Page 62: of Offshore Engineer Magazine (Apr/May 2013)

61 63

Subsea

Figure 1. The DTS was installed during 2012 and was commissioned last October. in Ireland, it includes an optical amplifer. The

HVDC cable is in black and the DTS system is in red.

distances. No electrical power is about 278km long. Sensa is the mechanical parts; it simply transfers used around the measurement zone; inventor of DTS technology and light from a donor fber to the signal therefore they are intrinsically safe. has been designing, manufacturing, fber, thereby boosting the signal.

The fber is a practical and robust and supplying systems to power The amplifer itself is compact, material that can be installed to transmission and distribution with dimensions similar to a DVD measure temperature in a wide markets worldwide since 1991. disc. Two optical fbers enter the variety of locations. For the East-West Interconnector, amplifer and one fber leaves. the company deployed its Sensa The amplifer had previously only

Cable between Ireland and Wales Prime integrated long-range power been supplied by Sensa for use in

Ireland is currently taking some cable monitoring system for monitoring oil and gas pipelines, of its older coal-burning power temperature and strain to provide a but the experience gained in the stations offine. A subsea cable has temperature reading at 2m intervals oilfeld proved to be transferrable to been installed to allow the country all along the cable, which is a much this commercial power transmission to purchase base-load power from fner sampling interval than can project.

the UK. Additionally, when local practically be achieved with classic Specifc requirements for weather conditions lead to one or temperature probes. monitoring the East-West the other country producing an The maximum measurement Interconnector included storing excess of renewable energy, it will range of a single-fber optics DTS three months of hourly cable be possible to sell that energy to the system is currently about 50km. temperature measurements taken at other country. On the Irish side, ABB wanted 2m intervals along the route. Graphs ABB Sweden was awarded a the DTS control hardware to be of the cable temperature profle turnkey contract by EirGrid, operator within an electrical substation can be plotted for any given set of of Ireland’s national electricity grid, located 45km inland and to be able readings. The DTS can be remotely to supply and install the high- to measure the temperature of the programmed and interrogated. The voltage, direct-current (HVDC) cable for a further 25km subsea system, which is self-monitoring, power cable between Ireland and from the shoreline. This would was successfully designed and

Wales. Known as the East-West mean a single measurement length installed, and was commissioned in

Interconnector, this underground of 70km, which was beyond the October 2012 (Figure 1).

and undersea link has the capacity range of a normal DTS system. The The DTS system provides the 3D to transport 500MW – enough energy solution from Sensa was to include function of temperature, distance, to power 300,000 homes. ABB an optical amplifer that extended and time. The actual temperature asked Sensa to provide a solution the range of the DTS system by the data of the East-West Interconnector to monitor temperature at critical required 20km. cable is confdential, so the example points along the cable, which is The amplifer has no electrical or DTS data presented in this article

OE | April 2013 oedigital.com 64 oe_subseaSCHLUM_v2_single pages.indd 64 4/1/13 2:18 AM