Modem Countermeasures to Blackouts

摘要

SOME OF THE COMMON SCENARIOS IN THE EARLY STAGES OF A BLACKOUT ARE PARALLEL transmission paths overloading and tripping in a cascading sequence, system voitage collapsing due to a lack of reactive power reserves and, thus, a lack of voitage regulation ability, growing power oscillations on the system (small-signal instability), and transient rotor-angle instability. Many of the modern power-electronic-based transmission technologies can help to alleviate these types of problems. For example, high-voltage dc (HVDC) can be used to provide the benefits of interconnecting two systems (i.e., power transfer) while essentially acting as a barrier across which phenomena such as power oscillations are not propagated. Thus, HVDC can effectively shield one system from electrical disturbances on the other. In addition, flexible ac transmission systems (FACTS) can provide economic alternatives to building additional exfra-high-voltage (EHV) lines for Che purpose of increasing the power transfer capability across transmission corridors, thereby enhancing system dynamic performance. In this article, we discuss some of these technologies together with their potential benefits.