| CPC H02J 3/0012 (2020.01) [G01R 31/088 (2013.01); H02J 3/38 (2013.01)] | 7 Claims |
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1. A method for constructing a dynamic security region of a power grid based on an extended phase trajectory theory, comprising:
acquiring electric power system data, wherein the electric power system data comprises a power angle δ and an angular velocity difference Δω of a generator node after a fault occurs, identifying a leading generator group A through the power angle δ, and performing Complementary Cluster Center of Inertia-Relative Motion (CCCOI-RM) transformation on the angular velocity difference Δω to obtain a transformed angular acceleration γ;
for generators in the leading generator group A, changing output of each of the generators to search for a dominant instability critical point;
calculating a reciprocal of the slope of the tangent line of a trajectory of n swings of an extended phase plane based on angular velocity-angular acceleration in a fourth quadrant according to actual measurement information to obtain a stability index for identifying single-swing instability and multi-swing instability, and changing a disturbance output ΔP of the generator at the dominant instability critical point to solve a sensitivity of the extended phase trajectory; and
constructing a multi-modal practical dynamic security region based on the extended phase trajectory based on upper and lower output limits of the generator and an output limit of a balancing machine;
wherein a formula of calculating the reciprocal of the slope of the tangent line of the trajectory of n swings of the extended phase plane based on angular velocity-angular acceleration in the fourth quadrant according to actual measurement information to obtain the stability index f for identifying single-swing instability and multi-swing instability is as follows:
 wherein Δωi/Dγi is a negative reciprocal of the slope of the tangent line of the trajectory of the ith swing in the fourth quadrant, Dγ is an intercept value of the tangent line of the trajectory of the extended phase plane in the fourth quadrant on γ axis, and the stability of the system is judged by judging the sign of f when the ith swing leaves the fourth quadrant;
the method further comprising: correcting the stability index f, wherein a formula of judging the corrected transient stability is as follows:
 wherein Δωmin is a value of the angular velocity difference when the trajectory of the extended phase plane is currently swung out of the fourth quadrant, and γ is the transformed angular acceleration;
the method further comprising: performing injection power sensitivity analysis on multi-modal instability correction criterion based on the extended phase trajectory to obtain an effective mapping between the correction criteria and node injection power, and defining an extended phase trajectory sensitivity matrix S as follows:
 wherein when a change in the output of the generator is ΔP=[ΔP1, ΔP2, . . . ΔPn], a formula of judging the extended phase trajectory stability is as follows:
fi+SΔP<0
by introducing the upper and lower active output limits of the generator and the output limit of the balancing machine, an extended phase trajectory formula is expressed as follows:
 a change in the output of the balancing machine is as follows:
 according to a change Δfi in an extended phase trajectory correction criterion, a sensitivity Sj of a stability criterion of a generator i to a generator j is as follows:
 the expression of the dominant security region of the generator i is as follows:
 wherein fi=[f1, f2, . . . fn] is a stability index of the leading generator group A, and the extended phase trajectory fi at the dominant critical point of the generator i changes the disturbance ΔPj; and Pj is the injection power of all generator nodes.
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