15 / 2018-08-21 20:55:42

Study on multifactor combined aging characteristics of oil-paper insulation for transformer

Aging mechanism, oil-paper insulation, Multifactor aging, Transformer

Large oil-immersed power transformer is one of the most important equipment in power system. During the operation of the transformer, oil-paper insulation is subjected to various external stresses such as electricity, thermal, machinery and chemistry for a long time. Under the above stress, insulation pressboard and transformer oil will gradually age with the accumulation of running time. Some aging products will lead to the gradual decline of insulation and mechanical properties and may cause transformer faults. So, this paper designed the electric-thermal-vibration multi-factor joint aging test device in order to accurate diagnosis of aging oil-paper insulation, further perfect the process of aging test, and the more comprehensive simulation of transformer oil-paper insulation work environment. A comparative experiment of electric- thermal- vibration and electric-thermal joint aging is carried out. Through the comparative analysis of the dielectric spectroscopy of the two sets of aged samples, the degree of polymerization of the insulating paperboard and the moisture content of the insulating paperboard, it was found that the increasing trend of the dielectric loss curve of the electro-thermal-vibration combined aging oil-impregnated paperboard is more obvious than the electro-thermal combined aging sample at the high frequency; after the electro-thermal-vibration combined aging, the degree of polymerization of the oil-impregnated paperboard is faster and the internal moisture content is higher.