E-mail from ... Christchurch

To: Staff of TU Graz

Kia ora koutou!

I was in beautiful New Zealand, more precisely in Christchurch, where I completed a six-week research stay at the University of Canterbury (UoC). This great opportunity was made possible for me by Future Architecture of the Network (FAN) and the support of the International Office – Welcome Centre at TU Graz.

I conduct intensive research into the topic of direct current transmission using extruded MVAC cable systems at the Institute of High Voltage Engineering and System Performance. I am presently investigating various solid insulating materials for use under DC voltage stress. In the summer of 2025, PhD student Nalindi Herath from the UoC was a guest at TU Graz to get an overview of our research activities. During my stay, research into medium-voltage direct current transmission with regard to mixed-voltage stress was intensified and cooperation with the UoC strengthened. Also during my stay, I received great support from the Department of Electrical and Computer Engineering team and Andrew Lapthorn. We had the unique opportunity to discuss the results together on site and develop new approaches. The research results are to be published in a joint article.

In addition to the exciting work in the lab, it was of course also important to discover New Zealand with its diverse landscape and culture. In addition to the city and the surrounding area around Christchurch, I visited Dunedin in the south of the island and the west coast. I was also able to attend the FAN Conference in Wellington during my stay and present the paper ‘Feasibility of MVAC cable systems for MVDC/HVDC’. A personal highlight of the stay was the trip to Arthur's Pass with a visit to Otira Gorge, the Devils Punchbowl waterfall, a hike through the Cave Stream Scenic Reserve and a stop in Castle Hill together with colleagues from the UoC on the Waitangi Day public holiday.

Lessons Learned: New Zealand has extremely high UV values, often with a UV index (UVI) above 11. Due to the very thin ozone layer, low air pollution and geographical proximity to the Antarctic, UV radiation is more intense than in Europe. That's why sun protection is essential if you don't want to get sunburnt on day 1 like I did!

Ka kite anō and many greetings,

Patrik Ratheiser

(Institute of High Voltage Engineering and System Performance)

You can find this article and other articles to browse through in TU Graz people #96, the magazine for TU Graz employees and interested parties.