Power factor correction
- 2. Objectives •Define power factor. •Calculate the capacitor value required to correct AC series parallel networks to the desired apparent power. •Compare currents, voltages, and power in AC series parallel networks before and after power factor correction.
- 3. Importance of Power Factor •Consider the following example: A generator is rated at 600 V and supplies one of two possible loads. • Load 1: P = 120 kW, P.F = 1 Load 2: P = 120 kW, P.F = 0.6 •Generator current required to supplythe load
- 4. Importance of Power Factor • For the load with Fp = 0.6, the generator had to supply 133 more amperes in order to do the same work . • Larger current means larger equipment (wires, transformers, generators) which cost more. • Larger current also means larger transmission losses (think I2 R).
- 5. POWER-FACTOR CORRECTION FIG. shows the impact of power-factor correction on the power triangle.
- 6. Power factor correction capacitors for A, B, and C phases at the Crofton , MD substation Rating: 230 kV, 360 MVAR size comparison Capacitor banks
- 7. Power Factor Correction •Almost all loads are inductive. •To cancel the reactive component of power, we must add reactance of the opposite type. This is called power factor correction. Capacitor bank in shipboard power panel for FP correction
- 8. Power Factor Correction •Almost all loads (commercial, industrial and residential) look inductive (due to motors, fluorescent lamp). •Hence, almost all power factor correction consists of adding capacitance.
- 9. Power Factor Correction Solution Steps 1. Calculate the reactive power (Q) of the load 2. Insert a component in parallel of the load that will cancel out that reactive power e.g. If the load has QLD=512 VAR, insert a capacitor with QC=-512 VAR. 3. Calculate the reactance (X) that will give this value of Q Q=V2 /X 1. Calculate the component value (F ) required to provide that reactance.
- 10. Power Factor Correction •Transmission lines and generators must be sized to handle the larger current requirements of an unbalanced load. •Industrial customers are frequently fined by the utility if their power factor deviates from the prescribed value established by the utility.
- 11. Thank you