Large-scale Grid-connected Photovoltaic Plant Research Articles

Reliability Analysis and Repair Activity for the Components of 350 kW Inverters in a Large Scale Grid-Connected Photovoltaic System

The reliability of photovoltaic (PV) generators is strongly affected by the performance of Direct Current/Alternating Current (DC/AC) converters, being the major source of PV underperformance. However, generally, their reliability is not investigated at component level: thus, the present work presents a reliability analysis and the repair activity for the components of full bridge DC/AC converters. In the first part of the paper, a reliability analysis using failure rates from literature is carried out for 132 inverters (AC rated power of 350 kW each) with global AC power of 46 MW in a large scale grid-connected PV plant. Then, in the second part of the work, results from literature are compared with data obtained by analyzing industrial maintenance reports in the years 2015–2017. In conclusion, the yearly energy losses involved in the downtime are quantified, as well as their availability.

Large‐scale photovoltaic plant harmonic transmission model and analysis on resonance characteristics

Harmonics generated from large-scale grid-connected photovoltaic plant (GCPV) has the characteristics of high frequency and wide frequency range. So the adverse impact of distributed parameter of high-voltage cables becomes more significant. Based on an actual GCPV, harmonic output particularities were discussed according to its operating mechanism. Step-up transformer, reactive power compensation device, distributed capacitance of transmission line and the loads were considered, the passive multiport network model was established, and the transmission mechanism of harmonics in this network was analysed by the definition of resonance amplification factors. Double resonance curves of harmonic current were discovered, that is, the transmission line of different distance may amplify a harmonic current twice. The simulation and data measurement in the field were carried out based on a large-scale GCPV in Qinghai province. The proposed scheme was verified by the comparison of simulation data and measurements.