Lightning and surge protection for wind turbines

31/01/2022

In recent times you can’t look around without seeing wind turbines near your hometown. Although they seem like rugged well engineered providers of electricity, wind turbines are intricate build machines and there is a lot of protections in place to keep this machine safe. Today we’re going to look at one very important topic regarding the protection of wind turbines, namely lightning and surge protection.

Due to their exposed location and height, wind turbines are vulnerable to the effects of direct lightning strikes. Studies have shown that there’s an average of 10 lightning strikes on wind turbines per year. For this reason, comprehensive lightning and surge protection measures are required.

Image 6* (in the gallery below) shows the tip of one of the wings of a wind turbine. This one specific got stripped of its coatings (either due to bad care or an incident which occurred before these tests). As you can see underneath all the coatings there is a conducting layer of copper to prevent the destruction of these wings. Inside the turbine the wiring continues and gets directed toward the earth. As you can imagine to protect this big turbine these tips and the internal wiring need to be checked frequently to prevent disasters.

In the past few years there isn’t only an increase in the amount being placed, but also how big they are becoming. (in 2010 the wind turbines reached heights of 160m and power of more than 7,5MW. In 2021 the height increased up to 240 meters and counting and power of more than 16MW.) This makes it harder and harder to test the lightning protection.

Image 4* shows a test on the inside of one of the wings of a wind turbine. This one specific is being tested before commissioning it for use. As you can see to perform this test on the inside you need quite the length of testing cable just for one wing. These tests are also performed while the turbine is deployed for example in offshore wind farms.

Our recommendation for the situation

  1. Megger DLRO2 – for a quick handheld indication up to 2A (3-fase measurement possible) and protected for up to 600V for inadvertent live connections without blowing a fuse;
  2. Megger DLRO10 & 100 - High or low output power selection for condition diagnosis for measurements that go above 2 Amps up to 100 Amps;
  3. Megger KC 50C/100C and 50E – test leads on reel for distances up to 100 meters with Kelvin clip function.

Specifically for testing the lightning protection on wind turbines these are our recommendations. Of course there is a lot more within a wind turbine that needs to be tested so it can stay operational. For the readers of this article we’ve added a product portfolio of Megger’s product specifically for wind turbines and their uses.

If you have any questions regarding this article or have an inquiry regarding the displayed products don’t hesitate to contact us through our contact form or by sending an e-mail to info@control-protection.be  


*The images mentioned in the text above can be found in the gallery below. Numbered in order (left to right).

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