In late 2022, CONDIS embarked on the journey to break several of its internal records and achieve a world first. The company won the tender to produce an 800kV Low Power Voltage Transformer (LPVT), more specifically a Resistive Capacitive Divider.
This mini-series takes you through the various stages in the design and construction of the 800kV from the perspective of the different people involved in the project. In this third and final chapter, Julien Rihani, Product Manager, and Minh Duc Vo, Lead Test Engineer, answered our questions about the testing phase.
What were the biggest challenges you had to face during the tests?
Julien Rihani: “The testing process presented numerous challenges. The primary difficulty involved handling the various devices under test (DUTs), each exceeding 700 kg in weight and measuring over 6 meters in length. This demanded extensive physical manipulation, complicating time, and space management within the lab hall. Meticulous daily planning of operations and resource allocation was essential.
Another major challenge was the tight schedule. Testing began at the CONDIS labs before transitioning to external facilities, with the final pieces needing timely dispatch to the end user. Constant adjustments and realignment were needed after each test day to ensure all pieces met the necessary customer requirements while achieving the ultimate delivery goal.”
What were the biggest unknowns at the start of the testing campaign?
Minh Duc Vo: “The two main challenges were to get a very accurate high voltage divider calibrated in time for the final tests and for the delivery to the customer.
It is as difficult to find a manufacturer able to deliver a high voltage divider with an accuracy in voltage of 0.01% as to find a laboratory able to calibrate it, and it happened that the manufacturer and the laboratory were in different countries. It was challenging to completely dismantle, deliver and assemble the divider at the laboratory, dismantle it again, and finally mount it at CONDIS premises.”
How does the acquisition of the 800kV reference divider expand the Rossens lab’s testing capabilities?
Minh Duc Vo: “The voltage divider will allow accuracy tests on dividers with nominal primary voltage Upr from 36/√3 kV up to 765/√3 kV. There was an interrogation whether the divider was maintaining its accuracy in such a wide voltage range but the manufacturer Haefely conducted special tests in order to ensure that the performance would be conform. For decades, Haefely and Condis have been excellent business partners, able to address specific testing requirements.”
