WIND & ENERGY
Wind turbines are subject to extreme loads throughout their lives. This is partly due to the structure of the turbines themselves – for example, the turbine blades and tower are only fixed at one end of the structure. As the wind speed increases, so do the loads the turbines are subjected to. This can reach levels almost 100 times greater than the design loads at rated wind speed, which is why many turbines are designed to shut down to protect themselves at higher wind speeds, however it is also one of the main reasons to carry out Inspections.
As a moving component, the rotor blades are subject to higher levels of loading and fatigue which has the potential to lead to crack formation. Welds and fastenings such as bolts are also prone to the presence of cracking and / or corrosion / erosion. Wind turbines also suffer damage from birds or other objects striking them as well as the impact of high wind speeds or lightning strikes. SONOMATIC NDT techniques are designed to detect all forms of fatigue associated defects as well as corrosion / erosion.
Whenever possible the presence of any defect will be confirmed using one or more NDT techniques. SONOMATIC fully reports on the type, size and position of any defect and with appropriate approvals and dependent on the defect type, SONOMATIC may be able to do an immediate repair, examples of our abilities in repairs include fiberglass blade repair of H-cracks, knuckle cracks, nose cone repair, lightning, ice and wildlife impact damage. SONOMATIC report any defects using our bespoke cloud-based e-reporting system.
If the defect is confirmed as within the acceptable tolerance levels, SONOMATIC will advise on NDT techniques to monitor the propagation over a set period of time.
When Should Wind Turbines Be Inspected?
Wind turbines generally require some form of inspection between two to three times per year. Whenever there are concerns for any structure based around fatigue failure from use over the lifespan of the asset, inspection should be carried out. The frequency of inspection is primarily dependent on environmental conditions including average wind speeds and turbulence intensities. Types of inspection can range from visual inspection to the use of more advanced NDT techniques to assure the structural integrity of the wind turbine.
Alternating Current Field Measurement (ACFM)
Alternating Current Field Measurement (ACFM) is an electromagnetic technique used for the detection and sizing of surface breaking cracks in metallic components and welds. It combines the advantages of the alternating current potential drop (ACPD) technique and Eddy Current Testing (ECT) in terms of defect sizing without calibration and ability to work without electrical contact respectively. Eddyfi® TSC Amigo2 ACFM system is engineered around a highly advanced signal acquisition and processing system able to process data significantly faster than the original Amigo, for a data range that’s 14 times better. This allows SONOMATIC to define smoother, higher resolution indications that increase the detectability of small defects and the coating thickness through which you can inspect. Wind Turbines inevitably go through challenging life-cycles causing deterioration and end up costing wind farm operators an extortionate amount of money to fix and in many cases instigating them to start all over again from scratch. Decommissioning or conducting major renovations are expensive paths to go down, as is operating a turbine below peak performance causing high costs and inefficiencies. To ensure a healthy life-cycle, it’s important that wind turbines are regularly inspected and maintained for as long as they are in operation. SONOMATIC'S team of highly trained technicians provide ACFM and Phased Array Bolt Inspections for wind turbines and their component parts during multiple stages of their life-cycle to ensure the best performance and minimal costs for the operators.
Phased Array Inspection
Phased Array (PAUT) is an advanced method of ultrasonic testing that has applications in medical imaging and industrial testing. When applied to metals the PAUT image shows a slice view that may reveal defects hidden inside a structure or component. SONOMATIC offers Phased Array Bolt Inspection using state of the art technology covering a wide range of applications from corrosion mapping to crack detection and characterization in welded pipes and plates, and can handle thick components, detect and characterise mis oriented defects. Bolt Inspection using the PAUT, with large-aperture probes 16-32 element channels, provides high capability of crack detection in bolts, thread or neck with live scans and screenshots. We are capable of detecting cracks in bolts at a very high capability and cover 100% of the bolt up to 1200mm.
Key Benefits of Wind Turbine Inspection Throughout the Life Cycle.
- Identify Areas of Concern, such as fatigue cracks, corrosion / erosion failure
- Extension to Lifespan of Wind Turbine Asset
- Accident Prevention
- Increased Asset Reliability
- Less Non-Productive time for Asset
- Maximise confidence, minimise costs, reduce risk.