Abstract
This paper proposes a "grey-box" dynamic equivalent model for medium voltage active distribution networks, taking into account a heterogeneous fleet of generation technologies alongside the latest European grid codes requirements. It aims to properly represent the transient behavior of the system upon large voltage disturbances in the transmission side. The proposed equivalent model is composed by four main components: two equivalent generation units, one for converter-connected units' representation, and another accounting for the synchronous generation units' portfolio; an equivalent composite load model; and a battery energy storage system, also converter-connected to the grid. The model's parameters are estimated by an evolutionary particle swarm optimization algorithm, by comparing a fully-detailed model of a medium voltage distribution network with the equivalent model's frequency domain's responses of active and reactive power flows, at the boundary of distribution-transmission interface substation.

Abstract
This paper addresses the stability analysis of a real island power system following the transformation occurring in the generation portfolio: from a 100 % synchronous-generation-based system (associated to a fleet of diesel generators) to a hybrid power system dominated by power electronics converters. The integration of a battery-wind-photovoltaic power plant in the island creates the necessary conditions for operating the system without synchronous units scenarios with a system dominated by power electronics - or, at least to minimize its use - scenarios with a reduced number of synchronous units in operation. The possibility of operating the system under these conditions is assured by grid-forming inverters connected to battery energy storage systems, that are responsible for performing frequency and voltage control tasks either in parallel with synchronous units or when synchronous units are disconnected. The resulting transient stability issues for the aforementioned operational scenarios are discussed and evaluated through dynamic simulations.

Abstract
The progressive decommissioning of large synchronous generators that should take place in face of increasing penetration ratios of Distributed Generation (DG) will demand additional control mechanisms for inertia provision and frequency and voltage regulation in the power system. The need to cope with increasing penetration ratios of DG in distribution grids, added to the necessity to integrate an expected massification of EV and distributed ESS, and to the necessity to enhance Power System resilience and controllability, makes the Smart-Transformer (ST) a suitable solution. In this paper it is demonstrated the feasibility of the ST to contribute to frequency control through the control of the resources available in the distribution AC/DC hybrid networks created from the ST. The feasibility of local droop controllers, acting on frequency and voltage magnitude of the AC/DC hybrid networks created from the ST, to achieve the aforementioned goal, is demonstrated through computational simulation.

Abstract
The large scale integration of inverter-based renewable generation in isolated power systems is posing stability concerns as a result of the displacement of the conventional synchronous machines (SM). In this sense, the integration of battery energy storage systems (BESS) connected to the grid through power converters operating as grid-forming units is mandatory in order to ensure system stability. Therefore, this paper aims to perform a dynamic stability analysis of an isolated power system regarding the installation of a BESS, where it is intended to determine the minimum required grid-forming power capacity of the associated power converter that guarantees system stability under several operational scenarios. Moreover, the expected interactions between the grid-forming inverter and the conventional SM are also addressed. © 2019 IEEE.

Abstract
This paper aims to describe the main outcomes of the ADMS4LV project which stands for Advanced Distribution Management System for Active Management of LV Grids. ADMS4LV targets the development and demonstration of a framework with adequate tools to optimize the management and operation of Low Voltage (LV) networks towards the effective implementation of Smart Grids. This work details the main functionalities of ADMS4LV and discusses their implementation. The validation of the functionalities is presented from demonstrations in a laboratorial setup, namely regarding the algorithms which using advanced data analytics, accomplish to operate LV networks with low observability, (i.e., with few real-time measurements) and without having full knowledge of the networks' technical characteristics, such as the consumers' phase connection to the grid. The assessment of the results shows the adequacy of the ADMS4LV solutions for deployment in distribution networks with current infrastructures, differing unnecessary investments in sensory devices. © 2019 IEEE.

Abstract
We present a novel fully distributed strategy for joint scheduling of consumption and trading within transactive energy networks. The aim is maximizing social welfare, which itself is redefined and adapted for peer-to-peer prosumer-based markets. In the proposed scheme, hourly energy values are calculated to coordinate the joint scheduling of consumption and trading, taking into consideration both preferences and needs of all network participants. Electricity market prices are scaled locally based on hourly energy values of each prosumer. This creates a system where energy consumption and trading are coordinated based on the value of energy use throughout the day, rather than only the market price. For each prosumer, scheduling is done by allocating load (consumption) and supply (trading) blocks, maximizing the energy value globally and locally within the network. The proposed strategy was tested using a case study of typical residential prosumers. It was shown that the proposed model could provide potential benefits for both prosumers and the grid, albeit with a user-centered, fully distributed management model which relies solely on local scheduling in transactive energy networks. © 2019 IEEE.