A Highly Sensitive and Durable Sensor for In Situ Hydrogen Measurement in Transformer Oil

Dissolved hydrogen, which serves as the primary indicative gas for early failures in oil-immersed transformers, can be monitored to provide early warning signs. However, current online monitoring methods for dissolved hydrogen suffer from drawbacks including low sensitivity, poor durability, and limited precision thereby failing to determine equipment status promptly prompuy and reliably. To overcome these limitations, a highly sensitive and durable sensor based on long-period fiber gratings (LPFGs) for in situ hydrogen measurement was designed and developed in this article. A measurement platform was constructed to acquire sensitivity measurements at various temperatures along with stability results. The results demonstrate that a highly sensitivity was achieved, with values of 0.303 pm/(LA) at 20 degrees C and 0.152 pm/(L/L) at 60 degrees C, respectively, representing an approximately three to eightfold increase compared with existing optical fiber hydrogen sensors. The durability of the sensor has been thoroughly demonstrated through long-term equivalent operation. Furthermore, the relationship between the transformer temperature and the sensor sensitivity was analyzed. Experimental results exhibited high repeatability confirming that the highly sensitive and durable sensor can be effectively deployed within transformers enabling in situ measurement, which provides a technical means for the online monitoring of the dissolved hydrogen in transformer oil.