特高压半波长交流输电系统过电压特性及对策

Characteristics and Countermeasures of Overvoltage in UHV AC Half-wavelength Transmission System

半波长输电线路（HWTL）过电压工况、产生机理及特性与常规输电系统有很大差异，过电压抑制是制约半波长输电技术工程应用的关键问题之一。为此，分析了半波长输电系统产生过电压的主要工况及机理，建立了特高压半波长交流输电系统仿真模型，研究了半波长输电系统在不同工况下的过电压幅值、持续时间和波形特征等特性。根据不同工况下的过电压特性，提出了相应的对策。研究表明，半波长输电系统发生接地故障时过电压最为严重，采用沿线装设金属氧化物避雷器（MOA）配合线路中部主动接地的措施，可将接地故障过电压限制在允许范围内，且MOA能耗满足要求。

The mechanism and characteristics of overvoltage of half-wavelength transmission line （HWTL） are different from those of the conventional lines. Overvoltage limitation is one of the key issues for the engineering application of half-wavelength transmission technology. We analyzed the generating condition and mechanism of overvoltage of HWTL, and established a simulation model of UHV half-wavelength AC transmission system. Furthermore, we studied the am- plitude, duration, and waveform characteristics of overvoltage of HWTL under different conditions. According to the overvoltage characteristics under different conditions, the corresponding countermeasures were put forward. The results show that the severest overvoltage is generated when ground fault occurs on HWTL. The fault overvoltage can be limited within allowable range by metal oxide arresters （MOAs） along the line and fast active grounding measure at the middle of the line. The energy of MOA during fault can meet the requirements.