As the Power transformer manufacturer, we are devoting ourselves to the production of power transformer for 20 years, keeping long-standing reputation for quality and striving to be consistent. Baoding Zhongyi Electrical Material Manufacturing Co., Ltd. is your first choice to transformers.
I.Leakage Reason of the Transformer
1.The transformer has many welding spots and its welding seam is long.
Oil-immersed power transformer is an aggregation of various welding and connectors based on the welded steel-plate shell. The rubber seals for a 31500 KVA transformer have about 27 connection points, and the rubber seals of all shapes have more than 30 pieces, including the welding between heat pipe ends and oil tank, the total welding spots can reach more than 70 pieces, with welding length of nearly 20m or so. So there may many leakage ways. The direct reason for leakage is due to failure of rubber seals and weld cracking, pores, slag etc.
2.Manufacturing Quality of Transformer
In the process of manufacturing, the transformer will cause pores, sand holes, empty solder and unsoldering phenomena due to casting and poor welding quality, resulting in the oil leakage of transformer.
3.Improper Hoisting and Transportation
During the course of consignment and construction & transportation, collision for components and parts and improper hoisting and transportation will result in the parts deformation, open weld of welding junction and cracks etc, causing the leakage.
4.Aging and Cracking of the Sealing Rubber Pad
Transformer leakage frequently occurred at the sealing rubber pad, mainly caused by the aging and cracking of the gasket. The quality of sealing pad can easily lead to aging and cracking of the gasket, resulting in oil leakage of transformer.
5.Other Reasons. In addition to oil leakage of sealing elements and welding seam, it also happened frequently at the conductive copper rods of the medium and small transformers, at the conductive copper plates of the special transformers and in the copper brazing place of the mounting seat. For various reasons, some manufacturers often use copper cast rod or plate instead of rolling rod or plate. Casting copper is easy to generate air holes, loose and slag inclusion, frequently form the through channels and lead to the leakage. The copper brazing of conductive copper plate and bearing is very brittle, which may lead to oil leakage due to cracking during the course of installing the transformer wiring or in operation. When the transformer is in operation , the transformer nut for connecting the sealing parts is often loose and cause the oil leakage.

Summary: Transformer oil has a strong penetration capacity at the high frequency high voltage. The traditional replacement welding process has the inevitable short comings, there are two key points to solve the problems: First, the sealing should be done in the condition of oil lubrication and without stopping the machine. Second, permeability of oil resistance after the completion of the oil seal means the service life. EG repair system is developed specifically for this purpose, greatly reducing the trouble for customers to stop the machine, which can resolve the oil leakage problem once and for all.