It is caused by insufficient damping 它是由于阻尼不足而造成的。
2.
According to these theories we know the reason of the emergence of low frequency oscillation is lacking positive damping even appearing negative damping . this problem can be classified as dynamic stability 从而得出,电力系统低频振荡是由于系统正阻尼不足甚至产生负阻尼而引起的,可以将其归类为动态稳定问题。