An improved method for assessing voltage stabilitybased on network decomposition

In this paper, we present an improved method for assessing the voltage stability based on network decomposition. It is an analytical approach to find the radial paths that are transformed into two-bus equivalents combined with an analytically proven test for the voltage-collapse proximity measure that has a physical meaning. The first modification allows for power-flow tracing that obtains the generator active- and reactive-power shares on each section of a radial path. The shares make it possible to allocate the transmission losses among the generators, which are required to assess the voltage-collapse proximity. Based on the reactive-power tracing, the improved approach also makes it possible to assess the availability of reactive-power sources and their ability to supply load buses. The proposed solution is faster than the existing search algorithm and gives more accurate results. The method was tested on the IEEE 39-bus test system.