Tedagua completes the Spence Mine desalination plant and its substation power supply systems

In April of 2020, the final power supply systems were completed at the substations of the Spence Mine (Mejillones - Antofagasta, Chile) desalination plant built by Tedagua. The expansion of the existing substation, Kapatur (with GIS technology), built during the first few months of this year, powered the Caitan substation, the power grid and the rest of the project's substations.

The conventional Caitan substation, which is connected via insulated bus ducts with Kapatr, is composed of a 220 kV feeder bay, with a 60 MVA step-down transformer plus another identical reserve transformer that lead to two 66kV output bays.

The substation powers two sections of high-voltage overhead lines. The first section, with a length of 16 km, connects to the substation of the desalination plant (PS1) and of the first pumping station. The second section, with a length of 19 km, connects the substation with the second pumping station (PS2) and continues for another 39 km up to the third and last pumping station (P3) of the project.

This overhead line is composed of over 600 18-meter long prestressed concrete supports, 3 underground sections and 11 metal lattice structures. The power line starts at an altitude of 30m ASL and reaches a geographic altitude of over 1,200m ASL, passing through all the geographic features in between.

The PS1 substation, located in the area of the desalination plant, is composed of two 66/6.6 kV transformers with a power of 15MVA each, and can alternate between powering the desalination plant and the first pumping station.

Substations PS2 and PS3 have two 66/6.6 kV transformers of 15 MVA each, which power the impulsion sections that drive the water toward the Spence mine, located at more than 1,500m ASL and at a distance of over 150 km from the shore.