Depending on the system, switching of fast-acting breakers, such as vacuum or gas-insulated breakers, can produce fast transient over-voltages inside transformer windings that, over time, may lead to failures. These failures result in unexpected system downtime and unrepairable equipment; both incredibly costly to network managers.
Hitachi Energy's Transient Voltage Protection technology eliminates this potential failure mode during network switching operations by using integrated winding varistors. With this, the transformer is protected from switching transients. This technology works in any electrical network without the need of additional system analysis for design.
The technology is simple. Varistors are placed strategically along the windings in proprietary arrangements to limit transient over-voltages from both breaker reignitions and amplified voltages from harmonic resonance. Combined with advanced winding design, the technology controls peak voltages indeterminant of the connected system characteristics. Compared to existing RC snubber circuit solutions, the Transient Voltage Protection technology eliminates the risk and maintenance that comes with oil-filled capacitors and does not affect the overall size of the installation. All the components of this technology are oil-free which greatly reduces installation costs and removes the risk of fires or spills; making it the safest solution for people, property and the environment.