Active substation design for distributed generation integration in the Afghanistan’s grid

Abstract

Energy has been harvested from water, wind and solar as isolated distributed generation (DG) to electrify rural households and villages in Afghanistan. Several solar PV and wind farms have been or planned to be built as isolated distributed generators in those provinces that have no access to national grid. While it is ideal that the national electrical grid be extended to those provinces and regions, these distributed generators are not compatible with the operating voltage specifications of the national grid. In this study, we have focused on changing the topology of distribution grid at the planning and design stage by introducing active devices to control voltage, especially in the weak nodes of the grid. At substations which convert DG to MV/LV, using two active devices such as On Load Tap Changing-Phase Shifting Transformer (OLTC-PST) and Static Synchronize Compensator (STATCOM) should be considered in the design. The integration a 1-MW wind power distributed generator in Panjshir province of Afghanistan with the national grid network is considered. Introducing these active devices that increases the installed DG power in weak networks is analyzed. An operation and control strategy for the Active Substation is verified by temporal power flow simulations. The results show that using these active devices can increase the active power injection capability in weak networks.