The challenge

Test and validation programmes for potentially game-changing new products can prove daunting yet remain crucial for gaining industry acceptance and, ultimately, market share. That challenge can carry additional weight when the test programme is required to demonstrate consistent long-term reliability, performance and quality in harsh subsea environments, many kilometres from shore.

Faced with this challenge, the new technology development team from Benestad – Aker Solutions’ Norwegian subsidiary – approached Stephen Thompson, Business Development Manager, Electrical Networks in late 2021 to discuss what solutions could be provided or engineered to meet their unique testing needs. After many meetings and discussions, an action plan was set In motion.

Based in Tranby to the south west of Oslo, Benestad manufactures high-performance penetrators, connectors, and sensors for the oil and gas and renewables industries industry, as well as specialty products for space and defence. The company’s products operate in harsh environments with zero accidents or failures having been recorded.

With support from the then UK Government BEIS (Department for Business, Energy & Industrial Strategy) ^*, preliminary discussions centred on how best to work together to create an international standard oscillating jumper test and validation programme to support the  Benestad’s recently developed 66kV power string, which includes a high voltage wet mate subsea connector. Such ‘wet mate’ connectors are designed to operate subsea, forming wet mateble ‘jumper cables’ connecting two separate high voltage points, essential to move subsea power distribution subsea and open for significant cost reductions

Having developed a 66kV wet mateable subsea power string in response to a identified Offshore wind market need – 33kV wet mate connectors having been the predominant market solution up to that point – the new product represented at the time a bold move by Benestad, ‘jumping up’ a full voltage level.

Close, mutually beneficial partnership

Benestad’s team visited ORE Catapult’s High Voltage test and mechanical handling facilities in Blyth several times throughout 2022 and into 2023, forging a close working relationship with the high voltage electrical team. The extended team selected IEC 61886-1 – the international Standard for Subsea equipment, including power connectors, penetrators and jumper assemblies up to 30kV – with pre-approved deviations aligned with the step up in cable size – as the benchmark for a rigorous test programme intended to replicate 30 years of continuous subsea performance.

Attention then shifted to designing and building the bespoke test rig. The connector termination including the jumper cable would be permanently submerged in a tank of artificial sea water, the system is subjected to a series of electrical tests designed to evaluate electrical performance between mechanical conditioning, replicating subsea deployment.

Performance testing regime

With delivery and set-up of the bespoke tank completed in September 2024, and the Benestad team on site, ORE Catapult’s high voltage team launched the month-long test programme in November 2024. They conducted insulation resistance, conductor resistance and high voltage partial discharge tests before, during, and following completion of the robust test programme, confirming performance of the jumper assembly.

Testing on the 66kV cable termination was successful and it was ultimately returned to Benestad’s Tranby headquarters for dissection.

With Benestad’s permission, the custom-built test rig remains at Blyth’s High Voltage laboratory, where we are in discussions with several other customers with a view to supporting new innovative products to market, through representative test and validation programmes.

^* The Department for Business, Energy & Industrial Strategy was replaced by the Department for Energy Security and Net Zero, Department for Science, Innovation and Technology (DSIT), and the Department for Business and Trade (DBT).