The Loeriesfontein Wind Farm and the Khobab Wind Farm in the Northern Cape last week marked a break through as the wind farms officially connected to the Eskom grid.
The wind farms have been integrated through Eskom’s Helios Substation and commissioning of wind turbines is reported to have began.
“We energized the wind farm substations with Eskom Transmission’s Helios substation on 28 September,” the country construction manager for Mainstream Renewable Power, Kevin Foster said. He further added that it marks a pivotal point in the construction of both wind farms. It will now continue the process of wind turbine commissioning.
Wind farms supplying electricity
The wind farms are expected to start supplying electricity to the national grid by early December. They will also continue to work closely with the various Eskom teams to achieve this milestone.
“We’re working together with the Eskom teams in the Northern Cape and Western Cape Operating Unit. This aims to ensure a smooth and safe energization as well as commissioning process,” Foster added.
Khobab Wind Farm confirmed the completion of all of their 61 wind turbine generators, on 8 September, more than two weeks ahead of the expected schedule.
How the substation works
Each wind turbine is connected to a step-up transformer which boosts the voltage output of the wind turbine generator from 690 V to 33,000 V. These transformers are located outside at the base of each wind turbine.
From there these medium-voltage structure power cables are routed underground from turbine to turbine according to grouped circuits. They also bring the collective circuit power from the step up transformers to convene at the wind farm’s substation. This is where the main transformer is situated.
The substation built on the wind farm is divided into two attached substations. One is owned and operated by the wind farm; and the other – along with the overhead line – is handed over to Eskom for ownership and operation. Each substation is given a unique name.
The two joined substations are situated in a central location to the grouped circuit power cables’ meeting point. At this end point of the circuits, the collective power from the wind farm is run through several power quality checks and various measurement devices.
Consequently, the power is directed through the main transformer where the voltage is increased again to 132,000 V.