Let’s get connected

Sometimes seen as the weak link in the system, subsea connectors have come a long way. With new challenges, larger throughput requirements, new materials and methods this is an ever-evolving technology, says Hydro Group Systems’ Bill Mildon.

Cable end preparation – prior to termination. Photo from Hydro Group Systems.

Subsea electrical and optical systems connection has been developed from decades of research and development, looking for cost savings, performance enhancements and ways to address environmental challenges.

Engineers and scientists have been supporting military operations and pushing oil and gas activities deeper, farther and faster. This in turn has helped the telecom industry maximize throughput of data, reduce downtime and lower the cost of systems at sea.

All such developments must include connections to communicate, supply power and monitor status. These connections have also evolved and are being made from new materials for new environments and new system requirements. In many cases the connector industry is trying to keep up with the system advances and, in some cases, is even getting ahead of the market need.

However, as metal, plastic and new exotic material housings improved, so did system requirements, with a desire for more data or power conductors in the connectors. This then drove the need for smaller conductors and higher-density connectors with acceptable dielectric materials.

On-site splicing of fiber optic terminations. Photo from Hydro Group.

As engineers worked on materials to house the epoxy – rubber, glass to metal seals or plastics inserts –we found that the increased power capability and huge increase in data transfer capability is critical in the progress of undersea systems. This new ability, to power larger systems and multiple systems with one input cable and connector plus the ability to add more sensors, is smarter and can handle faster data rates and increased bandwidth requirements.

But, each new development has its own set of problems, in one market or another, such as the military with concern over the submarine safety. Such problems led to the need for specific guidelines for designers and manufacturers of connectors to develop qualification testing to ensure specified requirements were met not only in performance and environmental testing, but material certification tests too. Products were now required to be “qualified” to a specification.

A subset of this trend is in fiber optic components, which we’re seeing being continuously developed for use with increasing bandwidth in data and faster speeds to get data from point to point. As the components and systems are developed, the interconnection is also modified to attach elements of the system together.

Subsea electrical umbilical termination unitcoaxial and electrical connector.

The fiber challenge was very difficult in the beginning and is still a stubborn medium today. It has enabled faster data transfer speeds, from kbits/sec to Tbits/sec, reduces cable size and weight, greatly reduces the number of repeaters required to carry the signal long distances and has little or no impact from interferences.

But, with ever deeper water requirements, explosive shock critical material needs and harsher environmental conditions to be met, each day is like the first in developing these new connectors for fiber systems. We are constantly working on the capability to tighten tolerances for superior alignment of the fiber termini and to reduce data loss, as well as techniques to polish the fiber without changing the characteristics of the light path. In the first systems, the insertion loss for a termini was in the 3dB (decibel) range and now we can achieve less than one tenth of a dB in loss.

Materials such as high density plastics and ceramics have been introduced to improve performance in the connector shell and termini alignment. What will be the next new material to allow smaller fiber termini? How many fibers can we put into one connector and perform to the requirements? When will we find the solution to using fiber for power efficiently? These and many other questions are being asked daily, as technology moves forward for the subsea market.

Subsea turbine – medium voltage termination.

But, with a seabed filled with dry mate connectors, wet mate connectors, electrical and optical connectors, there’s another broader goal: to develop this technology for multipurpose use across an array of projects, and to make them far more reliable, while reducing costs.

This will again mean new technology requirements. In some cases, it is viable to use induction coils for power connections and with some power levels we can also transfer data on the power line without the use of a connector – this technology is one that is in use and in continuous development.

The use of acoustic data transmission from subsea components in some systems eliminates the need for connectors and will be looked at for many systems once the data rates can be achieved at a much higher level than they are today. But, the frequency range and distance limitations are a challenge, and the fact the signal is transmitted, which can be detected by others, is a potential security problem.

Hybrid coaxial and electrical connector.

Some of the latest technologies include radio frequency signals and Wi-Fi transmission over very short distances between subsea connectors, and they offer some promise.

As in the past, there will be challenges along the way. In the past, some have not met performance expectations, there have been design errors, manufacturing flaws and some anomalies resulting in failure and/or catastrophic failure. Nonetheless, there are many submarines, oil and gas systems, telecom systems and oceanographic systems in use with no connector failures or limited connector failures worldwide.

All in all, connectors are currently the best solution for subsea connections, be it dry mate or wet mate. Whether the solutions for the new challenges we face look or act like a connector, as we know it today, is a different matter, but it will still play the same role in connecting subsea components.

To achieve our goals, communication between engineers, system designers, project managers and program offices is crucial. Connectors should be considered in the initial design stage and not as an afterthought when completing the system.

It is possible the connector can be bought off the shelf, just as it is possible that it will need to be developed or modified to meet specific system requirements. But, there is positive progress being made in this bespoke technology and it will continue.

William (Bill) Mildon is president of Hydro Group Systems in Pinellas County, Florida, a subsidiary of UK-based Hydro Group. Bill has held a number of senior positions, most recently as technical director at Nest Technical Services. He has lead teams in submarine penetration designs, under water connectors and numerous fiber optic inter-connect products.