Fiber-Based Quantum Sensor for High-Voltage Grid Current Measurement Using Integrated Diamond Quantum Sensor

In this report, we propose a quantum sensing architecture for high-voltage (HV) grid current measurement based on an integrated diamond quantum sensor (DQS). The DQS is installed in the HV line for non-invasive busbar current measurement. An optical fiber composite insulator (OFCI) is employed to deliver 532 nm laser for diamond excitation, 860 nm laser to energize sensing system and 830 nm light for communication between equipment on high-voltage and low-voltage side. The OFCI ensures robust insulation performance while facilitating high-precision, long-distance current measurements. Dual-channel microwave (MW) configuration implemented in the board-level measurement system tracks two resonant frequencies along the nitrogen-vacancy (NV) axis, effectively suppressing temperature drift. This quantum sensing scheme achieves a measurement range of up to 5000 A with an accuracy of 0.15%. This configuration presents a novel approach and reliable system for the practical application of quantum sensors in HV grid monitoring.