Monitoring the condition of transformer insulating oil has been considered as a crucial and effective measure for preventive maintenance of power transformers. Various properties of the oil can be monitored such as the dissolved gases, furan content, and inhibitor content. This paper focuses on the inhibitor content in insulating oil. Currently, Fourier transform infrared (FTIR) spectroscopy in accordance with the IEC 60666 standard is used for the measurement of inhibitor concentration in insulating oil. However, this technique involves site sampling, transportation to a laboratory and an expensive instrument. This work proposes the characterization of inhibitor content in insulating oil in the near-infrared (NIR) waveband, which would lead to the design of a faster and cheaper detection system for inhibitor content. It was found that the inhibitor content exhibits an optical absorbance peak at 1403 nm, which was not reported in any previous work. A mathematical model was then created to describe the relationship between the concentration of inhibitor, the area under the absorbance spectrum and the peak optical absorbance. The model was verified, and the results showed a root mean square error (RMSE) of 0.0458.

监视变压器绝缘油的状况已被认为是预防性维护变压器的关键和有效措施。可以监测油的各种特性，例如溶解气体，呋喃含量和抑制剂含量。本文重点研究绝缘油中的抑制剂含量。当前，根据IEC 60666标准的傅里叶变换红外（FTIR）光谱用于绝缘油中抑制剂浓度的测量。但是，该技术涉及现场采样，运输到实验室和昂贵的仪器。这项工作提出了近红外（NIR）波段绝缘油中抑制剂含量的表征，这将导致设计一种更快，更便宜的抑制剂含量检测系统。发现抑制剂含量在1403nm处显示出光吸收峰，这在任何先前的工作中均未报道。然后创建一个数学模型来描述抑制剂浓度，吸收光谱下的面积和峰值吸光度之间的关系。对该模型进行了验证，结果显示均方根误差（RMSE）为0.0458。