Abstract
During the last years, several plans for offshore grid development in Europe have been under discussion as a result of the need for the integration of large amounts of offshore wind power, providing additional transmission capacity and building adequate conditions for the single European electricity market. From the system operation viewpoint, technical constraints justify the need for adopting High Voltage Direct Current (HVDC) technology with Voltage Source Converters (VSC) for offshore grid development rather than conventional AC connections. Additionally, reliability and flexibility of operation is pushing for the development of the Multi-Terminal DC (MTDC) grid concept, by which a set of offshore wind farms is connected to a set of onshore AC nodes via a (possibly meshed) DC grid structure. This concept is in line with the envisioned plans for the development of the pan-European Transmission System. A broad range of aspects related to MTDC grids planning, operation, and technology was dealt within the TWENTIES European research project (2009-2013). In particular, this paper presents some results regarding the impact of MTDC systems on the AC systems they are connected to: specific focus is devoted to provision of advanced ancillary services (primary frequency controls, Fault Ride Through capability to AC faults, reactive power support), to the possible contribution of the MTDC grid in enhancing the operational security of AC systems and in restarting them after partial or complete blackouts. To emphasize the advanced functionalities that can be provided for overall system operation, this MTDC grid is referred to in the paper as "DC Grid" (DCG). Simulation results illustrate the potential benefits for the AC systems deriving from the described advanced control functionalities of DCGs. The work has been carried out within TWENTIES Working Package 5.

Abstract
The integration of distributed Battery Energy Storage Systems (BESS) at the Medium Voltage (MV) and Low Voltage (LV) networks increases the distribution grid flexibility to deal with high penetration of Renewable Energy Sources (RES). In addition, it also enables the deployment of key self-healing functionalities, which allow the islanded operation of small sections of the distribution network. However, new planning and real-time operation strategies are required to allow the BESS coordinated control, as well as a cost-effective and stable operation. This paper presents new tools developed for the planning and real-time operation of distribution networks integrating BESS, particularly when operating islanding. For real-time operation, a short-term emergency operation-planning tool assesses the feasibility of islanded operation of a small section of the distribution network. The long-term impact of a BESS control strategy for islanded operation is assessed through a Life Cycle Analysis (LCA) tool. The results and implementation experience in real distribution network are also discussed.

Abstract
Large horsepower induction motors play a critical role in the operation of industrial facilities. In this respect, the distribution network operators dedicate a high priority to the operational safety of these motor loads. In this paper, the induction motor starting is modeled analytically and in a semi-static fashion. This model is imbedded in a convex distribution system restoration problem. In this optimization problem, it is aimed to determine the optimal status of static loads and the optimal dispatch of distributed generators such that: a) the induction motors can be reaccelerated in a safe way and, b) the total power of static loads that cannot be supplied before the motor energization, is minimized. The proposed optimization problem is applied in the case of a distribution network under different simulation scenarios. The feasibility and accuracy of the obtained results are validated using a) off-line time-domain simulations, and b) Power Hardware-In-the-Loop experiments.

Abstract
This paper presents two innovative Fault-Ride-Through (FRT) strategies suited for Smart-Transformers (ST) supplying hybrid AC/DC distribution grids within a microgrid environment. The first strategy is suited for ST without a local energy storage, where its Medium Voltage (MV) inverter is operated in grid-tied mode. The proposed approach relies on the voltage sensitivity of resources connected to the ST fed distribution networks aiming to limit the MV inverter current. The second strategy is suited for ST incorporating local energy storage and operating its MV inverter in grid-forming mode, thus enabling islanding operation of a MV grid section. The proposed FRT strategy aims to regulate ST's output voltage by calculating the maximum voltage drop in the coupling filter in order to control the output current. The proposed strategies are evaluated exploiting appropriated simulation models and extensive operating conditions.

Abstract
The operation of isolated power systems with 100% converter-based generation requires the integration of battery energy storage systems (BESS) using grid-forming-type power converters. Under these operating conditions, load dynamics influences the network frequency and voltage following large voltage disturbances. In this sense, the inclusion of induction motor (IM) load models is required to be properly considered in BESS power converter sizing. Thus, this paper presents an extensive sensitivity analysis, demonstrating how load modeling affects the BESS power converter capacity when adopting conventional control strategies while aiming to assure the successful recovery of all IM loads following a network fault. Furthermore, this work highlights that generators with converter interfaces can actively contribute to mitigate the negative impacts resulting from IM loads following a network fault. Thereby, two distinct control strategies are proposed to be integrated in the power electronic interfaces of the available converter-based generators: one to be adopted in grid-following converters and another one suitable for grid-forming converters. The proposed control strategies provide an important contribution to consolidating insular grid codes, aiming to achieve operational scenarios accommodating 100% penetration of converter-based generation with a significative percentage of the IM load composition without resorting to a significative increase in BESS power converter sizing.

Abstract
Evaluating the effectiveness of teaching and learning core knowledge outcomes and professional skills is a highly challenging task that has not yet been satisfactorily addressed at higher education level. The iTeach European project consortium developed a framework for assessing the effectiveness of various pedagogical methodologies in chemical engineering education, including those aiming to promote important core competencies related to employability, in a range of geographical and educational contexts. The framework was firstly implemented in a core chemical engineering area (reaction engineering) to check its usability and robustness, and subsequently was also tested on a range of subject areas from various branches of engineering and other disciplines, one of which is analysed in more detail in this contribution. The results of this broader assessment encompassed a much more diverse student body with varying educational experiences and a wider range of different teaching methodologies. The outcomes of this assessment are highlighted and the benefits of such an objective approach for evaluating teaching effectiveness is discussed. Crown Copyright