STUDY OF ISLANDING TEST METHOD USING MULTIPLE INTERCONNECTED PHOTOVOLTAIC INVERTERS: EXAMINATION BY DIFFERENCE IN MOTOR LOAD INSTALLATION CONDITIONS

摘要

There are high expectations for photovoltaic (PV) power generation systems as a means of curbing the carbon dioxide (CO_2) emissions that cause global wanning. Recently there has been rapid growth in the use of PV power generation systems installed locally (i.e. concentrated interconnection) to a specific power distribution system, and therefore there are issues regarding the safety of such systems and the quality of the electric power generated, such as rises in system voltage, increases in higher harmonics, and the emergence of the phenomenon of islanding operation.This may be attributed to the launch by the New Energy and Industrial Technology Development Organization (NEDO) of verification research for concentrated interconnection PV power generation systems as a five-year program beginning in fiscal 2002 to aid the smooth and reliable growth of residential PV power generation systems in concentrated interconnection. The research and development concerned has included engineering development to meet the technical requirements for performing concentrated interconnection, such as the construction of systems allowing the effective utilization electric power generated by PV power generation systems. However, since no method of evaluating devices for detecting islanding operation during concentrated interconnection of PV power generation systems exists, there is an urgent need to establish a method of testing multiple interconnected photovoltaic inverters, and this has resulted in the launch of a two-year program of basic experiments and study of test methods beginning in fiscal 2006.In this report, we identify issues that need to be resolved when developing the testing method, and perform studies under different motor load installation conditions, one of the issues to be examined.