【摘要】 依据电力电子变压器PET(PowerElectronicTransformer)的功率特性,提出了一种利用PET改善电力系统动态特性的新方法。PET副方接入输电线路,原方接无穷大系统,这时PET等效为一个可控电压源,建立发电机励磁和PET所构成电力系统的数学模型,分别以发电机功角、角速度、机端电压为状态变量,以发电机励磁电压、可控电压源的幅值和相角为控制变量。在此基础上推导了PET和发电机励磁的最优协调控制规律。仿真分析发现,通过PET与系统间功率的迅速交换和双向流动,提高了系统阻尼,有效抑制了扰动下的系统振荡。更多还原

【Abstract】 According to the power characteristics of PET(Power Electronic Transformer),an ap-proach to improving power system dynamic characteristics with PET is proposed. The secondary side of PET is connected with the transmission line and its primary side with an infinite-bus system,and it can be equivalent to a controllable voltage source. A mathematical model of the power system with generator excitation and PET is established,in which the power angle,angular velocity and terminal voltage are state variables and the excitation voltage of generator,amplitude and phase-angle of the controllable voltage source are control variables. An optimal coordinated control strategy for the generator excitation and PET is deduced. Simulation shows that,the rapid power exchange and bi-directional power flow between PET and system occur increases system damping and suppresses system oscillation under disturbances. This project is supported by Natural Science Foundation of Hubei Province(2001ABB026).更多还原