Optimal allocation, sizing, and optimal design of control structures for a stronger grid
By Ms Nancy Van Nieuwenhove | 12 December 2020
2nd Year PhD candidate, Faculty of Engineering/ Department of ECSE
Research interests: Renewable energy, control interactions, optimisation, stability of power systems
Sajjad Hadavi holds a Bachelor in Electrical Engineering from Amirkabir University of Technology (AUT, Iran) and a Master's in Electrical Engineering from AUT. “From my childhood, I was inspired by wind turbines, massive structures with clean energy capabilities. During my bachelor's degree at AUT, I found my way into the energy sector. When I finished my master’s degree, I worked in a power systems company where my job was to test loads and do some forecasting. It was a very important task, as the other issue we have with renewable energy is the power generation uncertainty linked to the weather changes.”
Sajjad translated his keenness to be part of a 100 percent renewable energy future by starting a PhD in Electrical Engineering. Sajjad's PhD research, supervised by Dr Behrooz Bahrani (Senior Lecturer, Faculty of Engineering/ Department of ECSE and Director of Grid Innovation Hub, Faculty of Engineering), focuses on investigating weak grids, the integration of renewable energy in weak grids and enhancing the grids strength with new assets and control structures. “At first, I wanted to study microgrids and smart grid power system, but because Australia is leading the way in renewable energies, I decided to do a PhD to sharpen my skills and knowledge about renewable energy technology, the operation and modelling of wind and solar farms, their control methods, and their impacts on the Australian power system. I am working on the transmission network, in high-level wind and solar farms. My study is about enhancing the strength of the grid.”
Due to environmental issues and climate change, fossil-fuel-based generators need to be replaced by renewable energy resources, which introduces new challenges for the power systems, such as low inertia and weak grids. In traditional generators, the massive rotating parts provide inertia and help the system to be stable. Wind farms have rotating parts, but those are decoupled from the grid, and cannot help the grid to be stable. Another impact of high renewable energy integration in the grid is that most of the power plants are in remote areas (ie, offshore wind farms), and long transmission lines increase loss and instability in the system. “Australia was the first country with those issues, because of its long transmission lines.”
“The increasing number of weak-grid-connected renewable energy resources in power systems has created various challenges in recent years. Some examples include undamped voltage oscillations in the ERCOT power system (in Texas, America) and sub-synchronous resonance in the North-China power grid. Several solutions for these challenges have been proposed, such as Static Compensators and Synchronous Condensers (SynCons). However, their installation/ operation costs and lead-time bring new challenges. Additionally, the interaction of new assets and the existing renewable energy farms can cause stability issues in a weak grid. There is a need to operate the strengthening assets optimally, which means optimal allocation, sizing, and optimal design of their controller”.
This year, Sajjad Hadavi received a scholarship from the Monash University Grid Innovation Hub (GIH) for his contribution towards energy optimisation research; Stability Enhancement And Interaction Of Grid-Strengthening Assets And Renewable Energy Farms In Weak Networks. “With the ARENA funds, we can have adequate experimental facilities to implement our proposed methods and algorithms in real life. Furthermore, the ARENA and GIH initiatives prepare a way to have contact with the industry and be aware of practical challenges due to renewable energies in the Australian power system. Consequently, we can be sure we can solve real issues and challenges in the Australian power system”.
Sajjad is familiar with Australian power system topology and standards and proposed a method to solve optimisation issues in the system. The method for optimal allocation and sizing of SynCons with Meta-heuristic optimisation algorithms. He used a convex optimisation for optimal allocation and sizing of SynCons in a large power system.
He also proposed an optimal design of a SynCon exciter controller.
And finally he designed a framework to study the interaction of renewable farms with the system. “What I study is the big picture and all the equipment in the system and the interactions. If my framework works, we can reshape the controller and investigate the instability margin, then we can solve any issues and make sure that if we want to add any wind or solar farm to the system, it can happen without any instability or blackout. For example, the cause of the blackout in South Australia in 2016, was a fault in the line of the wind farm, that caused five wind farms to also trip out, and a lot of power went out from the system and caused a blackout.”
In 2021, Sajjad would like to “introduce a framework for a stable operation of a power system with high penetration of renewable energy resources and find a way to investigate the interaction of existing and future renewable resources on each other”.