No Silver Bullets for Power Station Maintenance

Although today we have comprehensive methods for technical testing and sophisticated models for calculating and forecasting component behaviour, many of the defects identified in thermal power stations and process plants in recent years have been the result of inadequate servicing and maintenance. 

The problems in thermal power stations can be attributed to the fact that the ideal maintenance strategy is found only rarely, because stakeholders frequently focus on short-term cost reductions based on methodological approaches. When cost pressures increase, plant managers’ willingness to invest often decreases.

Operating costs may drop when modernisation measures and the acquisition of new equipment are postponed or fail to materialise at all; the operating risks, however, will increase. Stakeholders seeking to counteract this trend must choose the maintenance strategy best fitting the case at hand.

Failure recovery, preventative maintenance, condition-based maintenance, predictive maintenance, risk-based maintenance, reliability-centred maintenance or total productive maintenance – the strategies to choose from are virtually boundless.

However, ”maintenance” can never be equated with ”remediation” and ”repair”. And as the operating performance of every plant is unique, none of the possible approaches can be applied ”as is”, but must be adjusted to the case at hand.

A glance at the applicable standards and regulatory acts also fails to provide a solution. They are applied during manufacturing, before the plant is placed into service and in periodic inspections. But how can we succeed in achieving the right cost-benefit ratio when it comes to maintenance during operation?

Filtering out the Relevant Influencing Factors 

Deterministic approaches in maintenance focus mainly on causal ”if-then relations” based on detailed knowledge of the relevant components. While these approaches have proved their worth from the perspective of safety technology, they have repeatedly resulted in excessive maintenance measures because of the safety factors that must be observed in design.

Probabilistic approaches by contrast add probabilities to these ”if-then relations”. Risks are quantified by their frequency of occurrence and the severity of their consequences, thus enabling experts to prioritise actions and reduce costs. The downside includes uncertainties concerning the quality of the input data, and the high costs and efforts involved in complex events and fault-tree analyses.

A maintenance strategy tailored to the needs of a plant requires systematic knowledge of operations, plant condition and possible defects. Interconnected process equipment, machinery and electrical, instrumentation and control systems in particular are becoming the focus of particular interest.

Maintenance professionals should perform overall analysis to determine the key influencing variables and damage mechanisms. To do so, they combine deterministic and probabilistic tools, non-destructive testing, fracture mechanics and the finite element method. Some of the cracks and defects identified may not need to be repaired provided reliable assessment of their further propagation and behaviour can be made. 

Leadership skills are one of the key success factors in ensuring maintenance is used preventatively to maintain and optimise function. As this type of maintenance requires both ”creativity” and a solution-orientated approach, the engineers in charge must be able to motivate staff while at the same time assume responsibility for risks. They need to establish an organisation that is based on division of labour and characterised by outstanding clarity, consistency, employee appreciation and trust.

tuv

Hans Christian Schröder

TÜV SÜD Industrie Service GmbH,
www.tuev-sued.de/is

Asset Management | 19.5.2016

Latest articles

Neste Engineering Solutions has performed a dynamic simulation for Kiilto Oy

Neste Engineering Solutions has performed a dynamic simulation for Kiilto Oy, a producer of chemical industry products. The purpose of the dynamic simulation was to get a better understanding of how Kiilto's production facility's polymerizing reactor behaves in possible disturbances. The production facility is located in Tampere, Finland.

Asset Management | 31.1.2019

5 Benefits of Using Ticketing Software

Customers are always inclined toward companies that provide quality customer service. This is something that strongly influences the profitability of your business. In case of poor customer experience, they would be less likely to do business with the company once again or convey their negative experience to friends and family discouraging them to patronize your brand.

Cmms | 29.1.2019

Emission-Free, Efficient and Safe: The Future Urban Construction Site

A lot of work lies ahead for the construction industry: According to estimates, by 2050 two thirds of the world's population will live in large cities. At the same time, the industry is about to see massive changes through macro trends such as electric mobility, digitalization and assistance systems.  

HSE | 29.1.2019

Clariant Partners with ExxonMobil and Renewable Energy Group to Advance Cellulosic Biofuel Research

Clariant, a world leader in specialty chemicals, announced that it has signed a joint research agreement with ExxonMobil and Renewable Energy Group (REG) to evaluate the potential use of cellulosic sugars from sources such as agricultural waste and residues to produce biofuel, which has the potential to play a role in reducing greenhouse gas emissions.

R&D | 25.1.2019

Robots Are What We Make Them

At a Belgian factory, the following sign stands next to a gigantic industrial robot: “This machine has no brain. Use your own.”

Applications | 23.1.2019

It’s About “Time”

At Bentley Systems, we have been talking to our users, especially owners, and it has become clear that despite our collective best efforts, there is a gap in the market.  Owners need easy access to real-time, accurate, engineering information and they need tools that make it simple to keep engineering data up-to-date, especially those engaged in brownfield and revamp projects.  It takes too much time and effort to gather and verify the information they need to make decisions effectively. And for older plants that do not have 3D models, there is simply no visual way to verify and check information easily.

Partner Articles | 10.12.2018

Maintenance: A Necessary and Important Function in the Future

Euromaintenance 2016 will take place in Athens at the end of May. It is the ideal moment to reflect on maintenance in a European context. Euromaintenance is known as the summit for all involved in maintenance across Europe, it’s the place to be. The conference, with the support of the EFNMS, is the only commercially independent conference covering the topics we deal with in the maintenance world.

EFNMS | 20.5.2016