Understanding Maximum Demand Calculation: A Comprehensive Guide
If your MD is 500 kVA but your typical load is 350 kVA, you are overpaying. Solutions:
Engineers typically use one of four approaches outlined in standards like AS/NZS 3000 or BS 7671: Maximum Demand Tables - ELEK Software maximum demand calculation
The Formula: $$MD = \sum (Individual Loads \times Demand Factor \times Diversity Factor)$$
Example: For domestic lighting, you might only count the first 20 points at 100% and the remainder at 50%. This method is more accurate when you have
Harmonics: Modern electronics (LEDs, computers) can create "dirty" power that increases the neutral current, affecting the total demand profile. Conclusion
Power Factor (PF): Crucial because utilities often bill demand in kVA (Apparent Power), not kW (Real Power). affecting the total demand profile.
A coincidence factor of 1.0 means everything peaks together. A factor of 0.8 means only 80% of the individual peaks occur at the same time. This method is more accurate when you have historical submeter data.