Fiber-Integrated Diamond Quantum Sensor for High-Voltage Current Measurements

Abstract

In power network systems, there is an urgent demand for highly accurate and miniaturized sensors, owing to their high safety level and limited installation space. Current sensors in high-voltage grids are required to accommodate harsh environments and provide accurate measurements of several kiloamperes. Thus, this study proposed an integrated quantum diamond sensor to facilitate high-accuracy, large-dynamic-range current measurements. The design incorporated optical fiber and directional microwave (MW) antennas to drive the diamond sensor, which significantly reduced the size and power consumption on the high-voltage side. Remote-control and demodulation systems are installed more than 10 m away from the low-voltage side. The proposed approach achieved zero power consumption on the high-voltage side and ensured efficient signal transmission. A passive diamond probe manufactured using microfabrication processes facilitated miniaturization and practical deployment. Through parameter optimization, a magnetic detection sensitivity of 4.86 nT·Hz^−1/2 is achieved at a safe distance of 11 m, which can be further optimized to 0.77 nT·Hz^−1/2 with enhanced MW power. This sensor achieved a current measurement error of ±0.4% in the 1000 A measurement range. Thus, this study provides a new solution for the application of diamond quantum sensors in power systems.