Question

Section 2.3 Com Ps OL source load capacitor SL = 125 kVA Qc = 42.13 kvar = 36.870 Qs = 3287 kvar 10s = 18.19" P = Ps-PR-100 kW After the capacitor is connected, the power facto

Figure 2.6 depicts this circuit as a voltage source applied to a resistor and inductor in parallel (disregard the capacitor for part A), which is to be an equivalent to the load.  Why is a resistor and inductor in parallel used for the load versus just using a resistor?

Find the following (show calculations):

Real power absorbed by the load.

Apparent power of the load.

Reactive power of the load.  Don’t use the tangent function.  Instead, find the reactive power using the apparent power you calculated in part b.

Real power delivered by the source.

Apparent power of the source.

Reactive power delivered by the source.  Again, don’t use the tangent function.  Find the reactive power using the apparent power.

Now add the capacitor as shown in Figure 2.6.  The capacitor changes the source power factor to 0.95 lagging.Find the following (show calculations):

Real power provided by the source.

Apparent power provided by the source.

Reactive power delivered by the source.  Don’t use the tangent function.

Why does the power delivered to the load remain the same?

Why does the reactive power absorbed by the load remain the same?

Explain how the capacitor reduces the reactive power delivered by the source?

The text says that ‘the end result of power factor correction is improved efficiency.’  How and why is there improved efficiency?

Open up the PowerWorld Simulator and run the Example 2_3 case found in the folder of Cases under Chapter 2.

Run the case with 0 kvar for the capacitor.  Take a screenshot, including the time stamp.

Run the case with 20kvar for the capacitor.  Take a screenshot, including the time stamp.

Explain all the changes and lack of changes between the two scenarios.  Include a table, and then explain the changes.

Explain how the rates of the arrows reflect the two different scenarios.

Calculate the power factor for the case with 20kvar for the capacitor.

Answer 1