倪以信动态电力系统PowerSystemDynamics.pptVIP

Power System Dynamics-- Postgraduate Course of Tsinghua Univ. Graduate School at Shenzhen NI Yixin Associate Professor Dept. of EEE, HKU yxni@eee.hku.hk Introduction 0.1 Requirements of modern power systems (P. S. ) 0.2 Recent trends of P. S. 0.3 Complexity of modern P. S. 0.4 Definitions of different types of P. S. stability 0.5 Computer-aid P. S. stability analysis 0.6 Contents of our course Introduction (1) 0.1 Requirements of modern power systems (P. S. ) Satisfying load demands (as a power source) Good quality: voltage magnitude, symmetric three phase voltages, low harmonics, standard frequency etc. (as a 3-phase ac voltage source) Economic operation Secure and reliable operation with flexible controllability Loss of any one element will not cause any operation limit violations (voltage, current, power, frequency, etc. ) and all demands are still satisfied. For a set of specific large disturbances, the system will keep stable after disturbances. Good energy management systems (EMS) Introduction (2) 0.2 Recent trends of P. S. Systems interconnection: to obtain more benefits. It may lead to new stability issues ( e.g. low-frequency power oscillation on the tie lines; SSR caused by series-compensated lines etc. ). Systems are often heavily loaded and very stressed. System stability under disturbances is of great concern. New technology applications in power systems. (e.g. computer/ modern control theory/ optimization theory/ IT/ AI tech. etc. ) Power electronics applications: provides flexible controller in power systems. ( e. g. HVDC transmission systems, STATCOM, UPFC, TCSC, etc.) Introduction (3) 0.3 Complexity of modern P. S. Large scale, Hierarchical and distributed structure, Non-storable electric energy, Fluctuate and random loads, Highly nonlinear dynamic behavior, Unforeseen emergencies, Fast transients which may lead to system collapse in seconds or minutes, Complicated control and their coordination requests. -