Integration of Unified Power Quality Conditioner UPQC with Distributed Generation Network AMIT SHRIVASTAVA Professor Department of Electrical & Electronics Oriental College of Technology , 462022,Bhopal, INDIA amitshri77@yahoo.com PAYAL DESHPANDE Research Scholar Department of Electrical & Electronics Oriental College of Technology , 462022,Bhopal, INDIA payal_deshpande@rediffmail.com Abstract - In this paper a technical view of the integration of a Unified Power Quality Conditioner (UPQC) in a distributed generation network is presented. Although the primary task of UPQC is to minimize grid voltage and load current disturbances along with reactive and harmonic power compensation, additional functionalities such as compensation of voltage interruption and active power transfer to the load and grid have also been identified. Also with demerits of DG sources, the importance of Energy Storage System of UPQC is mentioned. Index- Distributed Power Generation, Microgrid, Power Quality, Unified Power Quality Conditioner (UPQC) I. INTRODUCTION The attention to distributed generating (DG) sources is increasing day by day. The reason is their important roll they will likely play in the future of power systems (Blaabjerg et al, 2004), (Barker and deMello, 2000).The increasing demand of Distributed Generation (DG) in recent years, to minimize the gap between the supply and load demand, is introducing some voltage and current disturbance and harmonics due to the generator types and the interfacing power electronics converters. Therefore, quality of power supply has become an important issue with the increasing demand of DG systems either connected to the grid through grid- tie inverters or work in isolated (microgrid) mode. The need for monitoring of power quality in low voltage distribution levels and ways to mitigate the problems are also increasing due to better customer service, reasonably priced meters, telecommunication development, network planning and regulation requirements. Implementation of Custom Power Devices (CPD) like UPQC in DG or microgrid systems to improve the power quality is gaining greater importance. More DGs such as Photovoltaic or Wind Energy Systems are now penetrating into the grid or microgrid. Again, numbers of nonlinear loads are also increasing. Therefore, current research on capacity enhancement techniques of UPQC to cope up with the expanding DG or microgrid system is necessary. Recent reports [2-9] show that significant research and development has been carried out on the application of UPQC to DG integrated network. As UPQC can compensate for almost all existing PQ problems in the transmission and distribution grid, placement of a UPQC in the distributed generation network can be multipurpose. As a part of integration of UPQC in DG systems, research has been done on the following two techniques: DC-Linked and Separated DG-UPQC systems. A structure has been proposed in [2, 4-7], as shown in Figure 1, where DG sources are connected to a DC link in the UPQC as an energy source. Fig.1.UPQC with DG connected to the DC link This configuration works both in interconnected and islanded mode (shown in Figure 2, 3). In Interconnected mode, DG provides power to the source and loads whereas in islanded mode DG (within its power rating) supplies the power to the load only. In Addition, UPQC has the ability to inject power using DG to sensitive loads during source voltage interruption. The advantage of this system is voltage interruption compensation and active power injection to the grid in addition to the other normal UPQC abilities. The system’s functionality may be compromised if the DG resources are not sufficient during the voltage interruption conditions. Economical operation of the