Closure on "Generalized theory of instantaneous reactive quantity for multiphase power system"

For original article by X. Dai, G. Liu and R. Gretsch see ibid., vol.19, no.3, p.965-72, July 2004. For discussions by Francisco de Leo/spl acute/n and Jose/spl acute/ Cohen, and J.L. Willems see ibid., vol.21, no.1 p.540-1, January 2006.