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 location in distribution systems was tested and evaluated in the National 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 also prepared in CINELDI [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 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 simulation of a grid 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 in an advanced algorithm for optimal placements of sensor that can be used for fault location in smart grids [5], where the effect of 5G 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 regulatory 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 will be reached if the ICT equipment is utilized appropriately 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.