A Generalized Load Flow Method to Assess Steady-State Equilibrium of Power Systems

Continuous advances in terms of the capability of modern computers allow the development of power systems analysis tools that takes into consideration aspects that are usually neglected for power flow calculation. Examples are detailed models for generators, turbines, speed and voltage controllers that are usually over-simplified, flexible AC transmission systems devices, induction generators, dynamic loads, etc. This paper presents a generalized power flow method able to include the steady state characteristics of any dynamic device by using the same models considered for time domain simulation. The method solves simultaneously the power system set of algebraic and differential equations at the steady-state equilibrium, allowing monitoring the dynamic devices performance when certain parameter is changed, such as the load level or the voltage setpoint of a given controller, or after the occurrence of contingencies. Simulations in a 16-machines/69-buses test system show that the proposed method provides the system post-disturbance equilibrium point with the high degree of accuracy of time domain simulation and the low computational requirements of conventional power flow.