Research On Steady State And Transient Operational Characteristics Of UHV Half-wavelength AC Transmission System

To meet the development needs of the country’s social and economic, the pace of China’s power construction has been accelerated in recent years, in the process, the development of power industry still faces many problems, the most important issue is the imbalance situation between the demand and the distribution of China’s electric power. Half-wavelength AC Transmission (HWACT) technology receives much concern in China and abroad as a very competitive transmission scheme. In this paper, the Steady State and Transient Operational Characteristics of ultra-high voltage (uhv) Half-wavelength AC Transmission System is analyzed. Firstly, an accurate π-type equivalent of half-wave transmission line has been calculated. Verify the accuracy of the two piecewise equivalent methods of half-wavelength line. Then Stable-state characteristics of half-wave transmission system accessing into the ultra-high voltage network are obtained by simulation analysis, including the effect of the power and power factor on the distribution of voltage along the line, line loss rate, current distribution of power transmission network, power frequency overvoltage along the line during no load, load rejection and fault conditions. Steady-state simulation results show that over-voltage occurs when half-wave line transport more than natural power, power factor can influence the location of maximum or minimum voltage. Line loss rate is minimum when transport natural power, In the case of load rejection and short-circuit conditions, over-voltage may occur. In addition, build two-area and ten-machine system example, in this network, the limit static voltage stability of half-wave and ordinary long-line transmission grid is analyzed. Analyse the Transient Operational Characteristics of half-wave line and ordinary long-line, effective running control strategy has been proposed in order to make sure the safe operation of the whole grid. Lastly, put forward some reference suggestions for the design of the half-wavelength line accessing into the system based on the simulation result.