Partial Least Squares (PLS) Integrated Fourier Transform Infrared (FTIR) Approach for Prediction of Moisture in Transformer Oil and Lubricating Oil

Table 2

Average % RMSE for subsets of low and high moisture concentrations in lubricating oil according to spectral regions at 3750–3400 and 1700–1600 cm⁻¹.

Concentration range (ppm)	% RMSE
	1700–1600 cm^−1		3750–3400 cm^−1
	Training set	Test set	Training set	Test set
0–1000	36.81	48.69	32.21	50.36
1000–5000	10.46	13.03	10.12	14.61