Variable shunt reactor explained

Variable shunt reactors are used in high voltage energy transmission systems to stabilize the voltage during load variations. A traditional shunt reactor has a fixed rating and is either connected to the power line all the time or switched in and out depending on the load. Recently ^[1] variable shunt reactors (VSRs) have been developed and introduced on the market. The rating of a VSR can be changed in steps: the maximum regulation range depends on the capability of the on-load tap changer used in combination with the regulation winding used for the shunt reactor. The maximum regulation range has increased over the years,^[1] from 50%, up to 80% at some voltage levels.^[2] VSRs are considered^[1] technically advanced products and are mainly supplied by larger global manufacturers.

Advantages

The variability brings several benefits compared to a traditional fixed shunt reactors. The VSR can continuously compensate reactive power as the load varies and thereby stabilise the voltage. Other important benefits are:

• reduced voltage jumps resulting from switching in and out a traditional fixed shunt reactor
• flexibility for future variation in load and generation patterns
• improved interaction with other transmission equipment and systems such as coarse tuning of SVC equipment
• limiting the footprint of a substation: if parallel, fixed shunt reactors can be replaced with one VSR
• a VSR can be used as a flexible spare unit and be moved to other locations in the power grid if needed
• mitigation of zero-miss phenomenon, while energisation of long power lines and cables^[3]

External links

• http://www05.abb.com/global/scot/scot252.nsf/veritydisplay/dadf3c1d27681cc48525775400608bb5/$file/1zse954001-21_vsr_pamphlet.pdf
• http://www.getra.it/default.php?mcat=azi&cod=casehistory&scod=casepower&id=320
• http://www.swedishneutral.se/main.php?name=shunt_reactor

Notes and References

1. Web site: Technology and utilisation of oil-immersed shunt reactors. 2016 .
2. Web site: (Variable) Shunt Reactor. 2024-01-13 . www.entsoe.eu . https://web.archive.org/web/20231001082109/https://www.entsoe.eu/Technopedia/techsheets/variable-shunt-reactor . 2023-10-01 . live.
3. Web site: Hitachi Energy Publisher .