Under Voltage Load Shedding Algorithm using Fast Voltage Stability Index (FVSI) and Line Stability Index (LSI)

As demand grows and grids become complex, voltage stability has been researched throughout the years. A problem occurs if loads, particularly reactive loads are greater than generation, which causes the voltage to drop and could affect the entire grid. An Undervoltage Load Shedding (UVLS) scheme is one of the ways to prevent such scenarios from happening. Using MATLAB to interface and process data from OpenDSS we used an IEEE 39 bus model, and use FVSI and LSI stability indices to determine which loads to shed when undervoltage condition occurs. From the results and statistical treatment with t-value around 0.498353 to 0.908307 which is lower than the 95% confidence interval of ±1.986675, it can be concluded that the system performance after load shedding does not significantly differ than the base case, hence it is considered stable after the said load shedding is performed.