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In those electrical systems with an implemented secondary voltage regulation based on the reactive power of traditional fossil fuels power stations, it becomes more important that new renewable sources power plants participate to the voltage control. In this paper it is studied a voltage control for large photovoltaic systems. The control is applied to an actual large photovoltaic power plant. Simulations...
Electric storage brings significant benefits to the electric systems by counteracting the strong constraint that the generated power has to be instantaneously balanced by load. This paper analyses the prospect of the introduction of a storage device into a small distribution grid considered as an energy hub.
The paper proposes an application of a hierarchical automatic voltage regulation scheme for a cluster of hydro power plants connected to HV networks. The topology considered in the paper is a radial network in which the hydro power plants are connected to each other and have a single point of connection at the HV level. The technique proposed in the paper is based on well-assessed control strategies...
This paper proposes an application of a hierarchical automatic voltage regulation scheme for wind power plants connected to HV networks. The proposed control schemes is based on a given topology of wind power plants. In particular, we assume that wind generators are connected to each other and have a unique point of contact at the HV level. The secondary voltage control scheme proposed in the paper...
The increasing complexity of ship's Integrated Power Systems (IPSs) led to the need of a review of conventional design process. Moreover, several stakeholders influence ship design, each of them aiming to protect its own interests, in particular when responsibility of accidents has to be defined. Dependability could be the tool to modify conventional design, transforming it into a dependability oriented...
Distributed Generation (DG) operating in a distribution network influences active power losses. In this paper power losses have been estimated for an actual low voltage distribution network and compared for different situations according to the DG penetration and placement of the power units. A practical method to place new DGs is presented. The basic idea is to minimize power losses, while complying...
Static frequency converters, which are the core element of high voltage direct current transmission systems and FACTS devices, are becoming a mature technology for applications in medium voltage distribution networks. This paper considers a novel device, namely, the back-to-back connector, which provides a medium voltage dc link with control capabilities similar to high-voltage back-to-back VSC-HVDC...
In this work a possible interconnection in MV between two DSO located in two bordering European countries is analyzed. Legal concerns regarding the connection are treated both at European and at national level.
We calculate the historical payback time (PBT) and internal rate of return (IRR) for domestic photovoltaic systems installed at different times between 2003 and 2014, in three different Italian locations (North, center, South, thus representing different levels of energy yield). We show that over time, even though rather different regimes of governmental incentivization and end-user energy prices...
Hierarchical automatic voltage regulation is implemented in several power systems using the reactive power capabilities of controlled alternators in transmission networks. With the introduction of power plants based on Renewable Energy Sources (RES), in the transmission network there are new possible participants to the voltage regulation which replace in part the traditional large alternators. The...
Several countries are undergoing a considerable development of distributed generation (DG). Hence, Distribution System Operators (DSO) are coping with unprecedented technical issues which force introducing new connection rules for customers that produce energy. This work focuses on voltage control issues of distribution systems with inclusion of distributed generation. A review of the standards that...
In recent years, several countries have published new technical rules for the connection of distributed generators to medium and low voltage networks. A common requisite is that distributed generators should be able to module both active and reactive power. The paper duly reviews these rules and presents a variety of simulations referred to actual distribution networks using a new software tool: DOME.
Power quality is a key issue in islanded electric power systems. Considering the intrinsic weakness of islanded grids, this paramount aspect is not of easy accomplishment. To fulfill power quality requirements in these weak electric systems, high performance voltage and frequency controls are needed, although the interactions between these controls can lead to stability issues. In particular, frequency...
Distributed Generation is growing at important rates due to several reasons, including, in some countries, the strong penetration of renewable generating plants. Voltage rise is a considerable problem that prevents generators from injecting more active power into distribution networks. After a review of recently proposed mitigation techniques, a voltage rise mitigation technique is presented. The...
Secondary Voltage Regulation (SVR) is part of the hierarchical control system of EHV transmission network, currently operated by the Italian Independent System Operator. SVR is being actuated using automatic voltage and reactive power regulators, named SART, in power stations rated more than 100 MVA. Each SART receives from the Regional Voltage Regulator a reactive level signal and implements it by...
Several factors lead to the increase of Distributed Generation (DG), including the ongoing penetration of electric power plants from renewable sources. However, most of present distribution networks have been designed as passive networks and present some relevant problems that prevent a strong penetration of DG. One of the major problems is the voltage rise due to active power injections made by distributed...
Several different models for the propulsive shaft system have been proposed in literature. In this paper, the so called thruster level model is considered. Basically the system is composed of a propulsion motor, a transmission device (a shaft) and a propeller. In all-electric ships, propulsion is realized utilizing electrical drives. Time varying propeller loading induced by waves, hydrodynamics effects...
The use of General Purpose Processors (GPP) in conjunction with Real Time Operating Systems (RTOS) derived from non real time operating systems gives new solutions to the industrial control designer. Several factors work towards this direction and bring advantages in terms of reduced time for development and low cost of deployment. In particular, the Real Time Application Interface (RTAI) is a real...
This work presents the design and development of an innovative system aimed at detecting, recording and transmitting electrical and climate data from a PV field. Data are to be taken both from the PV modules and from the power conditioning system of a given PV field, through appropriate sensors, to monitor: climate data (irradiance, temperature), electrical quantities (voltage, current, power), performance...
Linux operative system, extended with the real time application interface (RTAI), makes it possible to realize industrial motion controls. This requires general purpose processors (GPPs) instead of dedicated DSPs or microcontrollers. RTAI offers the possibility of designing and developing motion controls using high level object languages (i.e., Simulink). The main advantages brought using Linux-RTAI...
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