Question

A balanced, wye-connected load drawing 15 kW at 0.6 power factor lagging is connected in parallel with a balanced delta-connected load drawing 10kVA at 0.8 power factor leading. The two loads are supplied by a balanced 3-phase source of 415 V line voltage.

Determine the single-phase equivalent circuit of the three-phase circuit.

Answer 1

To determine the single-phase equivalent circuit of the three-phase circuit, we need to calculate the impedance of each load and convert the wye-delta connection to a single-phase circuit.

Step-by-step explanation:

To determine the single-phase equivalent circuit of the three-phase circuit, we need to calculate the impedance of each load and convert the wye-delta connection to a single-phase circuit.

For the wye-connected load, we can calculate the impedance using the power factor. The apparent power (S) is given by S = P / (power factor) = 15 kW / 0.6 = 25 kVA. The impedance (Z) can be calculated using the formula Z = S / (V Line) = 25 kVA / 415 V = 0.0602 Ω.

For the delta-connected load, we can also calculate the impedance using the power factor. The apparent power (S) is given by S = P / (power factor) = 10 kVA / 0.8 = 12.5 kVA. The impedance (Z) can be calculated using the formula Z = S / (V Line) = 12.5 kVA / 415 V = 0.0301 Ω.

Therefore, the single-phase equivalent circuit consists of a wye-connected load with an impedance of 0.0602 Ω and a delta-connected load with an impedance of 0.0301 Ω.