---
title: Growing Undersea Infrastructure Redefines Quality Requirements
description: Our factory vulcanized joint know-how provides you with all the needed technology to manufacture factory joints for high voltage subsea XLPE cables.
image: https://blog.maillefer.net/hubfs/Imported_Blog_Media/WindFarm_100dpi.jpg
---

![WindFarm_100dpi](https://blog.maillefer.net/hs-fs/hubfs/Imported_Blog_Media/WindFarm_100dpi.jpg?width=591&name=WindFarm_100dpi.jpg)

Since the early times of extruded high voltage subsea XLPE insulated cables, it has been mandatory to develop reliable in-house solutions for jointing either XLPE or lead extrusion lengths. The manufacturing lengths are connected by so called Factory Vulcanized Joints (FVJ). The factory joints make it possible to proceed with the application of subsequent cable layers in processes not sensitive to restarts after a break.

The development of XLPE subsea cables has been promising during the last 25 years, including progress in material quality, compound handling systems, extrusion technologies and quality control during manufacturing. This progress has led to an increase in the number of installations of high (HV) and extra high voltage (EHV) subsea XLPE cables. In addition, the installation lengths at all voltage levels have also increased during the same time, which makes it clearly important to develop a reliable concept for in-house jointing of subsea cables.

#### Maillefer technology

The technologies attributed to cable manufacturing are available on the open market. While FVJ has been an in-house competence for decades, we have recently developed FVJ specifically for HV AC subsea cables up to 245 kV. The development includes a vulcanization modeling software that optimizes the insulation curing process for joints. This technology is part of the Maillefer Consultation portfolio. Our FVJ know-how provides you with all the needed technology for manufacturing factory joints.

FVJ is an integral part of the whole subsea cable system. For reliability reasons, FVJ is required to have equal performance as the XLPE cable and a low statistical scatter in dielectric strength. Furthermore, an elaborated selection of equipment, consumables, tools, processing parameters, temperature and cross-linking simulations, quality control, and know-how throughout the manufacturing steps are all necessary for a mature technology.

Manufacturing FVJ is similar to the concept of manufacturing a short length of XLPE cable, having equal electrical, thermal and mechanical properties. The principal of FVJ is shown in Figure 1.

![Factory_Joint_001](https://blog.maillefer.net/hs-fs/hubfs/Imported_Blog_Media/Factory_Joint_001.jpg?width=2560&name=Factory_Joint_001.jpg)

*Figure 1. Factory vulcanized joint for HV AC subsea cables.*

#### Quality control

The manufacturing of a Factory Vulcanized Joint along with continuous quality control is divided in five main steps:

- Welding of conductor
- Inner semi-conductive layer restoration and vulcanization
- Insulation restoration and vulcanization
- Outer semi-conductive layer restoration and vulcanization
- Final quality control, e.g. local Partial Discharge (PD) and/or X-ray detection.

For HV and EHV subsea cables, additional steps are commonly found, like the restoration of lead and polymeric sheaths. The temperature distribution during manufacturing must also be simulated in a modeling software, verified and fine-tuned. An example of temperature distribution from a simulation is shown in Figure 2.

![TemperatureDistribution_FVJ_w_Text](https://blog.maillefer.net/hs-fs/hubfs/Imported_Blog_Media/TemperatureDistribution_FVJ_w_Text.jpg?width=3313&name=TemperatureDistribution_FVJ_w_Text.jpg)

*Figure 2. Example of temperature distribution in a factory vulcanized joint.*

Quality control assurance during FVJ manufacturing includes:

- Welding (inclusions, voids), X-ray
- XLPE material cleanliness and handling
- Processing parameters (temperature and pressure vs. time)
- Dimensions, thicknesses and eccentricity.

The design and manufacturing techniques (handcrafting) and quality control of Factory Vulcanized Joints are also essential. By working together with us, you can reach the tight technical requirements within a realistic time frame without sacrificing FVJ quality.

**Timo Mäkelä  
**Process Specialist, MV&HV Cable Solutions  
[timo.makela@maillefer.net](mailto:timo.makela@maillefer.net)

 Topics: [Product quality](https://blog.maillefer.net/tag/product-quality), [Wire & cable manufacturing](https://blog.maillefer.net/tag/wire-cable-manufacturing), [Innovation](https://blog.maillefer.net/tag/innovation)

- [Tweet](https://twitter.com/share)

### Astonishing Curing Calculation for Flexible ...

##### Tags: Solutions, Maillefer, Performance, Value Corner, Novelties & Launches, Wire & cable manufacturing, Innovation

Astonishing Curing Calculation for Flexible Factory Joints Flexible vulcanized joints (FVJ) also known as flexible factory joints are typically used ...

[Read more](https://blog.maillefer.net/-astonishing-curing-calculation)

### Paper about Factory Joints for DC Cable at ...

##### Tags: Extrusion, Wire & cable manufacturing, quality, high voltage, XLPE, subsea cable

Few publications exist and are readily available which treat factory joints in the area of Extra High Voltage DC cable. This paper sheds some light ...

[Read more](https://blog.maillefer.net/paper-about-factory-joints-for-dc-cable-at-jicable-23)

### Run Times Reach New Heights

##### Tags: Uppgrade solutions, Solutions, Maillefer, Performance, Production Capacity, Value Corner, Novelties & Launches, References, Wire & cable manufacturing, Innovation

Run Times Reach New Heights The performance of extruded high voltage XLPE insulated cables is improvable by reducing the degassing burden and ...

[Read more](https://blog.maillefer.net/-value-corner-runtime-newheights)

```json
{
  "@context" : "http://schema.org",
  "@type" : "BlogPosting",
  "author" : {
    "@type" : "Person",
    "name" : "Timo Mäkelä"
  },
  "dateModified" : "July 13, 2022, 6:20:37 AM",
  "datePublished" : "2017-07-26 04:00:00",
  "headline" : "Growing Undersea Infrastructure Redefines Quality Requirements",
  "image" : {
    "@type" : "ImageObject",
    "url" : "https://info.davis-standard.com/hubfs/Imported_Blog_Media/WindFarm_100dpi.jpg"
  },
  "mainEntityOfPage" : {
    "@id" : "https://blog.maillefer.net/growing-undersea-infrastructure-redefines-quality-requirements",
    "@type" : "WebPage",
    "description" : "Our factory vulcanized joint know-how provides you with all the needed technology to manufacture factory joints for high voltage subsea XLPE cables."
  },
  "publisher" : {
    "@type" : "Organization",
    "address" : {
      "@type" : "PostalAddress",
      "addressCountry" : "United States",
      "addressLocality" : "Pawcatuck",
      "addressRegion" : "CT",
      "postalCode" : "06378",
      "streetAddress" : "1 Extrusion Drive "
    },
    "alternateName" : "Davis-Standard",
    "description" : "We help wire, cable, pipe and tube manufacturers to exceed their goals.",
    "email" : "info.finland@maillefer.net",
    "image" : {
      "@type" : "ImageObject",
      "url" : "https://info.davis-standard.com/hubfs/Imported_Blog_Media/WindFarm_100dpi.jpg"
    },
    "logo" : {
      "@type" : "ImageObject",
      "url" : "https://info.davis-standard.com/hubfs/Maillefer_Davis-Standard_Integration_Logo_vertical_CS6-RGB.jpg"
    },
    "name" : "Maillefer",
    "sameAs" : [ "https://www.linkedin.com/company/maillefer-extrusion-oy", "https://twitter.com/MailleferGroup" ],
    "telephone" : "844-693-2847",
    "url" : "https://www.maillefer.net"
  }
}
```