利用暂态能量流的次同步强迫振荡扰动源定位及阻尼评估

近年来,随着大量电力电子装置接入电网,次同步振荡越发复杂,难以准确判断振荡的主要诱发因素或元件。应用暂态能量流进行次同步强迫振荡扰动源定位及阻尼评估。提出了次同步振荡分析中暂态能量流的计算方法,将元件端口瞬时电压、电流从abc坐标系转换到xy坐标系计算暂态能量流。然后在汽轮发电机组多质量块详细模型下推导了能量流的组成,包括暂态能量和阻尼消耗的能量,说明了次同步振荡中暂态能量流和阻尼的关系,若元件吸收能量,则具有正阻尼。次同步强迫振荡中扰动源不断发出能量,通过计算网络中的振荡能量流和能流功率,即可定位扰动源。在PSCAD/EMTDC电磁暂态仿真软件下搭建了不同算例进行仿真研究,结果验证了所述方法的有效性。

Disturbance Source Location of Subsynchronous Forced Oscillation and Damping Evaluation Using Transient Energy Flow

In recent years, with large amounts of power electronic equipments connected to power systems, subsynchronous oscillation is becoming increasingly complicated. So it is difficult to identify the main cause of oscillation. Disturbance source location of subsynchronous forced oscillation and damping evaluation are carried out based on transient energy flow. The computation formula of transient energy flow for subsynchronous analysis is studied. To compute transient energy flow, instantaneous voltage and current of component ports in abc axis are converted to xy axis. The composition of transient energy flow in a detailed generator model with multi-mass torsional shaft is derived, which is transient energy and dissipated energy by damping. This explains the relationship between energy flow and damping. The positive value of the power of energy flow injected into a component represents energy dissipation. The component is considered possessing positive damping if it absorbs energy. In subsynchronous forced oscillation, as the disturbance source steadily generates energy, the source of disturbance can be located by calculating the oscillation energy flow and energy flow power in the network. Different test cases are built and simulated under electromagnetic transient simulation software. The validity of the method is verified by the simulation results. This work is supported by National Natural Science Foundation of China(No. 51377002)and State Grid Corporation of China(No. 5201011400M5).