▎ 摘　　要

The safe operation of power transformer is vital to the reliability of modern power network. The bushing is a key component of transformer that serves to connect the transformer windings to the transmission lines. Due to its intricate structure and severe operating conditions, the bushing is among the most frequent cause of transformer failure. Therefore, it is essential to monitor the condition of transformer bushing for maintaining the safe and stable operation of grid. In this paper, we propose a graphene piezoresistive pressure sensor based on handkerchief paper (GHPPS) to monitor the internal pressure of transformer bushing. The GHPPS possesses a highly porous structure and a fibrous tissue, and exhibits a superb sensitivity to the variations of bushing internal pressure. Moreover, we compared the sensitivity and conductivity of the sensors with different paper layers. The GHPPS with 8 layers owns the highest sensitivity (15.6 kPa(-1)), the smallest response time (60 ms) and recovery time (75 ms), and the best stability. In addition, a hierarchical alarm device is used to test the monitoring capability of GHPPS at different pressure levels. The results prove that the GHPPS is a promising tool for monitoring conditions.