Abstract:
The power system Sri Lanka is an islanded power system of a relatively small size. Other than
the coal power plants, combined cycle plants and gas turbines, a significant portion of
electricity requirement is supplied by large hydro, mini hydro and other non-conventional
renewable energy power plants. Accordingly, the power system of Sri Lanka can be identified
as a low-inertia power system.
CEB, the power transmission operator of Sri Lanka, adheres to N-1 reliability in the
transmission network. They are not expected to keep N-1 reliability in generation according to
the current practice. It means that the internationally practiced power system reliability levels
do not exist in the power system Sri Lanka.
Even before Non-Conventional Renewable Energy (NCRE) additions, the power system was
largely dependent on under-frequency load shedding (UFLS) after large generator
disconnection. Introducing NCRE to the power system has worsened the situation further.
The aim of the study was to identify the behavior of the power system of Sri Lanka during and
after generation disconnection and study possible methods to improve the power system
performance after generation disconnection event. The impact of battery energy storage
systems on frequency response was studied for the power system of Sri Lanka. A cost analysis
on battery energy storage system was performed. Increase in costs was also calculated if an
internationally practiced level of spinning reserve is maintained in the power system Sri Lanka.
Suggestions to improve the performance of the system are included in the thesis, based on the
findings of the research.
