Abstract:
in the modcrn world, the importance of uninterrupted supply of electricity cannot
be overemphasized. Per cupil<!consumption of electricity is lUlivcrsaily adop!cd as
a yardstick of the living standard of a nation. It is needle8s to argue that
unintermptcd and reliable supply of electricity can significantly enhance our socioeconomic
life. Thrce principal componcnt~ in a typical ele<:tric power supply
system are (a) the generating plant (b) the transmission system and (c) the
distribution nctwork. All ofthcsc components must function properly to ensure the
quality of electricity supplied.
The present study is concerned with the perlormance characteristics of the
distribmion network in the context of reliability. The distribution network plays a
vi!.'!l role in the lotal power system. This links the eonsumcrs and sells electricity
produccd by the generating plants. A number of factors influence the smooth
fllnctioning of the network system. Network structure, method of operation.
fluctuation or voltage ami frequency, nature of protection system, maintenance
management, organi/.ational structure etc. can be identified as the major factors.
In this study attempt has been made to investigate the reliability of electricity in
Kawran Bffi'.ar sub. station covering a part of Dhaka city. Appropriate reliability
indices have been calculated using the data and information collected from the
concerned persons and department,>. Reliability uf electricity, as conceived in
consumers' point of view, is the total timc of the year during which electricity
supply over the network i~available. The parameters concerning the reliability of ,
electricity can be the number of interruptions at the load poinl, duratiun of
interruptions, and the number of consumers affected.
The distribution netwurk under study having about 17 (seventeen) vulnerable
elements is effectively a series system without any parallel facility. Failure of one
or more of the elements in the system results in disruption of electricity ~upply of
the selecled part. Data and information gathered from relcvant sourees for
the year 2001 have been utilized to evaluate the expected failore rate of the
-
elements. These results have heen used to determine [he overall reliability of the
system.
The average outage durntion has been estimated to be about 38 hours in the year.
This parameter for a developed country like France is only 0.82 hours. Failure rates
for individual elements of the systcm have been evaluated and the rates for
s\vitchgear, overhead line, underground cable, transfoffiler are unusually high
compared to any developed nation. Though this study is confincd within a part of
Dhaka, the scenario can be treated as represcntative for the whole of the city.
The significant identifiable rem,ons behind this frustmling scenario of electricity
sllpply arc poor maintenance, usc of low quality and nnn-standard materials and
components, lack of tmining of the personnel, lack or commitment, unplanned
gro"'th of the city etc. The situation can be improved if the abovc mentioned
problems arc properly addressed and appropriate measures are taken. Effective
management system including modem database system has to be implemented.
Considering the enonnous loss due to interruptions in electricity supply, parallel
network system may be advantageous. However, the benefit-cost analysis is
essential prior to making such decisions for huge investment.
