IIIc-3 - Installation Guidelines: Electrical

Photovoltaic systems are designed to feed either to grid or direct consumption. Due to global concerns, significant growth is being observed in Grid connected solar PV Plants. Since the PV module generates DC power, inverter is needed to interface it with grid. The power generated by a solar PV module depends on surrounding such as irradiance and temperature. This paper presents modelling of solar PV arrays connected to grid-connected plant incorporated with irradiance and temperature variation, to design simulator to study and analyse effect on output power of solar PV arrays with irradiance and temperature variation, also to estimate the output power generated by PV arrays. The mathematical model is designed implemented separately on simulator for each PV components connected in PV systems, which are PV cell, Module, sting, array and field of arrays. The results from simulation based on model are verified by the data collected from power plants and experiments done on solar PV cell.

Before a PV module is integrated into a PV system it has to be handled and transported. This handling and transport is a critical stage of the PV-modules life. In order to identify critical handling steps we accompanied the installation of PV systems and compiled a list of typical and exceptional handling situations. From these observations we developed test to be performed in the laboratory. The tests are designed to account for the mechanical installation conditions as well as for the module temperature during the installation. As a result we find that the most critical handling step is the lay down of the PV module with sunny side up. During the lay down of the module one might let drop the module on one side from a low height. For one module type we found even for a 5 cm drop height more than 5 cracked cells after the drop. In contrast a vertical drop of a framed PV module results in no cell breakage at all. Additionally the risk of cell breakage rises for static loads by at least factor two with PV module temperature of -5°C compared to 25°C. Therefore one should avoid installing PV modules below the freezing point.

One of the current technologies widely used to extract the earth’s renewable energy is solar modules, which harness energy from the sun; however, their operating conditions and their energy storage capacities vary greatly under different weather conditions. The high-speed Flywheel Energy Storage System (FESS) presents a promising prospective solution for solar energy storage and utilization. Accurately modeling FESS can lead to its efficient design and control. In this paper, a fully integrated FESS, with comprehensive photovoltaic (PV) system, has been modeled to simulate the overall energy harvesting capabilities, power output, and efficiency. The solar module has been modeled using the one-diode solar cell model technique to predict the overall system efficiency and determine the most efficient time of day for switching between the FESS’s charging (morning time) and discharging mode (night time). To validate the developed model using experimental data, four 250 Wp Ankara Solar PV modules and a Balance of System (BOS) were installed. The solar irradiance, wind speed, cell temperature, solar module, FESS output voltage and current were logged during the system’s operation. The theoretical model predicted that the energy output for the test day was 4.80 kWh, while the experimental analysis showed that the solar modules produced 4.68 kWh, only 2.5% percentage difference. The theoretical and experimental power curves followed the same trends throughout the day, which assures that the model could accurately predict the daily energy output of the solar array. The efficiency of the solar module was determined to be 15.3%. The solar module simulation serves as a repeatable replication of the actual solar module source, which enables convenient, low-cost estimation of the solar module-FESS system under different environmental conditions. The developed solar module was integrated with a brushless DC motor and flywheel models to simulate the FESS response. Relative to the input solar energy input of 4.68 kWh, the daily energy stored in a flywheel was 3.51 kWh, giving the overall solar-module-FESS system an efficiency of 74.7%. After the experimental setup completion of FESS, the integrated solar module-FESS model will be tested for its overall power output and efficiency against the traditional solar module-battery-system.

This paper presents an experimental investigation on photovoltaic array (PV array) power output affected by partial shading conditions (PSCs). An experiment setup of a PV array with a series configuration using 2 × 4 photovoltaic modules (PV modules) was built. The power output loss due to the shading effect on the first photovoltaic cells (PV cell) connected with bypass diodes of each photovoltaic module, installed in the PV array in the horizontal direction, was evaluated. Depending on the direction of the sun relative to the PV array configuration, the shading percentage was measured during the test and recorded the current and voltage of the PV array. The performance evaluation of the PV array configurations is referred to with respect to the values of maximum power voltage, the maximum power current, maximum power output, power output losses and fill factor (FF). The experimental results show that 44% shading of the first PV cells affects PV array power output loss by more than 80%.

Solar energy has become a promising renewable energy source due to rising worldwide energy demand and environmental concerns in recent decades. This study examines temperature, solar irradiance, and series resistance (Rs) as internal and external elements affecting solar panel efficiency to optimise photovoltaic (PV) performance. Sunlight increases current and voltage outputs, but incidence angle, air dust, and pollution can reduce efficiency. Therefore, solar panels should be orientated and cleaned often. Open-circuit voltage (VOC), maximum power output (Pmpp), and fill factor (FF) decrease performance at high temperatures. Water cooling or cooling plates can save PV cells from overheating. Finally, Power dissipation across resistance lowers voltage and current output as Rs increases. Preventive maintenance, material selection, and production techniques can lower Rs and maximise efficiency. This research emphasizes the importance of addressing environmental and material factors in solar panel installation and maintenance to achieve optimal efficiency and reliable energy generation in PV systems.

