Measurements in Modern Electric Grids in the Presence of Power Converters
Distributed energy resources and multi-terminal mixed ac-dc grids lead to a massive presence of power-electronics converters in power grids, making the measured electric signals much more complex and richer than ever before. Due to dynamics and disturbances, voltages and currents are far from sinusoidal (ac) and stationary (dc), thus requiring cutting-edge instruments based on new measurement models, methods, and technologies to monitor different quantities and parameters. This tutorial presents the theoretical aspects of measurement models (signal representation) and the technical needs (accuracy, synchronization, architectures, etc.) for monitoring purposes, along with two practical application challenges:
- Besides a brief overview of IEC standardisation work on measurement methods for supraharmonics, measurement of distorted signals in ac grids are illustrated by case studies (PV inverter, EV charging) from laboratory and field measurements. Results of measurements performed in a laboratory scale islanded microgrid are also presented.
- After describing the automation system of a multi-terminal MVDC system, with multiple converters and control centers, the state-of-the-art about measurements on the MVDC grid is presented, elaborating also on the higher layer state estimation application, which relies on both MVDC and MVAC grids measurements. Future developments for reliable MVDC grid monitoring are also discussed.
Paolo Attilio Pegoraro received the M.S. (summa cum laude) degree in telecommunications engineering and the Ph.D. degree in electronic and telecommunications engineering from the University of Padova, Padua, Italy, in 2001 and 2005, respectively. From 2015 to 2018 he was an Assistant Professor with the Department of Electrical and Electronic Engineering, University of Cagliari, Cagliari, Italy, where he is currently Associate Professor. He has authored or co-authored over 110 scientific papers. His current research interests include new measurement techniques for modern power networks, with attention to synchronized measurements and state estimation. Dr. Pegoraro is a Senior Member of IEEE Instrumentation and Measurement Society TC 39 (Measurements in Power Systems) and a member of IEC TC 38 (Instrument transformers)/WG 47. He is an Associate Editor of the IEEE Transactions on Instrumentation and Measurement.
Jan Meyer received his Ph.D. degree in electrical power engineering as well as the postdoctoral qualification in Power Quality from Technische Universitaet Dresden, Dresden, Germany. He is currently a Senior Lecturer and Team Leader of the Power Quality Research Team at the same university. His research interests include network disturbances and their assessment, especially for distortion below and above 2 kHz, accuracy of Power Quality measurements as well as analysis of big data resulting from Power Quality measurement campaigns. He is member of several national and international working groups on EMC standardization, several CIGRE working groups and the CIRED technical committee. He gives regular talks on recent topics in the field of Power Quality and organizes seminars in the field of network disturbances.
Gaurav Kumar Roy received his bachelor’s studies in SRM university, India, and a master’s degree in RWTH, Germany, in 2013 and 2017. He is currently pursuing his Ph.D. degree in Automation of complex power systems in RWTH Aachen. He was involved in implementing the automation system for the Multi-terminal DC grid for RWTH Aachen, and his current interests lie in power system reliability, automation system for smart grids, and DC technologies.