Abstract:
In an era where Sri Lanka economy is going towards a drastically higher growth it is
highly important to have a reliable electricity network in the country. To improve the
reliability of the distribution network, Distribution Licensees improve the system
capacity and at the same time install protective devices to reduce the interrupted area due
to an electrical fault in the network. For this Auto Reclosers and Fuses are used in the
Distribution Network.
In developed countries the installation of Protective devices are done optimally and
techniques have been developed. In Sri Lanka, the process of planning, design and
construction of transmission and medium voltage power lines is solely authoritative by
Transmission Licensee and Five Distribution Licensees of the country. At present there
is no proper way of selecting optimal location for the installation of Auto reclosers is
practiced in either of these Licensees.
As the first step of this study, a research survey was done about the optimal location
selection methods researched in other countries. A suitable objective function was
modeled to find the optimal location to install an Auto Recloser with the constraint of
finding two optimal locations in series.
This report will discuss the objective function formation to find the optimal location for
the Auto Recloser and also as a supporting study a pilot project done on how to coordinate
the fuses with the Auto Reclosers and the Circuit Breakers at the Grid
Substation is also included.
Major Findings of this research: Optimal locations to install an Auto recloser for a feeder
according to the SAIDI values of substations and the energy consumptions of bulk and
retail consumers connected to that specific feeder.
Findings of the pilot project: how to co-ordinate the fuses installed on a feeder and how
to decide the rating of a fuse to be installed on the feeder by maintaining the protection
co-ordination with other protective devices on the feeder.