The installation of different renewable energy systems is gaining momentum globally, as governments and industry seek to reduce carbon emissions and fossil fuel usage. PV systems have become more common place, as evidenced by the number of PV array roof-installations visible in many communities today. However, it is assumed that the modules in these arrays are identical, as it is important to have similar currents flow through each branch of an array. Partial shading or unmatched PV modules may lead to power mismatches, hot spots and ultimately a lower overall output power than what is desired. The purpose of this paper is to present a simplified measuring approach to validate the operating performance of two identical PV modules by determining their switch-on time. Any significant differences in switch-on time between identical PV modules could lead to possible power mismatches in a PV array. Results confirm that both PV modules are very similar in switch-on time, with an average on-time difference of 2 minutes and 27 seconds.. This indicates that both PV modules start operating at roughly the same time of the day, thereby providing similar current flows which contribute to the optimum performance of a PV array.

Solar trackers rely on a direct-current (DC) motor driver circuit to control the movement of the solar panel. However, conventional DC motor drivers used in solar tracking system do not provide any options for speed and torque control. Hence, the fixed speed of the DC motor leads to either too fast or too slow tracking movement. Usually, the output torque is set to the maximum. If the load (solar panels' weight) is small, the maximum torque is not fully utilized and therefore energy is wasted. So, a fully adjustable DC motor driver for solar tracking system shows great potential in commercialization because highly energy efficient DC motor driver circuit can improves the total efficiency of the solar tracker. Fewer solar panels are needed when they are attached to high efficiency solar tracking system, which will be reflected to lower system cost. Therefore, this enhanced motor driver will bring significant impact to the solar energy industry. The proposed DC motor driver is fully adjustable in term of speed and torque. The speed and torque of the motor is directly proportional to the output voltage and output current of the proposed DC motor driver, respectively. Adaptive controlling of the output voltage and current are possible by installing algorithm in the microcontroller of the DC motor driver and it can be reprogrammed according to the requirement. The speed control makes the solar tracking system to track the Sun more accurately and the torque control saves energy.

This paper proposes the active module considering shadow influence of photovoltaic system. The PV system is consisted series-parallel connection of PV module. The voltage and current between PV modules become imbalance when shadow occurs to PV module. If shadow occurs to the series connection PV module, the output current is limited to current of shaded PV module. Also if shadow occurs to the parallel connection PV module, the output voltage is limited to voltage of shaded PV module. These problems are caused power loss. Therefore, this paper proposes the active module that is consisted fixed module and variable module. The active module can compensates the shadow influence by changing connection of a variable module when shadow is occurred to PV module. A validity of the active module proposed in this paper proves through comparing with performance of conventional PV module.

Despite their maturity and market dominance, crystalline silicon (c-Si) solar cells and modules continue to develop rapidly, with increasing efficiencies and reducing cost ($/W). This contribution describes recent progress at SERIS with industrially relevant crystalline silicon solar cells and modules, covering both p-type and n-type cells. Since the costs of the solar cells and modules as a proportion of the costs of complete PV systems continue to fall, a premium is placed on cell efficiency as this reduces the balance of system (BOS) cost (in $/W) of PV systems. Thus, cost-effective monocrystalline high-efficiency silicon solar cells such as SERIS’ 23.5% efficient passivated-contact technology (“monoPolyTM”) have enormous market potential. Good progress is also being made in the SERIS laboratory with small-area perovskite/silicon tandem solar cells, giving efficiencies of over 25% in 4-terminal configuration. Keywords: Solar energy, photovoltaic devices, crystalline silicon solar cells, PERC solar cell, monoPolyTM solar cell, passivated contacts, perovskite solar cells, perovskite/silicon tandem solar cells.

In the mid-1980s Ascension Technology's principals, then working at the Massachusetts Institute of Technology, developed the Roof-Jack mounting system for attaching PV arrays to pitched, shingled residential roofs. The driving motivation of that effort was to simplify and reduce the cost of residential PV array balance-of-systems. Since that time the Roof-Jack mounting system has been used successfully in more than 40 pitched-roof PV array installations across the country. In anticipation of the installation of grid-connected PV system for the Environmental Protection Agency's Photovoltaic Demand Side Management demonstration (EPA PV-DSM), Ascension Technology undertook a similar engineering effort targeting cost reduction of balance-of-systems for flat-roof PV array installations. As a result, they have completed the design and fabrication of a mounting system which greatly simplifies the installation of PV arrays on typical flat-roof commercial buildings. This paper describes this mounting system, including loading analysis and experience with installations in Massachusetts and elsewhere in the country as part of the EPA PV-DSM demonstration. >

