{ "background": "Power-distribution systems in many developing nations face significant challenges in balancing infrastructure investment with long-term operational efficiency. There is a notable scarcity of rigorous, field-based evaluations of the cost-effectiveness of different equipment strategies within these constrained contexts.", "purpose and objectives": "This study aimed to develop and apply a quasi-experimental methodology to empirically evaluate the comparative cost-effectiveness of alternative power-distribution equipment systems deployed within a national utility's network.", "methodology": "A difference-in-differences framework was employed, analysing operational and cost data from multiple network segments before and after the installation of new equipment types. The core statistical model was $Y{it} = \\beta0 + \\beta1 \\text{Treat}i + \\beta2 \\text{Post}t + \\beta3 (\\text{Treat}i \\times \\text{Post}t) + \\epsilon{it}$, where $Y_{it}$ is the total cost per unit of reliable energy delivered. Robust standard errors were clustered at the substation level to account for serial correlation.", "findings": "The intervention employing modernised, fault-tolerant switchgear demonstrated a statistically significant reduction in total lifecycle cost per MWh delivered. The estimated average treatment effect was a 17.3% cost reduction (95% CI: 12.1% to 22.5%) compared to conventional equipment upgrades in control segments.", "conclusion": "The quasi-experimental design provided robust, field-derived evidence that strategically selected, higher-capital-cost equipment can yield superior long-term cost-effectiveness in this operational environment by drastically reducing failure-related operational expenditures.", "recommendations": "Utilities should integrate prospective quasi-experimental evaluations into procurement planning to guide capital allocation. Policymakers should support regulatory frameworks that consider total lifecycle cost, not just initial capital outlay.", "key words": "cost-benefit analysis, difference-in-differences, distribution networks, lifecycle costing, power infrastructure", "contribution statement": "This paper