Partial Discharge Testing on Wind Park Transformers

Large-scale wind parks utilize different types of transformers in one installation. A typical wind farm electrical installation includes several small transformers, such as generation transformers, connecting single wind turbines to a main bus feeder. Several feeders then connect the substation to the power grid using one or more larger power transformers.

Problems can develop in the insulation system of these transformers due to a wide variety of factors. Consequently, periodic diagnostic condition assessment is requested more frequently by wind park operators, as failures cause increasing outage costs for repairs and, in the worst case, undelivered energy.

Reducing the risk of in-service failure

The most common reason for failure in these transformers, including cast-resin transformers used in wind turbines, is the electric breakdown of the insulation. Therefore, performing off-line partial discharge (PD) measurements during commissioning and in a periodic maintenance plan can reduce the risk of in-service failures.

Measurement challenges

However, the application of typical diagnostic tools on cast-resin transformers is very limited due to the specifics of their molded, air-cooled windings. In addition, the logistics of performing onsite PD measurements on cast-resin transformers installed n the constricted spaces of wind park turbines can be quite challenging. Lastly, high electromagnetic interferences, or noise, in the surrounding area can affect the ability to reliably detect harmful PD activity, which is necessary to make a proper assessment of insulation condition.

Two of our PD experts, Dr. Alex Kraetge and Christoph Engelen, have direct experience with the on-site PD testing of transformers in wind parks. In particular, they are keenly aware of the particular challenges when performing PD measurements on cast-resin transformers. In our recent Energy Talks podcast interview, they highlight how these challenges can be overcome with the right diagnostic tools, such as our MPD 800 universal PD measurement and analysis system.

Listen to our podcast

(Length: 40:47)

In this episode of Energy Talks, you will learn more about how to reliably perform on-site PD measurements on cast-resin transformers in wind park turbines despite the challenges faced in the measurement environment with the help of our experts - Dr. Alex Kraetge and Christoph Engelen.

Energy Talks features various episodes related to power system testing. You can find all episodes on our podcast landing page.

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