特高压混合无功补偿空载线路合闸过电压幅频特性

Overvoltage Amplitude and Frequency Characteristics of Energizing Unloaded UHV Transmission Line With Hybrid Reactive Compensation

混合无功补偿有望在特高压输电线路获得应用,其与电网交互影响亟待研究。在介绍混合无功补偿关键元件及结构组成的基础上,考虑两种电源电压相位角极端情况,仿真分析了安装混合无功补偿前后特高压空载线路合闸过电压幅频特性。基于等值集中参数电路和拉普拉斯变换方法,推导计算了可控高抗不同补偿度下空载线路合闸过电压各分量振荡频率与对应幅值以及瞬时最大值的变化情况,从理论上总结了可控高抗补偿度分级变化对合闸过电压的影响规律。基于上述理论方法,考虑可控高抗补偿度分级变化情况,研究了串补不同布置方式下空载线路合闸过电压工频分量和瞬时最大值的变化曲线。从空载线路合闸过电压幅频特性角度得到的研究结果,将为特高压混合无功补偿的参数优化和布置方式的选择提供分析基础和理论依据。

Hybrid reactive compensation may find applications in ultra high voltage（UHV） power systems, however, the mutual influence between hybrid reactive compensation and UHV transmission line becomes an urgent research subject. Considering two extreme conditions of supply voltage phase angle, the overvoltage amplitude and frequency characteristics of energizing UHV unloaded transmission line with and without hybrid reactive compensation are simulated and analyzed, based on the introduction of key components and the structure of hybrid reactive compensation. Using equivalent lumped parameter circuit and Laplace Transform, the oscillating frequency, corresponding voltage amplitude and instantaneous maximum variations of overvoltage of energizing unloaded transmission line with different compensation degrees of controllable shunt reactor are deduced and computed. Consequently, the relationship of compensation degree＇s stepped variation and the overvoltage is summarized theoretically. Based on the above method and considering the compensation degree＇s stepped variation, the variation curves of fundamental component and instantaneous maximum of overvoltage of energizing unloaded transmission line under different arrangement of series compensation are studied. In view of the overvoltage amplitude and frequency characteristics of energizing unloaded transmission line, the research results provide analysis foundation and theoretical basis for parameter optimization and arrangement selection of the hybrid reactive compensation in UHV transmission line.