含直驱型风机电力系统的动态安全域

Dynamic Security Region of Power Systems With Direct-Drive Permanent Magnet Synchronous Generators

直驱永磁型风机是风机未来的发展方向,其大量并网将给电力系统的暂态稳定性带来新的影响。计算了含直驱型风机电力系统的动态安全域,通过时域仿真验证了其准确性;采用拟合法对系统动态安全域边界进行拟合,经大量仿真发现,含直驱型风机电力系统的动态安全域边界可以用超平面方程表示,误差在工程应用范围内;对比了3种系统边界的变化,并对其进行了机理探讨;探索了单台和多台直驱型风机接入下系统安全域边界的变化规律。同步电机系统、双馈型风机系统和直驱型风机系统边界依次外扩。单台风机接入时,不同风机容量下的边界具有近似平行性且边界间距离与风机容量增量成正比;多台风机接入时,安全域边界变化与系统风电渗透率和风机距故障线路的电气距离均相关。

Direct-drive permanent magnet synchronous generators(DDPMSGs)are expected to be the future direction of wind power generators.It will make a difference to transient stability of power systems due to its large amount of integration.In this paper,dynamic security region(DSR)of power systems with DDPMSGs is calculated and its accuracy is verified through time domain simulation.Fitting method is used to calculate DSR boundary.Extensive simulations show that the DSR of power systems with DDPMSGs can still be represented with a hyper-plane equation and the error is within acceptable range of engineering applications.Boundaries of 3 systems are compared.Besides,the change mechanism is studied.It turns out that the DSRs of systems with synchronous motors,double fed induction generator(DFIG)and DDPMSG expand in sequence.The DSR boundary variations for single or multiple DDPMSGs areexplored.Theboundaries corresponding to different wind capacity are approximately parallel when single generator is connected.Further,the boundary distance between them is linear to change of wind turbine capacity.The changes of boundaries are related to both system wind power penetrance and electric distance between DDPMSGs and fault line when multiple generators are connected.