Results:

• A Data-driven Approach to Grid Impedance Identification for Impedance-based Stability
• A Robust Circuit and Controller Parameters’ Identification Method of Grid-Connected Voltage-Source Converters Using Vector Fitting Algorithm
• Analysis of sensor data for dynamic line rating
• Blockchain Support For Time-Critical Self-Healing In Smart Distribution Grids
• Distributed ADMM* strategy for optimal control of DERs and OLTCs in a radial distribution grid
• Distribution Grid Fault Location Based on Entropy Minimization
• Feasibility check of topology changes in radial distribution networks
• Observability in TSO/DSO interface
• Open-Source Distribution System Load Flow 
• Physics informed neural networks in radial load flow calculations
• Single line to ground-fault locations method developed and tested in simulation
• State estimation algorithm for monitoring distribution grid

Smart grid operation
CINELDI's Knowledge base

This research area focuses on fault localization, protection, and automation in distribution grids. The emerging digitalization in distribution grids brings new possibilities for fault detection, fault handling, and automated response to fault situations. However, large-scale deployment of new localization and protection technologies requires evaluation in real and lab environments. Another challenge is how to leverage new ICT infrastructures such as 5G for protection and automation systems such as self-healing and distribution grid reconfiguration.

First, in CINELDI, a novel concept for fault localization in distribution systems was tested and evaluated in the Smart Grid lab. This concept was tested on a ring configuration and it was based on impedance-based protection [1]. Second, a review of the fault responses of inverter-interfaced distributed energy resources (DER) in distribution grids was prepared [2]. Traditional protection schemes are based on over-current protection that is ineffective in alleviating fault response in DER which is largely determined by its control. A comparison between literature reporting results was presented. Third, since the grid companies and end users currently use a lot of resources to deal with earth faults in low voltage distribution, a detection and location scheme for earth faults was proposed using smart meters [3]. Numerous tests in this work showed that AMS meters can provide useful and reliable information about earth faults. Then, two novel current-based methods for locating earth faults were presented in [4]. The methods are based on the utilization of sequence components of standard current and voltage measurement at a primary substation, and they do not require new devices or measurements in the field. Both methods were tested with a grid simulation, based on data provided by a Norwegian grid operator, and their prediction performances were investigated considering different scenarios on fault resistance, load asymmetry and measurement errors. Finally, CINELDI has also contributed to an advanced algorithm for optimal placements of sensor that can be used for fault location in smart grids [5], where the effect of 5G failure was also investigated in [6].

In [7], a distributed control strategy based on the Alternating Direction Method of Multipliers (ADMM) is developed to coordinate DERs with other voltage regulating devices. The method is compared with other distribution grid control architectures such as centralized and local.

Automated fault location and handling play a key role in improving the reliability of the new distribution grids. The envisioned self-healing characteristic can be reached if the ICT equipment is utilized appropriately in combination with protection equipment. CINELDI results can give a step forward into leveraging capabilities of the ICT infrastructure for implementation of new fault location methods [3]–[5]. In addition to new protection concepts, control architectures are investigated aiming for resilient distribution grid operations [7].

Selected publications from CINELDI:

1. T. Haugan, "Hafslund Use Case - Concept for fault localisation in ring-connected networks", CINELDI Internal (memo), 2019.
2. J. I. Marvik, "Fault responses of inverter-interfaced DER - literature review", SINTEF Energy Research, CINELDI Internal (memo), Mar. 2019.
   
3. H. Taxt, "Test av jordfeildetektering ved hjelp av AMS", SINTEF Energy Research, CINELDI Internal (memo), Aug. 2022.
   
4. T. A. Zerihun, T. Treider, H. Taxt, L. Nordevall, and T. Haugan, "Two novel current-based methods for locating earth faults in unearthed ring operating MV network", presented at the ESPR, 2021.
   
5. R. Muka, M. Garau, and P. Heegaard, "Genetic Algorithm for Placement of IEDs for fault location in smart distribution grids", The 26th International Conference and Exhibition on Electricity Distribution, 2021, pp. 1639–1643, doi: 10.1049/icp.2021.1640.
   
6. R. Muka, M. Garau, B. Tola, and P. E. Heegaard, "Effect of 5G communication service failure on placement of Intelligent Electronic Devices in Smart Distribution Grids", in 2021 IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids (SmartGridComm), Aachen, Germany, Oct. 2021, pp. 308–314. doi: 10.1109/SmartGridComm51999.2021.9632333.
   
7. J.R.A. Klemets, and M.Z. Degefa, "A Distributed Algorithm for Controlling Continuous and Discrete Variables in a Radial Distribution Grid", IEEE Access, 11, pp.2488-2499, 2023.