Estudio de estabilidad de voltaje en estado estacionario de un sistema eléctrico de potencia usando curvas PQ

Abstract

The PQ curves are a tool related to the evaluation of voltage stability in steady state of electrical power systems, the method for their elaboration is based on the use of the parameters of transmission lines, as well as the solution of power flows. In this context, the present work proposes a method for the analysis of the voltage stability in an electrical power system, with variables that define its behavior, and do not vary with time, applying the known PQ curves. The PQ curve methodology is implemented in the DIgSILENT Power Factory software, using the programming language available in this computational package. The resulting coding allows to evaluate the stability condition of the electrical power system from the voltage point of view, through the development of a procedure that, making use of second degree equations, as well as mathematical arrangements of translation and rotation of axes, allows to reduce the general equation helping to build the PQ graph more easily. To test the methodology, a general code is developed that helps determine if the IEEE 9-bar and 4-bar SEP systems from the Grainger & Stevenson Power Systems Analysis reference are stable by constructing the PQ curves. After applying the methodology, the stability of the system is evaluated, based on the analysis of the constructed PQ curves, thus verifying the stability zones where the system works normally, as well as the possible regions that can cause a voltage collapse.