Power system frequency management challenges - a probabilistic approach to assessing wind farm potential for aiding system frequency stability

With the increasing wind penetration level in power systems, transmission system operators have become concerned about frequency stability. The inertia of variable speed wind turbines are decoupled by power electronic converters from the power network and therefore do not intrinsically contribute to power system inertia. Besides, as wind plant displace conventional generation and their inertia, substantial reduction in power system inertia may occur. Variable speed wind turbines can be controlled to provide synthetic inertial response but have no direct contributions to power system inertia levels. A probabilistic approach to assessing wind farm potential for aiding frequency stability in power systems is proposed, and the method will be applied to the GB power system. The impact of the aggregate inertial response on arresting frequency fall is examined assuming a sudden generation loss of 1800 MW in the GB power system. The results show that inertial response from wind can reduce the maximum rate of fall of frequency and the minimum system frequency following the event (frequency nadir).