Powerfactor Improvement

Network characteristics
Network voltage and frequency are the basic
factors required to size a LV correction cubicle.
Reactive power Q varies according to voltage
square and frequency.
Q = U2 x C x w
where :
Q = reactive power
U = network voltage
C = capacitance
w= 2pf
f = network frequency
Compensation schematic diagram
Qc = Pa (tg j – tg j')
Calculation table for kvar to be installed
before capacitor power in kvar to be installed per load kW, to reach the power factor
compensation (cos j) or the tg j at a given valueCalculating the reactive power

to be installed
This is calculated:
c either from the electricity bills to avoid paying
reactive energy
c or from the tg j and a target tg j’.
These calculation methods are described
in detail in the Rectiphase “LV reactive power

Calculation table for kvar to be installed
before capacitor power in kvar to be installed per load kW, to reach the power factor
compensation (cos j) or the tg j at a given value
tg j 0.75 0.59 0.48 0.46 0.43 0.40 0.36 0.33 0.29 0.25 0.20 0.14 0.08
tg j cos j cosj 0.80 0.86 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1
1.33 0.60 0.584 0.733 0.849 0.878 0.905 0.939 0.971 1.005 1.043 1.083 1.131 1.192 1.334
1.30 0.61 0.549 0.699 0.815 0.843 0.870 0.904 0.936 0.970 1.008 1.048 1.096 1.157 1.299
1.27 0.62 0.515 0.665 0.781 0.809 0.836 0.870 0.902 0.936 0.974 1.014 1.062 1.123 1.265
1,23 0.63 0.483 0.633 0.749 0.777 0.804 0.838 0.870 0.904 0.942 0.982 1.030 1.091 1.233
1.20 0.64 0.450 0.601 0.716 0.744 0.771 0.805 0.837 0.871 0.909 0.949 0.997 1.058 1.200
1.17 0.65 0.419 0.569 0.685 0.713 0.740 0.774 0.806 0.840 0.878 0.918 0.966 1.007 1.169
1.14 0.66 0.388 0.538 0.654 0.682 0.709 0.743 0.775 0.809 0.847 0.887 0.935 0.996 1.138
1.11 0.67 0.358 0.508 0.624 0.652 0.679 0.713 0.745 0.779 0.817 0.857 0.905 0.966 1.108
1.08 0.68 0.329 0.478 0.595 0.623 0.650 0.684 0.716 0.750 0.788 0.828 0.876 0.937 1.079
1.05 0.69 0.299 0.449 0.565 0.593 0.620 0.654 0.686 0.720 0.758 0.798 0.840 0.907 1.049
1.02 0.70 0.270 0.420 0.536 0.536 0.563 0.597 0.629 0.663 0.701 0.741 0.783 0.850 0.992
0.96 0.72 0.213 0.364 0.479 0.507 0.534 0.568 0.600 0.634 0.672 0.712 0.754 0.821 0.963
0.94 0.73 0.186 0.336 0.452 0.480 0.507 0.541 0.573 0.607 0.645 0.685 0.727 0.794 0.936
0.91 0.74 0.159 0.309 0.425 0.453 0.480 0.514 0.546 0.580 0.618 0.658 0.700 0.767 0.909
0.88 0.75 0.132 0.282 0.398 0.426 0.453 0.487 0.519 0.553 0.591 0.631 0.673 0.740 0.882
0.86 0.76 0.105 0.255 0.371 0.399 0.426 0.460 0.492 0.526 0.564 0.604 0.652 0.713 0.855
0.83 0.77 0.079 0.229 0.345 0.373 0.400 0.434 0.466 0.500 0.538 0.578 0.620 0.687 0.829
0.80 0.78 0.053 0.202 0.319 0.347 0.374 0.408 0.440 0.474 0.512 0.552 0.594 0.661 0.803
0.78 0.79 0.026 0.176 0.292 0.320 0.347 0.381 0.413 0.447 0.485 0.525 0.567 0.634 0.776
0.75 0.80 0.150 0.266 0.294 0.321 0.355 0.387 0.421 0.459 0.499 0.541 0.608 0.750
0.72 0.81 0.124 0.240 0.268 0.295 0.329 0.361 0.395 0.433 0.473 0.515 0.582 0.724
0.70 0.82 0.098 0.214 0.242 0.269 0.303 0.335 0.369 0.407 0.447 0.489 0.556 0.698
0.67 0.83 0.072 0.188 0.216 0.243 0.277 0.309 0.343 0.381 0.421 0.463 0.530 0.672
0.65 0.84 0.046 0.162 0.190 0.217 0.251 0.283 0.317 0.355 0.395 0.437 0.504 0.645
0.62 0.85 0.020 0.136 0.164 0.191 0.225 0.257 0.291 0.329 0.369 0.417 0.478 0.620
0.59 0.86 0.109 0.140 0.167 0.198 0.230 0.264 0.301 0.343 0.390 0.450 0.593
0.57 0.87 0.083 0.114 0.141 0.172 0.204 0.238 0.275 0.317 0.364 0.424 0.567
0.54 0.88 0.054 0.085 0.112 0.143 0.175 0.209 0.246 0.288 0.335 0.395 0.538
0.51 0.89 0.028 0.059 0.086 0.117 0.149 0.183 0.230 0.262 0.309 0.369 0.512
0.48 0.90 0.031 0.058 0.089 0.121 0.155 0.192 0.234 0.281 0.341 0.484