IMPACTS OF INTEGRATING SOLAR AND WIND PLANTS INTO THE POWER NETWORK OF BHUTAN

Abstract

Hydropower has been the primary source of electricity in Bhutan, and to achieve power security and sustainability, alternative renewable energy sources (RES) such as solar and wind are being explored. However, the literature reviews present that bus voltage is the most affected parameter during integration. Therefore, this paper presents the impact on the bus voltage due integration of RES into the power network of Bhutan. The measured weather and power grid parameters were used as inputs to the solar and wind farm models developed in MATLAB/Simulink. The output from Simulink was then used as input to the solar and wind model in DIgSILENT Power Factory. The existing Bhutan power grid from 33kV and above has been developed in DIgSILENT to study power flow and results were validated against relevant standards. The voltage profile at the individual bus was maintained at 0.95 to 1.05 p.u. The varying hourly load for 24 hours at the different substations was considered. A quasi-dynamic simulation was performed to study the impact on voltage stability of buses at different penetration levels with every 5% increment. It was observed that at a 25% penetration level, the voltage falls below the accepted limit of 0.95 p.u. The Levelised Cost of Energy for the wind was calculated to be Nu. 13.37/ kWh and Nu. 6.02/ kWh and Nu. 6.51/ kWh from Shingkhar and Yongtru solar, respectively.