Real-time primary frequency regulation using load power control by smart transformers

In the last years, the energy production share of power electronics-based generators has kept increasing with respect to the synchronous generation. These power electronics-resources do not offer rotational inertia, resulting in a decrease of the total system inertia and thus in larger frequency deviations during disturbances. Among several corrective solutions studied in the literature, controlling the load consumption is a promising one. Fast in power response and widely distributed in the grid, load control is able to work as power reserve (both upward and downward) during frequency variations. In this regard, a smart transformer (ST)-based solution is proposed. The ST is able to shape load consumption accurately by means of an online load sensitivity identification-based control, and can support the primary frequency regulation in the power system. This paper presents an ST-based real time frequency regulation (RTFR) controller that varies load consumption by means of a voltage-based load control, in response to the frequency deviation in the power grid. The proposed method is described analytically and tested by means of power-hardware-in-loop experiments in order to show the effectiveness of the RTFR controller in real-time conditions and applications.