Need help with 3 phase q

Thread Starter

trx

Joined Sep 27, 2009
1


Can anyone pleae help me with this questione.. How do I fine the impedance of the circuit ???


A factory draws a total of 415kVA from a 2.4kV (line voltage) 3-phase supply. If the plant
power factor is 0.875, calculate:
a. The impedance of the plant per phase
b. The phase angle between the line-to-neutral voltage and the line current​
c. Draw a phasor diagram showing the voltages and currents of the three phases
 

t_n_k

Joined Mar 6, 2009
5,455
There are a few approaches but I normally take this one

* Calculate the VA load per phase - Q
* Calculate the line-to-neutral voltage - Vln
* Calculate I line = Q/Vln
* Impedance per phase Zph = Vln/I line
* Calculate current phase angle (θ) with respect to Vln where θ=acos(pf) and assume it is lagging pf
* Draw your phasor diagram remembering that in a balanced 3-phase system the line currents and their phase angles will be equally balanced.
 
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