Risky business

Don't be fooled into believing that Condition Based Risk Management (CBRM) is just another bit of industry jargon or management theory. The fact is that CBRM has already changed the way UK electricity network companies maintain and replace their assets. And it's rapidly taking root across the world, in industries from petrochemicals to food processing.

"CBRM is a radically new way of managing assets - and as with all changes, there will be winners and losers within the industry as a result," according to Dave Russell of power engineering solutions provider EA Technology, which developed the process in conjunction with several major UK electricity operators.

"There are tremendous business opportunities for contractors who are prepared to embrace the potential of CBRM. Those who ignore it are in danger of being left behind," he warned.

CBRM is now a fully integrated management process. Data about the present condition of assets is collected, then interpreted in the light of detailed knowledge of how similar assets perform and degrade over time. This enables the production of a health index for each asset, which gives an accurate indication of its probability of failure.

The consequences of failure and options for intervention (replacement, refurbishment and maintenance) are then factored in to produce a model of the risks of failure (lost production, cost, injury etc.). This provides all the information managers need to decide how and when to apply maintenance interventions or replace assets.

Less is more

"CBRM means inspecting more and maintaining less. It also means the service life of assets can be extended considerably," Russell explained. "The implications for asset owners are far reaching. They benefit from lower operating costs, lower costs of renewing capital equipment and the ability to make more intelligent investment decisions.

"Reducing the frequency of invasive maintenance also pays dividends in terms of improved reliability and safety, because maintenance procedures commonly result in new faults - and fewer shutdowns ensure that production is uninterrupted."

CBRM has been made possible by significant advances in non-invasive techniques for collecting data about the actual condition of transformers, switchgear, cables etc. At the same time, knowledge of degradation and failure processes, built up over 40 years, has enabled the data to be translated into powerful management information.

"Combining condition monitoring data from a specific asset with records of failure and degradation patterns for assets of that type means that we can produce a highly accurate prediction of its probability of failure, the point at which it will next require active maintenance and the length of its remaining service life," said Russell.

"With CBRM, each asset is given a health index rating that is updated during subsequent inspections and provides the basis for decisions on when to maintain or replace it.

"Groups of assets can be treated in the same way. So, for example, in the case of a set of identical switches in identical operating conditions, we only need to monitor and interpret the data from a representative sample. The results can then be applied to all of them."

CBRM also gives managers important new abilities to prioritise maintenance and replacement, because it factors in both the risk and consequences of the failure of each asset. For example, a switch or transformer that is essential for the operation of a critical process is accorded a higher priority than an asset in a non-critical application.

"The benefit of implementing CBRM fully is that owners have the advantages of an integrated management system, which enables them to maintain or improve the reliability and performance of their assets, while at the same time reducing their maintenance and capital renewal costs. A classic win-win solution," stated Russell.

Electric avenues

Not surprisingly, given the regulatory pressures on them to improve network performance while containing costs, UK electricity companies have been the first to adopt CBRM. They have been followed by petrochemicals operators with large electricity assets, such as Shell and BP - and now it is being taken up by everyone from Far East network operators to international manufacturers.

Far from signalling a reduction in business for contractors involved in providing conventional periodic maintenance services, or installing replacement assets, Russell believes CBRM is a new opportunity for them.

"Larger contractors in particular should embrace the potential to offer their clients CBRM packages, including long-term management of assets. They can also provide a wide range of added value services by employing the techniques which have made CBRM possible," he urged.

Foremost among these techniques is the recent availability of a comprehensive range of tools for detecting, monitoring and locating partial discharge activity in high voltage assets. Although partial discharges have long been recognised as an indication of the deterioration of assets, they have assumed far greater importance during the development of CBRM.

The facility to measure accurately the scale, location and frequency of partial discharge (PD) activity has become one of the most useful methods for gathering data about many hv assets. When interpreted in the light of known patterns of degradation and failure, it provides the basis for a detailed assessment of their true condition and predictions of their future performance.

"The growth of the market in PD equipment and the services it enables people to provide is remarkable," said Russell. "PD techniques have developed from providing simple fault diagnostics on individual assets, to enabling comprehensive surveys of the condition of whole plants and networks. Once operators realise the quality and quantity of information that PD investigations can supply, it's a short step for them to buy into complete CBRM solutions," he added.

Product placement

Advances in PD products have made them far more affordable to deploy, as well as more flexible in their range of applications. For example, EA Technology has developed the world's first partial discharge activity detector to employ both transient earth voltage (TEV) and ultrasonic sensors in a handheld unit little bigger than a TV remote control. Gone are the days when PD detection equipment was so big and expensive that it was only suitable for fixed installations.

Called UltraTEV, the unit gives an instantaneous reading of the presence of partial discharge activity, at threshold levels which indicate the need for further investigation and/or that it is not safe for personnel to approach the asset. It is so effective as both a ‘first warning' PD detector and personal safety device that Irish electricity company ESB has issued UltraTEVs to every one of its engineers and several UK operators are in the process of doing the same.

PD products now range from portable units for locating and measuring individual faults, to semi-permanent equipment sets for long-term monitoring of the condition of complex installations, with automatic reporting of data for analysis.

Other non-invasive condition monitoring technologies are also coming onstream rapidly, including live tank oil sampling, which has made it possible to take samples safely from live oil-filled high voltage assets, including switches and transformers. As with investigating patterns of partial discharge activity, analysis of oil provides a highly accurate picture of the present condition of the asset and the ability to predict its future performance.

"Understanding condition is the future of asset maintenance," concluded Russell. "Clients all over the world are waking up to the benefits it can deliver, and it's time contractors did too."

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