Abstract:According to statistics, the insulation fault is one of the most important reasons for electrical equipment, therefore the study of transformer insulating state monitoring has great significance to ensure safe operation of power system. The accuracy of insulation condition assessment is a key issue for online dynamic monitoring the transformer insulation status. The evaluation result is randomly influenced by various internal and external factors, which makes its modeling complex. An online monitoring system of transformer based on grey target theory is proposed. Through improving traditional grey target theory, and calculating the affection of different insulation indexes by weight coefficient method, the rationality of the evaluation result is guaranteed. Experiments show that this method can reasonably and objectively assess transformer insulating state, providing an important reference for maintenance plan of transformer.