Converter transformers arrive at Haywards substation

5 September 2011

Two of the four 240 tonne converter transformers due at Haywards substation were delivered in the early hours of Monday 29 August and Monday 5 September. They are the largest pieces of equipment to be delivered as part of the Pole 3 Project and require a 36 axle truck and trailer unit. They must be delivered during the night when state highways 2 and 58 have little traffic.

After arriving in Wellington by ship, the transformers were barged to a quarry in Seaview, then in a separate trip they were transported by truck to Petone and over the railway on specially made ramps. They stayed in the car park at Petone Bowl and were finally delivered in separate journeys to Haywards.

Much planning is involved in deciding the routes trucks must take to avoid all low and weight restricted bridges, traffic and tight turns. Specialist heavy haulage companies are needed to perform this task.

At Timaru, the two transformers will be offloaded from the heavy lift ship onto the port for storage in a secure facility until transport to Benmore substation later in the year.

The remaining four transformers are due to arrive in New Zealand in October. Separate shipments were planned as a risk mitigation measure.

The transformers are a major component of the process that Pole 3 undertakes to convert electricity from DC to AC and vice versa. Operating together as a 3-phase unit, the conversion capacity is 700 MW, which is the amount of electricity consumed by the Wellington, Wairarapa and Kapiti regions combined.

Facts and figures

The weight of each new transformer is 240 tonnes when transported, 330 tonnes when operating
Quantity: four transformers at each site – Haywards and Benmore – three in service and one spare
Manufactured: by Siemens of Germany, six were made in Nuremberg, Germany and the other two in Zagreb, Croatia. These first four transformers are from Germany.
Total estimated cost of the Pole 3 project is $672 million
Capacity of Pole 3 is 700 MW
Total capacity of the HVDC link will be increased to 1000 MW in 2012
Total capacity of the HVDC link will be increased to 1200 MW in 2014
The total length of HVDC transmission line 571km
The length of HVDC submarine cable is 40km
The HVDC was first commissioned 1965