Thyristor Lifetime Prediction Based on Thermal Resistance Update Strategy

Thyristor failures in high-voltage direct current (HVDC) transmission systems can trigger cascading converter valve malfunctions, potentially leading to widespread transmission outages and significant economic impacts. The accurate prediction of thyristor remaining useful life therefore represents a fundamental challenge in ensuring HVDC system reliability. This study presents a novel thermal resistance-adaptive lifetime prediction methodology that advances conventional approaches in three key aspects: First, the proposed method classifies thyristor aging into five distinct phases, with thermal resistance values updated for predictive analysis within each phase. Second, it implements a phased aging process characterization. Third, it incorporates damage accumulation physics. Unlike traditional models that assume constant thermal resistance parameters, the proposed approach demonstrates substantially improved prediction accuracy through experimental validation, offering utilities a more reliable tool for maintenance planning and system health assessment.