scholarly journals A Measure of Capacity Contribution of Static Mono-Si Photovoltaic Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Constantinos Varnavas ◽  
Andreas Poullikkas

Photovoltaic (PV) systems generate electricity in the daytime when system demand is generally moderate to high. For Mediterranean countries, there is also seasonal coincidence of high system demand and high PV load factors. The present study quantifies the above statements by calculating the load factor of the PV system when system demand is high (above 90–99% of the maximum demand of the month). The percentage of time the PV load factor is above 90% for these periods of maximum demand is evaluated. The PV load capacity contribution is defined in this study as the minimum PV load factor during these periods of high demand. Actual generation data from a static (without tracking) mono-Si PV system, recorded every half hour for the year 2010 are compared to system demand data. The seasonality analysis indicates that PV contribution to capacity is only significant during the months May–October. For the months November–April, when daily demand peak occurs during the evening, PVs do not contribute towards capacity. The evaluated capacity contribution of PV systems depends on the threshold of maximum demand considered (90%–99%). For the threshold of 95%, the capacity contribution for May–October ranges between 27%–41% of PV installed capacity.

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Fernando Lessa Tofoli ◽  
Dênis de Castro Pereira ◽  
Wesley Josias de Paula

The generation of electricity from photovoltaic (PV) arrays has been increasingly considered as a prominent alternative to fossil fuels. However, the conversion efficiency is typically low and the initial cost is still appreciable. A required feature of a PV system is the ability to track the maximum power point (MPP) of the PV array. Besides, MPP tracking (MPPT) is desirable in both grid-connected and stand-alone photovoltaic systems because the solar irradiance and temperature change throughout the day, as well as along seasons and geographical conditions, also leading to the modification of theI×V(current versus voltage) andP×V(power versus voltage) curves of the PV module. MPPT is also justified by the relatively high cost of the energy generated by PV systems if compared with other sources. Since there are various MPPT approaches available in the literature, this work presents a comparative study among four popular techniques, which are the fixed duty cycle method, constant voltage (CV), perturb and observe (P&O), and incremental conductance (IC). It considers different operational climatic conditions (i.e., irradiance and temperature), since the MPP is nonlinear with the environment status. PSIM software is used to validate the assumptions, while relevant results are discussed in detail.


Author(s):  
I. A. Elzein ◽  
Yu. N. Petrenko

In this article an extended literature surveying review is launched on a set of comparative studies of maximum power point tracking (MPPT) techniques. Different MPPT methods are addressed with an ultimate aim of how to be maximizing the PV system output power by tracking Pmax in a set of different operational circumstances. In this paper maximum power point tracking, MPPT techniques are reviewed on basis of different parameters related to the design simplicity and/or complexity, implementation, hardware required, and other related aspects.he technology of solar systems has been booming for a while due to its ability to replace current fossil fuels like coal and gas for generation of electricity that produce air, water, and land pollution. In addition it decreased the issue of global warming and climate changes substantially due to being produced in a clean environmental manner and was proved to be an Eco-friendly resource of energy. The photovoltaic systems’ manufacturing process has been improving continuously over the last decade and photovoltaic systems have become an interesting solution. Precisely, PV systems are constituted from arrays of photovoltaic cells, choppers (mainly buck-boost or boost DC/DC converter), MPPT control systems and storage devices and/or grid connections. To improve the efficiency of such systems, various studies have been performed. The demand of PV generation systems seems to be increased for both standalone and grid-connected modes of PV systems. Therefore, an efficient maximum power point tracking (MPPT) technique is necessary to initialize the process of tracking the maximum power point MPP at all environmental conditions and then force the PV system to operate at that MPP point.


