Impact of Grid interconnected micro-hydro based mini-grid system on Local Distribution Grid: A Case study of Taplejung mini-grid, Nepal

Rajmani Bajagain, Nawraj Bhattarai, Tek Raj Subedi

Voltage Profile, Losses, Local Distribution Network, Economic Development

Electricity is essential for accelerating the economic development of any country and is also taken as an important input to improve quality of life. Micro hydro power plants are very much successful for rural electrification in Nepal as compared to other countries in the world. Till 2018, more than 3000 MHPs aggregating to 35 MW of generation capacity have been developed in Nepal. It cost about NPR17-25 per kWh for Nepal Electricity Authority (NEA)’s grid to deliver electricity in the rural hilly areas (depending on the distance) whereas it cost about 9-15 per KWH via a 50-100 KW MHP that is connected to the grid. So, In Nepal, it is more economically feasible for interconnected the existing isolated mini grid Or MHPs to the Local Distribution grid. Mini-Grids are electricity distribution systems containing loads & distributed energy resources within clearly defined electrical boundaries acting as a single controllable entity with respect to the utility grid that can be operated in a controlled and coordinated way to operate in both grid connected or island mode. This paper presents the impacts of installing mini-grid on a distribution grid. The work is focused on analyzing the impact of mini-grid installation on distribution grid operation including voltage analysis and power losses of the system. Different DG penetration levels, locations and the impacts of installing one large-scale DG on the main distribution line and distributing it several locations on voltage profile and losses are explored.

The research involves several case studies that explore the impacts of installing distributed generation (DG) on a distribution network operation including the voltage profile and losses of the system. Water Turbine Generators are introduced as Distributed Generators (DGs) at various nodes and the impacts that DG produces on power losses and voltage profile is studied. Simulated results obtained using load flow are presented and discussed.

https://dx.doi.org/10.31873/IJEAS.7.04.09