特高压半波长交流输电系统稳态及暂态运行特性

Steady State and Transient Operational Characteristics of UHV Half-wavelength AC Transmission System

分析了半波长交流输电线路的特性,验证了在仿真分析中半波长线路的分段等值法的准确性。通过仿真分析,得出半波长线路接入特高压电网中的稳态及暂态特性:包括功率以及功率因数对沿线电压分布的影响,线损率、输电网潮流分布、甩负荷以及故障情况下输电线路沿线过电压情况。仿真结果表明,沿线在输送超过自然功率时会出现过电压,功率因数影响沿线最大电压的位置,线损率在输送自然功率时最小,在甩负荷以及短路故障情况下,沿线会出现不同程度的过电压等。基于仿真结果,提出了半波长交流输电线路接入电网的设计建议。

The features of half-wavelength AC transmission （HWACT） are analyzed and the accuracy of sectionalized equivalence of HWACT applied in simulation is verified. Through simulation and analysis the steady state and transient operational characteristics of HWACT connected to UHVAC power grid are obtained, including the influences of transmitted power and power factor on voltage distribution along HWACT line, line loss rate, power flow distribution of transmission network and overvoltage of HWACT line under load shedding, no-load line and fault conditions. Simulation results show that overvoltage appears while the transmitted power exceeds natural load of HWACT line; power factor influences the position where the maximum voltage along the line appears; the line loss rate reaches its minimum value when the transmitted power is equal to its natural load; overvoltages with different maximums appear while load is shed or short-circuit fault occurs, etc. According to simulation results, some suggestions on the design of HWACT line are proposed.