Abb has a wide range of voltage transformer and emf is the inductive voltage transformer. Emf is broadly used for power networks with insulated or grounded neutral points. More than 55,000 units have been delivered since the 1940s. Salient features are as follows:
1 its extremely low core flux density enables the emf to withstand continuous over voltages.
2 an over dimensioned core effectively counteracts ferroresonance, both harmonic and sub-harmonic.
3 the core and windings are placed in an aluminum tank and with quartz and mineral oil.
4 a nitrogen gas cushion is used to compensate oil expansion. This design is maintenance and inspection free.
5 emf is also available with silicone rubber insulators, giving you an even better performance in heavily polluted environments.