“…A sudden increase in load, loss of a heavily loaded transmission line, failure in protective coordination system or insufficient reactive power supply could lead to voltage collapse or in more serious cases can lead to cascading outages and blackouts. Several major voltage collapse cases had been reported in France in 1987, Sweden in 1983, in Japan in 1987 [3], in the USA in 1996 and 2003 [4,5], Italy in 2003 [5], and England in 2003 [5].…”