Figure 3.1:A typical electrical power generation,
transmission, and distribution system.
The secondary distribution system is thatportion of the network
between the primary feeders and the utilization equipment. The
secondarysystem consists of step-down transformers and secondary circuits
at utilization voltage levels.Residential secondary systems are
predominantly single-phase, but commercial and industrialsystems
generally use three-phase power [ 66 ].
In Iraq the transmission portion of the system is typically
designated to operate at 132 and 400 kilovolts (kV) and above, while the
distribution portion operates between 400 volts and 3 3 kV. A further
distinction is often made between primary distribution (voltages between
11 and 3 3 kV) and secondary distribution ( 400 volts) systems. Industrial
and commercial customers with large power demands often receive service
directly from the primary distribution system [86].
3.3 Problem Description
In this thesis a modern SCADA system is planed, designed and
analyzed to connect twenty (400,132, 33, and 11 KV) substations for
electrical power distribution purposeswith modern and suitable Giga