7IEEE Std. 1159 - 1995, IEEE Recommended Practice for Monitoring Electric Power Quality[S].
8Bollen M H J. Understanding Power Quality Problems Voltage Sags and Interruptions[M]. New York: IEEE Press,2000.
9Heine P, Pohjanheimo P, Lehtonen M, a al. A method for estimating the frequency and cost of voltage sags[J]. IEEE Trans on Power Systems, 2002, 17(2) : 290-296.
10Bollen M H J, Qader M R, Allan R N. Stoehastical and statistical assessment of voltage dips[C] // IEE Colloquium on Tools and Techniques for Dealing with Uncertainty, London, UK : 1998.