How to Access Featured Paper and Presentation of the Month!

You now have the option to read the paper and listen to the conference presentation.

Our Featured Technical Paper and Presentation is from the Proceedings of the 2011 International Conference of Doble Clients. The Paper is called: 500 kV GSU Failure Due to Air Bubble Formation.

Paper Abstract: 

The purpose of this paper is to provide a summary of the results of a failure investigation of a 400 MVA, 512.5/22 kV single-phase Generator Step-Up transformer, and present the recommendations of the investigation. The failure occurrence led to an extensive root cause investigation by Mitsubishi Electric, Dominion, and other industry experts. The findings of the investigation suggested that negative pressure existed within the main tank which resulted in air bubble formation. It was determined that the most likely cause of the negative pressure was an inadequate conservator tank breather system and an extended cooling pump operating time of a few hours prior to energization. This allowed air bubbles to form and collect in the HV bushing turret causing a reduction in the dielectric strength of the oil and led to a voltage breakdown between the 500 kV bushing shield and the bushing turret. Furthermore, there is strong correlation with this transformer failure and those of other catastrophic 500 kV shell form ODAF cooled transformer failures that Dominion experienced in the 1980’s, which were thought to be caused by static electrification but no obvious signs were discovered due to the extent of the damage.

Doble Clients:

If you already have access to the Doble Portal – our on-line Resource Library – this paper and presentation can be found in the 2011 Conference Proceedings. To enter the Portal, click here. 

If you are a Doble client – and you do not currently have access to the Portal - sign up now! 

The Portal is free benefit for Doble Services Agreement Clients.
Clients can send an email to papers@doble.com and we will sign you up for Portal access. Be sure to include your complete contact information in your email. You will receive a reply with your user name and password.

If you are not a Doble Client:

To download the Featured Technical Paper, click here.

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