ABB REG670 Applications Manual page 666

Section 17
Monitoring
660
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.
TankMass: This setting is used to set the transformer tank mass. This mass is only the
tank and fittings that are in contact with heated oil.
LoadLoss: This setting is used to set the transformer load loss at rated condition.
TTLoadLoss: This setting is used to set the transformer load loss arrived from type
test.
NoloadLoss: This setting is used to set the transformer no-load loss.
TTNoloadLoss: This setting is used to set the transformer no-load loss arrived from
type test.
Winding time constant is the time for winding temperature to rise over the oil
temperature to reach 63.2% of the difference between the final rise and initial rise
during a load change. The winding time constant may be estimated from the resistance
cooling curve during thermal tests or calculated by the manufacturer using mass of the
conductor material. The function has the following settings related to winding time
constant.
WdgTmConstMode: This setting is used to select the winding time constant mode of
input to the function. It has three options:
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
1MRK 502 071-UEN -
Application manual