides effective reference.