故障位置对交直流外送系统暂态功角稳定性的影响分析

分析电源中心交直流外送系统中故障位置对暂态功角稳定性的影响.以三机系统为例建立数学模型,其中2台等值机位于电源中心内部.简化模型后,给出2台相互耦合的等值机转子运动方程.根据转子运动方程中各项的物理意义,分情况讨论了不同位置发生故障后系统的暂态功角稳定性,并结合实际系统运行特点进行概括,得到结论如下:当电源中心内部交流联络线潮流较轻时,电源中心的交流外送通道发生故障,系统更易发生功角失稳;反之,电源中心内部发生故障,系统更易发生功角失稳,并对内部故障位置进行区分.最后,通过基于陕西电网陕北交直流外送系统的算例验证了结论的正确性.

Analysis on effect of fault location on angle transient stability for AC/DC sending system

The effect of fault location on angle transient stability for power generation center in AC/DC sending system is analyzed. Taking the three-machine system as an example, the mathematical model is established, in which two equivalent machines are employed to represent the power generation center. The rotor motion equations of two coupling equivalent machines are derived based on a simplified model. According to the physical meaning of each item in the rotor motion equation, the impact of different fault locations on angle transient stability under different conditions are discussed. Then, the corresponding conclusions are summarized based on the operation characteristics in realistic power systems. In the case that the tie-line of the internal power generation center is not heavily loaded, the fault on external AC sending channel is more likely to result in the angle instability. Otherwise, the impact of fault on internal power generation center is more serious and internal fault locations are classified. Finally, the case study is carried out on the northern Shaanxi AC/DC sending system of Shaanxi power grid, which verifies the correctness of above conclusion.