ABB REC670 Applications Manual page 559

1MRK 511 401-UUS A
Bay control REC670 2.2 ANSI
Application manual
• Winding 1&3: Only winding 1 and winding 3 CTs are available. This option can be
selected when three winding transformer is considered.
• Winding 2&3: Only winding 2 and winding 3 CTs are available. This option can be
selected when three winding transformer is considered.
• All windings: All windings CTs are available. This option can be selected for both
two and three winding transformer.
RatedVoltW1: This setting is used to set the rated voltage of winding 1 in kV.
RatedVoltW2: This setting is used to set the rated voltage of winding 2 in kV.
RatedVoltW3: This setting is used to set the rated voltage of winding 3 in kV.
UPerTap: This setting is used to set the voltage increment/decrement between two
successive tap positions (ΔV) in kV.
Time required for the top oil temperature in relation to ambient temperature to reach its
ultimate value is a function of the thermal oil time constant. The function has the
following settings related to oil time constant.
OilTmConstMode: This setting is used to select the oil time constant mode of input to
the function. It has three options:
• Standard: Oil time constant is taken from the IEEE or IEC standard as selected for
the temperature calculations.
• User defined: Oil time constant is provided by the user through setting. The value
may be given by the transformer manufacturer.
• Calculated: Oil time constant is calculated by the function based on the
transformer parameters given by the user.
OilTimeConst: This setting is used to get the oil time constant from the user and this
will be used when OilTmConstMode setting is selected as User defined. Likely it is
between 1 and 3 hours.
AvgOilTmpRise: The top oil temperature is based on the average temperature rise of the
lumped mass. In the case of transformer, this would be the average oil temperature.
This setting is used to set the average oil temperature rise above ambient temperature
in K (Kelvin). This value should be obtained from the manufacturer based on certified
heat run test reports conducted at maximum rating given in the name plate.
CoilCoreMass: This setting is used to set the transformer coil and core assembly mass.
This mass consists of all winding mass, core mass and paper mass of the transformer.
OilMass: This setting is used to set the transformer oil mass. This mass consists of free
oil mass and oil insulation mass of the transformer.
Section 17
Monitoring
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