The concentric relaxation phenomenon of the average power dissipation distribution was proposed in order to locate the source of power system forced oscillations fast and exactly.During the constant amplitude oscillation stage,the frequency deviations and power deviations were represented with phasors.Then two criterion of the distribution of average damped energy were deduced,in which the total power dissipation injected into a node is zero, and this power at the beginning and the end of a branch is nearly equal.The concentric relaxation pattern of average power dissipation distribution was inferred due to the radial structure of power grid.This pattern was verified by a simulation of 10-generator 39-bus system.The concentric relaxation pattern is helpful for drawing up a scheme for fast locating disturbing source of forced oscillation and avoiding the erroneous judgment.