Author(s):  
Syafaruddin Syafaruddin

It is crucial to improve the photovoltaic (PV) system efficiency and to develop the reliability of PV generation control systems. One of the approaches to increase the efficiency of PV power generation system is to operate the PV systems optimally at the maximum power point. However, the PV system can be optimally operated only at a specific output voltage; otherwise the output power fluctuates under intermittent weather conditions. In addition, it is very difficult to test the performance of PV systems controller under the same weather condition during the development process where the field testing is costly and time consuming. For these reasons, the presentation is about the state of the art techniques to track the maximum available output power of photovoltaic systems called maximum power point tracking (MPPT) control systems. This topic could be also one of the most challenges in photovoltaic systems application that has been receiving much more attention worldwide. The talks will cover the application of intelligent techniques by means the artificial neural network (ANN) and fuzzy logic controller scheme using polar information to develop a novel real-time simulation technique for MPPT control by using dSPACE real-time interface system. In this case, the three-layer feed-forward ANN is trained once for different scenarios to determine the global MPP voltage and power and the fuzzy logic with polar information controller takes the global maximum power point (MPP) voltage as a reference voltage to generate the required control signal for the power converter. This type of fuzzy logic rules is implemented for the first time in MPPT control application. The proposed method has been tested using different solar cell technologies such as monocrystalline silicon, thin-film cadmium telluride and triple junction amorphous silicon solar cells. The verification of availability and stability of the proposed system through the real-time simulator shows that the proposed system can respond accurately for different scenarios and different solar cell technologies. In other cases, one of the main causes of reducing energy yield of photovoltaic systems is the partially shaded condition. Although the conventional MPPT control algorithms operate well in a uniform solar irradiance, they do not operate well in non-uniform solar irradiance conditions. The non-uniform conditions cause multiple local maximum power points on the power-voltage curve. The conventional MPPT methods cannot distinguish between the global and local peaks. Since the global power point may change within a large voltage window and also its position depends on shading patterns, it is very difficult to recognize the global operating point under partially shaded conditions. From these reasons, the presentation will address the effectiveness of the proposed MPPT method to solve the partially shaded conditions under the experimental real-time simulation technique based dSPACE real-time interface system for different size of PV arrays, such as 3x3(0.5kW) and 20x3(3.3kW) and different interconnected PV arrays, for instance series-parallel (SP), bridge link (BL) and total cross tied (TCT) configurations.


2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Evan Riley ◽  
Scott Olson

The potential flash glare a pilot could experience from a proposed 25-degree fixed-tilt flat-plate polycrystalline PV system located outside of Las Vegas, Nevada, was modeled for the purpose of hazard quantification. Hourly insolation data measured via satellite for the years 1998 to 2004 was used to perform the modeling. The theoretical glare was estimated using published ocular safety metrics which quantify the potential for a postflash glare after-image. This was then compared to the postflash glare after-image potential caused by smooth water. The results show that the potential for hazardous glare from flat-plate PV systems is similar to that of smooth water and not expected to be a hazard to air navigation.


2015 ◽  
Vol 12 (2) ◽  
pp. 51
Author(s):  
M. H. Albadi ◽  
N.A. Al-Mashaikhi ◽  
S. Al-Hinai ◽  
R. S. Al-Abri ◽  
A.S. Al-Hinai ◽  
...  

This paper investigates the utilization of photovoltaic (PV) systems in a rural area electricity network. The Rural Area Electricity Company of Oman is planning to install a 304 kW PV system at the powerhouse of the Almazyonah network. Based on the available network data, a power flow model of the system under study was built and the system’s performance was studied. The location and installed capacity of the planned PV system were optimized based on loss reduction.  


2020 ◽  
Vol 190 ◽  
pp. 00033
Author(s):  
Rattanaprapa Charoenwattana ◽  
Umarin Sangpanich

This paper investigates effects of voltage unbalance and energy losses due to the connection of rooftop photovoltaic systems in a low voltage distribution system of a housing estate, which has light loads during daytime. The paper presents a case study of a real distribution power system of housing estate in Thailand. Voltage unbalance and energy losses were simulated by using system characteristic and load data from GIS database of PEA with the DIgSILENT Power Factory program. The key findings of our analysis are as follows. Firstly, the number of installable 1-phase rooftop PV systems varies directly with load density. Secondly, the number of installed 1-phase rooftop PV systems can be increased if the installation locations are closer to the transformer. For 3-phase rooftop PV systems, their installations do not have any effects on the voltage unbalance. Furthermore, system energy loss relates to the load density and PV system installation locations in the same way as the voltage unbalance. The key implication of our study is that the installation of 1-phase rooftop PV system should be granted based on a careful consideration of the installation location and the load density.


