Session: 14-01-01: General Topics on Risk, Safety, and Reliability I

Paper Number: 143076

143076 - a Study on Structural Safety Evaluation Technology for Seperately Assembled Radiators With a Transformer 

In transformers, radiators are heat exchangers which are used to maximize heat dissipation from the transformer oil to the external cooling medium. Transformer oil carries the heat generated by electrical losses from within the transformer winding to the radiator.

When a transformer is loaded, the current starts flowing through its windings. Due to this flowing of electric current, heat is produced in the windings, this heat rises the temperature of transformer oil. We know that the rating of any electrical equipment depends upon its allowable temperature rise limit. Hence, if the temperature rises of the transformer insulating oil is controlled, the capacity or rating of transformer can be extended up to significant range. The radiator of transformer accelerates the cooling rate of transformer. Thus, it plays a vital role in increasing loading capacity of an electrical transformer. This is basic function of radiator of a power transformer.

Radiators are usually installed on transformers in two ways. The first way is mounting directly to the transformer tank wall. The second way is installing separately from the transformer. It is called the separate radiators assembly.

In this paper, equations were derived in order to select the optimal length of base plates of a separate radiators assembly to prevent rollover. The risk of rolling over exists when installing 1 set of radiators on one side only during assembly process under conditions where the anchor bolts are not fixed to the base plate during the assembly process, which is different from the site installation condition. Therefore, contact condition between ground and base plate is frictional contact condition.

Additionally, wind forces were calculated based on the SBC(Saudi Building Code) standard that has the most structurally harsh conditions. Power transformers and separate radiators assemblies are installed primarily in open, flat areas with no other buildings nearby. Therefore, they should be evaluated for structural safety against wind loads from the surrounding area. Transformers are less susceptible to structural failure due to wind loads because they are filled with heavy materials such as insulation oil and active parts structures, but separated radiators assemblies require a structural review.

Then, analysis based on numerical method of real separate radiators assembly were conducted to verify structural safety. As a result, the optimal length of base plates of a separate radiators assembly and the design improvement of a separate radiators assembly considering their allowable stress was derived to secure the structural safety again the wind force. Through this process, the evaluation technology suggested in this paper was validated.

Presenting Author: Minok Yun HD HYUNDAI ELECTRIC

Presenting Author Biography: Minok Yun is a senior researcher from HD HYUNDAI ELECTRIC, Republic of Korea. Minok Yun has a bachelor's in Mechanical Engineering Design and master's in Mechanical Engineering from Kyungpook National University.

Authors: