Implementation of Power System Stabilizers in a Power Grid: A Case Study

Power utilities constantly seek cost effective ways to improve stability and reliability of power grids. A key responsibility of transmission planning engineers is to ensure a power system remains stable under normal and disturbance conditions. The implementation of power system stabilizers (PSSs) on excitation control of large synchronous generators is a more contemporary approach to defending the system against disturbances. This paper demonstrates the value of power system stabilizers through a case study by analyzing a real-life event that occurred on a 230 kV transmission system that resulted in the loss of power to numerous customers in a power grid in Canada. This disturbance occurred on May 22, 2018 in which the loss of a 230 kV line caused power oscillations on a nearby 13S kV line that eventually tripped and resulted in a significant drop in the system frequency. The dynamic stability analysis for the case study is performed using PSSOE. It is found that power system stabilizers can significantly reduce power oscillations on the 138 kV system and avoid customer outages.