TWO-YEAR PERFORMANCE COMPARISON ASSESSMENT BETWEEN CENTRAL AND- MULTISTRING-BASED INVERTERS INSTALLED IN LARGE-SCALE PHOTOVOLTAIC POWER STATIONS IN GREECE

摘要

In the last year's 29th EU PVSEC, the authors presented a one-year real-life performance behaviour assessment of the two main inverter technologies used in large-scale grid connected PV Power Stations (PPS). This paper is intended to present a full two-year performance comparison between central and multistring inverters. In this context, the main purpose of this research study is to provide an updated comprehensive assessment of performance advantages and disadvantages of the inverter technologies under examination. This shall be effect by applying the second year's data in the comparison assessment and by re-evaluating the first year's results. The comparison assessment will use a full two year real-life data derived from the operation of two 500kWp grid-connected PPS, located close to the city of Lamia in Central Greece. Both PPS are designed, installed and maintained by the same EPC contractor. The same type of polycrystalline modules is used, adopting also the same panel tilt and shading angle. At the same time however, PPS "A" is based on the operation of one central inverter, while PPS "B" uses 25 multistring inverters. The inverters used in both parks are supplied from the same manufacturer. In this way, the technical design features and the adjacent location of the two PPS enable in depth analysis via the direct comparison of the inverters' performance indices as proposed by the IEC 61724 international standard. Through analysis of the monitored data, the results indicate a small advantage for the central configuration. Further to that, the list of each system's advantages and disadvantages was updated. Monitoring will be continued and a more detailed insight on the overall performance of the two PPS will be reported in the future.