ABB 615 series Technical Manual page 285

1MAC059074-MB A
615 series ANSI
Technical Manual
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Figure 134: Effect of the Weighting factor p factor and the difference between the two
time constants and one time constant models
The actual temperature of the transformer is calculated by adding the ambient temperature
to the calculated temperature.
Θ = ∆ + Θ Θ
amb
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Θ temperature in transformer (°C)
ΔΘ calculated temperature rise (°C) in transformer
Θ set value of the Env temperature Set setting or measured ambient temperature
amb
The ambient temperature can be measured with RTD measurement. The measured
temperature value is connected, for example, from the AI_VAL3 output of the X130
(RTD) function to the AMB_TEMP input of 49T.
The Env temperature Set setting is used to define the ambient temperature if the ambient
temperature measurement value is not connected to the AMB_TEMP input. The Env
temperature Set setting is also used when the ambient temperature measurement
connected to 49T is set to "Not in use" in the X130 (RTD) function.
Section 4
Protection functions
(Equation 15)
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