The new 38 kV 25 kA Current-Limiting Molded Vacuum Interrupter (MCLVI) from Thomas & Betts was designed for use in wind farm towers as large as 3 MVA. The unit incorporates Elastimold’s combination of EPDM molded insulation with a current-limiting fuse and vacuum interrupter. This addition to the solid-dielectric family of switchgear uses a vacuum interrupter to clear low-magnitude faults in series with a Hi-Tech current-limiting fuse to clear higher-magnitude faults, substantially reducing energy let-through. The unit includes Thomas & Betts' current sensor and internal controls. If a single current-limiting fuse clears a fault, the MVI will sense an imbalance and trip to prevent single phasing.
The small, lightweight unit is maintenance-free and environmentally friendly, containing no gas or oil, and is also available for subsurface, vault, padmount or riser-pole applications. Choose a stacked, linear or back-to-back arrangement. When used for transformer protection, the fuses can be coordinated with the vacuum interrupter so that the fuses will only operate in the event of a transformer failure.