Tutorial on Sub-synchronous Resonance Protection Applied to Inverter Based Renewables

With the increased use of renewables, inverter connected energy resources such as wind farms and PVs are being widely integrated into the transmission system. Events in the transmission system can cause interactions between the natural frequencies of the power system and the controllers in the inverter system. This could sometimes result in sub-synchronous oscillation conditions leading to wide system damages. On the other hand, the conventional monitoring, control, and protection devices that operate based on power frequency measurements may not trigger, operate, or respond during these conditions.This paper provides a tutorial on sub-synchronous oscillation conditions generated due to the integration of inverter connected energy resources, including useful information for system, protection and control engineers.