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PROTECTING POWER TRANSFORMERS FROM COMMON ADVERSE CONDITIONS PDF

PROTECTING POWER TRANSFORMERS FROM COMMON ADVERSE CONDITIONS PDF
Power transformers play a significant role in power system delivery. Proper application of relay elements that monitor a transformer’s thermal state and through-faults can provide both short and long term benefits. These benefits include:

•  Transformer overload protection, including cyclic
overloads
•  Continuous transformer thermal status indication that
allows the system operator to make transformer loading decisions based on transformer thermal state
•  Cooling system efficiency indication
•  Records of cumulative per phase I2t values as seen by the transformer
•  Settable I2t alarm thresholds that can notify the system operator of excessive through-fault current seen
by the transformer
•  Cumulative I2tvalues as a measure to prioritize transformer maintenance

Overexcitation is a system condition and is not limited to generating stations. Proper application of Volts/Hz elements can prevent damage to transformers resulting from system overvoltage or underfrequency conditions.

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