Most electric utilities have separate
department for power system planning and
operation each with specific defined objectives.
Planning department is more concerned with
planning using an off-line network model and
development of the power system network for the
available resource utilization in order to meet the
long term demand. Thus the studies prepared by
planning department require maintenance of a
proposed topological model of the area of interest.
The network data base model adapted in such
studies is generally on a bus oriented formats [1]
where information on concerning the internal
devices details of a substation are absent. It is also
common practice in bus-oriented model to lump
the loads or generations at one bus instead of
individual devices representation as depicted in
Fig. 1. Considering the power flow is dictated by
the topology on network, such representation is
sufficiently justified for off-line analysis. The two
most common formats used by utilities today are
the IEEE Common format dictated by the
Institution of Electrical and Electronics Engineers
and the Power Technologies, Inc format. Most
standard power network analysis software for offline
planning purposes uses any of these formats
for the network model. Representation of bus
oriented model for a typical station having
generations, one transmission line and one
transformer is given in Fig. 1.