This
paper reports a method for substation planning - the
exact location for the substation is identified from
a given set of locations. The load points are connected
to the substation in the optimum route using knowledge-based
expert systems to avoid any obstruction between any
two load points. This also reduces the overall feeder
length. The optimum branch conductors are selected using
the method proposed by Tram and Wall (1988) to reduce
further costs. The effectiveness of the proposed method
is demonstrated with the help of an example.
It
is important to have effective planning of distribution
substations in order to get high standards of power
reliability, security and quantity, and also to ensure
maximum utilization of optimal investment. Although
the optimum location of a substation reduces the system
cost and system loss, sometimes it is not possible to
use the exact optimal location of substation either
due to geographical or social causes. The near optimal
position is used in such cases. If a number of locations
for the substation are provided, the location that gives
minimum loss and cost is selected.
Literature
survey shows that a good amount of research work has
been carried out for distribution system planning. Adams
and Laughton (1974) proposed the fixed and variable
costs of power flow for a particular connection. Crawford
and Halt (1975) suggested a procedure that utilizes
the transportation model framework to find the optimal
substation service boundary. This method was based on
the analysis of loads and feeder on a grid basis, which
can be used empirically to identify the desirable substation
locations and their sizes. Wall et al. (1979)
proposed a method for distribution system planning using
a linear transshipment model, which, however, may not
be feasible due to the assumption of linearity. Thompson
and Wall (1981); Sun et al. (1982); and Fawzi
and El-Sobki (1983) proposed methods for distribution
system planning using branch and bound criteria that
fathom some f the possible combinations prior to their
solutions. El-Kady (1984) suggested a method, which
explicitly includes time-dependent fixed and variable
charges, as well as time dependent cost of losses. Nara
et al. (1992) suggested a multi-term distribution
expansion-planning model while proposing a new decomposition
algorithm based on the branch exchange method to solve
large-scale problems. Goswami (1997) has proposed an
algorithm for the radial system using the branch exchange
technique, which is highly time consuming due to the
requirement of a complete power flow after each branch
exchange. |