基于低成本單片機的相量測量單元提高智能電網可靠性

　　8月14日，安大略和美國東北部八個國家的2003， 50萬人失去了電力。一個炎熱的下午和克利夫蘭附近一座燃煤發電站意外的破裂，引發了連鎖反應，在94分鐘內，美國東北部大部分地區都陷入了黑暗之中。花了24個多小時才恢復了電網大部分地區的電力，完全恢復了滿足該地區需求的生產能力，幾乎花了兩周時間。它將永遠被銘記為2003的大停電。

　　令大多數電網運營商吃驚的是，一場看似無辜的事件可能會導致整個電網崩潰。當輸電線路接近最大容量時，克利夫蘭的一個局勢被允許超過90分鐘未被發現。炎熱的夏季空氣對該地區的空調產生了巨大的電能需求。當燃煤發電站脫機時，當地輸電線路超載，導致線路延伸并向地面下沉。當線路接觸到允許在傳輸線下面生長的樹時，線路短路到地面，導致自動電路保護中斷。這就給剩余的線帶來了更多的壓力。一個小時后，其他三條線路失靈，俄亥俄電力公司的剩余電力線路也出現了災難性的浪涌，引發了其他幾條線路斷路器。由于剩余的輸電線路沒有足夠的能力攜帶整個區域所需的能量，整個電網在90秒內倒塌。這家電廠關閉了。由于無法提供所產生的能源，一些核電站被迫執行緊急程序，關閉核反應堆。這是一個對核反應堆造成損害的程序。在電網上恢復電力幾乎花了四天時間，近兩周時間才使所有反應堆恢復滿負荷運轉。

　　An investigation of The Great Blackout revealed that the power grid control systems were antiquated and largely unable to monitor and protect the health of the grid. Time was never an issue. It took 31 minutes from the moment the Cleveland power station failed until the first transmission line collapsed. The situation looked manageable for another 61 minutes， until more transmission lines started burning out. The men and women controlling the grid were caught completely off guard because they had no means to detect warning signals from the power grid. Without access to real time information， the power grid control rooms were unable to predict where the next error would occur and plan corrective actions. The investigation concluded that the disaster could have been avoided if the power grid had been equipped with better monitoring systems. The U.S. Department of Energy considers the US-Canada blackout in 2003 to be the single most important motivator behind the Smart Grid initiative.