--- title: "Define coverage factor" subject: "Transmission and Distribution System Design" chapter: 6 key: "semester_8/transmission_and_distribution_system_design:define-coverage-factor" source: https://www.bctengineer.com/q/semester_8/transmission_and_distribution_system_design/define-coverage-factor site: BCT Engineering --- # Define coverage factor Transmission and Distribution System Design · Chapter 6: Electrical Load Characteristics and Load Forecast - Asked in: 2069 Bhadra (old course), 3 marks - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_8/transmission_and_distribution_system_design/define-coverage-factor - Whole chapter: https://www.bctengineer.com/md/semester_8/transmission_and_distribution_system_design/chapter-6 ## Question Define coverage factor with respect to distribution consumer characteristics and discuss its significance on the design of distribution system. ## Short answer Coverage factor is the ratio of expected connected consumers to potential consumers by design year. It directly scales the effective consumer count for sizing transformers and feeders, influencing capital cost and reliability. ## Answer **Coverage factor** (electrification coverage factor) is the fraction or percentage of the potential consumers of a load centre who are expected to actually take an electricity connection by the design year: $$ \text{Coverage factor} = \frac{\text{Number of consumers actually connected}}{\text{Number of potential consumers}} $$ For example, if a village has 200 households and 140 are expected to be connected by the 5th year, the coverage factor is 70%. It is less than 100% because some households cannot afford connection or wiring costs, are far from the LT line, use other sources (solar home systems, micro-hydro), or join gradually after the line is built. **Significance in distribution design:** - Effective consumers in the design year $= N_0 (1+p)^n \times \text{coverage factor}$; this directly sets the peak demand used to size the distribution transformer and LT feeders. - Too high a value oversizes transformers, increasing cost and no-load losses; too low a value causes early overloading and voltage problems. - It is used to estimate revenue and the economic viability of rural electrification projects. - Coverage usually rises over time, so the design must allow for future additions (spare transformer capacity or space for upgrading). ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Coverage factor is: A. Fraction of potential consumers expected to be connected by the design year B. Ratio of average to peak load C. Yearly growth in kWh per consumer D. Fraction of land covered by the line Answer: A. It is the number of consumers actually connected divided by the number of potential consumers. (Key point: Definition) 2. How is the effective number of consumers in the design year found? A. N0 x coverage only B. N0 (1+p)^n x coverage factor C. N0 / coverage factor D. N0 (1+p)^n + coverage Answer: B. Population growth is applied to the potential consumers and then multiplied by coverage; this sets the peak demand. (Key point: Use in design) 3. What happens if the coverage factor is taken too low? A. Transformers oversized with high no-load loss B. Nothing changes C. Early overloading and voltage problems D. Higher revenue Answer: C. Too low an estimate undersizes the transformer and LT feeders; too high oversizes them. 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