Capability chart for the planning of reactive power sources

The planning for reactive power sources can be set in the same logical framework as the planning for other components of the system by describing the ability of the system to face the load demand by means of the capability chart of the system. A reliability index is defined based on the capability chart, thus giving evidence to the role played by reactive powers in determining the aforementioned ability. The plots of this index and of an economical indicator against the total amount of reactive compensation allow evaluation of the technical and economical effectiveness of the installation of reactive power sources. Various plots can be drawn, depending on the choice of the nodes at which to install the compensating devices and of their share of the total amount of compensation. In the paper, the capability chart, the definition of the reliability index, and some criteria for choosing the installation nodes and their share of total compensation are recalled; a simplified economical indicator is then adopted, and the results on a study case are presented in terms of plots of the reliability index against this indicator