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This study introduces a quadratic programming-based optimisation method to coordinate electric vehicle (EV) charging and photovoltaic (PV) curtailment in unbalanced low voltage (LV) networks. The proposed model is defined as a convex model that guarantees the optimal global solution of the problem avoiding the complexity of non-linear models and surpassing the limitations of local solutions derived from meta-heuristics algorithms reported in the literature. The coordination is carried out through a centralised controller installed at the header of the LV feeder. The objective of the proposed strategy is to minimise the power curtailment of all PV systems and maximise the power delivered to all EVs by optimising at every time step a suitable setpoint for the PV units and the charging rate of each EV connected without surpassing network constraints. A new energy-boundary model is also proposed to meet the energy requirements of all EVs, which is based on a recurrent function that depends on the arrival-and-desired energy states of the vehicle to compute its charging trajectory optimally. The effectiveness of the proposed coordination strategy was successfully proven through three scenarios in a laboratory environment, making use of two commercial EVs and a PV inverter in a Power Hardware-in-the-Loop setup.

. (2014). Aplicación de los sistemas fotovoltaicos conectados a la red: estado del arte. Revista Tecnura, Edición especial, 157-172. ResumenEn este trabajo se describen todos los conceptos necesarios para lograr implementar un sistema fotovoltaico como alternativa para ser utilizado como generador distribuido. Para ello, se realiza un pequeño estado del arte en el cual se manejan conceptos básicos, desde el funcionamiento de una celda solar hasta conceptos de redes inteligentes aplicados en la gestión de la demanda. Asimismo, se abarca un repaso sobre los marcos regulatorios existentes en Colombia, donde se habla de generación distribuida debido a la falta del mismo. Es necesario comparar tales regulaciones con los diferentes marcos regulatorios existentes en otros países, como Alemania, España y EE.UU., para obtener un modelo de trabajo idóneo. Finalmente, se decide utilizar un generador fotovoltaico conectado a la red de baja tensión como alternativa en los sistemas de generación distribuida, ya que con estos se pueden realizar balances energéticos, esto en caso de que en el país en donde se emplee esta alternativa no se tenga establecido un marco regulatorio adecuado, de manera que el usuario no tenga problemas con las entidades regulatorias actuales. Palabras clave: balance energético, energías renovables, generación distribuida, gestión de la demanda, sistemas fotovoltaicos. AbstractThis paper outlines all necessary concepts to successfully implement a photovoltaic system as an alternative in a distributed generation scheme. For this purpose, it is made a short state of the art in which basic concepts are addressed, from a solar cell operation to smart grid concepts applied on demand management. Likewise, a review of the different regulatory frameworks in Colombia is entailed, especially those related to distributed generation, due to the lack of these ones. It is necessary to make a comparison with other regulations from other countries,

With the growing adoption of electric vehicles (EVs) and residential photovoltaic (PV) systems around the world, the distribution system operators (DSOs) are facing several technical challenges on their network planning and operation, particularly on low-voltage grids. As the aggregators are intermediary actors at that system level, they are a promising figure to coordinate these devices in an aggregated manner to help to mitigate adverse effects like overloading of network assets. However, to do so, proper coordination techniques among these entities and the DSO should be developed to avoid further investments in new network assets. In this context, a centralised coordination strategy among aggregators at the DSO level is proposed. By employing a linear programming model, the optimal export limit of PV and charging profile for each aggregator is dictated by the DSO, maintaining the operational limits of the network assets. A case study on two aggregators with moderate and critical penetration levels was carried out. Results show that, by controlling the aggregated export limit of PV power and the aggregated charging rate of EVs, high penetration levels can be integrated into current networks with minor or no need for reinforcing network infrastructure.

The European Union’s vision for energy transition not only foresees decarbonization of the electricity sector, but also requires commitment across different sectors such as gas, heating, and cooling through an integrated approach. It also sets local energy communities at the center of the energy transition as a bottom-up approach to achieve these ambitious decarbonization goals. The energy hub is seen as a promising conceptual model to foster the optimization of multi-carrier energy systems and cross-sectoral interaction. Especially in the context of local energy communities, the energy hub concept can enable the optimal design, management, and control of future integrated and digitalized networks where multiple energy carriers operate seamlessly and in complementarity with each other. In that sense, the optimal design and operation of energy hubs are of critical importance, especially under the effect of multiple objectives taking on board not only technical, but also other aspects that would enable the sustainability of local energy communities, such as economic and environmental. This paper aims to provide an in-depth review of the literature surrounding the existing state-of-the-art approaches that are related to the design and operation optimization of energy hubs by also exploring their interaction with the external network and multiple markets. As the planning and operation of an energy hub is a multifaceted research topic, this paper covers issues such as the different optimization methods, optimization problems formulation including objective functions and constraints, and the hubs’ optimal market participation, including flexibility mechanisms. By systematizing the existing literature, this paper highlights any limitations of the approaches so far and identifies the need for further research and enhancement of the existing approaches.