Main System and Microgrid Support using a Distributed Generator through Back-to-back Inverters

Abstract

This paper discusses the interconnection of a Dis-a rural area or in a forested area where extension of the tributed Generator (DG) to an ac distribution system and a main system grid would be obstructed by environmental or microgrid using power electronics based back-to-back Voltage economic constraints. A microgrid could also be connected to Source Converters (VSCs). The DG is assumed to produce a the main system grid and exchange power with it. Utilities constant dc output voltage. The DG is connected to the microgrid geneall seste rirementexhat the wit of Utive through a VSC that ensures that the voltage of the microgrid is generally impose the requirement that the amount of reactive regulated to be balanced sinusoids having a fixed peak despite power injected into the distribution system should be minimal. the loads of the microgrid being unbalanced and non-linear. The This paper proposes the concept of a DG that supports a DG is also connected to the main ac system through another microgrid and also provides a prespecified amount of real VSC. The VSC interfacing the DG to the main ac distribution system controls the real power to be injected into the distribution power to the main system. The DG is assumed to produce system. The main system VSC also additionally performs as a constant dc output voltage. The DG is connected to a an active filter by compensating for non-linear and unbalanced typical 1 MVA, 11 kV distribution system and a 1 MVA, 11 loads that may be connected to the main distribution system load kV microgrid through back-to-back power electronics based bus. Control of both the VSCs have been described. The DG is icrogrid through baCkoa powe tronics asd seen to perform effectively even when the main distribution bus Volte Source converte VSCs step-up transformers and voltages are unbalanced and distorted. Simulations performed filters [5]. The switching of the VSCs are controlled so that the using PSCAD/EMTDC support the theory presented in the paper. DG can inject a desired amount of real and reactive power into the main distribution system and regulate the microgrid voltage Index Terms-Distributed Generation (DG), Voltage Source to be balanced sinusoids having a fixed peak. Moreover, the Converter (VSC), output feedback control. additional benifit of compensating for unbalance and nonlinearity of loads connected to the main distribution bus is also provided [6]- [9]. This back-to-back converter connection