Electrical impact of photovoltaic plant in distributed network

This paper presents the problem of the power penetration of photovoltaic (PV) systems in urban networks. After a qualitative problem description, two different environments for the PV systems have been analyzed: rural and urban networks. Concerning the rural network a single line has been simulated in order to evaluate the relation between the number of PV system installed along the line and the maximum PV power installable. In the second part of the paper the possible problems due to the power penetration have been examined concerning a clustered PV system that will be installed in the city of Torino (Italy) in ambit of an EU project

Electrical Impact Of Photovoltaic Plant In Distributed Network

This paper presents the problem of power penetration of photovoltaic (PV) systems in urban networks. After a qualitative problem description, two different environments for PV systems have been analyzed: rural and urban networks. Concerning the rural network, a single line has been simulated in order to evaluate the relation between the number of PV systems installed along the line and the maximum PV power installable. In the second part of this paper, possible problems due to power penetration have been examined concerning a clustered PV system that will be installed in the city of Torino (Italy) within the ambit of the EU project called POLYCIT

Are manufacturing I-V Mismatch and Reverse Currents Key Factors in Large Photovoltaic Arrays?

In this paper, two factors typical of large photovoltaic (PV) arrays are investigated: one is the current-voltage (I-V) mismatch consequent to the production tolerance; the other is the impact of reverse currents in different operating conditions. Concerning the manufacturing I-V mismatch, the parameters of the equivalent circuit of the solar cell are computed for several PV modules from flash reports provided by the manufacturers. The corresponding I-V characteristic of every module is used to evaluate the behavior of different strings and the interaction among the strings connected for composing PV arrays. Two real crystalline silicon PV systems of 8 times 250 kW and 20 kW are studied, respectively. The simulation results reveal that the impact of the I-V mismatch is negligible with the usual tolerance, and the insertion of the blocking diodes against reverse currents can be avoided with crystalline silicon technology. On the other hand, the experimental results on I-V characteristics of the aforementioned arrays put into evidence the existence of a remarkable power deviation (3%-4%) with respect to the rated power, linkable to the lack of measurement uncertainty in the manufacturer flash reports

Analiza svojstava izmjenjivačkih mrežnih priključaka fotonaponskih sustava

The present trend towards extended adoption of energy production from renewable sources is leading to increased attention towards the diffusion of grid-connected photovoltaic (PV) systems. Different technologies are available for the connection of the PV systems to the grid through inverter-based Power Conditioning Units (PCUs). This paper presents the results of a comparative study referred to the characteristics of different types of PCUs, based on the experimental results obtained for a wide range of solar irradiance and operating conditions. The performance of the grid connection has been characterised by using a set of parameters, referred both to the DC and to the AC side of the inverter, such as the efficiency of the maximum power point tracking, the DC/AC efficiency, the power factor and the harmonic distortion of voltage and current at the interface with the grid. The PV systems have been further characterised by considering their ability of avoiding the undesired islanding operation through relatively fast detection of the islanding conditions and fast PV system shutdown. The results are discussed and compared to the specifications provided by the manufacturers and to the limits imposed by some standards.Sadašnji trend koji vodi prema sve većoj potrebi za proizvodnjom energije iz obnovljivih izvora energije usmjerava povećanu pozornost prema primjeni fotonaponskih (PV) sustava spojenih u mrežu. Različite su tehnologije raspoložive za spajanje PV sustava na mrežu preko izmjenjivačkih energetskih jedinica (PCU). Ovaj rad prikazuje rezultate usporednog proučavanja karakteristika različitih tipova izmjenjivačkih energetskih jedinica (PCU) na osnovi eksperimentalnih rezultata dobivenih za široki opseg Sunčeva zračenja i uvjeta rada. Svojstva mrežnog spoja okarakterizirana su korištenjem skupa parametara koji se odnose i na istosmjernu (DC) i na izmjeničnu (AC) stranu izmjenjivača, kao što su efikasnost praćenja točke maksimalne snage, DC/AC efikasnosti, faktor snage i harmoničko izobličenje napona i struja na spoju s mrežom. Fotonaponski sustavi su dalje okarakterizirani uzimajući u obzir njihove sposobnosti izbjegavanja neželjene operacije otočnoga rada njegovom relativno brzom detekcijom i isključivanjem. Provedena je rasprava o rezultatima, a zatim su rezultati uspoređeni sa specifikacijama dobivenim od proizvođača i s ograničenjima proisteklima iz nekih standarda

A method for obtaining the I-V curve of photovoltaic arrays from module voltages and its applications for MPP tracking

For the purpose of control and monitoring of a Photovoltaic (PV) system its current-voltage (I-V) charac- teristic curve is traced. Usually such a test involves the interruption of the normal operation of the PV systems. In this paper a method for tracing the I-V curve from on-site measurements is proposed. During the measurement of the characteristic curve the normal operation of the PV system is not inter- rupted. The subjects of tracing the characteristic curve and Maximum Power Point Tracking (MPPT) of PV arrays are generally dealt with separately but the proposed method performs the measurement of the characteristic curve quickly and so it can also be utilized for MPPT purposes. Simulations and experi- ments have been conducted to confirm the operation of the proposed metho

Hourly Simulation of Energy Community with Photovoltaic Generator and Electric Vehicle

Europe has set the ambitious goal to become the first carbon-neutral continent by 2050. Therefore, it has undertaken several initiatives to promote the energy transition, including the active participation of citizens in the energy sector. In this context, recent European directives introduced the concept of energy community, whose members can consume, share, and store energy locally produced. This work proposes an energy and economic simulation of a renewable energy community powered by a 19.2 kWp photovoltaic system in the province of Cuneo, in Piedmont (Italy). The community consists of a prosumer, which owns the photovoltaic system and a charging station for electric vehicles, and other 17 energy users. Suitable indicators to assess the energy performance of the community (self-consumption and self-sufficiency) were evaluated starting from the estimated production and consumption power profiles. Then, an economic simulation was carried out to assess the economic return on the investment for the member who bore the initial costs and the annual economic savings for the others

Long-Term Monitoring of Photovoltaic Plants

This paper deals with a data-acquisition system that has been specifically developed for a long-term monitoring of ten different photovoltaic plants. The main goals of the system consist in estimating the drift of the plant components, mainly photovoltaic modules and power inverters, and comparing the performance of the ten plants, which are based on different technologies and architectures. Owing to these goals, the traceabilityassurance of the obtained measurements is mandatory, hence the data-acquisition system has been designed to be easily calibrated and, if necessary, adjusted to compensate for measuring-chain drifts. In addition, the measurement uncertainty, which has to be suitable to distinguish the behaviour of the different PV plants, has to be stated for each of the estimated parameters. A brief description of the data-acquisition system is provided and its measurement capabilities are highlighted in terms of measured quantities and expected uncertainty. Results that refer to a period of thirty months are also reported