Field validation of CORECHECK enables post-installation integrity verification of composite core conductors on a 380 kV line

As part of its 2045 objectives to support the accelerating energy transition, the Dutch transmission system operator TenneT is deploying HVCRC composite core conductors on a large scale, through frame agreements with Epsilon Cable' stranding partners Nexans and De Angeli Prodotti.
In this context, CORECHECK, Epsilon Cable's composite core integrity monitoring technology, was successfully validated in real installation conditions on a 380 kV transmission line.

Composite core conductors can be sensitive to improper handling during transport and installation, while no practical field method has historically been available to verify their internal integrity. CORECHECK addresses this gap by enabling direct verification of the structural integrity of HVCRC composite cores at every stage of a project.

Discover CORECHECK® monitoring technology : https://www.epsilon-cable.com/solutions/corecheck-monitoring

CORECHECK relies on a breakdown voltage test to detect internal defects and damage within the composite core. The method leverages the insulating properties of the glass fiber outer layer of the composite core to assess the integrity of the entire core.
Because it is based on a well-established inspection principle in the electrical industry, the test is familiar to operators and requires minimal training.

The system is designed for field use: each test takes approximately five minutes per conductor and can be performed by a single operator using lightweight equipment, without disrupting installation schedules.

The integrity of the composite core was verified throughout the project lifecycle: after pultrusion of the core by Epsilon, after conductor stranding by Nexans, upon delivery of conductor reels on site, and after installation by the EPC.
Testing was performed under demanding field conditions, including strong winds, dense fog, heavy rain and sub-zero temperatures, and proved compatible with complex configurations such as the presence of nearby energized parallel circuits.

A field feedback video from TenneT and Nexans is available here: https://www.epsilon-cable.com/case-studies/corecheck-deployment-on-a-380-kv-line-in-tilburg-the-netherlands

Beyond providing a clear pass/fail signal, CORECHECK ensures full traceability of each test, with systematic recording of project data, operator identification, conductor batch and measurement results. This enables consistent quality documentation and strengthens confidence for both utilities and contractors.

A technical paper on CORECHECK will be presented at CIGRE Paris 2026, expanding on field data collected during this project and building on the initial paper presented at the 2024 session, which introduced the technology principles.

To support adoption, Epsilon Cable regularly conducts hands-on field demonstrations, allowing utilities, EPC contractors and stranders to evaluate CORECHECK in real operating conditions.

A recent session conducted with several European utilities is available here:
https://vimeo.com/1167764389/bd7be17861?fl=ip&fe=ec

Epsilon Composite, LA MAILLARDE 5 ROUTE D'HOURTIN 33340 GAILLAN-EN-MEDOC
Press contact: Aurélien CHAUSSAT

About Epsilon Composite and Epsilon Cable

Epsilon Composite designs and manufactures carbon fiber composites for industrial, civil engineering, aerospace and energy markets since 1987.
It is a pioneer and world leader in high-performance composite materials thanks to the pultrusion process. This highly efficient technology combined with the extraordinary properties of carbon fibers is the ideal solution to manufacture the cores of advanced conductors, also known as High Capacity / High Temperature Low Sag ("HTLS") conductors.
The mid-size industrial company is family owned. Since 2023, Sumitomo Corporation (Japan) has joined the company's capital as a minority shareholder, to support the ambitious growth of its Epsilon Cable division.
Its headquarters and main facility are located in France, with subsidiaries in Japan, India and Mexico to serve clients worldwide.


Epsilon Cable is the company's division specialized in advanced conductors, designed to improve line ampacity, reduce sag and minimize electrical losses.
Thanks to their strong lightweight composite core made of aerospace-grade carbon fiber, glass fiber and epoxy resin, Epsilon Advanced Conductors such as HVCRC® allow to easily and cost-effectively double the ampacity of High Voltage overhead lines, to mitigate sag issues and to reduce electrical losses, therefore cutting down on CO2 emissions and ensuring a quick return on investment for utilities.
With a proven track record of more than eight thousand kilometers of conductors installed worldwide in the past 20 years, Epsilon Cable is at the forefront of the energy transition and serves the most demanding utilities to help them strengthen and modernize their power grids.

This release was published on openPR.