TY - JOUR
T1 - Direct optical techniques for the measurement of water content in oil-paper insulation in power transformers
AU - Rodríguez-Rodríguez, Joaquín H.
AU - Martínez-Pĩón, Fernando
AU - Lvarez-Chvez, José A.
AU - Jaramillo-Vigueras, David
AU - Robles-Pimentel, Edgar G.
PY - 2011/6
Y1 - 2011/6
N2 - Paper-oil insulation in power transformers is degraded and gradually damaged due to electrical, chemical, mechanical and moisture factors. It is well established from several studies that moisture is a major source of insulation failure in high voltage power transformers. Measurement and monitoring of moisture is essential to predict life and operation condition for power transformers. This paper presents direct optical measurement of water content at paper insulation immersed in transformer oil inside a test cell, which contains a water source, and a capillary paper bridge to transfer water to the paper inside an oil reservoir. Optical measurement of water content was carried out in the near infrared from 900 to 1500 nm band. Experimental studies of light transmission in transformer oil and water are discussed. The criteria to establish the best optical bands for maximum sensitivities are given. The measurement limitations, calibration procedures and an error analysis are presented. The resulting technique can be used for on-line measurements in electrical apparatus that use oil-paper insulation under large electrical field gradients. The presented method has advantages, since it is a direct and fast technique to measure the water transfer to paper immersed in oil, and it could be applied in compact portable equipment at a low cost.
AB - Paper-oil insulation in power transformers is degraded and gradually damaged due to electrical, chemical, mechanical and moisture factors. It is well established from several studies that moisture is a major source of insulation failure in high voltage power transformers. Measurement and monitoring of moisture is essential to predict life and operation condition for power transformers. This paper presents direct optical measurement of water content at paper insulation immersed in transformer oil inside a test cell, which contains a water source, and a capillary paper bridge to transfer water to the paper inside an oil reservoir. Optical measurement of water content was carried out in the near infrared from 900 to 1500 nm band. Experimental studies of light transmission in transformer oil and water are discussed. The criteria to establish the best optical bands for maximum sensitivities are given. The measurement limitations, calibration procedures and an error analysis are presented. The resulting technique can be used for on-line measurements in electrical apparatus that use oil-paper insulation under large electrical field gradients. The presented method has advantages, since it is a direct and fast technique to measure the water transfer to paper immersed in oil, and it could be applied in compact portable equipment at a low cost.
KW - NIR spectroscopy
KW - moisture measurement
KW - oil-paper insulation
KW - optical transmittance
KW - power transformer
UR - http://www.scopus.com/inward/record.url?scp=79956117503&partnerID=8YFLogxK
U2 - 10.1088/0957-0233/22/6/065706
DO - 10.1088/0957-0233/22/6/065706
M3 - Artículo
AN - SCOPUS:79956117503
SN - 0957-0233
VL - 22
JO - Measurement Science and Technology
JF - Measurement Science and Technology
IS - 6
M1 - 065706
ER -