Lightning Shielding with Shading Avoidance for a Photovoltaic (PV) Farm

Western China has good conditions for constructing large-scale photovoltaic (PV) power stations; however, such power plants with large fluctuations and strong randomness suffer from the long-distance power transmission problem, which needs to be solved. For large-scale PV power stations that do not have the conditions for simultaneous hydropower and PV power, this study examined long-distance delivery mode and energy storage optimization. The objective was to realize the long-distance transmission of electrical energy and maximize the economic value of the energy storage and PV power storage. For a large-scale PV power station, the energy storage optimization was modelled under a given long-distance delivery mode, and the economic evaluation system quantified using the net present value (NPV) of the battery was based on the energy dispatch optimization model. By contrast, a lithium battery performance model was developed. Therefore, further analysis of the economics of the energy storage and obtaining the best capacity of the energy storage battery and corresponding replacement cycle considered battery degradation. The case study of Qinghai Gonghe 100 MWp demonstration base PV power station showed that the optimal energy storage capacity was 5 MWh, and the optimal replacement period was 2 years. Therefore, the annual abandoned electricity was reduced by 3.051 × 10 4 MWh compared with no energy storage. The utilization rate of both the PV power station and quality of the delivered electricity were modelled to realize a long-distance transmission to the grid net. This will have an important guiding significance to develop and construct large-scale single PV power stations.

Considering the recent drop (up to 86%) in photovoltaic (PV) module prices from 2010 to 2017, many countries have shown interest in investing in PV plants to meet their energy demand. In this study, a detailed design methodology is presented to achieve high benefits with low installation, maintenance and operation costs of PV plants. This procedure includes in detail the semi-hourly average time meteorological data from the location to maximise the accuracy and detailed characteristics of different PV modules and inverters. The minimum levelised cost of energy (LCOE) and maximum annual energy are the objective functions in this proposed procedure, whereas the design variables are the number of series and parallel PV modules, the number of PV module lines per row, tilt angle and orientation, inter-row space, PV module type, and inverter structure. The design problem was solved using a recent hybrid algorithm, namely, the grey wolf optimiser-sine cosine algorithm. The high performance for LCOE-based design optimisation in economic terms with lower installation, maintenance and operation costs than that resulting from the use of maximum annual energy objective function by 12%. Moreover, sensitivity analysis showed that the PV plant performance can be improved by decreasing the PV module annual reduction coefficient.

Performance study on a grid connected 20 kWp solar photovoltaic installation in an industry in Tiruchirappalli (India)

This study developed a rational approach to the consideration of solar photovoltaic (PV) power plants applied to electric utility systems, then performed a requirements assessment and preliminary impact and penetration analyses by studying PV generation in three actual utility systems. Conventional utility loss-of-load probability and production simulation methods were used, along with a PV plant performance model developed for the study.Evaluations were based on comparison of total utility generation system costs with and without PV plants. The study is reported under the following sections: 1) geographic areas for photovoltaic power plants; 2) siting of photovoltaic power plants; 3) electric utility characteristics; 4) photovoltaic power plant characteristics; 5) methods of study; 6) study inputs; 7) results; 8) cost and performance goals for viability; 9) reference PV selection; 10) reference PV plant definitions; 11) comparison with conventional generation; 12) requirements for PV applications; 13) preliminary impact analysis; and 14) preliminary penetration analysis. (WHK)

Allocation and smart inverter setting of ground-mounted photovoltaic power plants for the maximization of hosting capacity in distribution networks

