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Abstract-This paper aims at proving the application of the fault location method based on the Electromagnetic Time Reversal (EMTR) to multi-terminal HVDC (MTDC) networks. In particular, the paper integrates the EMTR fault location technique with the protection scheme recently proposed within the EU project TWENTIES. Further, in view of the peculiarity of the fast protection schemes required by HVDC applications, the paper discusses the performances of the EMTR-based fault location technique by using limited time-windows over which the fault-generated electromagnetic transients are time-reversed. The paper also discusses the advantage of the EMTR fault location related to the use of a single observation point to the case of MTDC grids. Indeed, such a peculiarity may represent a major advantage avoiding necessary time synchronization between the MTDC-fault recording stations and might represents, also, a backup protection system. The performances of the proposed method are validated by numerical simulations obtained using the EMTP-RV simulation environment where electromagnetic fault-transients are reproduced with reference to the MTDC benchmark network of the project TWENTIES.

Primary frequency control is the automatic mechanism implemented on power systems to regulate the power balance through frequency and hence, its action should be taken into account when modeling any contingency state leading to a modification of the active power balance (e.g. generator failures). This paper presents a fully distributed method to solve the DC security constrained power flow (DC-SCOPF) that takes into account the automatic primary frequency response of generators after an incident. In more detail, we extend existing distributed DC-SCOPF formulations by: (1) introducing a new variable representing the frequency deviation; and (2) enhancing the local problem of each generator to consider how it adjusts its production after each contingency following its primary frequency regulation curve. The computation of the frequency deviations in the DC-SCOPF problem is formulated into a suitable form (i.e. in the form of a general consensus problem) so that smaller problems, corresponding to individual sub-regions or actors, can be solved and coordinated via the alternating direction method of multipliers (ADMM) in a distributed manner. In this way, actors of the system do not need to exchange any confidential information with other actors during the optimization procedure. A salient feature of our approach is that it can consider contingencies that lead to area separation without any prior specification of the topology and thus can adapt to many kinds of situations that are of interest in interconnected systems. Extensive simulation results on several standard IEEE systems show the good performance of the proposed model and algorithm in terms of convergence speed and accuracy as well as its capacity to deal with the disconnection of areas in interconnected systems.

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The large-scale deployment of distributed generation including intermittent renewable energy sources introduces several challenges to power systems operation and planning. Although power systems often evolve in a fairly incremental way to meet these challenges, the ambitious objectives for RES development in the next decades (2030-2050), together with the deployment of storage options and active demand, indicate that a more essential paradigm change shift may be required. This paper presents the future challenges and the state of the art of research works that study new concepts for the power systems of the future, with a particular focus on the Web-of-Cells concept, multi-microgrids, the fractal grid approach and autonomic power systems.

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Vehicles of the future will store, transport and use large amounts of electrical energy. The main components of DC networks are power electronic converters. Combinations of such converters are known to be unstable in certain situations. By investigating the causes of instability and comparing current methods, a state space representation is chosen for converter modelling. The concepts of sensitivity and participation factors applied to network models are proposed to address the requirement for algorithms aimed at optimisation. Conclusions are drawn for converters under development for aircraft systems. It is possible to identify parameters responsible for instability, sensitivity to network parameters at different operating points and the safety margins available. Thanks to this method, passive elements are optimised by reducing their global weight and volume.