  The increasing penetration of power-electronic-interfaced devices is expected
to have a significant effect on the overall system inertia and a crucial impact
on the system dynamics. In the future, the reduction of inertia will have
drastic consequences on protection and real-time control and will play a
crucial role in the system operation. Therefore, in a highly deregulated and
uncertain environment, it is necessary for Transmission System Operators to be
able to monitor the system inertia in real time. We address this problem by
developing and validating an online inertia estimation algorithm. The estimator
is derived using the recently proposed dynamic regressor extension and mixing
procedure. The performance of the estimator is demonstrated via several test
cases using the 1013-machine ENTSO-E dynamic model.
