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• The lightning transient behaviours of the large scale wind turbine (WT)-Photovoltaic (PV)-battery energy storage system (BESS) hybrid system is first studied. • Those from Overheadline outside substation and transmission tower of WF endanger the power equipment installed in the substation. • The surges from PV mainly affect the equipment within PV system, and they have a relatively small influence on the hybrid substation. • The string structure of PV system and the star arrangement for WF is preferred from the viewpoint of lightning protection. The lightning transient overvoltages in the hybrid wind turbine (WT) -photovoltaic (PV)- battery energy storage system (BESS) is investigated in this paper. A hybrid system model is devolved in the environment of EMTP. The high-frequency (HF) models of components in the hybrid system are established, including PV string, inverter, cable, power transformer, wind tower, DC/DC converter and so on. Then, three types of overvoltages caused by lightning striking PV array, transmission tower of wind farm (WF) and terminal tower of 500 kV substation are thoroughly studied. The installation mode of surge protection device (SPD) within PV system is discussed. Finally, the influence of WF and PV system topologies on lightning surge is discussed. The results show that lightning surges from the PV system do not affect the WF, the BESS, and the hybrid substation. Regarding lightning surges from the substation side, the string structure exhibits a significant decrease of 72.8% in voltage compared to its central structure in PV system. Observing WF, when comparing the star structure against the radial connection, there is a reduction of 63.4% in lightning voltage in the former. [ABSTRACT FROM AUTHOR]

The study and the optimization of single devices, plants and integrated systems among producers and users, must be performed considering the possibility of energy storage and conversion among different forms of energy in order to reach the best overall energetic and environmental performance. Small CHP distributed plants are particularly interested in these challenges, both in stand-alone and grid-connected configurations. In this paper, the optimal design and management strategy of a trigeneration system composed by a PV plant, a diesel CHP engine, a reversible heat pump and a boiler is studied. The possibility of hybrid storage by means of a hot and a cold reservoirs, a pack of batteries, and a pumped hydro energy storage is investigated. By applying a model based on the Particle Swarm Optimization, the devices size and the operation strategy are simultaneously optimized. The most suitable devices' hourly-based operation profile and the best management strategy of the energy storages are predicted. The minimization of the overall costs is the problem's optimization target, while the main constrain is the fulfillment of the users' request of electricity, heat, cooling and drinking water. [ABSTRACT FROM AUTHOR]

Photovoltaic and wind power generations are currently seen as sustainable options of in rural electrification, particularly in standalone applications. However the variable character of solar and wind resources as well as the variable load demand prevent these generation systems from being totally reliable without suitable energy storage system. Several research works have been conducted on the use of photovoltaic and wind systems in rural electrification; however most of these works have not considered other ways of storing energy except for conventional battery storage systems. In this paper, an energy dispatch model that satisfies the load demand, taking into account the intermittent nature of the solar and wind energy sources and variations in demand, is presented for a hybrid system consisting of a photovoltaic unit, a wind unit, a pumped hydro storage system and a diesel generator. The main purpose of the developed model is to minimize the hybrid system’s operation cost while optimizing the system’s power flow considering the different component’s operational constraints. The simulations have been performed using “fmincon” implemented in Matlab. The model have been applied to two test examples; the simulation results are analyzed and compared to the case where the diesel generator is used alone to supply the given load demand. The results show that using the developed control model for the proposed hybrid system, fuel saving can be achieved compared to the case where the diesel is used alone to supply the same load patters. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents two novel hourly energy supervisory controls (ESC) for improving long-term operation of off-grid hybrid systems (HS) integrating renewable energy sources (wind turbine and photovoltaic solar panels), hydrogen system (fuel cell, hydrogen tank and electrolyzer) and battery. The first ESC tries to improve the power supplied by the HS and the power stored in the battery and/or in the hydrogen tank, whereas the second one tries to minimize the number of needed elements (batteries, fuel cells and electrolyzers) throughout the expected life of the HS (25 years). Moreover, in both ESC, the battery state-of-charge (SOC) and the hydrogen tank level are controlled and maintained between optimum operating margins. Finally, a comparative study between the controls is carried out by models of the commercially available components used in the HS under study in this work. These ESC are also compared with a third ESC, already published by the authors, and based on reducing the utilization costs of the energy storage devices. The comparative study proves the right performance of the ESC and their differences. [Copyright &y& Elsevier]

This paper deals with the control and implementation of a bidirectional Z-source inverter for a photovoltaic-diesel generator-energy storage hybrid system. The proposed control strategy is based on the voltage regulation across one of the Z-network capacitor (V cz), through a buck-boost converter of the storage system side. In some critical situations, where the load power is important, the V cz voltage regulation is no longer able to ensure the duration of the necessary state shoot-through for the maximum power point tracking achievement. In this context, the diesel generator can therefore be solicited to ensure the shoot-through duration and achieve maximum power point tracking so that it can be used more advantageously without any harmful effects on the Z-source inverter operation. The effectiveness of the proposed control strategy is evaluated and validated by extensive simulations and experiments. [ABSTRACT FROM AUTHOR]