ABB RELION RET670, Руководство по применению

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• Three Phase Trafo : The function considers the given transformer as three phase
transformer.
• Single Phase Trafo : The function considers the given transformer as single phase
transformer.
Based on the settings TrafoRating and TrafoType , transformer parameters are selected
for temperature calculations. Both IEEE and IEC standards defines the transformer
parameters based on three categories of transformer rating.
In the case of three phase transformers:
• If the transformer rating is less than 2.5 MVA, the function considers this as a
distribution transformer.
• If the transformer rating is less than 100 MVA, it is considered as a medium power
transformer.
• If the transformer rating is above 100 MVA, it is considered as a larger power
transformer.
In the case of single phase transformers:
• If the transformer rating is less than 0.833 MVA, the function considers this as a
distribution transformer.
• If the transformer rating is less than 33.3 MVA, it is considered as a medium
power transformer.
• If the transformer rating is above 33.3 MVA, it is considered as a larger power
transformer.
NoOfWindings : This setting is used to set the number of windings in the transformer.
The options are :
• Three winding : The function considers the given transformer as three winding
transformer.
• Two winding : The function considers the given transformer as two winding
transformer.
Based on the setting NoOfWindings , hot spot temperature of the winding 3 is either
calculated or assigned as zero.
ConstSelection : This setting is used to select the transformer parameters taken either
from IEC 60076-7 standard or IEEE C57.96-1995 standard. The options are:
1MRK 504 163-UUS A
Section 18
Monitoring
Transformer protection RET670 2.2 ANSI 905
Application manual