Residual Voltage Transformer (RVT)

residual voltage transformer

Residual Voltage Transformers (RVTs) are a category of instrument transformers which are used in electrical systems to protect capacitor banks from earthing faults and prevent damage. The main function of these class of instrument transformers is to detect neutral to ground fault conditions and discharge the capacitor banks as and when required automatically. In an electrical system in normal working conditions, the windings of an RVT will have no voltage output. On the other hand, in the event of an earth fault a voltage will be developed across the open delta winding of the transformer which will activate the relays and cut the power connection thereby protecting the measuring equipments from damage.

The function of RVTs is similar to voltage transformers in some areas. However their and utility is different from one another. It is probably one of the reasons why many people consider RVTs as a sub-group of voltage transformers.

Macroplast manufactures Residual Voltage Transformers for varied system voltages. The most common systems voltages are 11 kv, 33kv system voltages in which five limb core construction is employed instead of conventional three limb construction. The outer two limbs carries the residual flux and the secondary windings are connected in open delta fashion.