Interaction of Transformer Oil Parameters on Each Other and on Transformer Health Index Using Curve Estimation Regression Method

Table 1

Comparison of two regression methods to predict the relationship between transformer health index (HI) and oil breakdown voltage (BDV).

Equation	Model summary					Parameter estimates
	R-Square	F	df1	df2	Sig	Constant	b1	b2	b3
Inverse	0.251	39.585	1	118	0	0.957	−3.536	—	—
Cubic	0.413	27.216	3	116	0	0.544	0.021	0	3.62E-6

Dependent variable: HI; independent variable: BDV.