Traditionally, the detection of high-resistance earth faults has been a difficult task in compensated medium-voltage (MV) distribution networks, mainly due to its very low-current fault. To date, several techniques have been proposed to detect them: using current injection in the neutral, superposing voltage signals, varying the value of the arc suppression coil, etc. These techniques use different detection parameters, such as fault resistance to earth, line asymmetries, or partial residual neutral voltages. In this paper, phase asymmetry is defined as a new parameter that can be used, together with the aforementioned techniques, in order to improve the reliability and efficiency of the detection process in single-phase earth faults, especially for compensated networks. The use of this parameter has been validated through extensive simulations of resistive faults up to 15 kΩ , with the use of RESFAL software, which is based on Matlab/Simulink.

Almost three decades have passed since the Rio declaration, and after numerous initiatives developed to include sustainability in higher education, with the support of Education for Sustainable Development, it is worth wondering at what point is the process of inserting sustainability in university degrees. To clarify this question, engineering students were inquired, at the University of the Basque Country (UPV/EHU), about their perception of the insertion-level of sustainability and the importance they give to it (in environmental, social, and economic dimensions). The novelty of this study lies in the use of a new questionnaire, based on the students’ activity. The instrument was designed ad hoc and was previously validated for this study. The results indicate a low insertion level of sustainability in its three dimensions in three engineering degrees analysed. Nevertheless, the research also shows that the students give great importance to Sustainable Development (SD), either in academic, personal, or professional spheres. The low insertion level of SD and the high interest of students should be considered by the academic institution as an opportunity to deep in its holistic approach to promote the integration of SD in university curricula, not only in engineering degrees.

This paper presents a new method of detecting low-current faults in high impedance grounded distribution networks, in both compensated and ungrounded medium voltage networks. Based on monitoring the residual variations of line and phase asymmetries, the proposed algorithm can be used in combination with other steady-state data-based methodologies, in order to detect the existence of a single-phase ground fault, as well as identify the faulty feeder and phase. Although it could also be used in compensated networks by means of other techniques (such as the injection of zero-sequence currents in the neutral), the algorithm described in this paper has been developed by using superposed voltages, so as to make its application possible in compensated and ungrounded distribution networks. Furthermore, the reliability of this algorithm has been extensively tested in Matlab/Simulink, considering a wide range of resistive faults, and its practical applicability has also been described.

This work considers three research objectives: to analyze the perception of instructors of the incidence of PBL/PrBL on content learning and skill development; to identify the success factors that they believe promote learning when using them, as well as their importance; and to identify the difficulties they face, and the frequency with which they occur. The responses to a questionnaire administered to 50 instructors who participated in a specific training program were analyzed. The results show that the instructors’ perception is that both models contribute to a better understanding of the contents with regard to their practical application, and to a high level of skill development in their students, with the most favored being group work, decision-making, autonomous learning and problem solving. The instructors consider important success factors to be student involvement in their own learning from the very beginning, feedback from the professor, the tasks having been well-designed and team work and cooperation among students. The most common difficulties identified in our study correspond to the excessive workload associated with monitoring the students, and managing and developing within the established time the planning of their tasks and activities, although there is a medium level of incidence in this regard, and it may be due to the characteristics of the training program received. Exploring these aspects in greater depth in future investigations could facilitate the development of more effective teaching practices.

In engineering education, when choosing methodologies to promote the development of professional skills that satisfy both, the requirements of the evaluation agencies and employers, two options, among others, are being considered: Problem-based learning (PBL) and Project-based learning (PjBL).However, there is a certain discrepancy in published research regarding to the suitability of applying one or other methodology, and about the way they should be integrated into the engineering academic programs. Moreover, no meta-analysis using a significant number of subjects has been found in the literature that quantitatively compares the influence of both methodologies to the development of professional skills. This study makes a first approach using the students' assessment of the methodologies, with a questionnaire, as common comparison test. A set of statistical tests of comparison of means values were conducted between two groups of students (PjBL and PBL students). The results show that project-based learning seems to have more influence to develop professional skills in engineering studies at the University of the Basque Country