Contents I. Introduction
The Indian electricity grid is undergoing a slow transition from its traditional form into a smart grid. The inclusion of Distributed Energy Resources (DER)and its integration with the traditional grid through the medium-voltage distribution systems is improving the grid performance. The initiative towards a decentralized grid was taken by the Government of India (GoI)through the Electricity Act 2003, which primarily focused on distributed generation aiming at rural electrification. The particular act promotes stand-alone renewable energy systems to form DER. This initiative was followed by the National Electricity Policy 2005, where the focus was on developing a reliable rural electrification systems through decentralized DER, integrated with the conventional grid. Two GoI schemes which namely, the Rajiv Gandhi Grameen Vidyutikaran Yojna and the Remote Village Electrification Scheme are aimed at providing up to 90% capital subsidy for rural electrification projects using decentralized DER [1]. The development of a DER based grid would enable a paradigm shift from electromechanical systems to power electronics based grid interfaces. This would make the grid interfaces highly efficient and robust [2]. But as compared to the conventional electromechanical systems, the limitations like low overvoltage capability and limited over current flexibility are a concern for the power electronic converters used. Moreover, a grid system is highly influenced by the presence of DER would have higher penetration level from renewable energy sources also would have reduced inertial response. But this has to be monitored rigorously to avoid major transient related setbacks on the grid. The high initial cost involved in developing a BESS (Battery Energy Storage Systems)is the major blockade in the promotion of renewable based charging facilities. Until the battery storage costs are drastically reduced, the storage and utility providers have to search for creative methods to operate the DER systems economically. The area where the BESS in DER could play a vital role in modern grid is in the short term variability of the power grid. This enables, to even regulate the power quality. The frequency and voltage regulation in the grid through short term charging and discharging could be performed. The idea of development of a virtual DER is a concept which has come up with the evolution of the Electric Vehicle (EV) based mobility studies. The scope of tapping into the Battery bank of an EV or a Hybrid Electric Vehicle (HEV) is an exciting new avenue of research. The growing concern on environmental pollution and the stringent pollution norms including the upcoming BS VI norms has affected the automotive industry. The drastically depleting fossil fuels have forced countries including India to promote EVs and HEVs. But a traditional grid system like in India is not equipped to handle such a huge load in terms of EV and HEV charging from the grid. Therefore, scope of utilizing EV or HEV as an auxiliary power source has to be explored, that would be able to provide stability to the grid in terms of active and reactive power regulation. This would enable to perform peak shaving and valley filling and would also improve the overall power quality of the grid. The authorities have proactively started measures towards this cause as the GoI has initiated promotion through its EV policy and states like Karnataka through the Karnataka Electric Vehicle and Energy Storage Policy 2017. A new policy has also been initiated called Kerala Electric Vehicle Policy in the state of Kerala, which are the indicators of the promotions.
