Voltage stability in distribution network

Abstract

Voltage stability studies and to maintain the flat voltage profile is quite important in order to maintain the healthy operation of electric power network as well as to provide the quality and cheap electric energy to the modern power users. Further with the advancement of power electronics technologies and its application to design flexible alternating current transmission devices (FACTS) have made it easier to alleviate the voltage stability problem in a quicker and cheaper way in the modern DNs. Therefore, this research work shows an attempt to investigate and solve the problem of voltage instability in the distribution network (DN) with the help of FACTS. All buses and lines are calculated in terms of voltage stability index (VSI) and to identify the optimal location of FACTS. The bus or line with minimum voltage profile in terms of VSI are more sensitive to the voltage collapse and it may further lead to blackouts. Hence, the FACTS are permanently installed at the weakest point to enhance voltage profile and improve the voltage stability in the DN. The present study is tested on standard IEEE-15 bus DN and application results are shown to verify the feasibility of the present studies for DN. The beauty and future promise of UPFC in power quality improvement was authenticated on the IEEE-15 bus DN carried out using MATLAB software tool, five different scenarios were considered by increasing the load up to 40% at an interval of 10% from its nominal operating load. With the aim of determining the impact of UPFC on bus voltage and system losses, the load flow analysis was contributed on each scenario with and without UPFC placement in the DN. After UPFC placement there was a significant enhancement of voltages of all busses as well as weakest bus voltage jump from 0.5750 to 0.9750 p.u. and shifting that bus as well as system from voltage instability to stable zone. The active and reactive power loses were decrease by 9.83% and 27.27% that fulfil the beauty of the UPFC installation in the DNs as well as it promise to mitigate the voltage instability problem of the modern DNs