The electrical property of insulation materials used for electrical equipment decreases gradually under electrical

thermal and mechanical stresses

so researches on aging mechanism and life models of insulation materials are of vital significance to insulation life evaluation. Consequently

firstly

we summarized life models under the stresses of electrical

thermal and mechanical stresses based on traditional macroscopic insulation aging models. Secondly

we summarized several insulation aging life models due to micro-defects induced by space charge effects from microscopic aspects. Finally

we put forward the research direction and development tendency of aging models for insulation materials for further research. The advantages/disadvantages of different macroscopic life models were analyzed according to comparisons. And damage effects of space charge on insulation materials（formation and enlargement of micro-voids

occurrence of partial discharge

and initiation and growth of electrical trees inside insulation

etc.） were analyzed from microscopic angle. Life models of insulation materials based on space charge effects were adopted to evaluate life of insulation under DC fields. It is pointed out that researches of insulation life models should focus on micro rather than macro

adopt various advanced microscopic and macroscopic measuring and analysis methods

and tightly combine simulations with experiments

so as to create insulation life models with specific physical meanings and accurate failure time using dynamic analysis methods.