Controlling Voltage Sensitive Loads Using Smart Transformers for Frequency Regulation of a Power System

With the growing share of Renewable Energy Sources (RES) in the modern grid, the overall inertia of the utility is abating. Once the contribution from power electronics-based generators becomes comparable to conventional generators, the frequency control capability of the system will degrade drastically. Although various inertial emulation methods have been proposed in the literature, the regulation of load consumption is considered to be the most effective one. To this end, this paper investigates load frequency control of interconnected control areas integrated with smart transformers (STs) and high voltage direct current (HVDC) systems. The role of the ST will be to control the load profile using On-Line Load Sensitivity Identification-based control and assist in the frequency control process. The investigation shows that the contribution from ST in the primary loop can improve the dynamic performance of the power system overall by reducing peak deviations and oscillations. The test system is penetrated with RES units such as photovoltaic systems in the presence of parallel high voltage alternating current and HVDC tie-lines.