O. Abarrategui

DC fault detection in VSC-based HVDC grids used for the integration of renewable energies

Considering the relevance that HVDC systems are expected to have in the future of power networks, this paper aims to provide a wide overview of the protection against DC faults. In particular, the detection and location techniques that have been proposed to date are analyzed, focusing on the approaches that are set to be applied in modern HVDC networks, which comprise VSC-HVDC and MTDC systems. Although these systems present a series of remarkable advantages compared to the traditional LCC-HVDC systems, they require a fast detection and tripping of the fault, which is an important challenge in the design of the protection system.

A Solid-State Fault Current Limiting Device for VSC-HVDC Systems

Abstract Faults in the DC circuit constitute one of the main limitations of voltage source converter VSC-HVDC systems, as the high fault currents can damage seriously the converters. In this article, a new design for a fault current limiter (FCL) is proposed, which is capable of limiting the fault current as well as interrupting it, isolating the DC grid. The operation of the proposed FCL is analysed and verified with the most usual faults that can occur in overhead lines.

Work in progress: Project-based learning for electrical engineering

This paper presents ProElec project, which links all the subjects of the electrical engineering field through the academic itinerary of Civil Engineering and Mining and Energy Engineering students at the University of the Basque Country UPV/EHU. Based on Project-Based Learning (PBL), ProElec aims to lead students from 2nd year up to the Bachelor thesis in a dynamic learning process. In order to build the necessary specific and transversal competencies, students will have to design an electrical installation, from the technical, economical and legislative point of view along different subjects. This way, students build their own knowledge autonomously emphasizing their leading role in the teaching-learning process. The aim of the paper is to describe the background, framework, implementation and objective tasks of ProElec project. As preliminary results surveys from students are presented, where it can be observed that the experience has been so far positive.

Fault Current limiting in VSC-HVDC systems with MMC converters

High Voltage Direct Current (HVDC) transmission systems are playing an important role due to their economical and technical benefits in the countries where the electric grid is expanding fast. However, fault current interruption is still an unsolved challenge in these HVDC grids. In order to interrupt undesirable currents, DC circuit breakers can be used, but their capability is limited. With that scenario, Fault Current Limiters (FCL) arise as a good approach in order to reduce fault currents to a more manageable level allowing to increase the transmission ratings of an electrical system, without changing the equipment. Thus, the existing equipment would be able to handle the new currents and protect properly the system. In this paper, the general characteristics and classification of FCLs are explained. After that, a Solid State FCL is applied on a VSC-HVDC system with MMC converters. A simulation case of its optimal behavior is presented.