Preliminary Industrial DG Set Capacity Screening Estimator
Sizes diesel generator kVA capacity from base linear and motor loads, accounts for starter inrush (DOL, Star-Delta, Soft Starter, VFD), and selects standard commercial ratings within the ISO 8528 classification framework.
Commercial Sizing Methodology & Emission Compliance
Commercial Ratings & ISO 8528 Framework
- Commercial DG Rating Schedule: Standard manufacturer market rating steps (15, 25, 30, 45, 62.5, 82.5, 100, 125, 160, 200, 250, 320, 380, 400, 500, 600, 625, 750, 1000, 1250, 1500, 2000 kVA) used for preliminary commercial selection.
- ISO 8528-1: 2018 Framework: Classifies generating sets by application (Emergency Standby Power - ESP, Prime Power - PRP, Continuous Operating Power - COP, Data Centre Power - DCC).
- CPCB-IV+ Emission Note: Central Pollution Control Board Stage IV+ regulations enforce statutory emission limits (PM, NOx, CO, HC) for engines up to 800 kW. Compliance is a statutory procurement mandate in India.
Screening Equations
S_start = (P_largest / 0.80) × K_starter [kVA]
S_target = max(S_run / 0.80, S_run + 0.35 × S_start)
Inrush factors: DOL (6.0×), Star-Delta (2.5×), Soft Starter (3.0×), VFD (1.2×). The 80% continuous load limit (S_run / 0.80) is an explicit engineering/design utilization assumption to provide thermal headroom, NOT a universal mandatory ISO 8528 requirement. Final set selection must remain manufacturer and project verified.
This calculation provides preliminary engineering screening. Project-specific DG set selection requires transient voltage dip analysis (≤ 15–20%), transient frequency dip analysis (≤ 8–10%), alternator subtransient reactance ($X''_d$), step-load sequencing, and site de-rating for temperature ($>40^\circ\text{C}$) and altitude ($>1000\text{m}$) verified by a licensed engineer.