Sub Synchronous Oscillation in Asynchronous Generators Serving to Wind and Hydro Power Systems – A Review
Vijay Mohale, Thanga Raj Chelliah
Abstract
Sub Synchronous Oscillation (SSO) is generated in long distance transmission lines due to the usage of series compensation. This SSO disturbs the constancy as well as security of the power systems. Application of asynchronous generators with large rated power electronic converters (PEC) makes the system further complicated e.g. 250 MW hydro generating unit requires 25 MW PEC for 10% speed variation. SSO phenomenon should be accurately detected within short duration of time for the avoidance of its harmful influences on power systems. In this paper, the SSO phenomena is discussed to reclassify the present SSO phenomena by including the interaction between a doubly-fed induction machine (DFIM) and converter under sub synchronous torsional interaction (SSTI), considering wind and hydro power applications. Moreover, the state-of-the-art SSO reduction approaches have also been explicated along with their advantages and limitations. Finally, it outlines the challenges and future work in studying SSR reduction method on DFIM based system.