Thevenin’s equivalent based P–Q–V voltage stability region visualization and enhancement with FACTS and HVDC

•Voltage stability boundary enhancement with FACTS devices.•Impact of HVDC on voltage stability boundary.•Indices for the placement of FACTS devices and HVDC.•Comprehensive study with FACTS devices for VSB enhancement.

Voltage source converter based Flexible Alternating Current Transmission System (FACTS) devices are considered to be key technology to alleviate voltage instability. This paper examines the enhancements in feasible operating P–Q–V space with FACTS and HVDC. Thevenin’s equivalent at the load bus is applied to draw P–Q–V curve (shows the boundary of the maximum real, reactive power and the minimum voltage magnitude) and area of voltage stability region (AVSR) in a three-dimensional diagram. A visualization framework for voltage stability region in MATLAB environment is implemented to study the impact of FACTS (SVC, STATCOM, and TCSC) and HVDC. The best possible location of shunt controllers is obtained using AVSR and index ‘L’. The line stability indices are calculated and compared to verify the weakest line for installation of series controllers. The inclusive study has been performed on IEEE-14 and IEEE-30 bus systems. The results show the enhancement in area of voltage stability region in all cases with maximum in case of HVDC.

Graphical abstractImpact of FACTS and HVDC on voltage stability region of bus 14 of IEEE 14 bus system.Figure optionsDownload full-size imageDownload as PowerPoint slide