POWER-GEN Asia 2018

Solutions for Operational Challenges in Low Voltage High Current Hybrid Microgrid (Room Garuda 9, 1st Floor)

19 Sep 18
2:30 PM - 4:00 PM

Tracks: TRACK E - Distributed Energy Resources

Speaker(s): Amit Gupta, Chief of Rolls-Royce Electrical , Rolls-Royce Singapore Pte Ltd; Souvik Dasgupta, Principal Technologist, Rolls-Royce Electrical, Rolls-Royce, Singapore Pte. Ltd; Marcus Muecke, Senior Manager, Electrical Systems and Automation, MTU Onsite Energy GmbH ; Simon Pfluger, Technology Manager, MTU Friedrichshafen GmbH; Subhrakanti Nanda, Research Associate, Rolls-Royce Corporate Lab @NTU, Rolls-Royce Corporate Lab @NTU; Suman Mondal, Research Fellow @ Rolls-Royce Corporate Lab @ NTU, Rolls-Royce Corporate Lab @ NTU; Johannes Demharter, Senior Expert, Diesel Systems Power Gen, MTU Friedrichshafen GmbH; Sathish Kumar Kollimalla, Research Fellow, Rolls-Royce Corporate Lab@ NTU , Rolls-Royce Corporate Lab@ NTU ; Shicong Yang, Lead Engineer , Rolls-Royce Singapore Pte.Ltd

A microgrid can be represented as a small-scale power system network comprising of generating sources, loads and storage. A more complex network known as Hybrid Microgrid (HMG) combines the benefits of both ac and dc systems. In this paper we document the design of a full-scale low-voltage high-current HMG intended for standalone operation. This microgrid system is designed to be intelligent and robust, offering significant benefits with regards to reliability and security. There are also a number of operational challenges that need to be addressed while designing control and protection systems in order to ensure that the present levels of power system reliability are not significantly affected and the potential benefits of DG are fully harnessed. Some of these challenges arise from invalid assumptions that have been applied to conventional distribution systems, while others are the result of stability issues formerly observed only at the transmission system level. Here we refer particularly to grid-connected current control and lack of inertia within power electronic interfaced units. Other issues include the low X/R ratios typical of low voltage grids, uncertainty of generation output and unbalanced system conditions. Furthermore, integration of DG units at low voltage levels can cause reverse power flows and lead to complications in protection coordination, undesirable power flow patterns and difficulties in achieving voltage control. In order to make microgrids more acceptable to industry, the above mentioned shortcomings and challenges are investigated and addressed. As a result, various control methods, including well know methods such as droop control and virtual synchronous generator (VSG) have been proposed to ensure true plug and play operation. These proposed control methods increase the options available to the power industry to not only accommodate but also reap the benefits of an ever increasing penetration of renewable power generatio