MatHematicAl fRamework for harMONic stabilitY assessment of power electronics-based power systems


In HARMONY will be developed a mathematical framework capable of simulating all components in HPS for system stability assessment studies. The developed tool will be comprehensive and user-friendly for the analysis of stability assessment and the mitigation of instabilities in the power systems of interest. It will be efficient in investigating multi-terminal HVDC power systems (offshore and onshore side), interconnections between transmission and distribution power system side, controller interoperability, and HVDC protection. Presently available commercial tools require expensive equipment, with long-time model development, and computationally and time expensive simulations (minutes to hours). In contrast, the newly designed tool will provide execution time in the range of several seconds using general-purpose CPUs.

Project description

The digitalization of power systems and the application of renewable energy sources (RES) have resulted in the increased penetration of power electronics equipment. The increased amount of power electronics connections in hybrid power systems (HPS) may cause unstable system operations. Namely, power electronic converters act as a negative resistance over the wide range of oscillation frequencies which are commonly known as a spectral range. When interconnected to the remaining power system, the converter can “push” the power system into unstable operating regimes. Furthermore, both AC and DC power systems are vulnerable to various spectral components caused by the converter’s internal dynamics. Spectral components with frequencies of 2ω, 3ω, and 6ω, for ω being the line angular frequency, are the most prominent.

It is of utmost importance to identify which spectral components can influence the undesirable behavior of the power system. These harmonics can cause oscillations, and even instabilities causing system failures with large consequences like blackouts.

In this project, the harmonic behavior of the power electronic converters will be identified.

Intended deliverables

The project is divided into 3 work packages (WPs):

WP1: Developing models for the HPS and dynamic phasor (DP) components’ models
WP2: Developing optimization models for harmonic and DP analysis of the AC-DC power system
WP3: Mathematical framework implementation and testing


M1: Power electronic converters’ spectral and DP model validation by experiments (in RTDS laboratory, after 1.5 years from the project start).
M2: Design and interconnection of spectral, DP, and power flow models of the power electronic converter (end of year 2).
M3: Tested validation of the complete framework by experiments (in RTDS laboratory, after 2.5 years from the project start).

TUD team

Postdoc Researcher:
Dr. R. (Robert) Dimitrovski

Postdoc Researcher:
Dr. D. (Dongyu) Li

Postdoc Researcher:
Dr. S. (Sounak) Nandi

D. (Dongyu) Li

Dongyu Li (Student Member, IEEE) received the B.E. degree in energy and power engineering from Northwestern Polytechnical University, Xi’an, China, in 2014, and the M.Sc. degree in sustainable energy technology from Xi’an Jiaotong–Liverpool University, Suzhou, China, in 2017. He is currently working toward the Ph.D. degree with the Department of Electrical, Computer and Software Engineering, The University of Auckland, Auckland, New Zealand., From 2014 to 2015, he was with Daya Bay Nuclear Power Operations and Management Co., Ltd., Shenzhen, China, specializing in vibration fault detection. His research interests include fault detection, localization, and isolation in the voltage-source converter HVdc system. He joins TU Delft as a postdoctoral researcher in the Harmony.

S. (Sounak) Nandi

Sounak Nandi was born in West Bengal, India, in 1992. He is currently working toward the Ph.D. degree in high voltage engineering with the Department of Electrical Engineering, Indian Institute of Science, Bangalore, India. His research interests include high voltage engineering, polymeric insulators for outdoor applications, computational electromagnetics, numerical techniques in electrostatics, over voltages in power systems, composite insulation for transformers, and dielectric breakdown physics. He joins TU Delft as a postdoctoral research fellow to contribute to the Harmony project.

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