Use of hidden inertia from wind generation for frequency support in power grids

The increase in energy production from non-programmable renewable sources has radically altered the production scenarios, bringing undeniable environmental benefits but also some criticalities for the power networks. One of the most impacting issues is network inertia decrease. Currently wind and photovoltaic generators do not contribute to system inertia, reducing system stability in case of power unbalance. In this paper is described active power response of wind generators in case of under-frequency transients and is investigated the possibility to provide an inertial response, through a modification of their control system. Results of simulations in Matlab-Simulink environment are presented. The analysis of these results suggests ideas for a possible update of Italian Grid Code.