July 2022
Hyperion Power Services provides expertise to several generating plant Owners and to the Peruvian grid operator (COES) to resolve the Sub Synchronous Resonance (SSR) issue in Peru
The SSR phenomenon has been a serious concern to generating companies in Peru following the catastrophic failure of four GE Frame 7 units, all located in a plant in Southern Peru.
Our Hyperion Power Services was called to provide a world class expert in SSR remediation who, working with the Grid Operator for Peru, COES and the plant Owners, scientifically modeled the grid and demonstrated the reason for failure.
Three of the four turbines and two of the four generators were replaced and/or repaired at great cost. COES issued an RFP and HPS proposed ways to minimize/eliminate the SSR risk on the grid.
About the SSR phenomenon
Sub-Synchronous Resonance is relevant to various generator types, and proper analysis and control measures are crucial to prevent instability in power grids. It can occur in grids that connect different types of power generators:
Wind Turbines: In remote areas, wind farms are connected to the grid via long transmission lines. When DFIG-based wind turbines are integrated into such series-compensated grids, SSR becomes a concern. SSR refers to low-frequency oscillations caused by the interaction between the wind turbine controllers and the series-compensated power grid.
Steam Turbines: In power systems with series compensation, steam turbines can experience SSR. The interaction between the mechanical shaft system and the electrical system can lead to sub-synchronous oscillations.
Hydroelectric Generators: Hydro generators, especially those with long transmission lines, are susceptible to SSR. The hydro generator’s rotor dynamics and the grid’s impedance play a role in these oscillations.
Gas Turbines: Gas turbines connected to series-compensated grids may encounter SSR. The control system and grid characteristics influence the severity of these oscillations.