Daniel Terungwa

Rhino and Buffalo are set to enter Namibia’s border and join the NamPower family by mid-2022. This is coming years of planning, immense procurement challenges and a touch of Covid-19,

Rhino and Buffalo are NamPower’s new eagerly awaited mobile substations, rated 20MVA with multiple voltage ratios of 132/66kV to 33/11kV and 132/66kV to 22/11kV respectively.

The Mobile Substations Project was embarked on during 2016 with the main objective of providing security of supply during transformer failure at a substation, by enabling restoration of power supply through the mobile substations. In addition to this benefit, the mobile substations will also be used to facilitate an alternative temporary power supply where new installations, maintenance or upgrading must be conducted.

According to NamPower’s Managing Director, Mr Kahenge Haulofu, “The mobile substations are strategic transmission assets aimed primarily at mitigating the risk posed by prolonged supply interruptions to the customer. The acquisition of the mobile substations will allow NamPower to better uphold its pledge of ensuring security of supply to the nation.

Adding these two mobile substations to NamPower’s transmission fleet will also support NamPower in providing a temporary point of supply to major customers within a significantly shorter time period than would normally be required to provide permanent supply.

The scope of the project entails the specification, design, manufacturing, testing and delivery of two complete fit-for-purpose multi-ratio, outdoor, Mobile Substations with capacity of 20 MVA each.

The specifications for the Rhino and Buffalo Mobile Substation units were concluded during 2017. Market research indicates the estimated budget will be outside of NamPower’s procurement threshold, therefore the procurement must be administered by the Central Procurement Board of Namibia (CPBN) on behalf of NamPower.

The specifications were submitted to the CPBN in March 2018 for approval and the bid was finally advertised to the public on 4 February 2019. The final Bid Closing Date was 3 June 2019 and a total of eight bids were received.

The evaluation was concluded within three months where-after the Notice of Selection of Award letter was sent out to all bidders on 14 August 2019. ABB South-Africa (Pty) Ltd was selected as the Successful Bidder and the contract was signed on 4 December 2019.

During January 2020 the detailed design and procurement of all the major components of the Mobile Substations started. These major components include the Transformer, High Voltage Switchgear, Medium Voltage switchgear, Combined Neutral Electromagnetic Coupler with Neutral Earthing Resistor and Auxiliary Transformer (NECRT), Protection Automation Equipment and the Cables.

NamPower stated that it is worth noting there are no standard designs available for these specific multi-ratio mobile substations. As such, the designs of Rhino and Buffalo proved to be complex where weight and size are limiting factors, amongst others. “The project is currently at the stage where all the major components’ detailed designs have been concluded, and manufacturing as well as installation is well underway. The critical path milestone of installation and final testing for both units is set to be concluded by the end of February 2022, where after both mobile substations will be delivered and handed over to NamPower.