Question

The symmetrical load below is connected to a three-phase network. A line current of 25A has been measured. The load resistors have a value of 18 Ω.

What is the line voltage of the three-phase network?

Answer 1

The line voltage of the three phase network is 346.41 V

Step-by-step explanation:

Star Connected Load

Resistance, R₁ = R₂ = R₃ = 18 Ω

For a star connected load, the line current = the phase current, that is we have

`I_L = 25 \, A = I_(Ph)`

Whereby the the voltage across each resistance =
`V_R` is given by the relation;

`V_R` =
`I_(Ph)` × R

Hence;

`V_(Ph)` =
`V_R` =
`I_(Ph)` × R = 25 × 8 = 200 V

Therefore we have;

The line voltage,
`V_(L)` = √3 ×
`V_(Ph)` = √3 × 200 = 346.41 V.

Hence, the line voltage of the three phase network = 346.41 V.