Evaluation and prediction of secondary circuit state of gateway metering voltage based on grey theory

To address the sharp increase in the number of secondary metering circuits at substations, heavy on-site inspection workloads, long time intervals, and the inability to dynamically monitor intermediate states, a secondary circuit status evaluation and prediction trend based on a comprehensive subjective-objective evaluation method and the analytic hierarchy process is proposed. This method identifies secondary circuit faults and develops status-based maintenance strategies accordingly. The results show that the trend prediction method based on grey theory is both accurate and feasible, providing theoretical support and guidance for the status evaluation and health prediction of tunnel measurement points.