Date of Award

May 2018

Degree Type


Degree Name

Master of Science



First Advisor

Lingfeng Wang

Committee Members

David C Yu, Wei Wei


electronics, islanded microgrid, reliability evaluation


With power electronics being widely applied in microgrids, they become a key part in micro-grid and the reliability assessment considering power electronic devices have become a hot research topic, and much work has been done to evaluate the reliability of power electronics in microgrids. However, the impact of operational failure of power electronics on the overall microgrid reliability has not been studied yet.

This thesis has three objectives. The first objective of this thesis is to construct a systematic operational failure rate model of power electronic systems. The power generated from renewable generation units, such as PV arrays or wind turbines, is uncertain and difficult to predict. With the operational impact based on operational conditions taken into consideration, the evaluation of reliability is more accurate and it will make a great contribution to the design process and avoid costly expenses caused by undesired failures in microgrids. The second objective is to apply this model to do reliability assessment of the overall islanded microgrid with high penetration of renewable energy generation systems. In addition, this paper combines several reliability assessment methods. The third objective is to improve the reliability of the microgrid system by replacing the conventional battery storage system to the hybrid energy storage system. Based on this proposed model, the operational failure models for the power electronic systems in an modified benchmark 0.4 kV test system were built and tested, and then the sensitivity analysis, exploring the influence of various factors, was studied.