School of
Information Technology and Electrical Engineering

Speaker: Md. Monirul Islam
Seminar Date: Thu, 15/08/2019 - 11:00
Venue: 78-344
Host: A/Prof Mithulan Nadarajah

Seminar Type:  PhD Thesis Review


In the recent decade, there has been a significant proliferation of power electronics based Renewable Energy Sources (RES) in power systems all over the world. It is worth mentioning that enormous efforts are still being made to achieve further growth. Among many RES, photovoltaic (PV) plants have been recognized as one of the fastest growing technologies owing to its availability, low maintenance, and declining installation cost. This flourishing scenario has led to apprehensions regarding likely degradations of overall reliability and stability of modern power systems, since synchronous generators are being replaced which resulted in reduced system short circuit level and inertia. In 21st century, voltage instability has played a key role in some of the blackouts all over the world, which can be occurred both in short and long terms. However, the growing PV generators along with the increasing induction motor loads in Distribution Networks (DNs) have been making the network more vulnerable to Short-Term Voltage Instability (STVI). Acknowledging this issue, present grid codes demand the incorporation of Dynamic Voltage Support (DVS) capability with PV plants to ensure secure and reliable operation of modern power systems. This research rigorously investigates the Short-Term Voltage Stability (STVS) of DNs with high PV penetrations, and proposes remedial measures. The impacts of different levels of PV penetration followed by the DVS with different control strategies on the STVS are thoroughly examined. A new DVS strategy considering inverter current limits is also proposed to further augment the STVS.

The DNs are inherently unbalanced due to its unbalanced loads, line configurations and un-equal single-phase PV penetrations. Therefore, it is essential to better understand how the unbalances could influence the STVS. To this end, the effects of imbalance on the STVS, which was overlooked in the current literature are critically investigated. In order to mitigate any adverse effects, economic and effective solutions are provided. Moreover, the occurrence rate of unsymmetrical faults is higher than the symmetrical one. Thus, this thesis thoroughly assesses the impacts of negative-sequence power on the STVS and voltage swell following an unsymmetrical fault. A new method is proposed to effectively regulate the dynamic voltages within limit. As the future of automobile is moving towards Electric Vehicles (EVs), this thesis also evaluates the suitability of EVs for dynamic voltage support. A new Vehicle to Grid (V2G) approach is proposed for the enhancement of STVS in DNs.


Md Monirul Islam received B.Sc. degree in Electrical and Electronic Engineering from the Rajshahi University of Engineering and Technology (RUET), Rajshahi, Bangladesh, in 2009, and M.Eng.Sc. degree in Electrical Engineering from the University of Malaya, Kuala Lumpur, Malaysia, in 2015. Currently, he is pursuing PhD in the Power & Energy Systems Research division at the School of Information Technology and Electrical Engineering, The University of Queensland, Australia. His research interests include advance converter topologies and controls, renewable energy integration, large-scale electric vehicles, and power system voltage stability.