Robust Convergence of Power Flow using Tx Stepping Method with Equivalent Circuit Formulation
For power system operators and planners, this method enables reliable power flow convergence for large-scale systems without requiring a good initial guess, addressing a key bottleneck in grid planning and operation.
The paper extends an equivalent circuit formulation for power flow analysis with a novel continuation method (Tx stepping) to achieve robust convergence to the high voltage solution from arbitrary initial guesses, demonstrated on 75k+ bus test cases of the U.S. Eastern Interconnection.
Robust solving of critical large power flow cases (with 50k or greater buses) forms the backbone of planning and operation of any large connected power grid. At present, reliable convergence with applications of existing power flow tools to large power systems is contingent upon a good initial guess for the system state. To enable robust convergence for large scale systems starting with an arbitrary initial guess, we extend our equivalent circuit formulation for power flow analysis to include a novel continuation method based on transmission line (Tx) stepping. While various continuation methods have been proposed for use with the traditional PQV power flow formulation, these methods have either failed to completely solve the problem or have resulted in convergence to a low voltage solution. The proposed Tx Stepping method in this paper demonstrates robust convergence to the high voltage solution from an arbitrary initial guess. Example systems, including 75k+ bus test cases representing different loading and operating conditions for Eastern Interconnection of the U.S. power grid, are solved from arbitrary initial guesses.Interconnection of the U.S. power grid, are solved from arbitrary initial guesses.