Qr = P * (tanφ - tanφ_des)
Qc = Qr / (2 * π * f * U²)
Qc = Qr / (2 * π * f * U² * 3)
Qr = Reactive power (VAr)
Qc = Power factor correction capacitor (F)
P = Active power (kW)
U = Voltage (V)
f = Frequency (Hz)
π = 3.1415926535
φ = Phase shift between voltage and current
Power factor correction (PFC) is a technique that improves the efficiency of an electrical system by adding capacitors to offset the reactive power generated by inductive loads (e.g., motors, transformers). This reduces current draw, minimizes energy losses, and lowers utility bills. This tool calculates the required capacitor capacity (in kVAR) to raise the power factor from its current value to a desired level.
Commonly used in industrial plants, commercial buildings, data centers, and other facilities with significant inductive loads.
| Parameter | Description |
|---|---|
| Voltage | Operating voltage of the system. 1. Single-phase: Enter **Phase-Neutral voltage** 2. Two-phase / Three-phase: Enter **Phase-Phase voltage** |
| Frequency | Number of cycles per second, unit: Hertz (Hz). Typically 50 Hz or 60 Hz |
| Load | Active power consumed by the load, unit: kilowatts (kW) |
| Current Power Factor | Existing power factor value between 0 and 1. For example, 0.7 indicates low efficiency |
| Desired Power Factor | Target power factor after correction. Must be higher than the initial value. Recommended: ≥ 0.95 |
| Capacitor Voltage | Rated voltage of the capacitor bank. Must match system voltage (e.e., 400V, 415V) |
| Connection Type | Configuration of the capacitor bank: 1. Star (Y): Suitable for high-voltage or balanced three-phase systems 2. Delta (Δ): Common for low-voltage or high-current applications |
The required reactive power compensation (Qc) is calculated using:
Q_c = P × (tanφ₁ - tanφ₂)
Where:
Q_c: Required capacitor capacity (kVAR)
P: Load active power (kW)
φ₁: Initial phase angle, where cosφ₁ = PF₁
φ₂: Target phase angle, where cosφ₂ = PF₂
For a 100 kW load with initial PF = 0.7 and target PF = 0.95, approximately 58 kVAR of capacitance is needed.
1. Monitor power factor regularly and use automatic switching capacitor banks
2. Select capacitors with appropriate rated voltage to prevent overvoltage or under-voltage operation
3. Use step-controlled capacitor banks for dynamic compensation
4. Avoid over-correction, which may cause capacitive conditions, resonance, or voltage rise
5. Combine with power quality analyzers for real-time data and improved accuracy
The power factor correction calculator is designed for industrial and commercial power‑distribution systems. It calculates the required kVAR capacity of capacitor banks based on load active power, existing power factor and target power factor.
It supports star and delta connections for reactive‑compensation design in factories, buildings and data centers with inductive loads.
The theoretical maximum power factor is 1 and cannot exceed 1. Over‑compensation should be avoided.
It introduces capacitive reactive power and may cause voltage rise or resonance. In practical projects, target power factor is usually set between 0.95‑0.99.
The calculator outputs total required kVAR, which is independent of connection topology.
However, star and delta connections change the voltage stress on individual capacitors. Capacitor rated voltage must match connection type and system voltage to prevent component damage.
This tool calculates theoretical compensation capacity under ideal sine‑wave load conditions.
For real procurement, take harmonics, switching steps and standard capacitor ratings into account. Step‑controlled capacitor banks are recommended.
Always cross‑check with on‑site power‑quality analyzer measurements.
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