Mitigating Transformer Failures in Offshore Wind Power Using Online Monitoring

Abstract Transformers in offshore wind farms face significant reliability challenges, with failure rates estimated between 5% and 7% annually. Harsh environmental conditions—including moisture ingress, thermal stress, mechanical vibrations, salt contamination, and power harmonics—accelerate insulation degradation, leading to catastrophic failures. These failures cause unplanned downtime ranging from weeks to months, with financial impacts exceeding €500,000 per day in lost revenue and repair costs reaching up to €5 million per unit. This study aims to evaluate the effectiveness of online condition monitoring in mitigating transformer failures, reducing downtime, and improving operational resilience in offshore wind power applications.