The repair of high-voltage line faults necessitates the rapid determination of the cause of the fault by measuring the surrounding electric field. The piezoelectric-piezoresistive coupling electric field sensor， designed based on the principle of inverse piezoelectric effect， can complete the non-contact measurement in a complex environment， owing to the advantages of high safety， high sensitivity， and good linearity. This study performs field strength measurement using the finite element simulation and experimental measurement when the orientation angle between the electric field sensor and the measured electric field intensity is within the range 0° -75° . The experimental results showed that when the orientation angle was less than 45， the difference between the measured and simulation results was less than 1 mV. Based on this experiment， theoretical analysis and verification were conducted to determine the feasibility of detecting the cause and location of the fault by using a UAV carrying the electric field sensor to scan the transmission line.