The customer is not greatly concerned with an inefficient power factor, provided that sufficient

power reaches the load. To make the customer more aware of power factor considerations, the

power company may install a penalty on the customer’s bill. A typical penalty power factor chart

is shown in Table 1. Power factors below 0.6 are not permitted, if a customer records power

factor below 0.6 a 25 percent penalty is applied.

Table 1. Penalty for low power factor

Power factor Penalty

0.9 and higher none

0.8 to 0.899 1%

0.7 to 0.799 2%

0.6 to 0.699 3%

An industrial plant you work for connects four loads in parallel to a 400V, 50 Hz supply.

Load 1 absorbs 50 kVar at 0.7 lagging, load 2 absorbs 15 kW and generates 5 kVar, and

load 3 absorbs 5 kW at unity power factor, load 4 has an impedance of 20∠55°.

a) Calculate the branch currents and draw the phasor diagram

b) What % penalty does the company risk facing on its next bill?

c) As an electrical engineer in charge of power factor correction, with a p. f target of unity,

recommend the rating of element or equipment in kVar to use so as to avoid penalties.

- provide the branch currents and the phasor diagrams

- draw the power triangles before and after power factor correction.

d) Verify your answers using Matlab/Simulink

- show the rms currents on the Simulink model