The solar photovoltaic water pumping system is one of the major essential renewable energy applications, especially in rural areas. This work aimed to design four modules PV array for a PV based water pumping system and to achieve greater output power on varying partial shading and irradiation condition. The four-modules PV array adjusts the electrical configuration of panel depends on the insolation observed by the solar panels and Fully and Partial Shaded Condition (PSC). In this work the Switching network, reconfigurable program and reconfigurable PV controller units are proposed for consistent process of reconfigurable solar PV array. The proposed controller unit is designed and simulated in Simulink software to calculate system operation and output power under changing irradiance and PSC. The small scale prototype is developed in order to validate the results. The outdoor test results and its analysis shows the reconfigurable PV array is able to deliver maximum output on varying operating conditions. Maximum 53.87% percentage of power and 52% percentage running time of pump can be increased by using this reconfiguration strategy.

The installation of solar PV systems has led to a competitive market situation in recent years. Solar panels are being installed on a wide variety of sites and buildings. Companies are competing with each other to see who can do the job at a better price and who can do it in sometimes extreme conditions. Our work focuses on the dangers at height and how to avoid them. Workers, because of their lack of training, can often find themselves in situations that should result in a suspension from work by law or regulation, but without this knowledge, they can perform tasks that seriously endanger their health or their lives. Because the installation of solar PV systems is a relatively new industry, no two roofs are the same, and no two designs are the same. Thus, it is often only during installation that it becomes apparent that the work would require alpine engineering expertise, but employers, prioritising cost-effectiveness, fail to take this into account. This in turn puts the worker at risk, who is not aware of all the risk factors. We present the dangers of working at height with solar panels and propose a general training material that would make this field safer and, in so doing, significantly reduce the risks.

Photovoltaic (PV) array which is composed of modules is considered as the fundamental power conversion unit of a PV generator system. The PV array has nonlinear characteristics and it is quite expensive and takes much time to get the operating curves of PV array under varying operating conditions. In order to overcome these obstacles, common and simple models of solar panel have been developed and integrated to many engineering software including Matlab/Simulink. However, these models are not adequate for application involving hybrid energy system since they need a flexible tuning of some parameters in the system and not easily understandable for readers to use by themselves. Therefore, this paper presents a step-by-step procedure for the simulation of PV cells/modules/arrays with Tag tools in Matlab/Simulink. A DS-100M solar panel is used as reference model. The operation characteristics of PV array are also investigated at a wide range of operating conditions and physical parameters. The output characteristics curves of the model match the characteristics of DS-100M solar panel. The output power, current and voltage decreases when the solar irradiation reduces from 1000 to 100 W/m2. When the temperature decreases, the output power and voltage increases marginally whereas the output current almost keeps constant. Shunt resistance has significant effect on the operating curves of solar PV array as low power output is recorded if the value of shunt resistance varies from 1000 ohms to 0.1 ohms. The proposed procedure provides an accurate, reliable and easy-to-tune model of photovoltaic array. Furthermore, it also robust advantageous in investigating the solar PV array operation from different physical parameters (series, shunt resistance, ideality factor, etc.) and working condition ( varying temperature, irradiation and especially partial shadow effect) aspects.

In this study, based on the slope of power versus voltage, a novel MPPT algorithm using neural network compensator is proposed to avoid the oscillation problem and effect of uncertain parameters in photovoltaic (PV) systems. However, the characteristics of PV output voltage and output current are determined by the solar irradiation conditions, ambient temperature, and the load electrical characteristics, thereby the technologies of changing the location of the maximum power point must be developed in the applications of maximum-power-point-tracking (MPPT) control in order to make the PV arrays get the optimal efficiency from solar energy at different operating conditions. In this study, the uncertainties in PV systems are compensated by a neural network and the duty cycle of dc/dc converter is determined by a PI controller. The control objectives of this study is to achieve MPPT for the PV systems including solar cell arrays, a dc/dc converter, and an output load despite the variation of solar irradiation, ambient temperature, and the load electrical characteristics in PV systems. From experimental results, the validity of the proposed MPPT controller can be verified under a certain solar irradiation and a partially shaded condition, respectively.

Maximization of power from a solar photovoltaic (SPV) module is of special interest as the efficiency of the SPV module is very low. The present work describes the maximum power point tracker (MPPT) for the SPV module connected at variable load conditions. A personal computer (PC) is used for control of the MPPT algorithm. The power tracker is developed and tested successfully in the laboratory. The simulations are carried out in Matlab/Simulink. Data acquisition, monitoring, and control are done by the dSPACE software. Different types of algorithms are studied. The algorithm implemented here is “perturb and observe” in a microcontroller-based PC to extract maximum power from the SPV module. The measured parameters such as panel voltage, current, and power are obtained with and without MPPT systems and have been tested on the SPV Module at various load conditions, different temperatures and insolation labels. The comparative results with and without MPPT are shown; the results show that the tracking capability with MPPT improves as compared with without MPPT.