AQ-T257 is a transformer protection device with a differential protection function and an integrated automatic voltage regulator function. The relay also provides complete current-based and voltage-based protection functions as well as full measurements. You can add up to nine (9) I/O or communication cards into the device for extensive monitoring and control applications. AQ-T257 communicates using various protocols, including the IEC 61850 substation communication standard.
The AQ-T257 transformer protection device has two software options: the “A” variant (AQ-T257A) includes all the protection functions for transformers including differential protection, while the “B” variant (AQ-T257B) also includes the automatic voltage regulator that allows you to control more than one transformer at the same time. For more details on the software options, please see the order code below.
Highlight:
A large I/O capacity.
Automatic/manual voltage regulating (AVR) and/or parallel voltage regulating.
Complete transformer protection.
2nd and 5th harmonic blocking.
Automatic verification of a connection group and nominal value settings.
Overloading and through fault statistics for preventive maintenance.
Power and energy measurement accuracy of up to 0.2 %.
Technical data
AQ-T257A – Standard transformer protection functionality
AQ-T257B – Standard transformer protection functionality + Transformer AVR (automatic voltage regulator)
