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.
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.
High-voltage substations impose stringent requirements on current measurement, demanding simultaneously high electrical insulation and stable, high-precision performance. Here we propose and experimentally validate an all-fiber quantum current transformer based on nitrogen-vacancy (NV) centers in diamond. The transformer employs four optical fibers to realize power delivery and signal transmission between the high-voltage and low-voltage sides, completely eliminating metallic electrical connections. The system achieves a magnetic sensitivity of 4.05 nT/Hz 1/2 , with highly linear current response ( R 2 = 0.998) and a measurement accuracy better than 1%. This all-fiber architecture satisfies the dual constraints of high-voltage insulation and low power consumption while preserving the metrological precision of quantum sensing, providing a viable pathway toward non-invasive precision current monitoring in next-generation smart substations.
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.
Negatively charged nitrogen-vacancy (NV) centers in diamond have been extensively studied as a promising high sensitivity solid-state magnetic field sensor at room temperature. However, their use for current sensing applications is limited due to the challenge of integration and miniaturization of the diamond NV sensor. Here, we demonstrate an integrated NV sensor fabricated with standard microfabrication process. The sensor device incorporated with a toroidal magnetic yoke enables a high-precision wide range direct current sensing with galvanic isolation. The performance of the diamond NV current sensor in an open loop configuration has been investigated. A current measuring range of 0 A ~ 1000 A with an uncertainty of 46 ppm are achieved. Taking advantage of dual spin resonance modulation, temperature drift is suppressed to 10 ppm/K. This configuration opens new possibilities as a robust and scalable platform for current quantum sensing technologies.
This dissertation presents the development and characterization of fully integrated quantum sensors based on nitrogen vacancy (NV) centers in diamond. While existing NV-based sensors are typically large and complex, this work focuses on miniaturizing the technology and demonstrating its application as a current sensor. The primary research question addressed is whether fully integrated NVbased quantum sensors with LED excitation can be realized with performance comparable to conventional sensor technologies. To this end, two sensor prototypes were developed: one as the smallest fully integrated NV quantum sensor with a complete electrical interface to date, achieving a sensitivity of 32 nT/ √ Hz; and another as the first NV-based sensor implemented on a flexible PCB, which is even smaller and achieves a sensitivity of 96 nT/ √ Hz. Thereby both sensors utilize randomly oriented diamond microcrystals. Methodologically, a novel procedure for determining the orientation of the diamond crystals was developed, allowing for effective signal extraction despite the random crystal orientation. Further, magnetic fields were simulated using COMSOL Multiphysics to investigate the feasibility of applying these sensors for current measurements. In this context, a new measurement concept for determining currents in segmented multi-wire cables of three-phase power grids was developed, demonstrating the potential of NV-based sensors in smart grid applications. The results indicate that these quantum sensors can be more easily integrated, even when diamonds are placed arbitrarily, thus paving the way for new applications in smart grid monitoring and other fields requiring compact, high-precision magnetic field sensors.
Diamond nitrogen-vacancy (NV) centers have attracted extensive research interest for quantum sensing applications across various physical domains, owing to their prolonged coherence times and the capability of optical readout at room temperature, which offers a promising technical pathway for detecting fast-responding and transient signals in emerging power systems. This work presents a quantum sensing device based on the Zeeman and Stark effects of NV centers, designed for power system measurement applications, with a rated voltage of 10kV and a rated current of 1kA, enabling simultaneous voltage and current sensing. The device achieves a measurement accuracy of 0.69% under the rated voltage of 10 kV and +0.23% under the rated current of 1 kA, verifying the feasibility of employing quantum sensing based on NV centers for simultaneous voltage and power measurements in power systems.
The nitrogen-vacancy centers in diamond have exhibited excellent sensing capabilities. By applying the resonance frequency tracking (RFT) method in a closed-loop system, magnetic-field measurements with a wide dynamic range have been demonstrated. However, the previous strategies employ phase-sensitive control signals, which degrade control robustness and reduce tracking rates, thereby impeding real-time measurements. Here, an amplitude–phase joint discrimination strategy is proposed to improve robustness, overcoming the limitations of existing strategies that are sensitive to phase delays in fluorescence signal transmission. Moreover, to improve the tracking speed, a customized device, integrating a fast-response lock-in amplifier (LIA) and a frequency-agile microwave (MW) source, is reported. The LIA achieves a response time as short as 20 μs, while the MW source reaches a frequency switching time of 1 μs. The proposed strategy and customized device are implemented and evaluated on an all-fiber quantum current sensing system. Test results show that the system achieves a maximum sampling rate of 20 kHz, with excellent linearity (a linear deviation of 0.37% over the range of 0-120 A) and high accuracy (a measurement error of 0.73% at 80 A), making it promising for a wide range of high-speed quantum measurement scenarios.