Title :
Dynamic thermal modeling of distribution transformers
Author :
Susa, Dejan ; Lehtonen, Matti ; Nordman, Hasse
Author_Institution :
Helsinki Univ. of Technol., Espoo, Finland
fDate :
7/1/2005 12:00:00 AM
Abstract :
A comprehensive test program was performed on a 2500-kVA oil natural-air natural cooling mode (ONAN) transformer without external cooling. It is shown that the hot-spot to top-oil temperature gradient depends on the transformer construction. The top-oil time constant formula, which has already been defined and validated in the authors´ previous work related to transformers with external cooling, is modified in order to take into account the basic design differences. The results are verified by thermocouple measurements and tests at varying loading current. The hot-spot and top-oil temperature responses predicted by the IEEE Loading Guide, Annex G, are also compared to the measured values.
Keywords :
cooling; distribution networks; power transformers; thermocouples; transformer testing; 2500 kVA; AnnexG; IEEE loading guide; comprehensive test program; distribution transformers; external cooling; hot-spot oil; loading current variation; oil natural-air natural cooling mode; thermal modeling; thermocouple measurement; top-oil temperature gradient; Capacitance; Cooling; Performance evaluation; Petroleum; Ribs; Surface resistance; Temperature; Testing; Thermal resistance; Transformers; Distribution transformer; hot-spot temperature; top-oil temperature;
Journal_Title :
Power Delivery, IEEE Transactions on
DOI :
10.1109/TPWRD.2005.848675
