基于电压相量空间的电网失步中心特性解析及精准定位方法

Power Grid Out-of-step Center Characteristic Analysis and Accurate Locating Method Based on Voltage Phase Space

利用电网广域相量信息,挖掘电网振荡特性并识别失步中心位置,为电网解列控制提供决策依据,对大电网在线暂态稳定主动防御具有重要的工程应用价值。首先,基于简单两机系统,在两机不同电势及系统阻抗分布情况下,探讨了两机相角差递增时各观测点的电压幅值、相角及电压相量的轨迹特征,表明失步中心相量轨迹为过零的圆;其次,基于电压相量图,在阻抗坐标空间内,推导并证明了失步中心所在位置阻抗分布为圆或直线的解析方程,该方程与两机电势及系统阻抗大小具有关联关系;进而,可实现失步振荡中心在线精准定位。简单两机系统和IEEE-9算例,验证了所提方法的有效性。

Using wide area phase information to mine out-of-step characteristics and locate out-of-step oscillation center, the decision-making basis for grid disassociation control during out-of-step oscillation process can be provided. It is of great engineering application value to online initiative defense for transient stability of large-scale power grid. Firstly, the evolution characteristics of the voltage amplitude, phase angle and voltage phase trajectory of each observation point with the increase of phase angle difference between the two machines were discussed, under the condition of different voltage and system impedance distribution based on the two-machine system. It showed that the phase trajectory of the out-of-step center was zero-crossing circle. Secondly, the analytical equation in which the impedance distribution of the out-of-step center was a circle or a straight line was derived and proved in the impedance coordinate space based on the voltage phasor diagram. The equation was directly related to the voltage of the two machines and the impedance of the system. Finally, the online accurate locating of out-of-step oscillation center can be realized. The proposed method was validated using two-machine and the IEEE-9 system.