A Quasi-Experimental Evaluation of Power-Distribution System Reliability in Ghana: A Case Study of Equipment Methodologies (2000–2026)

{ "background": "Chronic power outages in many developing nations are often attributed to ageing and inadequate distribution infrastructure. However, systematic, data-driven evaluations of the reliability performance of different equipment methodologies within these networks are scarce, hindering evidence-based investment and maintenance strategies.", "purpose and objectives": "This case study aims to provide a rigorous, quasi-experimental evaluation of the reliability of distinct equipment methodologies deployed within Ghana's power-distribution system. Its objective is to quantify the comparative performance of different transformer and switchgear types in terms of failure rates and outage durations.", "methodology": "A quasi-experimental design was employed, comparing reliability metrics across non-randomly assigned but matched groups of equipment. The core statistical model is a survival analysis using a Cox proportional hazards model: h(t|X) = h0(t) exp(\β1 X1 + \β2 X₂ + \ε), where X represents equipment type and operational environment covariates. Inference is based on robust standard errors clustered by geographical district.", "findings": "The analysis reveals a statistically significant divergence in reliability. Vacuum circuit breaker switchgear demonstrated a 34% lower hazard rate for unplanned outages compared to traditional oil-based units. Furthermore, the estimated coefficient for modern amorphous-core transformers indicated superior durability, with a 95% confidence interval for the hazard ratio excluding 1.", "conclusion": "The quasi-experimental approach successfully isolated the effect of equipment methodology on system reliability, demonstrating that technological choice is a critical determinant of distribution network performance in this context.", "recommendations": "Utilities should prioritise the procurement of vacuum interruption technology and amorphous-core transformers for future network reinforcement and replacement programmes. A phased asset management strategy targeting the most unreliable legacy equipment is advised.", "key words": "power distribution reliability, quasi-experimental design, survival analysis, asset management, developing infrastructure", "contribution statement": "This study provides a novel methodological framework for comparative infrastructure assessment in settings where randomised controlled trials are impractical,