*Reliability and Maintenance - An Overview of Cases*


Moreover, the reliability level during this mode of operation (**Figure 5b**) can also be increased by adding more generation sources within the maximum number

The reliability of the microgrid system without WPGS is calculated as 0.97, which is higher than that of a microgrid system with WPGS. This is due to the combination of generation sources in this mode of operation (**Figure 5c**), which are highly reliable than the generation source (such as WT) in the WPGS. The results of the reliability evaluation shows that the proposed microgrid system has the significant ability to generate sufficient power to ensure the reliable power supply in all operating modes. The reliability indices found in this study reveal that a microgrid system consisting of renewable energy sources such as wind, hydro, and storage is

This chapter discussed the reliability assessment of a microgrid system, comprising variable-speed wind generator units. This research was carried out on a microgrid system located at Fermeuse, Newfoundland, Canada. The mathematical model of microgrid system reliability is developed based on the reliability block diagram (RBD) concept. In addition, the reliability model of various subsystems in a variable-speed wind generator unit is developed considering the impact of stochastically varying wind speed. The developed microgrid system reliability model is implemented through Monte Carlo simulation using Matlab coding. The obtained

• The reliability performance of generating and supplying reliable power by the case study microgrid system during its various operational modes is found to equal 0.99 (grid-connected mode), 0.99 (isolated microgrid with WPGS), and

• This suggests that the microgrid has the ability to generate and supply power to the loads in a microgrid domain with a high degree of reliability. Such a reliability level is achieved due to maximizing the use of renewable power. The

• It is the authors' view that this reliability evaluation approach may be applied to assess the reliability of microgrid systems containing other intermittent

The developed and presented method in this chapter is implemented using simulation. However, this method is neither implemented in real time, nor is it sold to industry yet. This method needs further investigation to include other renewable sources such as solar-based ones. In addition, an experimental investigation is also required, which in

At present, the author is further researching the possibility of applying described

method for a microgrid that consists of a solar photovoltaic system and may be

This work is supported by a research grant from the National Science and Engineering Research Council (NSERC) of Canada, the Atlantic Innovation Fund

latter stems from wind generation systems as well as storage units.

turn may prove challenging, as a number of key issues need to be addressed.

of constraint (maximum number of WT system).

*DOI: http://dx.doi.org/10.5772/intechopen.86357*

reliable in generating and supplying power.

results are presented and discussed.

energy sources such as solar.

applicable to hot weather conditions.

**Acknowledgements**

**187**

0.99 (isolated microgrid without WPGS).

**6. Conclusions**

*Microgrid System Reliability*

#### **Table 1.**

*Reliability results of different subsystems in a variable-speed wind generator system.*


#### **Table 2.**

*Reliability results of distributed generation units.*


#### **Table 3.**

*Reliability results of microgrid system.*

higher than the other operational modes because all DG units are operating during this mode. Moreover, this mode has two generation sources which are assumed as highly reliable in power generation and supply.

On the other hand, MSR during isolated microgrid with WPGS varies depending on the number of WT system operating in the WPGS. It is worth mentioning that in an isolated microgrid system, all WTs in WPGS do not operate due to stability issues. This issue will occur since all WTs in WPGS will require reactive power for their operation during isolated mode. However, in an isolated mode, there is no such reactive power generation source to provide sufficient reactive power for all nine WT systems. Thus, the reliability calculation is carried out for a different number of WT systems in the WPGS, and the various reliability indices are found. On the other hand, it is important to note that the minimum reliability index found is 0.94, which is high.

## *Microgrid System Reliability DOI: http://dx.doi.org/10.5772/intechopen.86357*

Moreover, the reliability level during this mode of operation (**Figure 5b**) can also be increased by adding more generation sources within the maximum number of constraint (maximum number of WT system).

The reliability of the microgrid system without WPGS is calculated as 0.97, which is higher than that of a microgrid system with WPGS. This is due to the combination of generation sources in this mode of operation (**Figure 5c**), which are highly reliable than the generation source (such as WT) in the WPGS. The results of the reliability evaluation shows that the proposed microgrid system has the significant ability to generate sufficient power to ensure the reliable power supply in all operating modes. The reliability indices found in this study reveal that a microgrid system consisting of renewable energy sources such as wind, hydro, and storage is reliable in generating and supplying power.
