The impacts of distributed generation on voltage stability

Power system is forced to operate near to its stability limit due to the rapid growth of power demand. So, voltage stability has become a primary concern for power systems researchers. The imbalance between reactive power generation and consumption in the system causes voltage drop in the system which is the main cause of voltage collapse. In order to avoid this, most of the modern power systems are adopting the new emerging technologies like Flexible AC Transmission Systems (FACTS) devices and Distributed Generation (DG) systems etc. Conventional method of repetitive load flow analysis for stability study is highly time consuming. A Thevenin's equivalent network based voltage stability index is proposed in this paper which avoids the continuous load flow analysis. The index is used to identify the weakest bus in the IEEE 30 bus test system. The improvements of the proposed index with the addition of facts devices and DG technologies are visualized. Also the optimal location and size are investigated for which the stability improves to a maximum value.