Distribution network substations play a crucial role in the power system by receiving highvoltage power from the transmission system and stepping it down to a lower voltage for distribution to consumers. However, failures in substation components can lead to power interruptions and reduce system reliability. This thesis aims to identify the root causes of component failures in a substation and propose mitigation solutions to improve system reliability. The failure modes and effects analysis (FMEA) technique is used to identify the root causes based on the risk priority number (RPN). The study focuses on the bus bar, transformer, and circuit breaker components in the Gefersa substation located in Burayu, Oromia region, Ethiopia.Using recorded data and observed data, nine root causes of bus bar failure, including arc flash, cracking of connections, and ohmic heating, are identified for RPN analysis. The root causes of circuit breaker failure include external and internal causes, partial discharge, loss of dielectric properties, and contamination.ddd causes of transformer failure, such as overloads and external short circuits, are also identified. To address these issues, corrective actions are proposed, including implementing arc flash protection equipment, conducting preventive maintenance, performing real-time voltage and frequency analysis, regular inspections, and upgrading the skills of technicians. Keywords: Failure Mode Effect and Analysis, interruption causes, reliability index