Voltage stability analysis using L-index under various transformer tap changer settings

Voltage stability is a major problem in power system which depended on many factors like improper load forecasting, generator outage, line fault and shortage of reactive power supply etc. For a secure and economic power system operation voltage stability should be maintained within permissible limit. Voltage stability is a measure of whole power system quality. Voltage stability studies can done by analyzing reactive power production, transmission of power and consumption. In this paper voltage stability analysis of an IEEE 14 bus system is done by calculating L-index of the buses. From load flow studies optimized voltage is chosen, and by using these voltage values L-index is calculated. From the calculated L-index values we can find out vulnerable buses. How the transformer tap changing effect the voltage stability is also calculated here.