Power Factor Correction Calculator
ANA›Life Services Authority›National Calculator Authority›Power Factor Correction Calculator
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Power Factor Correction Calculator
Calculate the reactive power (kVAR) and capacitance required to improve your system's power factor to a desired target value.
Real Power (kW)
Existing Power Factor (0.01 – 1.00)
Target Power Factor (0.01 – 1.00)
System Voltage (V)
Frequency (Hz)
Calculate Results will appear here.
function powCalc() { const resultDiv = document.getElementById('pow-result');
const P = parseFloat(document.getElementById('pow-real-power').value); const pfOld = parseFloat(document.getElementById('pow-existing-pf').value); const pfNew = parseFloat(document.getElementById('pow-target-pf').value); const V = parseFloat(document.getElementById('pow-voltage').value); const f = parseFloat(document.getElementById('pow-frequency').value);
// --- Validation --- if (isNaN(P) || P ⚠ Please enter a valid Real Power greater than 0 kW.'; return; } if (isNaN(pfOld) || pfOld 1.00) { resultDiv.innerHTML = '⚠ Existing Power Factor must be between 0.01 and 1.00.'; return; } if (isNaN(pfNew) || pfNew 1.00) { resultDiv.innerHTML = '⚠ Target Power Factor must be between 0.01 and 1.00.'; return; } if (pfNew ⚠ Target Power Factor must be greater than the Existing Power Factor.'; return; } if (isNaN(V) || V ⚠ Please enter a valid System Voltage greater than 0 V.'; return; } if (isNaN(f) || f ⚠ Please enter a valid Frequency greater than 0 Hz.'; return; }
// --- Core Calculations --- // Reactive power before and after correction const Q_old = P * Math.tan(Math.acos(pfOld)); // kVAR existing const Q_new = P * Math.tan(Math.acos(pfNew)); // kVAR target
// Required capacitor bank size const Q_c = Q_old - Q_new; // kVAR to add
// Apparent power before and after const S_old = P / pfOld; // kVA existing const S_new = P / pfNew; // kVA target
// Capacitance: C = Q_c / (2π f V²) [Q_c in VAR, V in volts → C in Farads] const Q_c_VAR = Q_c * 1000; const C_F = Q_c_VAR / (2 * Math.PI * f * V * V); const C_uF = C_F * 1e6;
// Current before and after const I_old = (S_old * 1000) / (Math.sqrt(3) * V); // 3-phase line current (A) const I_new = (S_new * 1000) / (Math.sqrt(3) * V);
// --- Format helper --- function fmt(val, dec) { return val.toFixed(dec); }
resultDiv.innerHTML = `
ParameterBefore CorrectionAfter Correction
Power Factor${fmt(pfOld,3)}${fmt(pfNew,3)} Real Power (kW)${fmt(P,3)}${fmt(P,3)} Reactive Power (kVAR)${fmt(Q_old,3)}${fmt(Q_new,3)} Apparent Power (kVA)${fmt(S_old,3)}${fmt(S_new,3)} Line Current – 3φ (A)${fmt(I_old,3)}${fmt(I_new,3)}
Required Capacitor Bank: 🔋 Reactive Power (Qc): ${fmt(Q_c,3)} kVAR ⚡ Capacitance (C): ${fmt(C_uF,3)} µF (3-phase, line voltage basis) `; }
#### Formulas Used
Existing Reactive Power: Qold = P × tan(arccos(PFold))
Target Reactive Power: Qnew = P × tan(arccos(PFnew))
Required Capacitor Bank (kVAR): Qc = Qold − Qnew
Required Capacitance: C = Qc / (2π × f × V²) [Farads, line voltage]
Apparent Power: S = P / PF (kVA)
3-Phase Line Current: I = S × 1000 / (√3 × V) (A)
#### Assumptions & References
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