Guide For Loading Mineral-Oil-Immersed Overhead And Pad-Mounted Distribution Transformers Rated 500 KVA And Less With 65 Degrees C or 55 Degrees C Average Winding Rise
"This guide covers general recommendations for loading 65 ""C rise mineral-oilimmersed overhead and pad-mounted distribution transformers described in American National Standards and rated 500 kVA and less. (For transformers rated 501 kVA and larger@ see ANSI/IEEE C57.92-1981@ [31') Recommendations for 55 ""C rise transformers are included in this guide because a substantial percentage of these transformers are still in service. Loading recommendations in tabular form are contained in Section 5 of this guide. A method to establish winding temperature and loss of life by nomographs is also given in Section 5. The method used for the calculation of the loading guide tables in Section 5 is given in Section 6 of this guide. The recommendations of this guide are based on winding hottest-spot calculations only. Other factors such as listed in 3.6.1 may limit the permissible load to lower values."