This paper presents an approach to balance state of charge batteries. It is therefore to improve the lifetime of batteries in VPPs. According to the proposed method, the real-time SOC of DB will be tracking on the balancing SOC determined in VPP. | Vietnam Journal of Science and Technology 56 (1) (2018) 81-93 DOI: AN APPROACH TO BALANCE STATE OF CHARGES OF DISTRIBUTED BATTERIES IN VIRTUAL POWER PLANTS OF DC DISTRIBUTION NETWORK Nguyen Huu Duc Department of Renewable Energy, Faculty of Energy Technology, Electric Power University, 235-Hoang Quoc Viet, Ha Noi, Viet Nam Email: ducnh@ Received: 20 September 2016; Accepted for publication: 16 December 2017 Abstract. Small distributed energy sources could be aggregated to form a virtual power plant (VPP) in order to overall improve technical and market issues. VPPs should be composed of several distributed batteries (DB) to solve the problem of intermittency due to wind and solar. This paper presents an approach to balance state of charge batteries. It is therefore to improve the lifetime of batteries in VPPs. According to the proposed method, the real-time SOC of DB will be tracking on the balancing SOC determined in VPP. During operation, the difference of SOC among DBs will be shrunk and finally the share of exchange power among DB is equal. Moreover, the duration time to achieve the balancing SOC can be determined by adjusting the exponent parameter of SOC in the presented function. Keywords: droop control, virtual power plant, SOC, battery. Classification numbers: , . 1. INTRODUCTION With the strong growth of distributed renewable energy sources (DRES), virtual power plants have been considered an efficient solution to integrate such DRES. VPPs can facilitate integration of a large number of small-scale DRES [1-3]. Several VPPs have been deployed in The Netherlands, Belgium, the UK and Germany [4-6]. In such VPPs, it could be included different distributed energy storage systems (DESS). DRES are usually combined with DESS in order to solve intermittent issues caused by weather change. The advantages of the coordination between DESSs with RES are shown in [79]. Authors in [10] introduce the operational method in
