Analysis of Voltage Constraints Impacting the Security of Electricity Supply in a Self-Supplied Aluminium Smelter System

The challenges of ensuring the security of electricity supply (SoES) in large aluminium smelters—particularly those that are self-supplied—provide a compelling rationale for further investigation, as research on this class of industrial systems is limited. Firstly, this paper presents an expert technical perspective on the distinct characteristics and operational challenges associated with aluminium potline loads and their supply systems in self-supplied aluminium smelters. This study then examines the supply infrastructure at Emirates Global Aluminium’s plant in Dubai, which has an installed power generation capacity of 3000 MW, supplying a 2000 MW load on a continuous basis through a network of three 132 kV substations. This high-voltage network is modelled and simulated using the CYME network analysis software module. We consider the following key approaches to ensure stable system voltage for desirable SoES: steady-state voltage control, outage planning and reactive power reserve management, active power flow management and load participation. We then study the influence each of these has on the system voltage and, hence, on the overall SoES of the smelter, using time-domain voltage and frequency curves at key network nodes and active power flow through important network interconnectors. The simulation results clearly demonstrate a significant improvement in the base case event by positively damping the oscillations in these responses, highlighting the significance of maintaining a healthy system voltage within a limit of ±2% of the nominal voltage to ensure SoES of the smelter.