As the wind turbine industry grows, routine NDT inspection of turbines is increasingly important.

Introduction

Concerns about the environment have led to increased interest in the safer, renewable energy source of wind energy. As the wind turbine industry grows, reliable surveillance of turbines is increasingly important. Routine inspection reveals flaws in turbine structural parts before a major accident, and it also ensures that turbines are running at maximum potential. Wind turbine blades must be scrutinized the most by inspectors, because blade failure will result in costly repairs and a total operation shutdown. Various non-destructive testing methods can be performed on wind turbine blades. These methods include ultrasonic testing and eddy current testing.

Ultrasonic Testing on Wind Turbines

Ultrasonic testing is a common method for inspecting wind turbine blades. Ultrasonic testing devices are lightweight and do not require hazardous source materials. Specialized ultrasonic testing methods, such as phased array ultrasonic testing (PAUT), have more testing parameters and produce more detailed results than conventional ultrasonic testing. In addition, PAUT allows technicians to tilt the wavelength in multiple directions, while conventional ultrasonic testing only produces a fixed transmit position.



Flexible testing methods are particularly important for wind turbines as the geometries of the blades and other components of the turbines have irregular surfaces and geometries. Blades in particular usually have composite materials and thick damping which can make inspection difficult. Materials that may be present inside the turbine blade include:

Fiberglass

Resin

Steel

Aluminum

Iron

Eddy Current Testing on Wind Turbines

Eddy current testing (ET) is another popular non-destructive testing method for wind turbines. ET can be used to detect surface and near-surface flaws. Eddy current testing, like ultrasonic testing, does not require the use of hazardous materials or a constant electrical power source. ET instruments are incredibly lightweight and portable.

For turbines, the specialized method eddy current array testing (ECA) has some advantages over conventional eddy current technology. For example, ECA can scan welds composed of complex geometries and material types. Eddy current array testing also offers advantages such as: For turbines, the specialized method eddy current array testing (ECA) has some advantages over conventional eddy current technology. For example, ECA can scan welds composed of complex geometries and material types. Eddy current array testing also offers advantages such as:

Touchscreen interfacing

Intelligent software

Multi-coil probing

Conclusion

The lightweight, portable, and low-energy characteristics of ultrasonic testing and eddy current testing make them reliable NDT methods for wind turbine inspection. Both methods can detect smaller flaws more readily than other NDT methods and instruments. Specialized testing methods such as phased array and eddy current array can scan unconventional shapes and mixed material structures. These testing methods can also be performed relatively quickly. All these advantages mean that turbine NDT technicians can get quality results in less time, and this ensures that wind turbines stay operational.

Works Cited



NDT Product Department: Zetec. (2019, November 20). Wind Turbine Nondestructive Testing: What You Need to Know. Retrieved March 10, 2020, from https://www.zetec.com/blog/wind-turbine-nondestructive-testing-what-you-need-to-know/