HVAC Submarine Cables Optimization Transmission Strategies

Small groups of islands can be connected to the transmission grid through HVAC submarine cable line (CLs). Since the tourism sector has often a prominent role in their overall economy, the marked seasonal variation of the energy demand leads to an immediate impact on the cable loading. In low-load conditions, power losses along the cable are largely associated to its own charging currents. Power losses due to shunt reactors placed at both ends of the line are also considerable. Consequently, when low power flows are involved, the operation of the system at reduced voltages is required. The paper evaluates the opportunity of minimizing power losses as the transmitted active power changes by using Interconnection Transformers equipped with On-Load Tap Changers (OLTCs). The proposed solution aims to provide an accurate degree of control of the terminal voltages through the coordinated action of such devices.