Accurate and stable current measurement is critical in the monitoring, protection, and control of modern power systems. While traditional electromagnetic and electronic current transducers have been widely deployed, their performance is increasingly constrained by limitations such as narrow bandwidth and small dynamic range, posing challenges for integration in intelligent grid infrastructures. Accordingly, this paper proposes a quantum-enhanced optical current transducer (Q-OCT) that employs quantum precision measurement (QPM) techniques to overcome these limitations. The Q-OCT is designed based on the magnetic sensitivity of nitrogen-vacancy (NV) centers in diamond, which enables high-resolution, non-invasive magnetic field detection with excellent thermal and long-term stability. In addition, a fiber-optic coupling scheme is incorporated to consolidate pump and probe signals into a single optical fiber, significantly reducing the physical footprint of the sensor while preserving its accuracy. A prototype device is developed and experimentally evaluated under various operating conditions. The results demonstrate that Q-OCT achieves improved measurement accuracy, reduced drift, and enhanced adaptability, offering a promising solution for next-generation smart grid applications.