Operational Safety Risk Assessment for Electric Utilities Based on an Accident-Calibrated Cumulative Risk Index

In response to the issues of subjective weighting of indicators and insufficient consideration of the temporal dimension of risk factors in current operational safety risk assessments for electric utilities, this paper proposes a method for assessing operational safety risks in electric utilities based on the Accident-Calibrated Cumulative Risk Index (ACCRI). First, in accordance with current standards and operational guidelines, a multi-level indicator system covering four dimensions, namely human resources and personnel behavior, equipment and facilities, environment and conditions, and management and systems, is established to provide a systematic characterization of operational safety risks in electric utilities. On this basis, the ACCRI is defined by weighted accumulation of the average risk exposure values of tertiary indicators within their characteristic periods. Historical accident sample importance is used to calibrate and identify tertiary indicator weights and characteristic periods, thereby reducing the subjectivity of traditional expert-based weighting. Furthermore, considering the differing temporal-scale characteristics of various risk indicators, a characteristic-period identification model is established and solved using an improved sparrow search algorithm to balance the timeliness and accuracy of risk assessment. By incorporating chaotic initialization, Gaussian mutation, and adaptive weighting mechanisms, this algorithm enhances population diversity and balances global search capability with local optimization capability across different solution stages, thereby improving the solution efficiency and accuracy of the model. Finally, the case study preliminarily demonstrates that the proposed method can characterize the temporal-scale differences among risk factors and shows potential for engineering application under the available enterprise data.