基于等效仿真模型的VSC-HVDC 次同步振荡阻尼特性分析

电压源换相高压直流输电(VSC-HVDC)是基于电压源换流器(VSC)的新一代高压直流输电技术。该文首先分析VSC的工作原理，在此基础上建立以交流侧受控电压源和直流侧受控电流源描述的VSC等效仿真模型。通过与VSC-HVDC电路模型的时域和频域响应对比,验证利用VSC等效仿真模型分析VSC-HVDC次同步频率范围内动态特性的有效性。利用复转矩系数法的时域实现方法--测试信号法及VSC-HVDC等效仿真模型，可计算得到连续且光滑的发电机电气阻尼De特性曲线；基于De曲线，分析VSC-HVDC采用不同控制方式及比例积分(PI)控制器中比例系数和积分时间常数，对发电机电气阻尼特性的影响。最后对加入VSC-HVDC的IEEE第一标准测试系统的仿真表明，配置次同步阻尼控制器(SSDC)的VSC，通过对其有功功率或无功功率的动态调制，均可显著增加发电机的电气阻尼，有效抑制发电机次同步振荡。

Subsynchronous Oscillation Damping Characteristic Analysis for VSC-HVDC Based on Its Equivalent Simulation Model

VSC-HVDC is a new generation high voltage direct current(HVDC) transmission technology which is based on voltage source converter(VSC) . The operation principle of VSC was analyzed firstly. Then simulating the VSC's function by using controlled voltage source at the AC side and controlled current source at the DC side,its equivalent simulation model was established. Compared time domain response and frequency domain response got from VSC-HVDC's equivalent model and circuit model respectively,the validity of the equivalent simulation model for dynamic analysis in subfrequency domain was verified. Making use of the testing signal method and the equivalent simulation model,the generator's electrical damping curve was calculated smoothly and continuously under different VSC's control mode and the influence of controller's parameters on generator's electrical damping was also investigated. At last,simulation results in IEEE first benchmark system show that VSC equipped with subsynchronous damping controller(SSDC) can increase the generator's electrical damping remarkably and suppress the subsynchronous oscillation effectively by modulating its active power or reactive power dynamically.