Assessing the feasibility of integrating SITI MINI HYDROS onto the main grid.

Abstract

Siti 1 and Siti 2 hydro power plants (22.7 MW) are in Bukwo District in Eastern Uganda and power produced by the two hydro power plants is used for local demand. However, integration of these hydro power plants on to the main grid would create an impact on the distribution network due to associated benefits which include increased revenue due to reduction in the energy not served, increased redundancy on Tororo main 1 and 2 feeders, improved power quality to the final consumer due to improved voltage stability and reliability. The purpose of this research was to assess the feasibility of integrating Siti mini hydro’s on to the main grid. To achieve the project objectives, data was collected from UMEME using tools like ARC GIS and MS EXCEL. A single line diagram of the nearby distribution network was drawn and identified the various evacuation options. Network models and simulations were done in DIgSILENT power factory 15.1.7 version. Load flow analysis was then performed for the various options of integrating Siti hydro power plants on to the main grid. The feeder voltages for different feeders were determined before and after interconnection of the Siti hydro power plants for different options. Grid losses and feeder loadings were also determined for the different integration options, and techno-economic analysis made, and the most viable option recommended. Integration of Siti hydro power plants on to the main grid resulted in to increase in voltages. Evacuation to Kachumbala, Mbale substation and the Island mode yielded stable voltages within the acceptable range whereas evacuation to Kumi yielded low voltages. Evacuation to Kachumbala and Mbale substation resulted into total reduction in the power not served. Evacuation to Mbale substation resulted into low technical losses as compared to evacuation to Kachumbala. In conclusion, evacuation to Mbale substation was highly recommended since it had voltages within range of 0.9 to 1.1 PU, low technical losses of 5.51 MW and had the lowest payback period of 0.88 years.