APFC Capacitor Bank kVAR Sizing & Surcharge Screening
Computes required capacitive reactive compensation to elevate operating power factor, recommends standard modular stepping, calculates billing kVA demand reduction, and estimates indicative Discom penalty avoidance.
Governing Standards & Harmonic Design Advisory
Standards & Tariff Framework
- IS 13340 (Part 1: 1993): Specifications for Shunt Capacitors for AC Power Systems.
- Tariff Savings Classification: Rupee savings represent an indicative screening estimate based on typical two-part industrial tariff schedules (e.g. PSPCL Large Supply tariff conditions). Actual savings depend on billing mechanism (kWh with PF surcharge vs kVAh direct billing).
Harmonic Resonance & Reactor Advisory
Where significant non-linear loading or harmonic distortion is present (VFDs, rectifiers, induction heating), a harmonic/resonance assessment should be performed. Series detuned reactors (e.g. 5.67%, 7%, or 14%) may be required based on the resulting study to prevent harmonic resonance. Overcompensation into leading power factor must be avoided.
ΔS = (P_kW / pf_1) - (P_kW / pf_2) [kVA]
ΔI_415V = (ΔS × 1000) / (√3 × 415) [A]
This calculation provides preliminary engineering screening. Project-specific APFC panel manufacturing requires verification of background harmonic distortion, capacitor voltage withstand ratings (440V/480V/525V), controller C/k ratio, and automatic step sequencing by a qualified electrical engineer.