The optimal allocation of DG in distribution system is need to satisfy all of the operational constraints such as the limitation of active and reactive power generated, limitation of bus voltages, capacitor reactive power constraint.
Generation constraints: For stable operation, real and reactive powers supplied by DG are restricted by the lower and upper limits as follows 27:
? P?_gni^min?P_gni?P_gni^max (8)
? Q?_gni^min?Q_gni?Q_gni^max (9)
Voltage Constraint: the constraints of load buses voltage magnitudes to be restricted within their limits as follows 27:
Parallel capacitor Constraint: The capacitance size at the buses should not be beyond the allowable constraint 27.
?_(i=1)^nc?Q_cni ?Q_t (7)