Network Loss Analysis of Low-Voltage Low-Power DC Microgrids for Rural Electrification

Millions of people around the globe are suffering from energy poverty, particularly the inhabitants of Africa and South-East Asia. Electrification through national grids is cost-prohibitive with limited power generation sources in the third world countries. The low-voltage, low-power islanded DC microgrids are a practical option for rural electrification. In this paper, the detailed network loss analysis of four different microgrid architectures is performed using the modified Newton-Raphson power flow for DC systems. These architectures include, 1) Centralized generation centralized storage (CGCS), 2) Centralized generation distributed storage (CGDS), 3) Distributed generation centralized storage (DGCS), and 4) Distributed generation distributed storage (DGDS), which are implemented with both radial and ring interconnection schemes using time-varying load demand and dynamic PV generation. The comparative analysis on these architectures is performed with multiple conductor sizes and different low-voltage levels which indicates that distributed architecture with ring interconnection is more efficient and reliable in comparison to other architectures and interconnection schemes due to its high efficiency, low voltage drop, and reduced distribution losses. This analysis will be useful in optimal planning and designing of new and upgrading of existing low voltage DC (LVDC) microgrid systems systems.