Voltage Control of Active Distribution Networks with EV Charging Stations using Multi-Time Scale Model Predictive Control

Abstract

The rapid proliferation of photovoltaic (PV) units and controllable loads, notably electric vehicles (EVs), has significantly altered the operational dynamics of active distribution networks (ADNs), causing various issues. Their large-scale integration and uncertain behaviour induce frequent and severe voltage violations, thereby challenging traditional voltage regulation mechanisms, which involve localized control of on-load tap changers (OLTCs), static voltage regulators (SVRs), etc. For this purpose, coordinated voltage control (CVC) schemes have been developed, wherein the control capabilities of fast-acting devices, such as PV inverters and EV charger inverters, storage devices, and other power electronic interfaced devices, are utilized for voltage regulation and loss minimization. A multi-time scale model predictive control (MPC) based real-time receding horizon control mechanism, enabling coordination of diverse resources including OLTC, PV, and EV charging station (EVCS) inverters, and distribution static synchronous compensators (DSTATCOMs), lies at the core of this thesis. The multi-time scale design allows OLTC operation on a slower time scale, and coordinated operation of inverter-driven control devices (IDCDs) on a faster time scale.