Technoeconomic Assessment of Constructing a Solar Photovoltaic Plant (50 MW) in the Sughd Region, Republic of Tajikistan

The field of solar photovoltaic (PV) plants has seen significant growth in recent years, with an increasing number of installations being developed worldwide. However, despite advancements in technology and design, the impact of shading on the performance of PV plants remains an area of concern. Accurate 3D models produced using unmanned aerial vehicle (UAV) photogrammetry can provide aid to evaluate shading from nearby surroundings and to determine the potential of a site for electricity production via solar PV plants. The main objective of this paper is to address the problem of shadows significantly reducing energy yield in solar PV plants by proposing a methodology that aims at assessing the shading effects on PV systems and determining the optimal configuration for a PV module array using an accurate digital environment 3D model built using UAV photogrammetry. A high-level-of-detail 3D model allows us to evaluate possible obstacles for PV module array construction and accurately recreate the proximities that can cast shadows. The methodology was applied to grid-connected PV systems in Kaunas, Lithuania. The results of the case study show that electricity production in PV modules is highest at a 15° tilt angle when the distance between PV rows is 1.25 m. The proposed methodology gives an 11% difference in PV yield due to shading compared with other tools that do not include shading. This study also highlights that at least 30% financing support is necessary for solar PV plants to be economically attractive, resulting in a payback of 9 years and an internal rate of return of 8%. Additionally, this study can help optimize the design and layout of PV systems, making them more efficient and cost-effective.

Floating Photovoltaic (FPV) power plant on any water body is a Solar Photovoltaic (SPV) plant that is installed on water, instead of land. The water body may be lake, pond, river, canal etc. This paper attempts to calculate and compare energy generation from 1 MW SPV and FPV power plants at Jodhpur city in India using Excel spreadsheet. FPV power plant has numerous advantages over SPV plant. Some of them are: i) Higher electrical energy generation due to low module temperature; ii) Reduction in water evaporation from the water body and thereby conserving valuable potable water; iii) No land requirement for installing the power plant as FPV system floats on the water; and iv) Reduction in the length of power transmission lines as water bodies such as ponds are always close to inhabited areas. However, cost of installation of FPV increases due to need of floating platform on the water body. The solar radiation data for Jodhpur city are taken from National Institute of Wind Energy (NIWE) Wind-Solar data portal. The annual global horizontal radiation for the period of January 01st, 2016 to December 31st, 2016 is estimated as 1.98 MWh/m2. The annual performance ratio and capacity utilization factor for 1 MW SPV are estimated as 79.52% and 19.11% respectively. The annual performance ratio and capacity utilization factor for 1 MW FPV are estimated as 81.49% and 19.58% respectively. 1 MW FPV could save 191.174 million litres of water from being evaporated annually. FPV system compared to SPV system is found to have 2.48% higher energy generation annually with 14.56% reduction in average module temperature.

The last decade has seen an immense growth in renewable energy sources such as solar photovoltaic (PV) plants due to environmental concerns. Due to this rapid growth, solar PV plants are starting to have a larger influence on power system stability and thus their dynamic behavior cannot be ignored in stability studies. The lack of well-established models and parameter sets is the primary reason solar PV plants are not modeled with dynamic characteristics. This paper presents a method to define a standard parameter set for representing large-scale and aggregated solar PV plants in stability studies from the perspective of the transmission system operator (TSO). The method takes into account primarily the conditions provided in the grid connection requirements; for illustrative purposes, the connection requirements of the Netherlands are used. Additionally, a relationship defined as short-circuit current (SCC) PV ratio is proposed to estimate the effect of solar PV plants on transient stability. To illustrate the workings of the proposed ratio, the transmission network of the TenneT TSO B.V. in the Netherlands is used. The analysis demonstrated that high values of SCC PV ratio are an indicator that solar PV plants affect the transient stability while low values of SCC PV ratio showed that solar PV plants have minimal effect on the transient stability. Additionally, methods to improve the transient stability are provided which include limiting the operation regions of critical generators, increasing short-circuit ratio by adding a synchronous condenser or static compensator (STATCOM) and decreasing the reactance between the critical synchronous generator and faulted bus.

