A Smart load shedding system for appliances to improve power system stability in smaller isolated grids

Abstract

This work presents the development and system integration of a Smart Load Shedding System to improve power system stability in small and isolated grids, which are in the range of 2000-3000 MW. In grids similar to Sri Lanka, without power interconnection with any other grid and with very narrow margins to operate with, load shedding schemes are essential for maintaining stability under exceptional conditions. The system encompasses an advanced load shedding algorithm refined from existing techniques to adapt to local operation characteristics with a modified IEEE 14 bus system simulation model. The model has been further confirmed by simulation in RSCAD and PSSE environments. Simulation was performed with RSCAD software along with a Real-Time Digital Simulator (RTDS) to emulate dynamic behavior in grids accurately. A dedicated module for the smart appliance interface has been developed to interface with home appliances to initiate controlled tripping. In-depth data made available by the Sri Lanka Sustainable Energy Authority (SLSEA) has been used to study patterns of daily consumption to make the load shedding plan technically sound and economically feasible. The experimental result shows that the proposed system effectively corrects the frequency fluctuations and hence improves the overall stability of the grid.