Comparative case study of EAST, HTA, OESD and Sherpa methods in maintenance activities on high voltage electrical power networks

Maintenance activities on high voltage electrical power networks, particularly those conducted on energized systems above 13.8 kV, are among the most complex and safety-critical tasks in the energy sector. Such operations require not only technical expertise but also robust analytical methods capable of identifying human, organizational, and systemic factors that contribute to risk. This study contributes by proposing an integrated human factors framework tailored to live-line maintenance, combining task, error, temporal, and systemic analyses. Trought a comparative case analysis of four recognized human factors and task analysis methodologies: Event Analysis of Systemic Teamwork (EAST), Hierarchical Task Analysis (HTA), Operator Event Sequence Diagram (OESD), and Systematic Human Error Reduction and Prediction Approach (SHERPA). Through the application of these methods to simulated scenarios of live-line maintenance, the research examines their effectiveness in mapping task dependencies, predicting potential errors, and identifying systemic vulnerabilities. The results highlight that while HTA provides clarity in task decomposition, SHERPA adds predictive insight into error likelihood and mitigation strategies. EAST contributes a systemic perspective by modeling communication, resource allocation, and interdependencies across teams, whereas OESD offers design-oriented guidance to reduce error susceptibility in procedures and tools. The comparative findings emphasize that no single method is sufficient in isolation; rather, an integrated approach enhances both process safety and worker safety. The study employed simulated operational scenarios designed to replicate critical phases of professional maintenance operations in populated areas, including normal flight conditions, degraded system states, and emergency recovery situations, with the aim of observing adaptive strategies and decision-making under realistic constraints.

Keywords: Human Factors and Ergonomics, Risk Analysis, Working Safely with electricity.