A three$-$phase power system $220$V $/380$V$,50$Hz$,$ supplies three loads which include: $$ Lighting and office equipment representing $1\mathrm{.}8$ kW uniformly distributed on the three phases and unit power factor $(=).$ Three$-$phase machines each consuming $3$ kW with a power factor of $0\mathrm{.}6.$ A special device representing three identical impedances connection. Z j $(1015)$ on the $1)$ Calculate the active and reactive powers PZ and QZ consumed by the impedances $2)$ Calculate the total active power PT consumed by the three loads. $3)$ Calculate the total reactive power QT consumed by the three loads. $4)$ Deduce the total apparent power ST and the current line $$ Z $..5)$ Calculate the power factor of the three loads. Deduce the phase angle of the circuit.