MIGRATE – Massive InteGRATion of power Electronic devices Power quality in transmission networks with high power electronics penetration By 2020, several areas of the trans-European transmission system will be predominantly or exclusively supplied from renewable sources employing elements of power electronics. This will consequently lead to increased difficulties in ensuring dynamic stability of the electricity system, a greater need for upgrading the existing security systems, and the implementation of measures for mitigating the degradation of power quality due to propagation of higher harmonics. The project partners within MIGRATE therefore tried to find answers to questions related to new concepts of operation, protection, and ensuring power quality in changing conditions. The primary goal of the fifth work-package (WP5) led by ELES was to develop a simulation platform for studying the origin, propagation and consequences of higher harmonics and improving power quality in power-electronics networks in future so as to ensure safe operation of the grid and adequate quality of power supply to grid users. Besides harmonic distortion, other power quality phenomena was evaluated, for example, frequency variations due to the intermittent nature of renewable sources. WORK PACKAGE 5 RESULTS A probabilistic approach to assessing and mitigating harmonics propagation Tackling harmonic distortion starts with an assessment of how they propagate over the network in order to apply mitigation measures accordingly, which is a challenge, as there are numerous potential sources of harmonics that generate them in a random manner with variable propagation patterns. A probabilistic approach was therefore developed to assess harmonics propagation considering the uncertainties in harmonic sources’ location and rate of harmonic generation. This methodology therefore allows us to detect the most vulnerable areas in the network, identify harmonics propagation patterns, and assess the impact of the increasing presence of PE devices on these areas. Then, an optimization-based approach allows us to design the most cost-effective mitigation strategy. The methodology was implemented in a test network and its practical implementation illustrated in a real power system network. The probabilistic nature of the method enabled us to research future scenarios with various levels of power electronics penetration. The methodology facilitated identification of the most vulnerable areas and harmonics propagation patterns in the network, as well as the effect that the increasing presence of PE devices had on these areas. Figure 1: Illustrative example of harmonic distortion propagation on a test network, adopted to higher share of power electronic devices. Grid power quality improvement through the reduction of frequency variation by means of wind farm power output compensation Active power variations of renewable sources cause frequency variations, which are higher the lower the system inertia is. Therefore, one aspect covered in WP5 as part of power quality were increased variations in system frequency during normal grid operation with the higher penetration of renewables. The innovative mitigation method results in a significant reduction of frequency variations and will enable wind turbines to provide ancillary services and participate in the balancing energy market, while at the same time the total power output of wind farms will only be slightly reduced. The market for balancing energy targeted by this innovation already exists and is in a mature state. However, with the foreseeable development of RES, the market is predicted to undergo a structural change. Therefore, a growing demand for the balancing energy can be expected in de future, while only few offerings are available, making, it an emerging market. No Frequency Support Developed control Figure 2: Results of improved frequency stability. 4D visualization of harmonics propagation to support network monitoring by transmission system operators ODIN-PQ is a tool for the 4D graphical representation of harmonics propagation, enabling a rapid visual check of the power quality situation on the grid. The tool uses either real-time measurement results or simulations as inputs and provides video-style (time-lapse) animations on historic or simulated data for analysis and near- future scenarios study. The tool is available as a freeware desktop application under “ODIN PQ (Freeware) License Agreement” and can be downloaded at https://odinpq.eimv.si/. Ireland Voltage THD 60% wind THDu 95% Ireland Voltage THD 90% wind THDu 95% Figure 3: Example of THD values presentation for the case of Irish Grid (*values are results of simulation of future scenarios, not actual measurements) All results are available for download at: https://www.h2020-migrate.eu/ downloads.html PROJECT PROFILE Duration: 2016 – 2019 Project value: EUR 17.8 million (co-funded by the European Commission in the amount of EUR 16.7 million) Source of funding: Horizon 2020 programme (European Commission) Partners: Tallinn University of Technology (TUT), Elering AS, Landsnet, Fingrid, TenneT GmbH, Amprion GmbH, Leibniz Universität Hannover (LUH), TU Berlin, Scottish Power Ltd., University of Manchester (UNIMAN), University College Dublin (UCD), Delft University of Technology (TU Delft), Schneider Electric, Ecole Nationale Supérieure d’Arts et Métiers (Arts et Métiers ParisTech), ETH Zurich, ELES, d.o.o., Univerza v Ljubljani (University of Ljubljana) (UL), Elektroinštitut Milan Vidmar (Milan Vidmar Electric Power Research Institute) (EIMV), EnSiEL, CIRCE Foundation (Research Centre for Energy Resources and Consumption) Participating countries: Estonia, Finland, France, Ireland, Island, Italy, Germany, Netherlands, Slovenia, Scotland, Spain, Switzerland and Great Britain Website: www.h2020-migrate.eu This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 691800..