Comparative Analysis of CASE and PowerFactory Voltage Stability Modules

Small–signal voltage stability calculation is rarely or almost not carried out at all in long term plans and studies of power system development. On of results of this stability calculation is estimation of consumption maximum power at particular node. It is point at which active power at so called P–V curve has a maximum value. This point and entire P–V curve are determined by software using load flow calculation which is carried out for many cases whereby in each subsequent case power consumption of analysed node or group of nodes is increased by a certain value. Comparative analysis of CASE and DIgSILENT PowerFactory modules for small signal voltage analyses is conducted in this paper. Theoretical background of small signal voltage stability is briefly given at the paper beginning. Afterwards, it is presented how voltage stability modules work in both software along with comparative analysis of calculation results using the same, educational, simulation model. CASE calculation results using real model of Serbian transmission system are given at the final chapter of the paper.