Reliability Analysis of an Inverter at a Solar Power System in Bantul, Yogyakarta, using Random Forest

Photovoltaic systems are susceptible to various types of failures, such as system faults caused by weather conditions, soiled photovoltaic panels, partial shading, cable damage, short circuits, mechanical failures, and other disturbances. Reliability of photovoltaic systems is critical to ensuring a stable electricity supply. This research used real-time condition-monitoring data from an inverter of a Photovoltaic Power Plant in Bantul, Yogyakarta, Indonesia. In this study, a Random Forest Regression model was employed to predict the photovoltaic system voltage, achieving a coefficient of determination (R²) of 0.5964, indicating that the model explains approximately 59.74% of the variance in the actual data. Failure detection was performed using Residual-Based Anomaly Detection (RBAD), with a 5σ control limit applied to the residuals, resulting in 16 detected failure events over 9,664 operating hours. Based on these results, the Mean Time to Failure (MTTF) of the photovoltaic system was calculated as 593.75 hours, corresponding to a constant failure rate of 0.00168. Reliability analysis showed a gradual degradation over time, with reliability decreasing to 70% at 211 operating hours and 60% at 296 operating hours, indicating the necessity of periodic maintenance.