1 October 2019

Behind the scenes @ Weidmann - World’s largest Shield Rings

The world’s largest transformers demand the world’s largest components. At high voltages, especially in HVDC projects, the quality of components and adherence to strict tolerances is also essential.

Weidmann manufacture the world’s largest Shield Rings at both European and American facilities. But how are these constructed? And how are such large components shipped safely and securely to our customers? Let us take you behind the scenes at Weidmann.

Shield Rings are designed to handle the highest voltages in today’s energy transmission network. The first notable jump in ring size and voltage rating dates back to 1992 with the development of HVDC projects. Initially, the largest transformers required rings of up to 2.0 meters. Today we deliver rings of up to 3.75 meters for 1,100 kV DC projects. Our engineering services group validate and verify design requirements to ensure we produce and deliver components in line with the needs of our customers.

Weidmann use a range of our products to manufacture Shield Rings, including Transformerboard, Crepe Paper, Lahnband (copper or aluminum wrap), along with carbo epoxy coating as required. Special treatments are available for tropical destinations with high humidity to prevent additional moisture absorption.

The rings are manufactured by a combination of hand and automated machinery. The process is overseen by a production expert who continually checks and measures dimensions and readings to ensure the component is in line with the strict tolerances required by our customers.

Production operative, Robert Šicl, commented “Manufacturing the rings is not the challenge. Rather it is ensuring that they are within the customers required tolerances. In addition to our standard quality procedures, we have processes in place to check the tolerance throughout the production stage. The next challenge is moving them around. We have specific handling equipment, for example fork lift trucks that are capable of moving large products. Importantly, to protect our employees we have strict health and safety procedures in place for the correct handling of such products”.

But manufacturing such large components is not the only challenge. We then have to safely deliver them to our customers in the same condition they leave the factory.

Due to the size and shape of our Shield Rings, we developed a customized shipping crate that allows them to be securely loaded onto a standard European semi-trailer (length 13.6 m x width 2.45 m x height 2.45 m). The rings are packaged securely to protect them from weather and damage whilst in transit, and inserted into their custom crates at an angle of approximately 40 degrees. Once secured on the truck, they begin their journey. This journey often covers more than half the globe until they reach their final destination. Destined for a lifetime of operation in one of the world’s largest power transformers.

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