Three years operating results of microgrid with multiple power quality levels

This paper presents the progress and some results of a field demonstration of a multiple power quality supply system (MPQSS). The project was the first trial to take place in Japan in the area of power quality concepts and solutions. For this project, NTT Facilities developed and installed a multiple power quality supply system that has the capability to feed four classes of alternative current (AC) and one of direct current (DC) power while meeting various customer requirements. The system also has three types of distributed generator (DG): gas engine sets, fuel cells, and photovoltaic panels. The rated capacity of the DG s is just 1 mega-watt. NTT Facilities started the project in Fiscal Year (FY) 2004 and plans to continue it for four years. The project finished in FY 2008. However, the MPQSS has been working in the actual field since October 2006. Some sets of test data and an analysis using the data indicate that the developed system meets all the requirements for distributed generator related plants and has additional benefits. Obtained AC and DC data will hopefully be useful to establish power quality standards suitable for the ICT age.