This paper evaluates the impact of load dynamics on
torsional interactions by considering a mix of static and dynamic
loads aggregated at the bulk transmission level. This is essential
to investigate the importance of detailed load modelling for
subsynchronous resonance (SSR) studies to accurately assess
damping contribution and capture system dynamics. SSR
interaction with dynamic loads is investigated for both direct on
line and drive connected motor loads. Damping contribution
from dynamic loads is also assessed based on their location and
size. The interaction of dynamic loads with classical SSR
phenomenon is observed and introduced as the new concept of
(Subsynchronous Resonance Load Interactions (SSR-LI)). SSRLI
assumes critical importance for scenarios where the load and
generation centers are in close electrical proximity and impact of
loads on torsional damping is significant. Finally, the scope for
using existing converter interfaced motors for torsional mode
damping has been discussed.