Research Article

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

Table 4

Moisture concentrations predicted with PLSR using the spectral data at 1700–1600 cm−1 and the measurements attained using Kittiwake method.

Expected concentration (ppm)Predicted concentration in ppm (% error/CV)
PLS regression (n = 5)Kittiwake (n = 2)

068 ± 109 (NA/160%)500 ± 0 (160%/0%)
400264 ± 357 (34%/135%)600 ± 0 (50%/0%)
600850 ± 625 (42%/74%)550 ± 70 (8%/13%)
800795 ± 114 (0.63%/14%)759 ± 70 (5%/9%)
900892 ± 379 (0.9%/43%)700 ± 0 (22%/0%)
1200906 ± 336 (25%/37%)850 ± 70 (29%/8%)
18001726 ± 234 (4%/14%)900 ± 0 (50%/0%)
23001962 ± 347 (15%/18%)1000 ± 0 (57%/0%)
29002936 ± 449 (1%/15%)1250 ± 70 (57%/6%)

% error: percentage error; CV: coefficient of variation.