Table 1
| Load | Rating | Power Factor |
| Lighting | 41.1kW | 0.7 Lagging |
| Lights | 12.2 kVa | 0.67 Lagging |
| Ventilation fans | 9 kVa | 0.7 lagging |
| Heat pump | 18 kW | 0.707 Lagging |
| misc equipment | 11.3 kVa | 0.55 lagging |
| peak charging demand | 209 kW | unity |
Calculate the following for the car park using the datafrom Table 1:
a) the maximum real power demand P (kW)
b) maximum reactive power demand Q (kVAr)
c) the total apparent power demand S (kVA)
d) also, calculate the maximum current magnitude |I| ifthe supply voltage magnitude |V| is 3.3 kV and the supply frequencyis 50 Hz.
e) Calculate the overall car park powerfactor.
f) Calculate the rating of the capacitor bank (μF)needed to improve the car park power factor to unity.
g) Calculate the new maximum current magnitude, afterpower factor correction. Again assume the supply voltage magnitudeis 3.3kV and frequency is 50 Hz.
h) Select the cable ID from Table 2 that you would useto supply the car park BEFORE AND AFTER power factor correction hasbeen applied.
i) Comment on your result.
Table 2
Cable ID | Rating (A) | Cable ID | Rating (A) |
A | 20 | J | 100 |
B | 25 | K | 110 |
C | 30 | L | 120 |
D | 40 | M | 130 |
E | 50 | N | 140 |
F | 60 | O | 150 |
G | 70 | P | 160 |
H | 80 | Q | 170 |
I | 90 | R | 180 |
