A new tool for planning reactive power compensation is presented. It i
s based on the capability chart of the power system, which describes t
he domain of allowable operation of the system in the plane of total a
ctive and reactive load demand. Reliability concepts are used to descr
ibe the ability of the power system to face the load; the stochastic a
pproach is adopted because load demand is fundamentally uncertain. Res
ults for the AEP 14 bus test system are presented.