Integrated Transformer Health Estimation Methodology Based on Markov Chains and Evidential Reasoning

Table 2

Weighting factors of different inspection methods.

ET component	Inspection method	Weighting factor ()
Magnetic core	Open-circuit test/SFRA	5
Geometry end electric contacts of windings	Resistance testing	5
	Leakage inductance test/SFRA	5
Insulation	Insulation resistivity/tgδ and capacitance test	5
	PDC/RVM/FDS/water content in oil	4
	Furan derivative analysis	3
Bushings	tgδ and capacitance	4
On-line tap changer	Static/dynamic resistance testing	5
DGA analysis for the active part	Dissolved gas analysis (DGA)	4
Transformer oil	Physical and chemical oil characteristics	5
	Content of water in oil	4
Transformer tank and auxiliary equipment	Testing of cooling system and auxiliary equipment	2
	Visual inspection/leakage control	2
Work history	Loading and operation history	3