Estimates annual technical (I²R) energy loss on a distribution line from the coincident peak load, line resistance, and load factor, using the commonly-cited empirical relation between load factor and loss factor (LSF ≈ 0.3×LF + 0.7×LF²) when interval load data isn't available.
Standards followed
Commonly-cited empirical load-factor-to-loss-factor approximation (not an exact physical relationship — a well-known practical shortcut used across the industry)
What it can do
- Coincident peak load from individual peak and diversity factor.
- Peak line current and I²R loss at peak, from line resistance and system voltage/PF (or a directly entered peak current).
- Annual energy loss and cost, from the loss-factor approximation applied to the peak loss over 8,760 hours/year.
Example problem
500kW peak load, diversity factor 1.2, 60% load factor, 0.5Ω line resistance, 11kV, 0.9 PF, $0.12/kWh.
- Loss factor = 0.3×0.6 + 0.7×0.6² = 0.18 + 0.252 = 0.432.
- Coincident peak = 500/1.2 = 416.7kW.
- Peak current ≈ 24.3A → peak I²R loss ≈ 0.89kW.
- Annual loss = 0.89 × 0.432 × 8760 ≈ 3,352 kWh → cost ≈ $402/yr.
≈3,350 kWh/year technical loss.
Want the full step-by-step version?
The loss-factor approximation is a well-known empirical shortcut, not an exact relationship — for a rigorous study, use actual interval (15/30-min) load data to compute loss factor directly rather than this approximation.