The use of solar energy as source of power is becoming not a choice but a necessity due to the unprecedented growth in the demand and consumption of electrical power for various applications. The solar power from the Photovoltaic (PV) systems is currently used as a standalone PV system or integrated with the electric grid. However, the generated DC power from PV systems is not stable due to weather, atmospheric and environmental conditions, which requires the design of a DC power supply to produce a stable and regulated DC voltage output. In this paper, a new design of power supply is presented that provides a stable output voltage (Vout = +12 V, 0 V, -12V) over significant range of input voltage variations (Vin = +15 V to +50 V) emulating the variation of output voltage of PV systems. The stabilization of the output voltage reflects the effectiveness of the proposed design for photovoltaic systems applications. The system is simulated using NI-MULTISIM software. A satisfactory simulation result is obtained showing a strong promise to practically implement using discrete components.


Author(s):  
Ahmed Bouraiou ◽  
Ammar Neçaibia ◽  
Rachid Dabou ◽  
Abderrezzaq Ziane ◽  
Nordine Sahouane ◽  
...  

The electrical energy generation via the Photovoltaic system is widely utilized in the world especially in the countries where it is characterized by considerable potential of solar energy. PV systems are affected by several factors that can reduce its efficiency such as PV generator aging, failures. Photovoltaic systems monitoring is a important task for guaranteeing the reliability and stability of PV system operation. This paper addresses the monitoring of PV systems in renewable energy research unit in the Saharan region (URERMS) Adrar, through to give an insigth about the methods of measuring, acquisition, data storage of monitored parameters. In addition, the existing problems for insuring the suitable solution.


Author(s):  
Ramiro Alejandro Plazas Rosas ◽  
Édinson Franco Mejia ◽  
Martha Lucía Orozco Gutiérrez

The photovoltaic systems are electrical, electronic, and mechanical elements. These systems also face different environmental and operating conditions susceptible to failure. In addition, photovoltaic systems can be the only source of electricity generation, and an affectation on the energy supply can harm the community. In many places, photovoltaic systems are the only source of energy because they are not part of what is known in Colombia as the National Interconnected System (SIN). Which comprises the direct connection between large generators (hydroelectric and/or thermal plants) and consumers. In fact, PV system damage would affect food refrigeration or everyday things like charging a cell phone. Therefore, it is necessary to register, monitor the operation elements of PV systems, and develop strategies that allow the diagnosis to detect faults. In this work, we propose a fault-diagnosis using the PV systems measurements that is, power converter, photovoltaic panels with also mathematical models to determine the deviation between the estimated and measured signals as voltages and currents.


2021 ◽  
Vol 13 (9) ◽  
pp. 4709
Author(s):  
Ke Shi ◽  
Chuangyi Li ◽  
Choongwan Koo

Hong Kong’s government has recently introduced the feed-in tariff scheme to promote the photovoltaic (PV) system as a promising way to address global warming. The feed-in tariff scheme depends on the type of the PV system and its installed capacity. This study aimed to investigate the techno-economic feasibility of mono-Si and poly-Si PV systems in the rooftop area of a commercial building, Pao Yue-Kong Library of Hong Kong, under the feed-in tariff scheme. The analysis was carried out in two phases: (i) technical analysis of the rooftop PV systems by considering the shading effect and solar radiation and (ii) economic feasibility of the rooftop PV systems under the feed-in tariff scheme from the life cycle perspective. The main findings of the case study can be summarized: (i) the rooftop area of the target building would not be significantly affected by surrounding buildings; (ii) the highest amount of solar radiation was estimated at 136.96 kWh/m2 in October, while the lowest value was 55.64 kWh/m2 in February; (iii) the total amount of module energy yield from the mono-Si PV system was estimated at 917.58 kWh/kW, indicating that it was very similar but a little bit lower (i.e., 0.48%) than that for the poly-Si PV system (i.e., 921.98 kWh/kW); and (iv) payback periods for mono-Si and poly-Si PV systems were estimated at 8.67 and 8.31 years, respectively. The feasibility study can contribute to providing facility managers with a practical guideline to determine the appropriate strategy in implementing the PV systems in buildings under the feed-in tariff scheme.


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