Bryan Underwood Advisor: Prof. Gutschlag Alternating Current Power Factor Monitoring and Correction

Power Factor is the ratio of the active power to the apparent power P.F. = = Complex Power Diagram

 Poor power factor is due to inductive loads such as induction motors in air conditioners and refrigerators  A very low power factor usually results in the power company charging more on a utility bill

 Ameren Illinois requires Residential customers (rate DS-1) and Light Industrial Non-Residential customers (rate DS-2, DS-3) to maintain a power factor of 0.90 while Heavy Industrial Non-Residential customers (rate DS-4) must maintain a power factor of

 If the power factor falls below the minimum specified by Ameren and ComEd, they require corrective devices to be installed  Pacific Gas and Electric (PG&E) charges 0.6% more on a utility bill for each percentage point below a power factor of

 About 60% of the electrical load in the United States is due to AC electric motors 3  According to the U.S. Energy Information Administration (EIA), only about 25,000 out of 200,000 manufacturing companies participate in power factor correction (PFC) 4

 Increased I 2 R losses in transmission lines due to the additional current requirements needed to provide excess reactive power reduces efficiency, capacity, and profit margins  Increased current requirements result in higher transmission line, transformer, and switch gear current ratings

 Usually done by capacitor banks ◦ Generate “negative” reactive power Power Factor Correction (PFC)

Hampden Type WRM Phase Motor  220 V  1.4 A  1725 RPM  1/3 HP

SATEC PM172E-N 3-Phase Programmable Power Meter

 SATEC Power Analysis Software V1.4 Build 5  Configure basic setup of meter, set trigger points, and view event logs and waveforms

news.thomasnet.com directindustry.com  Larger meters have more relay inputs and outputs to permit more incremental values of capacitors to be switched as needed for more precise control of the power factor  More programming options provide more robust control for better power factor correction

Potter & Brunfield KRPA-11AG-120 Power Relays

 Capacitance is added to each line and can be varied from 1.6uF to 50uF

 Resistors are placed in series with the capacitor banks to reduce inrush currents

 Current through resistor with 10uF Capacitor  Power losses  Current w/ 20uF  Power losses  Current w/ 30uF  Power losses

 Relay coils are energized from SATEC meter when the power factor drops below a certain point ◦ Line current is also monitored to ensure no switching occurs when no load is present  Capacitors are added to the circuit in parallel with the motor ◦ Placed in parallel to maintain the same line voltages into the motor  Power factor can be varied over any desired range to avoid electric utility company charges  Project system maintains a power factor of above 0.98

Experimental Results -0.9

 Complete the theoretical circuit model and compare with experimental results ◦ Research how the meter calculates its values  Write tutorial on how to use power meter ◦ Will use as an appendix for final paper  Write final paper

pdf 3 ctor--revised pdf 4

System Values at Various Loads Motor Load Apparent Power (VA) Power Factor Active Power (W) Motor Speed (RPM) No Load ¼ Load ½ Load ¾ Load Full Load