The outage cost was estimated in a variety of ways since the first began use in utility planning about 20 years ago. In addition, the information of outage frequency and the outage duration tended to use increasingly with the outage cost for optimizing investment cost of power system reliability improvement [1].
J. Michael, T. Vardell and M. Johnson, “Power interruption costs to industrial and commercial consumers of electricity” IEEE Trans. Industry Applications., vol.33, pp. 1448-1458, Nov. 1997.