D3.1 - System Specifications

This document, D3.1 - System Specifications, defines the analytical requirements and design methodologies for Current Limiting (CL) devices intended for DC and hybrid AC/DC microgrid infrastructures. The content is aligned with the NOVETROL project’s objective of enabling safe and efficient power flow control in climate-neutral energy systems.

As included in the Description of Action, the requirements for the EMR-components are selected to comply to the different use-case scenarios and applications identified in T2.1. The specifications of the EMR components will be considered for each operating mode of the CL device (Fault current limiter - FCL, tuneable current limiter - TCL, and pre-charger - PC), in the use-cases defined by UPB and ACT. Real-device and components behaviour obtained through the other WP3 tasks will help to further refine the requirements for the different use-case scenarios modelled in T2.2.

After a brief review of the existing technologies and solutions for current limiting devices, the specifications definition starts by establishing mathematical models for the main components of the current limiter, the magnetic field generator and the EMR chips, and then combines these models to describe overall system behaviour. It also describes how magnetic flux density, inductance, and extraordinary magnetoresistance affect the resistance, efficiency, and fault current under different operating conditions.

The document introduces a multi-objective optimization framework to determine optimal design parameters for each use case. The optimization aims to minimize fault current while maximizing efficiency, subject to geometric, volumetric, and performance constraints. For example, the use case for a 48V, 20A system demonstrates the approach, achieving an efficiency of 99.5% and limiting fault current to 264A.

The five High-Level Use Cases (HLUC) described in Deliverable 2.1 are considered: photovoltaic installations, battery storage, DC-operated loads, hybrid AC/DC grids, and electric vehicle charging. The functional parameters can be classified in 30 specific scenarios grouped into three current bins ranging from below 50A to 1600A, covering power levels from small residential systems to high-power industrial applications. Each scenario was analysed to identify optimized designs, all of which achieved efficiencies above 98%. To improve economic viability, a down-selection process reduced the number of design variants from 30 to 10 while assuring compliance with performance criteria.

The document concludes that proposed system specifications can be used in the main use cases, at the same time outlining next steps, including validating optimized designs through simulation and real-world testing, further reducing design variants for cost-effectiveness, and preparing integration guidelines for DC distribution standards. Scalability for high-power applications such as industrial processes and megawatt EV charging is also identified as a future focus.