--- title: "Demand factor and diversity factor of substation" subject: "Industrial Power Distribution and Illumination" chapter: 1 key: "semester_6/industrial_power_distribution_and_illumination:load-centre-demand-diversity-numerical" source: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/load-centre-demand-diversity-numerical site: BCT Engineering --- # Demand factor and diversity factor of substation Industrial Power Distribution and Illumination · Chapter 1: Introduction - Asked in: 2069 Bhadra, 8 marks - Video: [Load Factor, Diversity Factor, Plant Capacity Factor, Utilization Factor, Reserve Capacity](https://www.youtube.com/watch?v=CeVFXs6mnUU) — Electrical Minus - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/load-centre-demand-diversity-numerical - Whole chapter: https://www.bctengineer.com/md/semester_6/industrial_power_distribution_and_illumination/chapter-1 ## Question What is electric load centre? In an industry, substation supplies power for four blocks. Block-1 has 6 no. of machines with rating of 70kW, 90kW, 20kW, 50kW, 10kW and 20kW respectively, while maximum demand of block-1 is 200kW. Block-2 has 5 no. of machines of 60kW, 40kW, 40kW, 70kW and 30kW and maximum demand of block-2 is 160kW. Block-3 and 4 has maximum demand of 150kW and 200kW respectively. Determine demand factor of block-1 and 2. If the maximum demand of substation is 600kW, find the diversity factor of the substation. ## Short answer An electric load centre is the point at the centroid of loads, distributing power to minimise voltage drop and losses. Demand factor of Block-1 is 200/260 = 0.769; of Block-2 is 160/240 = 0.667. Diversity factor of the substation = (200+160+150+200)/600 = 1.18. ## Answer #### Electric load centre An electric load centre is the point from which power is distributed to a group of loads, located at the centre of gravity of those loads (X = ΣPx/ΣP, Y = ΣPy/ΣP). Placing the substation there keeps LV feeders short, reducing voltage drop, losses and cable cost. #### Demand factor of Block-1 and Block-2 ```text Demand factor = Maximum demand / Connected load Block-1 connected load = 70 + 90 + 20 + 50 + 10 + 20 = 260 kW DF(1) = 200 / 260 = 0.769 Block-2 connected load = 60 + 40 + 40 + 70 + 30 = 240 kW DF(2) = 160 / 240 = 0.667 ``` #### Diversity factor of the substation ```text Sum of individual maximum demands = 200 + 160 + 150 + 200 = 710 kW Maximum demand of substation = 600 kW Diversity factor = 710 / 600 = 1.183 ``` **Answer: Demand factor of Block-1 = 0.769, of Block-2 = 0.667; diversity factor of the substation = 1.18.** The blocks do not reach their peaks at the same time, so the substation needs to be sized for 600 kW rather than 710 kW. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is the electric load centre? A. The centre of gravity of the loads, where the substation reduces feeder length B. The point with the largest single machine C. The utility meter location D. The point of lowest soil resistivity Answer: A. Placing supply at the load centre shortens LV feeders. (Key point: Load centre) 2. What is the demand factor of Block-1 (machines total 260 kW, MD 200 kW)? A. 1.3 B. 0.5 C. 0.833 D. 0.769 Answer: D. 200/260 = 0.769. (Key point: Block-1 demand factor) 3. What is the demand factor of Block-2 (connected load 240 kW, MD 160 kW)? A. 1.5 B. 0.769 C. 0.667 D. 0.4 Answer: C. Connected load = 60+40+40+70+30 = 240 kW, and 160/240 = 0.667. (Key point: Block-2 demand factor) 4. What is the diversity factor of the substation with substation MD of 600 kW? A. 0.845 B. 1.183 C. 1.0 D. 1.5 Answer: B. Block MDs sum to 200+160+150+200 = 710 kW, and 710/600 = 1.183. 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