Post Date
May 15 2023

Dr Raheel Zafar’s Cutting-Edge Power Grid Optimization Model

As summer approaches, high temperatures in Pakistan bring a host of challenges beyond the physical discomfort of the heat. With frequent power outages plaguing the country’s energy grid, keeping cool and comfortable can be a struggle. Pakistan, like many other countries, is turning to renewable energy like rooftop solar panels and net metering to power homes and businesses. However, unlike technologically advanced countries, Pakistan does not have a distribution management system (DMS) to handle the influx of renewable energy from rooftop solar panels.   
Dr Raheel Zafar, Assistant Professor from the Department of Electrical Engineering at LUMS, is working on solutions to help manage energy grids more efficiently and reliably, not only for Pakistan but globally. In 2023, he published two papers in IEEE Access, one as the first author of an international collaboration and the other one with his research assistant as the corresponding author. We will take a closer look at another one of Dr Raheel’s recently published papers in the reputed research journal, IEEE Transactions on Sustainable Energy titled Multi-Timescale Coordinated Control with Optimal Network Reconfiguration using Battery Storage Systems in Smart Distribution Grids

Dr Raheel Zafar explaining the use of GAMS software in this system-level research. This research is linked to his Faculty Initiative Grant at LUMS, an internal funding mechanism designed to support faculty members in their research and innovative projects. 


The paper proposes a new optimization framework to improve the performance of power distribution networks, which are responsible for bringing electricity from the transmission system to consumers. While the framework was developed by Dr Raheel, the co-author Dr Hemanshu R. Pota, Associate Professor at the University of New South Wales Canberra in Australia, provided valuable input during the structuring and revision stages of the article.  
The paper deals with feeder reconfiguration, which involves changing the network’s topology by opening and closing switches to modify the connections between parts of the network. Dr Raheel proposes the co-optimization of feeder reconfiguration, creating a plan to schedule the use of (1) traditional voltage regulating devices, such as the on-load tap changer (OLTCs), to regulate the voltage of the traditional power grid, and (2) utility-scale distributed energy resources like battery energy storage systems and photovoltaic (solar energy) inverter. 

The voltage limit violation caused by the increased integration of renewable energy sources is the main factor limiting the hosting capacity of distribution grids. The proposed control framework keeps the voltage magnitudes within the upper voltage limit of 1.05 per unit.  (a) The maximum voltage profile for the entire day. (b) The feeder voltage profile at time = 19:00.


To determine the optimal coordination between these different sources of power, Dr Raheel used a mathematical model called “mixed-integer second-order cone program”. This was solved using the GAMS software, an abbreviation for General Algebraic Modeling System, to find the best solution for the power grid, or “global optimum”, by exploring possible solutions and identifying the combinations that produce the best outcomes. Furthermore, the feasibility of the solution was tested using the Distribution System Simulator (OpenDSS) software. The model calculated an optimal switching plan on a daily basis, using 20-minute intervals for batteries and photovoltaic inverters, and hourly intervals for OLTCs. 
Through this model, Dr Raheel was able to reduce energy losses by a staggering 24,1% and improve load balancing by 25%, compared to the current fixed topology system. The model could be used for day-ahead scheduling, making it a promising solution for optimizing power distribution.