A. Etxegarai

Dynamic line rating forecasting based on numerical weather prediction

This paper describes the line rating forecasting techniques based on NWP models. Taking the wind power forecasting as a base for the overhead line rating forecasting, the paper identifies the differences between the wind power forecasting and the overhead line rating forecasting. Recent experiences about overhead line rating forecasting are also described. As a result, the requirements for the overhead line rating forecasting are defined. Finally, a pilot project of overhead line rating forecasting is presented and the results are discussed.

Impact of wind power in isolated power systems

Weak power grids with DG penetration show poor power quality, protection issues and frequency deviations under severe disturbances, especially in isolated networks. This paper explores the impact of wind power in weak isolated power systems. A small size island power system has been modeled and the impact of wind power on system stability has been studied. Two main aspects have been covered: the impact on frequency stability and on transient stability, as well as fault-ride through capability of the wind turbines.

Islanding detection of synchronous distributed generators

This paper analyses the performance of local passive islanding detection methods for synchronous distributed generators, under different grid and load scenarios. These methods monitor electrical parameters at the interconnection point of a distributed generator and detect island situation whenever these parameters change correspondingly. Lately, islanding detection research has been focused on inverter based systems. But synchronous generators still pose a challenge for study. With this aim, a low voltage distribution network with embedded synchronous generators has been modelled. The performance of frequency and rate-of-change-of-frequency relays have been evaluated, analysing the influence of power mismatch and generator characteristics on the islanding and also avoid false operation.

Evaluating the impact of geographic distribution of photovoltaic self-consumption on energy losses

Photovoltaic (PV) self-consumption concept has emerged as a sustainable and economically viable alternative to save electricity provided by electric utilities. There are several concerns about the massive deployment of PV self-consumption installations. One of them is the influence of such installations on energy losses. Several research works have indicated that PV self-consumption installations reduce or increase energy losses depending on their penetration level. These research works use a uniform geographic distribution of PV self-consumption installations. However, rural areas are more likely to have a higher PV self-consumption penetration rate than urban areas and so, a uniform distribution may not be a proper approach. This paper proposes a methodology with different levels of geographic distribution to evaluate this issue. This methodology has been applied to the electric network of Murcia (Spain). Simulation results show that there is a significant influence of geographic concentration or dispersion of PV self-consumption systems on energy losses.

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.

Evaluation of dynamic response in isolated power grids: Terceira island

Terceira island has a great potential for geothermal energy, which can contribute to increase the penetration of renewable energies in the generation mix. But as a small size island grid, several technical issues can appear. This paper models the power system in Terceira island before the installation of any new renewable power plant. Thus, the steady-state and dynamic performance of the power system is characterised and most critical scenarios are identified.

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.

Modeling and validation of photovoltaic plants using generic dynamic models

Dynamic simulation models of photovoltaic plants are needed during the design stage of the plant, to show compliance with grid code requirements, as well as after commissioning, to validate the model response with the real plant performance. Due to the large number of PV installations and inverter models, there is a strong need to move from specific manufacturers user models to generic models, as the ones proposed by the Western Electricity Coordinating Council (WECC). This paper discusses the need for generic models, introduces the photovoltaic plant model developed by WECC and presents a case of generic model parameterization and validation of a commercial three-phase inverter, based on factory test. The simulation results show the validity of the generic model to reproduce the Low Voltage Fault Ride Through (LVFRT) capability of the inverter.

Work in progress: TwittING project. Using Twitter in engineering education

This paper presents TwittING project, which aims to use Twitter as an educational tool for engineering students. The background of the project was the positive experience of a lecturer team with a Classroom Response System (CRS) based on clickers. TwittING aims to use Twitter as a question-based learning tool, but also as a dynamic platform for the peer-to-peer communication and learning assessment. Preliminary results regarding the experience of both students and lecturers are presented in this paper.

A Survey on Innovative Solutions and Projects for the Integration of Renewable Generation in Weak Power Grids

This paper deals with the most relevant issues about the integration of renewable generation in weak power grids. Initially, the main parameters that characterize these types of networks are reviewed, in terms of short circuit power, system inertia and frequency and voltage characteristics. Afterwards, improvement measures in the structure of weak power grids are proposed, analyzing different storage technologies in order to guarantee a high efficiency and reliability of the power system. Finally, the paper reviews the most prominent projects developed worldwide which include the integration of renewable energy in weak grids.