Construction inspections of wind farm foundations – how to easily generate savings in the on-going operation of a wind farm.

08/03/2021

Every Wind Farm Manager knows what wind farm management is about. In this article we will try to focus on less obvious aspects, such as random and unforeseen costs related to foundation repairs. Let’s stop for a little while with the words “random and unforeseen” – or, is that for sure?

Foundations are not the focus of attention among daily duties of a wind park manager. Wind analyses, adequate productivity, minimizing technical interruptions – these are the key issues. It is a common belief that if there is no water in the foundation or serious cracks on its surface, everything is just fine. If we don’t see the problem, it means there is no problem. The annual building inspections often come down to formal fulfilment of the building law obligation, at best in the form of a superficial visual inspection by engineers who are not necessarily experienced in a specific subject matter. 

Inspections of wind farm foundations – common problems with wind foundations

As we know, the foundations of wind turbines are one of the most complex engineering structures due to their intensive dynamic and recurring impacts.During the life of the wind park, the foundation carries up to several million load cycles resulting from the changing force and direction of wind gusts.

What are the most common symptoms of foundation problems?

·      water in the tower basement

·      concrete spalling

·      scratches on the foundation

·      floor loosening

·      wall dampness and fungus

·      corrosion on steel parts

·      washed out laitance

·      high strength mortar cracking

·      leaky insulation

·      tower movements against the foundation

·      cracked or sunken foundation embankment

Problems with the foundations almost never arise overnight. They are the result of slow escalation, crushing, emerging water, impact of forces and many other factors. A simple comparison to teeth can be used. Despite daily care and cleaning, systematic dental inspections remain a separate issue. A dentist appointment takes place when there is pain. The more urgent the pain is, the more pressing the dentist appointment’s date becomes. However, if we do not react quickly enough, the problem intensifies and its elimination means root canal treatment. Unfortunately for us, much more expensive and longer. However, if we went to a specialist twice a year for an ordinary check-up, we would probably end up with a quick detection of the appearing decay, almost painless and cheap removal of it, during one short appointment.

This analogy reflects the specific nature of the foundations. The first symptoms of defects are almost imperceptible to an untrained eye. Correct recognition thereof requires knowledge, experience and awareness of how the foundation works. 

Wind farm fondations inspections and repairs: How to generate savings?

The simple truth is:

The faster the defect is detected, the cheaper the repair. It also means a shorter period of the tower shut-down. Unfortunately, it often happens that a defect detected too late generates very significant financial outlays on its removal. The key to minimising the risk of unforeseen and random expenditure is a professional, annual inspection.

What should its scope be?

• Visual assessment of the technical condition of external foundations,
• Visual assessment of the technical condition of the foundations from the inside together with the inspection of the tower basement,
• Technical report together with photo documentation and recommendations.

 The photo report is extremely important in the context of a year-on-year comparative analysis of the state of the foundations and possibly a progressive failure in the context of planning countermeasures.

• Assessment of the efficiency of the fire protection system
• Assessment of the condition of technical elements of the tower (platforms, ladders, supporting elements)
• Visual assessment of the condition of tower segment connections, tower Shell

Only such a scope fulfils the scope of the annual building inspection beyond doubt

Additional electrical components, which we recommend to perform due to the requirements of insurers when paying compensation in case of fire or lightning include:

• Measurement of the foundation’s resistance to earth
• Visual inspection of the electrical system with protocol
• Visual inspection of lightning protection and earthing systems with protocol

To sum up, professionally conducted wind farm foundation constraction inspections are not only required by the Building Law, but most of all they are necessary to detect defects at the earliest possible stage.

 Seemingly harmless scratches on concrete can result in a major overhaul and expensive, unforeseen repair after the winter season. This can really be avoided by intervening early enough! The first symptoms of failure are often almost invisible and can be properly recognized by specialists in the design and repair of detail-sensitive foundations. In our opinion, only the combination of these two aspects in the experience of one company enables a comprehensive assessment of the technical condition.

Write to us: Office@gp-renewables.energy and ask for a service: Wind farm Foundation Maintenance Services (FMS)

It is a professional and dedicated service ensuring the safety of foundations and meeting the insurers’ requirements. FMS minimises the risk of unexpected and costly repairs of wind farm foundations and is the only annual wind foundation inspection carried out by foundation design and repair experts required by the building law.

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