Study On Overhaul Technology Of Large Power Transformer Hoods On Site

The overhaul of large power transformer hoods on site is a major overhaul work for all power operation and maintenance units.However,according to the current situation of the industry,most power operation and maintenance units outsource this work to the relevant overhaul enterprises.Because they are not familiar with the overhaul process,they lack systematic and perfect technical supervision means.Especially for the key links such as fuel saving tank and coil replacement,which are handled by hanging iron core,there is a lack of systematic research and summary,and the experience that can be used for reference is very limited.In this paper,the necessity of overhaul of large power transformer hoods is discussed in detail.Taking the overhaul of No.1 Main Transformer hoods of Tianshengqiao I Hydropower Station as an example,the process steps and technicians of overhaul of power transformers are elaborated from four aspects:preparation before overhaul,process control and research during overhaul,test after overhaul and risk analysis of safety and health rings.Art control,various tests and risk assessment.The dismantling and assembling technology of GIS equipment,the method of preventing insulation from damp,the process control of removing old coil and repairing iron core,the inspection of new coil and the control of field coil assembling technology are mainly studied.The project example fully demonstrates the results of overhaul of large power transformer hoods on site,and successfully solves a series of problems such as burning,melting and overheating caused by poor current flow on the surface of iron core sandwich.The grounding mode of iron core is changed from parallel connection to series connection,which eliminates the effect of large circulation caused by short circuit of oil passage between iron core stages in the operation of transformer.This paper eventually became the operation guide for the overhaul of large power transformer hoods in the field of this system,which has a great reference value for the power operation and maintenance units to carry out this work.