IEEE C57.96-2013 pdf free

IEEE C57.96-2013 pdf free.IEEE Guide for Loading Dry-Type Distribution and Power Transformers.
Loads above rating, based on this guide. may be applied only alter a thorough study has been made of all the othcr various limitations that may bc involved, Among thcsc limitations arc gas cxpansion and prcssurc in sealed dry-type units; the thermal capability of associated equipment. such as bushings. leads. connections, tap changers in all dry-type transformers: and ancillary equipment, such as cables, reactors. circuit breakers, disconnecting switches, and current transformers. Also, limitations may be imposed by voltage regulation necessary for satisfactory operation of connected apparatus and by the increased operating costs due to the higher losses accompanying loads above nameplate rating. ‘rhese may constitute the practical limit on load-carrying ability and should be considered before applying loads in excess of nameplate rating.
It is intended that dry-type transformers be installed based on the recommendations given in IEEE Std C57.94. If dry-type transformers arc installed in subsurface vaults or areas of minimum size where the nawral ventilation will significantly raise ambient ernperamre with changes in transformer losses, the increase in effective ambient temperature for expected increased transformer losses must be determined before loading limitations can be estimated.
Dry-type transformers are generally designed to permit loading in line with these guides. hut if there are any questions as to the capability of a particular transformer to carry the desired load, the manufacturer should be consulted for specific recommendations.
4.2 Transformer life expectancy
Rccommcndations in this guide are based on the life expectancy of transformer insulation as affected by operating temperature and lime and do not consider other factors that may affect transformer life, such as voltage stress or mechanical stress especially due to system voltage fluctuations or system faults.
The loading capability of transformers is related to properties ol the insulating materials and insulation systems. Transformer life expectancy is not accurately known for many reasons, but primarily due to varying loads and operating temperatures over the life of a typical unit. However, the information given regarding loss of life of the insulation is better understood, is considered to be conservative, and is the best that can be produced from present knowledge of the subject. (The word “conservative” is used in the sense that the expected loss of insulation life for recommended load will not be greater than the amount slated.)
4.3 Transformer rated output
The rated kilovolt-ampere output of a transformer is the load that it can deliver continuously at rated secondary voltage and rated frequency without exceeding the specified temperature rise under usual service conditions, as described in IEEE Std C57.l2.Ol. The term “rated output” or “rated load” used in this guide refers to nameplate rating of continuously rated transformers. For transformers that do not have a continuous rating or when such information is not indicated on the nameplate or the transformer operating manual, the manufacturer should be consulted for additional information.IEEE C57.96 pdf free download.