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

Performance evaluation of a rooftop solar photovoltaic power plant in Northern India

Conventional power plants affect the environment by emitting greenhouse gases and other toxic pollutants. On the other hand, the reserve of fossil fuel is depleting day by day. It has been becoming obvious that renewable energy can overcome these challenges enormously. Solar photovoltaic (PV) has been gaining a significant popularity among renewable energy sources since last decade. Solar PV power plants are replacing the traditional power plants. The annual investment of solar PV system rises with a high growth rate in recent years. In 2015, the investment in solar sector was USD 161 billion which was the highest among all renewable sources, e.g., wind, biomass, biofuel and geothermal. Now, the cost of electricity generation from solar PV system is comparable with the cost of electricity from traditional generation systems. By the end of 2016, the cumulative installed capacity reached at around 300 GW whereas it was only 17.06 GW in 2010. About 15,000 tons of carbon dioxide emission can be reduced every year by a 10 MW solar PV plants. However, this chapter presents a detail analysis of a large scale solar PV power plant. The comparative technical specifications of different components of large scale solar PV plant, e.g., solar module, inverter, tracker and transformer are presented in the chapter. In addition, necessary factors that influence the selection of a site for a solar PV plant are also discussed.

Solar energy is one of the most suitable renewable energy options in India. In the last decade, solar energy installations have received an ample impetus in India due to active initiatives taken by the Indian government. However, the solar energy potential of country’s North-Eastern (NE) part is not utilized effectively so far. In the present study, a comprehensive analysis of the feasibility of installation of a megawatt-level grid-connected solar photovoltaic (SPV) power plant in all the state capitals of NE India is carried out. The climatic data collected from various online sources and NASA climatic database were utilized in designing a 2 MW SPV plant. The theoretical procedure involved in designing the SPV plant is also presented in this study. PVsyst simulation software is used to predict the performance of 2 MW power plants for these eight states of India. From the analysis, it is observed that NE India has an immense potential for installation of solar energy conversion devices and thus it can be harvested economically. It has been observed that locations of Guwahati and Gangtok provide a high performance ratio of 0.855. Aizawl provides the minimum unit cost of electricity generated at a value of 3.88 INR/unit. The analysis also reveals that the Aizawl and Guwahati are the most suitable locations for installation of SPV power plant amongst the NE capitals.

This paper proposes a multifunctional control strategy for battery energy storage systems (BESSs) in solar photovoltaic (PV) plants to avoid the unacceptable PV-power ramp-rate caused by PV variability. In addition to the PV variability tolerant ramp-rate control, the proposed multifunctional BESS control strategy is capable of maintaining a user-specified charging profile to store excess PV power while providing backup power support and charge maintenance, by accommodating diverse control functions time to time. Four control functions, namely, Rest (RST), Surplus Energy Storage (STR), Back-up Power Support (SPT) and Charge Maintenance (CMT) functions, are proposed in this article. Besides, extendibility of the proposed multifunctional strategy is presented by adding two action strategies – one with the STR function and another with the SPT function. Validation of the proposed control strategy is conducted by using real historical data from a utility-scale solar PV plant located in Queensland, Australia. Numerical analyses show that the strategy can successfully keep the PV ramp-rate within specified limit along with the user specified charge profile. Further, exploiting the real-field data, the proposed strategy is demonstrated through a real-time co-simulation study conducted in a MATLAB interfaced RSCAD-RTDS platform that can be used as Digital Twin (DT) for the PV plant.

