In 2020, 330 kV and 750 kV transmission lines underwent live works with the replacement of 390 elements at three 330 kV–750 kV trunk transmission lines without lines disconnection. It made it possible to shorten the period of planned disconnection of lines for repairs by 59 days.
In particular, for the first time without de-energizing the OHL 750 kV, 4 insulators were replaced in the suspension insulator set at OHL 750 kV Vinnytska 750–Zakhidnukrainska. Over the year, live works were performed at OHL 330 kV Dnistrovska HPP–Kamianets-Podilska (replacement of 356 spacers) and OHL 330 kV Vinnytska 330–Bar (installation of 30 wind bracings).
The works were performed by specialists of NPC Ukrenergo’s Separate Subdivision Construction and Repair who passed three-month training at the Production and Training Centre Vinnytsiaelectrotechnology. Protective conductive suits and all necessary equipment was manufactured and certified in Vinnytsia Centre as well. The Company now has three such teams of 8 individuals each (in Vinnytsia, Zaporizhzhia and Bakhmut) qualified to perform 6 types of work at overhead lines without their disconnection: replacement of suspension and tension insulation, spacers, vibration dampers, tension adjustment in OHL wires, installation of wind bracings and replacement of caps above a suspension insulation set.
“In the context of enhanced requirements to the power grid reliable operation, quality of electricity transmission services in the market, and the future integration of the power system to the ENTSO-E Continental Europe network, live working will be in more demand. In particular, the technology allows avoiding the curtailment of generation output when line repairs are necessary, including urgent repairs. Besides, due to LW repairs of overhead lines, we shorten the number of scheduled disconnections over the year, maintain a reliable power supply for consumers, and reduce losses in the power grid,” said Oleksii Brekht, Director for Grid Operation and Development at NPC Ukrenergo.
The technology was recovered using the advanced expertise of France’s transmission system operator RTE enabling major improvements to the LW procedure. In particular, Vinnytsiaelectrotechnology experts developed the necessary design documentation, process flow charts and the standard, using their own resources they manufactured sample tools and protective means, and tested their reliability and properties in own certified laboratory.
The first practical LW training took place in December 2018 at Vinnytsiaelectrotechnology’s training base. And the first “touching the potential” was on 18 April 2019 at OHL 330 kV Vinnytska-Ladyzhynska TPP. Since then the experience and teamwork have been gained and polished at 330 kV and 750 kV overhead lines.
The plans for 2021 are to train and establish LW teams in each power system, and to expand the types of working without de-energizing trunk transmission lines. In doing so, we will be able to implement this technology in broader areas, shorten scheduled disconnections of overhead lines, and improve the grid availability index.
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