A hierarchy control strategy of distributed generation systems

An alternative energy supply to assist the main power stations in future power systems is expected to be distributed generation (DG), which is based on renewable energy sources (RESs). However, the rapid growth of power supply systems must also improve its reliability and supply quality. Interconnecting the DG systems to each other and to conventional power systems to operate in parallel in order to back each other up is an option. The key responsibility of the interconnected system is to control and maintain frequency and voltage of the power system. This is currently done using synchronous generators in many interconnected power systems. Doing this role with other DG technologies through their interface unit to the grid, namely the inverter is possible. This paper presents a control strategy of DG systems in interconnected grids. This proposed strategy is developed based on the control methodology of the interconnected conventional power systems. The results show that the proposed strategy is modular, flexible, and reliable and can simply be integrated into interconnected grids.