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Methods of computing steady-state voltage stability margins of power systems

United States Patent

9,921,602
March 20, 2018
View the Complete Patent at the US Patent & Trademark Office
Lawrence Berkeley National Laboratory - Visit the Technology Transfer and Intellectual Property Management Department Website
In steady-state voltage stability analysis, as load increases toward a maximum, conventional Newton-Raphson power flow Jacobian matrix becomes increasingly ill-conditioned so power flow fails to converge before reaching maximum loading. A method to directly eliminate this singularity reformulates the power flow problem by introducing an AQ bus with specified bus angle and reactive power consumption of a load bus. For steady-state voltage stability analysis, the angle separation between the swing bus and AQ bus can be varied to control power transfer to the load, rather than specifying the load power itself. For an AQ bus, the power flow formulation is only made up of a reactive power equation, thus reducing the size of the Jacobian matrix by one. This reduced Jacobian matrix is nonsingular at the critical voltage point, eliminating a major difficulty in voltage stability analysis for power system operations.
Chow; Joe Hong (Scotia, NY), Ghiocel; Scott Gordon (Albany, NY)
RENSSELAER POLYTECHNIC INSTITUTE (Troy, NY)
14/ 655,474
20150378387
May 7, 2014
STATEMENT OF GOVERNMENT INTEREST This invention was made with government support under contract EEC1041877 awarded by the National Science Foundation and contract DE-AC02-05CH11231 awarded by the Department of Energy. The government has certain rights in the invention.