Investigation of subsynchronous resonance risk in the 380 kV Turkish electric network

Subsynchronous resonance (SSR) occurs when a resonant frequency of a series compensated transmission system interacts with a natural frequency of the turbine prime mover. This form of SSR is referred to as torsional interaction which, under certain conditions, may become self-excited and cause serious damage to electrical equipment and turbine shafts. The presence of a thermal power plant (Kangal) in the close vicinity of a group of series capacitors in Eastern Turkey necessitated a careful investigation of SSR phenomena in the 380-kV network. Extensive computer simulations, utilizing both a frequency-scanning approach and time-domain analysis, revealed that under normal operating conditions the risk is minimal. However, due to inaccuracies in both the machine data and system data, and to the assumptions utilized, the results are non conclusive.<>