This work is a case study of 905 households, to present methods for optimizing the capacity of photovoltaic sytems (PVs)/energy storage systems (ESSs) for household to reach a desired energy self-sufficiency (70% to 90%). In order to calculate the capacity of PV and ESSs that would enhance the energy self-sufficiency of families in rural areas, the solar radiance data of the target area for the last five years and the average monthly power usage in the previous year were collected. Then, households with an average energy consumption of 250 kWh per month were chosen for this research. According to the simulation done using Solar Pro, the optimized capacities of PVs and ESSs are 2.67 kW and 7.15 kW, respectively, in order to achieve 90% energy self-sufficiency. We visualized the change in the optimum capacity of PVs and ESSs for the desired energy self-sufficiency. This study would be the base work for forming a grid-distributed energy network system by expanding the system to a national scale.
Unlike conventional photovoltaic (PV) modules that generate power by absorbing light through the front side only, a bifacial PV module can generate power by absorbing light through the rear as well as the front, which would lead to an enhancement of power generation. Particularly, bifacial PV modules would have the advantage of lower power loss in shaded environments than monofacial PV modules, thanks to the light absorbed through the rear side. To predict the power of a bifacial PV module in a shaded environment, modeling is suggested by considering the shaded areas, the operational status of the bypass diodes, and the temperature of the bifacial PV module. To verify the power prediction of a bifacial PV module with a shaded area, modeled and measured powers are compared, showing error rates of 7.28%. From the results of the power loss experiments for bifacial and monofacial PV modules in shaded environments, it is confirmed that the bifacial PV module shows a relatively low power loss rate when compared with the monofacial PV module, with a power loss rate being 87.26% of the rate for the monofacial PV module. Index Terms-Bifacial c-Si PV module, bypass diode, shading. I. INTRODUCTION O NE of the major interests of the photovoltaic (PV) power plant operators is the reduction in the installation cost of PV power generation systems [1]. It has been reported that the price of PV modules accounted for 24% of the unit cost of commercial PV power systems in 2018 [2]. One of the possible ways for lowering the cost of installing a PV power system would be the development of a highly efficient solar cell and module that could generate higher power for a given area. A bifacial PV module is a highly efficient PV module that can absorb light not only through the front, but also through the rear. Power generated through the rear side of a bifacial PV module varies with different reflective conditions [3]. However, the standardization of the output of a bifacial c-Si PV module under standard test condition (STC) was in
Fault detection and repair of the components of photovoltaic (PV) systems are essential to avoid economic losses and facility accidents, thereby ensuring reliable and safe systems. This article presents a method to detect faults in a PV system based on power ratio (PR), voltage ratio (VR), and current ratio (IR). The lower control limit (LCL) and upper control limit (UCL) of each ratio were defined using the data of a test site system under normal operating conditions. If PR exceeded the set range, the algorithm considered a fault. Subsequently, PR and IR were examined via the algorithm to diagnose faults in the system as series, parallel, or total faults. The results showed that PR exceeded the designated range between LCL (0.93) and UCL (1.02) by dropping to 0.91-0.68, 0.88-0.62, and 0.66-0.33 for series, total, and parallel faults, respectively. Moreover, VR exceeded the LCL (0.99) and UCL (1.01) by 0.95-0.69 and 0.91-0.62 for series and total faults, respectively, but not under parallel faults condition. IR did not change in series and total faults but exceeded the range of LCL (0.93) and UCL (1.05) by dropping to 0.66-0.33. Thus, faults in PV systems can be detected and diagnosed by analyzing quantitative output values.
PURPOSE: This study aimed to quantify the effects of whole body vibration (WBV) stimulation training on the muscle thickness and gross motor function in children with spastic cerebral palsy. METHODS: Twenty children diagnosed with spastic cerebral palsy were assigned randomly to the Whole Body Vibration (WBV) group (n=10) and control group (n=10). The WBV group received vibration therapy including five different therapy, and the control group received only five general physiotherapy sessions. After 10 weeks of intervention, the muscle thickness was measured using ultrasound, and the Gross Motor Function D and E items were
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