Required capacitor power Qc = P·(tanφ₁−tanφ₂) It is found by multiplying the active power (P) by the tangent difference between the current and target power coefficients. For example, to reach 150 kW and increase cosφ from 0.82 to 0.98, approximately 74 kVAr is required.

Qc = P × (tanφ₁ − tanφ₂) [kVAr]
Example calculation: For a 150 kW load, cosφ changes from 0.82 to 0.98 → tanφ 0.70 → 0.20; Qc = 150 × (0.70 − 0.20) ≈ 74 kVAr capacitor is required.

Compensation — Required Capacitor Power

Calculate the reactive power (kVAr) required to achieve the target power factor (cosφ). This complements the reactive penalty risk tool: a tool that identifies the problem, and a tool that sizes the solution.

Required capacitor
–
tanφ₁ → tanφ₂
–
Notes: Qc = P·(tanφ₁−tanφ₂). The result is indicative; in the actual panel design... Stepping, harmonic load (detuned/reactor compensation), and resonance. Engineering assessment is required. Values are calculated based on your inputs.
Get a quote for compensation design & inspection →

How is it calculated?

  1. Enter the active power (kW).
  2. Enter the current cosφ₁ and target cosφ₂ values (the target is usually 0.98).
  3. Press Calculate; the required kVAr will be displayed.

Frequently Asked Questions

How is capacitor power calculated?
The formula Qc = P·(tanφ₁−tanφ₂) uses the tangent difference between the active power and the current/target power factor.
Why is compensation necessary?
To avoid reactive energy penalties, reduce line losses, and efficiently utilize transformer/cable capacity.
When is reactor-based (detuned) compensation needed?
If the facility has a high concentration of harmonic-generating loads (inverters, LED drivers, etc.), reactor-based compensation is considered to prevent resonance.

Related tools and services

This tool and its content are for general informational purposes only; they do not constitute a binding inspection/declaration of conformity. Definitive results will be determined through on-site inspection in accordance with relevant legislation and standards. Get a quote →