Cong Wang wins 2020 Patrick Denantes Memorial Prize

Most of us would love to live on 100% renewable energy but in the last decade electrical distribution networks have changed, driven by the integration of renewable-energy sources, batteries and things like electric-vehicle charging stations. This poses formidable challenges to electrical grids in terms of quality of service and energy balance. Cong Wang, who was awarded his PhD in 2019 for his thesis “Inverse Problems and Optimal Power Flow in Active Distribution Networks”, has been working on solutions to some of these emerging problems.

Cong was supervised by Professor Jean-Yves Le Boudec, head of the Computer, Communications and Applications Laboratory (LCA2) within EPFL’s School of Computer and Communications Sciences, in collaboration with Professor Mario Paolone, head of the School of Engineering’s Distributed Energy Systems Lab. He developed a powerful and elegant mathematical theory around the problem of computing the state of an electrical power grid, given possible uncertain information about power injections. The work in his thesis forms the basis for a radically new method to control distribution-and-micro-grids by acting on individual power consumption and generation.

During his PhD work, Cong applied his method to the smart grid prototype at EPFL. This has now found an industrial application as his code is used by the Commelec Grid Agent, an auto-pilot management system that keeps grids in safe operating conditions and allows the integration of 100% renewable energy production. The Commelec Grid Agent was transferred to GridSteer, a start-up that emerged from the EPFL smart grid project.

It will be deployed in 2021 in a smart grid in the Swiss city of Aigle in partnership with Romande Energy and Migros, to control a grid with charging stations for electrical vehicles, solar panels and a stationary battery. Computing the charging setpoints of electrical vehicles without overloading the grid when solar panels fluctuate is a concrete application of one of the problems solved by Cong’s thesis. 

“It is a great honor to win this prize for my thesis on the operational security and optimality of AC active distribution networks, or ADNs, and it’s noticeable that generic models of ADNs, for example meshed network topology, and multiple unbalanced phases were employed throughout the thesis, making the findings valid and applicable in a large number of practical scenarios,” said Cong. 

Cong plans to continue his research on ADNs with more of a focus on measurement and instrumentation and is grateful for his time at EPFL, “during my PhD I learnt many important lessons. Among the most valuable was how to do independent research and this is also the most important lesson that I will teach my own students at Jilin University in China where I'm working now,” he continued. 

For Professor Le Boudec, Cong’s PhD research represents a rare example of a fundamental advancement of technology through science, “the thesis developed a powerful and elegant mathematical theory and obtained new results to an old problem. The core of the theory is exposed in a sequence of very elegant theorems, which are striking in their simplicity and generality. The thesis provides algorithms derived from this theory for practical application to smart grid controllers. In this work, Cong opens a radically new way to reason about the control of systems, such as electrical grids, but also networks of incompressible fluids, that can be modelled by quadratic, multivariate equations.”

Patrick Denantes was an IC doctoral student who passed away in a mountain accident in 2009. The annual prize in Patrick’s name honors his memory. The prize is awarded by a jury and presented to the laureate at the School’s end-of-year event. Financial sponsorship is provided by the Denantes family and the Nokia Research Center. The laureate receives a sum of CHF5,000.