Telecom Electric Limited

{{unreferenced, date=February 2020 Telecom Electric Limited began life as a small project within the

National Grid plc National Grid plc is a British multinational electricity and gas utility company headquartered in London, England. Its principal activities are in the United Kingdom, where it owns and operates electricity and natural gas transmission networks ...

to determine the feasibility of running suspended

optical fibre An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to ...

cables across the pylons of the high voltage power distribution network owned by the company. Three principal techniques were considered: # Optical Ground Wire (

OPGW An optical ground wire (also known as an OPGW or, in the IEEE standard, an optical fiber composite Ground wire (transmission line), overhead ground wire) is a type of cable that is used in overhead power lines. Such cable combines the functions of ...

), which replaced the earth wire that runs across the top of the pylons with a new cable that contained a tubular core in which up to 24 optical fibres could be placed. However this option was expensive to implement as it would mean writing off the capital value of the old earth cable many years before it was due to be replaced as part of the normal operation and maintenance cycle. Installation was also very expensive and methods to reduce costs in this area needed to be developed. # Wrapped Fibre (WF), which involved a new technique of taking a variant of underground cable and wrapping it in a spiral fashion around the earth wire. A specially adapted machine was designed for the job to that made installation cost-effective. The challenge for the company however was how to protect the fibres in the cable from damage caused by

starlings Starlings are small to medium-sized passerine birds in the family Sturnidae. The Sturnidae are named for the genus ''Sturnus'', which in turn comes from the Latin word for starling, ''sturnus''. Many Asian species, particularly the larger ones, ...

pecking at the cable sheath, which split open the cable exposing the fibres to water which would affect the optical transmission properties. # All Dielectric Self Supporting (ADSS) Cable, which consisted of non-metallic suspension components and was already used on low voltage power distribution networks in various parts of the world. However, it was found that at 275 kV and 400 kV, the voltages used on the National Grid infrastructure, the electromagnetic fields from the power cables were sufficient to induce microsparks inside the cable that degraded the dielectric materials causing the cable to fail and collapse. Following various trials, cost-effective installation methods were developed for OPGW and the starling problem was resolved, but no solution was found at that time for the ADSS deterioration problem. These changes made it possible to install a nationwide network within the budget constraints set for the project and approval was given to start. The other technical issues to resolve was what type of optical transmission equipment to use. A few years before a new standard for optical transmission systems called

Synchronous Digital Hierarchy Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diode ...

(SDH) had been developed and ratified as a global standard as a replacement for existing

Plesiochronous Digital Hierarchy The plesiochronous digital hierarchy (PDH) is a technology used in telecommunications networks to transport large quantities of data over digital transport equipment such as fibre optic and microwave radio systems. The term ''plesiochronous'' is ...

(PDH) equipment. As the Telecom Electric Project started manufacturers had started releasing SDH products onto the market and Russ Taylor, the SDH specialist in the TE team, after researching the UK SDH suppliers, recommended the project implement an all SDH network. This was a bold step at the time, but his research showed that with the right combination of suppliers, it was not only feasible, but would lead to a more efficient network with lower operating costs than the previous PDH products widely used and much more effective than starting with PDH and migrating to SDH over time. The team reviewed the research material and recommended to the newly appointed CEO David Dey, that

Nortel Networks Nortel Networks Corporation (Nortel), formerly Northern Telecom Limited, was a Canadian multinational telecommunications and data networking equipment manufacturer headquartered in Ottawa, Ontario, Canada. It was founded in Montreal, Quebec, ...

and GPT be selected as suppliers.

were selected to provide the core backbone SDH systems and GPT the edge access systems for SDH-PDH interfacing with the customer. The decision led what was to become Energis Communications Limited to be the first UK operator install an all-SDH network capable of providing a fully synchronous connection to any customer. This unique selling point was a key differentiator in the marketing strategy for the first five years of operation of the business. Telecommunications companies of the United Kingdom