Impact of subsystems on the overall system availability for the large scale grid-connected photovoltaic systems

Reliability analysis of PV generating systems in the islanded DC microgrid under dynamic and transient operation

“…The equivalent failure and repair rates of a PV string can be calculated as follows: $$\begin{equation}{\lambda _{PV - S}} = \sum\limits_{i = 1}^m {{\lambda _{PV - M,i}}} + \lambda {}_F\end{equation}$$ $$\begin{equation}{r_{PV - S}} = \dfrac{1}{{{\lambda _{PV - S}}}}\left( {\sum\limits_{i = 1}^m {{\lambda _{PV - M,i}}} {r_{PV - M,i}} + \lambda {}_F{r_F}} \right)\end{equation}$$where $${\lambda _{PV - S}}$$ and $${r_{PV - S}}$$ are the failure and repair rates of the PV string, respectively; $${\lambda _{PV - M,i}}$$ and $${r_{PV - M,i}}$$ are the failure and repair rates of the i ‐th PV module, respectively; and $${\lambda _F}$$ and $${r_F}$$ are the failure and repair rates of the fuse, respectively. In this paper, the PV‐module's failure rate varies in the available range of 0.0046 × 10 −6 –26 × 10 −6 failures/h, while its repair rate is from 0.00037 to 0.0667 repairs/h [5, 9, 27–30]. The failure rate of fast‐acting DC fuses is about 0.05 failures/year [6, 32], while its repair rate is zero because it is needed to use the new ones in case of a failure of the fuses.…”

“…It could be generally realized that the failure rate of PV modules significantly depends on weather conditions and operation and ambient temperatures more than electrical parameters such as dynamic-voltage levels, power losses, and fault currents because mechanical and chemical materials are mostly dominated in a structure of the PV module. In view of this assumption, this research will certainly use the fixed failure rate of PV modules under the dynamic and transient operation cases, which is properly calculated from [27][28][29][30]. More clearly, the PV-module's failure rate varies in an available range of 0.0046 × 10 −6 -26 × 10 −6 failures/h.…”

“…Ref. [5,9,[27][28][29][30] have calculated the PV-module's failure rate that almost varies in the available range of 0.0046 × 10 −6 -26 × 10 −6 failures/h depending on different weather conditions, the open-circuit and short-circuit faults. Therefore, this study will certainly use the failure rate of PV modules from these references.…”

“…From an above literature survey [1–42] along with some identified shortcomings, the main contributions of this research are given as the following. The reliability analysis of PV‐generating systems under the dynamic and transient operation of an islanded/off‐grid PV‐battery DC microgrid is performed in detail.…”

A Hybrid Cleaning Scheduling Framework for Operations and Maintenance of Photovoltaic Systems

“…The reliability and efficiency of PV systems raise more and more attentions as it is seriously influenced by environmental conditions and meteorological parameters. Technologies to increase the reliability and efficiency of PV systems have attracted numerous research interests and been significantly improved [3]- [5].…”