Features

Integrated three-phase differential relay, overcurrent relay and earth fault relay

Stabilized three-phase differential relays provide winding short-circuit and turn-to-turn fault protection for two-winding transformers and generator-transformer units, and winding short-circuit protection for generators.

Earth fault protection for transformer windings on the HV and LV side according to the required principle:

Stabilized differential current principle, high impedance principle, calculated or measured residual current principle or neutral current principle

Three-stage overcurrent protection for transformer and generator as well as two-stage backup protection for earth fault protection.

Differential relays with operating characteristics that can be easily adapted to different applications Short operating times, stable operation even in the event of partial saturation of the current transformer.

Prevents unwanted operation in the event of faults and transformer inrush currents outside the protective field.

Blocking based on the ratio of the second harmonic to the fundamental component of the differential current prevents unwanted operation in the event of transformer inrush currents.

Blocking based on the ratio of the fifth harmonic www.cniacs.com to the fundamental component of the differential current prevents unwanted operation in the event of transformer overexcitation.

– If the ratio of the fifth harmonic to the fundamental component of the differential current increases at high overvoltages, this blocking condition can be eliminated

Double-winding transformer protection without transformers – digital vector group matching on HV and LV side

Wide range of CT ratio corrections – precise corrections via digital settings Sensitive phase current and phase angle displays for easy checking of measurement circuits