Application

RET630 has been designed to be the main

protection and offer full protection for

two-winding power transformers. The

comprehensive transformer management

relay offers two predefined configurations,

of which one is intended for two-winding, high

and medium-voltage (HV/MV) transformer

applications not requiring restricted earth-fault

protection, and the other for such applications

requiring it.

Hot spot and aging rate monitoring is

introduced, which allows calculating the hot

spot temperature of the transformer winding

and the momentary aging rate. As a result,

the impact of thermal stress on the lifetime

of the transformer can be determined.

RET630 also features an integrated voltage

regulator. The voltage regulator allows automatic

and manual voltage regulation of power

transformers with a motor-driven on-load

tap changer.

An optional RTD/mA module offers eight analog

RTD or mA measuring inputs and four mA

outputs. The RTD and mA inputs can be used for

measuring the oil temperature at the bottom and

top of the transformer tank and the ambient

temperature, thus extending the functionality of

the thermal overload protection and preventing

premature aging of the transformer windings.