Pre-loading condition of xformers

Status
Not open for further replies.

electrics

Senior Member
but this concept is cited on naval electrical guide when talking of overload conditions of powertransformers, I see no relationship
"3.2.8.3 Overloads. Transformers have certain overload capabilities, varying with ambienttemperature, pre-loading, and overload duration. These capabilities are defined in ANSI Std.C57.92, Guide for Loading Mineral-Oil-Immersed Distribution and Power Transformers, andANSI Std. C57.96, Guide for Loading Dry-Type Distribution and Power Transformers"
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
"3.2.8.3 Overloads. Transformers have certain overload capabilities, varying with ambienttemperature, pre-loading, and overload duration. These capabilities are defined in ANSI Std.C57.92, Guide for Loading Mineral-Oil-Immersed Distribution and Power Transformers, andANSI Std. C57.96, Guide for Loading Dry-Type Distribution and Power Transformers"
This seems to be addressing the actual loading of a transformer prior to it being overloaded.

A transformer that has a pre-[over]loading condition of 25% FLA for the past 24hrs will be able to be overloaded more and longer than a unit that has been running at 80% load for the past 12 hours.
 

SG-1

Senior Member
but this concept is cited on naval electrical guide when talking of overload conditions of powertransformers, I see no relationship
"3.2.8.3 Overloads. Transformers have certain overload capabilities, varying with ambienttemperature, pre-loading, and overload duration. These capabilities are defined in ANSI Std.C57.92, Guide for Loading Mineral-Oil-Immersed Distribution and Power Transformers, andANSI Std. C57.96, Guide for Loading Dry-Type Distribution and Power Transformers"

Could possibly refer to the previous history of loads on the transformer, such as was it operated in a overload condition for any length of time that may have degraded it's insulation.

I think Jim is correct.
 
Status
Not open for further replies.
Top