Exploring HVDC Future via EU Research

The formidable project is entitled NEWGEN. It is funded by the EU’s Horizon 2020 research and innovation program. Our R&D platform is helping set the benchmark for HVDC PP cable.

Maillefer has the privilege to be member of a formidable research initiative involving ten European partners from five countries with a budget of 7.6 M€ and a duration of 48 months. The project is entitled NEWGEN. It is funded by the EU’s Horizon 2020 research and innovation program. Our role in the group is unique and powered by what defines us a provider of extrusion solutions.

NEWGEN project

We join experts on materials, sustainability, analytics and methods to determine what PP HVDC cables may look like in the coming years. The goal is to reach a Technology Readiness Level 5-6, which qualifies progression from basic research to the ability to demonstrate working technology in an industrial environment. NEWGEN lists the following expected outcomes:

• HVDC technologies allowing the integration of large share of renewables while concurrently addressing the security of supply.
• HVDC interconnections can act as a firewall blocking the spread of disturbances while permitting the interchange of power.
• Mastering HVDC technologies will open new business horizons for European companies in the
• global clean energy markets.
• Increased electricity system reliability and resilience.

Overview of the tasks

At this point, we have developed and assembled the lab line which serves to make the model cables composed of PP. The samples serve to compare against the classic XLPE type. The collective project lists several tasks split up amongst its members. Maillefer is assigned the following.

Task 2.1 - Cable extrusion equipment optimization

• Maillefer will produce the first model cables with current extrusion equipment and commercial thermoplastic blends for characterization using materials identified from prior phase
• Will develop new extrusion equipment solutions in order to improve HVDC cable properties when using PP based materials:
  - development of more efficient melting and mixing during extrusion process of thermoplastic in order to improve material homogeneity and electrical performance,
   - development of new extrusion crosshead solutions for novel thermoplastic HVDC materials to eliminate the electrical weak.

Task 2.2 - Extrusion process optimization

• Maillefer will optimize the cable extrusion process conditions for new thermoplastic insulations to improve the properties and overall reliability of HVDC cables:
  - characterization of different cable HVDC cable prototype samples at wide range of processing conditions (extrusion speed, cooling rate, cooling pressure vs. dielectric properties)
  - establishing processing-morphology-property relationships for thermoplastic insulation to enable production of high-quality defect-free cables.

Task 2.3 - Space charge optimized HVDC cable prototypes and cable model “A” samples

• Maillefer will produce multiple batches of two different kinds of cable samples using materials developed by other partners in the project
• Manufacture, life-size HVDC cables prototypes with optimal industrial scale equipment and conditions.
• Manufacture, smaller model cable “A” samples (as per Cigré 636).
• Both types of cables will be manufactured for new optimized HVDC materials developed in NEWGEN.

Experience from the industry

In NEWGEN, manufacturing of cable samples is important for full evaluation of the developed PP-based blends from WP1. Realistic processing conditions for the extrusion and cooling phases will have impact on the insulation material properties that would be difficult to estimate only from hot-pressed or extruded cast films. Compared to thin films, the model “A” cables have an order of magnitude thicker insulation while the HVDC prototypes have two orders of magnitude thicker insulation.

Much of the focus in tasks 2.1 and 2.2 is to understand the needed machinery and process modifications when transitioning from the industry standard XLPE to thermoplastic PP-based insulation materials in HVDC cables. Experience from the industry has revealed several areas for improvement, which were starting points for designing the first iteration of machinery improvements. The manufacturing of both types of cable samples using existing equipment, as well as some newly acquired equipment, will serve as a reference benchmark for the PP-based material. References will also be used to evaluate improvement needs and the effectiveness of future optimization in cable manufacturing equipment and processes.

At the forefront

It is exciting to be very much involved in top academic research. Our R&D platform for PP cable exists; the know-how and experience with different materials is growing ; and our network of expert partners with the capacity to collaborate with analytics and comparable data is expanding. As a provider of leading machinery for cable manufacturers our role is determinant in shaping the future of PP cable and green energy distribution.

Janne Harjuhahto
Process Development Manager
janne.harjuhahto@maillefer.net