Condition Monitoring of Transformer Breather Using Smart Photodiodes Array

A self-dehydrating silica-gel breather is an essential part of any transformer to prevent moisture ingress of oil. In this article, an online breather health monitoring system is developed using a smart photosensors array and a humidity sensor. The developed system monitors the change in primary components of the intensity of the color (red, green, and blue) of silica gel at different humidity levels. A smart photodiode array (TCS230) is interfaced with the microcontroller to convert the color change into a frequency change of pulse wave signal. Actual humidity and the desiccant (silica gel) color change inside the breather are monitored using the humidity sensor and the photosensors array respectively. The developed experimental setup is tested on a 200-kVA transformer silica-gel breather in the laboratory. The maximum and minimum uncertainty in the measurement of color intensity of the silica gel with humidity varying from 19%RH to 59%RH was found 0.47 and 0.18, respectively. The method is simple, noninvasive, durable, and inexpensive and it is not reported anywhere to the best of our knowledge. The proposed method may be used to monitor the saturation level of silica gel inside the breather to protect the power transformer from excess moisture contamination.