12.在電力系統穩定度分析中，等面積準則(Equal Area Criterion)適用於分析哪一種穩定度？(A)穩態穩定度(Steady-State Stability)(B)小擾動穩定度(Small-Signal Stability)(C)單機無限匯流排的暫態穩定度(Transient Stability)(D)電壓穩定度(Voltage Stability)