Remote CP Monitoring Assists Gas Distribution Company

A UK gas utility has implemented a remote CP monitoring system to help it improve pipeline protection and workforce efficiency. Wales & West Utilities (WWU) is an independent gas distribution business in the UK. It owns, operates, maintains and develops the gas network throughout Wales and southwest England, serving 7.5 million people. Its total length of pipeline network is 35,000 km.

WWU strives for excellence as recognized by its awards and levels of investment. In 2008 it was voted the gas industry’s “Network Operator of the Year” and received the industry’s “Award for Customer Services” in 2009 and 2010. In 2010, it was voted Utility Company of the Year by the Utility Industry Awards. Since 2005 it has invested £50m in information technology and - in the current price review period (2008-2013) - over £2m per week is being spent on improving assets and asset management.

As part of this improvement project, it was decided to implement remote monitoring of WWU’s impressed current cathodic protection system. This article outlines our experiences; we do not say that this is the only or best way but hope that the benefits and lessons learned will assist other gas utilities in their decision-making process.

Objectives
Previous experiences of monitoring CP remotely had proved unsatisfactory for a variety of reasons: 1) The earliest remote monitors had been installed using fixed PSTN phone lines which had become prohibitively expensive to operate and maintain; 2) Some transformer rectifiers in remote areas had been fitted with beacons that flashed in the event of a failure. In principle, these could be observed during aerial surveys; in practice the beacons were themselves unreliable and adverse weather conditions meant that faults could go undetected for prolonged periods; and 3) More recently, remote monitors had been used that were originally developed for other applications and modified for CP. However, they were limited to a single potential measurement and did not interface with the company’s asset management software.

The company’s requirement was for a cost-effective remote CP monitoring system that could 1) provide monitoring at transformer rectifiers and test posts, 2) switch the output of the rectifiers and 3) export CP data directly into the company’s asset management software. Apart from eliminating the manpower used to record measurements, it was felt that the system would greatly improve asset management by providing prompt notification of rectifier and CP faults. It would also make better use of the workforce by diverting their energies from simply monitoring the CP system into repairing and improving it.

System Selection And Financial Justification
Having assessed a number of supplier options and their specifications, the company identified the Merlin system, developed by Abriox, as the one that could completely meet its requirements.

The Merlin system comprised different monitor types, for installation at rectifiers and at test points, together with user software that enabled the pipeline engineer to quickly identify any alarms or deficient measurements. WWU carried out a trial of the system to confirm its suitability, following which a financial case was prepared for the project roll-out.