Interior point method applied to voltage collapse problems and system-losses-reduction

This paper deals with control action to avoid voltage-collapse problems and reduce system loss. First, an optimisation technique based on interior points is used to improve the system-operating conditions. For this purpose, only the voltage controls already available in the system are considered. Secondly, a tangent vector-based technique is used for voltage-collapse analysis and loss sensitivity studies. The optimisation technique is employed in order to quantify the actions qualitatively indicated by the tangent vector. In this case, local shunt compensation is considered. The effects of the system loss and load-margin variation are analysed for each case, and earning opportunities are included based on the new competitive environment. Tests are carried out using the interconnected Southeastern Brazilian system, where all the reactive power limits are taken into account