Power Triangle 123z1u

Power Triangle Power Factor Correction

Power Triangle • The representation of a right angle triangle showing the relation between real power, reactive power, and apparent power.

Real Power • The power which is actually consumed or utilized in AC circuits • Denoted by P • Sometimes called true power or active power. • Measured in Watts or kiloWatts

Reactive Power • The power which flows back and forth • Denoted by Q • Measured in volt-ampere reactive(VAR) or kilovoltampere reactive(kVAR)

Apparent Power

• The total power in ac circuit • Combination of true power and reactive power • Denoted by S • Measured in volt-ampere(VA) or kilovoltampere(kVA)

Power Factor •  The ratio of Real Power over the Apparent Power Power Factor = Real Power/ Apparent Power pf = P/S cos = P/S Real Power = Apparent Power x cos Real Power = Voltage x Current x cos P = VIpf

Example • A single phase load on 220 V AC source takes 100 W at 0.6 lagging power factor. Assume the load power factor will be brought to about 0.9. • Current at 0.6 lagging power factor Real Power = Spf P = Vipf I = P/Vpf I = 100/220(0.6) I = 0.75 Amperes

•  Apparent Power (S) S = VI S = 220(0.75) S = 165 VA Reactive Power Q = Ptan Q = 100(tan(53.13) Q = 133.33 VAR

Corrected Power Factor to 0.9 Current P = Spf P = Vipf I = P/Vpf I = 100/220(0.9) I = 0.5 Ampere

•  Reactive Power Q = Ptan Q = 100(tan(24.84)) Q = 48.43

• Total Reactive Power Total Reactive Power = Reactive Power old – Reactive Power New Q = Qold – Qnew Q = 133.33 – 48.43 Q = 84.9 VAR