Have you ever heard of Sub-synchronous resonance ?
No! then we have something interesting for you regarding SSR. First of all let us explain you what is exactly SSR.
Theory: Sub-synchronous resonance (SSR) is a phenomenon in which the resonant frequency of the electrical system coincides with the resonant frequency of the turbine generator shaft in such a manner that there is a continuous exchange of energy between the mechanical shaft of the turbine generator shaft and the electrical system. This exchange of energy causes torsional stress on the turbine generator shaft that can lead to severe damage such as cracks in TG rotor shaft. In some cases, the shaft can actually fracture
Well SSR (Sub-synchronous resonance) is a problem that is encountered very rarely and Probably The first world widely known incident of a turbine generator shaft failure was actually two failures at the Navajo Generating Station which is located in the south-western part of the US, which was in early 1970’s.
The latest turbine generator shaft failure happened due to the sub-synchronous resonance was in the Unit No.3 of KSK Mahanadi Power Company Ltd. Which is located in Akaltara, Chhattisgarh, India.It happened during the synchronization of the Unit No.3 in 2013.