Photovoltaic (PV) technology, as an efficient solution for mitigating impacts of climate change, has been increasingly used across the world to replace fossil-fuel power to minimize greenhouse gas emissions. With the world's highest cumulative and fastest built PV capacity, China needs to assess the environmental and social impacts of these established photovoltaic (PV) power plants. However, a comprehensive map regarding the locations and extent of the PV power plants remains to be scarce at the country scale. This study developed a workflow combining machine learning and visual interpretation methods with big satellite data to map the PV power plants in China. We applied a pixel-based Random Forest (RF) model to classify the PV power plants from composite images in 2020 with 30-meter spatial resolution on Google Earth Engine (GEE). The result classification map was further improved by a visual interpretation approach. Eventually, we established a map of PV power plants in China by 2020, covering a total area of 2917 km2. Based on the derived national PV map, we found that most PV power plants were sited on cropland, followed by barren land and grassland. In addition, the installation of PV power plants has generally decreased the vegetation cover. This new dataset is expected to be conducive to policy management, environmental assessment, and further classification of PV power plants.

Operational performance of megawatt-scale grid integrated rooftop solar PV system in tropical wet and dry climates of India

Short-term PV power prediction based on meteorological similarity days and SSA-BiLSTM

Electric power is a key driver of economic growth and prosperity.But access to electricity still remains a distant dream for majority of the population living in the remote and arid areas of developing countries mostly sub-Saharan Africa.With the growing demand for safe and reliable energy, solar as a source of energy remains the least utilized energy source in the Kenyan economy and yet one of the safest forms of energy.Solar photovoltaic (PV) systems have shown their potential in rural electrification projects around the world.A solar based mini-grid is a solar PV (photovoltaic) plant with a localized distribution network to a unit village, or a cluster of villages, providing alternating current (AC).Basically it consists of solar PV modules of a certain capacity, solar inverters for converting the D.C power to AC power, housing for the battery bank and plant control systems.In areas where there is no grid connection or where diesel generation is the main power source, PV plants are able to generate electricity efficiently and relatively cheap.This paper was aimed at developing a standard procedure for the design and analysis of a mini-grid connected solar PV systems using PV modules connected in an array field.The standard procedure developed was validated in the design of a 20 kVA mini-grid-connected solar PV system for Nanyuki town in Laikipia County, Kenya.The analysis and evaluation of the load capacity requirements for the solar mini-grid were done.Data collected from SWERA were compared with the local load requirements.Optimization of the load versus production capacity of the solar system was carried out.The results showed that a mini-grid system of 20 kVA might be developed at a capital cost of US$ 56,000 to cater for 8400 households including a school and dispensary.Analyses of the simulation results show that the project when implemented will supply about 61 KW•h electricity per day or 22.2 MWh annually, which is about 15% of Nanyuki's annual electricity consumption.The project also stands the chance of saving about 200 tonnes of CO2 which will have been emitted by a crude oil fired thermal power plant generating the same amount of electricity.At the prevailing tariff conditions in the country, this project can be considered as financially viable with feed-in tariff scheme or other incentives such as grants/capital subsidies when applied.However, the other non-financial benefits like the greenhouse gas emissions savings can, in the long run, help mitigate the adverse effects of the climate change problem plaguing the entire earth.

This paper presents an algorithm for the economical design of a utility-scale photovoltaic (PV) power plant via compromising between the cost of energy and the availability of the plant. The algorithm inputs are the plant peak power and the price of inverters with respect to their power ratings. The outputs are the optimum inverter ratings and the interconnection topology of PV panels. This paper introduces the effective levelized cost of energy (LCOE) (ELCOE) index as the core of the proposed design algorithm. ELCOE is an improved index based on the conventional LCOE that includes the availability of a power plant in economical assessments. The conventional LCOE index determines centralized topology (e.g., 1-MW inverter for a 1-MW PV power plant) for minimizing the energy generation cost, whereas based on ELCOE, a multistring topology (e.g., a 1-MW PV plant consists of fifty 20-kW inverters) despite of higher investment cost becomes the economically winning topology. Given the price of commercially available PV inverters at present, the case studies in this paper show that, for 0.1-100-MW PV power plants, the economical ratings of inverters range from 8 to 100 kW. The recently installed PV power plants confirm the feasibility of the calculations based on the suggested algorithm.

