Siemens Energy has been involved in the development of GIC-safe transformers since 1989, creating various calculation models, special algorithms and designs. Now, for Statnett, Siemens has been able to prove for the first time worldwide that GIC tests are also possible for variable shunt reactors (VSR).
In the Siemens Energy high-voltage laboratory in Weiz, Austria, experts have thoroughly tested VSRs for a worst-case scenario. The reactors withstood the simulated GIC storms without complication, and the test measurements confirmed complete DC-stability, harmonic-free operation and uncritical temperature behavior.
In order to compensate for the daily reactive power fluctuations in the high-voltage grid, Statnett opted for a VSR from the Siemens Energy plant in Weiz with a reactive power of 90 to 200 MVAr (megavolt ampere reactive) that can be adapted in stages without interruption. And this range of control allows Statnett to make fast, situation-specific adaptations of the momentary local reactive power demand. It also leaves them well prepared for future changes in grid requirements.