Power grids globally are currently facing challenges in inter-connecting larger capacity solar farms due to their inadequate power transmission capacity. This work proposes a novel control of grid-tied photovoltaic (PV) solar farm to improve transient stability limit and therefore improved power transfer capability of the transmission line. When solar PV output suddenly goes to zero, this new control scheme makes the inverter perform similar a STATCOM-a flexible AC transmission system (FACTS) device, provides voltage regulation at the point of common coupling and improves stability and subsequently the power transfer limits. During the sunny time, solar PV farm inject real power in to the grid via inverter, this new control makes the solar farm inverter provide voltage control with the remaining inverter capacity and thus increases power transfer limits significantly. To validate the proposed control, a Matlab/Simulink based simulation study is presented in two scenarios (i) 3-phase fault is applied on the test system under various PV penetration levels (ii) When solar PV output suddenly goes to zero. Results of the simulation confirm that augmentation in transient stability limit is achieved using proposed control.

The efficiency and profitability of photovoltaic (PV) plants are highly controlled by their operation and maintenance (O&M) procedures. Today, the effective diagnosis of any possible fault of PV plants remains a technical and economic challenge, especially when dealing with large-scale PV plants. Currently, PV plant monitoring is carried out by either electrical performance measurements or image processing. The first approach presents limited fault detection ability, it is costly and time-consuming, and it is incapable of fast identification of the physical location of the fault. In the second approach, Infrared Thermography (IRT) imaging has been used for the characterization of PV module failures, but their setup and processing are rather complex and an experienced technician is required. The use of Unmanned Aerial Vehicles (UAVs) for IRT imaging of PV plants for health status monitoring of PV modules has been identified as a cost-effective approach that offers 10–-15 fold lower inspection times than conventional techniques. However, previous works have not performed a comprehensive approach in the context of automated UAV inspection using IRT. This work provides a fully automated approach for the: (a) detection, (b) classification, and (c) geopositioning of the thermal defects in the PV modules. The system has been tested on a real PV plant in Spain. The obtained results indicate that an autonomous solution can be implemented for a full characterization of the thermal defects.

The paper introduces development of the high power inverters for the Power Conditioning System (PCS) for the large scale Photo Voltaic (PV) power plants. At first, the paper introduces a 500kW PCS with very high efficiency of 98.5%. The PCS also offers wide operation range in DC voltage and current. The wide operation range enhances the performance of the Maximum Power Point Tracking (MPPT) control to draw out the power from the PV cells as much as possible. Thus, the 500kW PCS maximizes the PV plant system efficiency. The key factors are the latest power semiconductor technology and circuit topology applied to the 500kW PCS. Then, secondly, the paper introduces a 100kW PCS cooled only by natural convection. This is the world first PCS eliminating the cooling fans, in this capacity range, realized by two key factors, loss reduction and sophisticated cooling design. This technology greatly reduces the maintenance works during the PV PCS life cycle and thus contributes efficient operation of PV plants. The cooling design and evaluation results are introduced in the paper. The 500kW and 100kW PCSs are expected to contribute highly efficient operation of large scale PV plants for its life cycle.

Characterization and mapping of photovoltaic solar power plants by Landsat imagery and random forest: A case study in Gansu Province, China

Models for the calculation of the production of large photovoltaic (PV) power plants with different types of modules (monofacial or bifacial) have been developed in detail in the literature. In addition, detailed models have been developed for PV power plants that have fixed modules as well as PV power plants with tracking the azimuth angle of the Sun and/or the tilt angle of the PV module. On the other hand, due to the increasing installation of PV power plant, their construction is often imposed on the field with complex geometry, so it is interesting to develop models that can optimize the spatial layout and geometric elements of panels on sloping surface in relation on horizontal. Namely, during various analyses in the literature, production models for PV power plants that are planned on sloping terrains have not been developed. Accordingly, in this paper, a procedure was developed for the calculation of the production of PV power plants that are placed on terrain that is not flat, but oriented towards the arbitrary side of the World and with an arbitrary tilt angle.