The provision of frequency droop (FD) curves is imperative in supporting communication-free grid operations, distinctly for power systems with utility-scale solar photovoltaic (PV) power plants. Besides, system compliant frequency/voltage excursions at PV power plant point of interconnection (POI) exert a high level of inherently stochastic dependence and parameter uncertainty, partially due to the PV power plant site-specific spatio-temporal meteorological conditions. Hence, a site-dependent variable FD has been modeled through controlled lab environment simulations with a real-time digital simulator, i.e., RTDS, and derived from integrating site-specific operating conditions imposed by PV-site steady-state loading levels during different hours of the day. The adaptive FD curve replicates close to linear FD droop deviations curve at each stable (reference) operating condition. For a more accurate characterization, this paper incorporates an additional layer of artificial intelligence, in recognition of the non-linearity of PV plant adaptive frequency droop curves. The results reflect on the effectiveness of a supervised machine learning approach, i.e., single neural networks (SNN) in the realization of the nonlinear adaptive frequency droop curve from the utility-scale solar PV power plant operation in a power system.

Accurate modeling of solar photovoltaic (PV) plant is of utmost importance to study system behavior during transient events. However, model accuracy and computational efficiency is inversely related, thus a simplified equivalent model for solar PV systems using collector system equivalencing approach is recommended for system modeling and grid interconnection studies by Western Electricity Coordinating Council (WECC). This paper compares steady state and dynamic behavior of a large 117-inverter based, 147-MW solar PV plant connected to IEEE 39-bus system, both at inverter terminals and at Point of Interconnection (POI) modeled with and without collector system equivalencing. These comparisons are performed under different scenarios including: single-generator model, two-generator model, five-generator model and a full scale model of PV plant. Our findings show that both the steady state and dynamic response of all models under all scenarios shows a good match.

This paper presents results of techno-commercial feasibility study comparing wireless over wired monitoring in installed solar photovoltaic (PV) plants. As subsidies for Solar PV projects are declining world-wide, the solar industry is looking for opportunities to reduce both the up-front capital expenditure (capex) and the operations and maintenance expenditure (opex) for solar PV plants. In addition, with increased penetration of renewable energy power plants, there is an ever-increasing need for greater levels of monitoring and control of renewable energy assets for better yield predictions, failure detection & resolution and grid integration purposes, to name a few. This paper addresses the paradox of improving cost-efficiency while simultaneously achieving increased level of monitoring of Solar PV assets by presenting results of a comparative study conducted on three operational solar PV plants. The cost-benefit model presented could serve as the basis for similar analysis for other geographies of the world in order to achieve reduced capex & opex of renewable energy plants while simultaneously monitoring greater level of details of the operating plants. Interestingly, the findings are applicable not only for solar PV plants but also other forms of power plants like wind farms, conventional power plants. The comparative analysis takes following aspects into account: 1) Technical specifications 2) Ease of installation 3) Reliability 4) Ease of Operations and Maintenance 5) Installation cost. Finally, a cost benefit break-even analysis for a range of project sizes is presented.

Distribution lines are generally protected by overcurrent relays. With the integration of an inverter-interfaced solar photovoltaic (PV) plant having a current-limiting feature, the fault current seen by the relay on the PV side of that feeder becomes comparable to the load current. The conventional overcurrent relaying principle is not suitable for distribution line protection. Distance relay may be a viable option for protection of distribution lines connecting the solar PV plant. However, positive- and negative-sequence source impedances of the PV plant depend on an inverter controller, which results in limited performance of fixed setting distance relay. This article proposes an adaptive distance relay setting to protect distribution line connecting the PV plant, using prefault voltage and current data at the relaying point. The method calculates positive- and negative-sequence PV source impedances for boundary setting of distance relay at the PV side. The proposed trip boundary is modified adaptively with the change in prefault conditions of the PV plant. Performance of the proposed method is tested for different control strategies and operating capacities of the PV plant and variation in the grid source impedance on a 34-bus distribution system. Real-time application of the proposed method is validated in hardware-in-the-loop using OPAL-RT simulators with IEC 61850 as the communication protocol and found to be accurate.

The DG (Diesel Generator) set generally operates at the low power factor due to the harmonics and reactive power demand of the loads and its voltages and currents deteriorate because of unbalanced and/or nonlinear loads. Moreover, in the existing system, the solar photovoltaic (PV) plant operates during the daytime only at unity power factor. Hence, the utilization factors of both the DG set and the solar PV plant are poor. This paper presents the use of a solar PV plant to improve the utilization of the DG set by controlling its voltage source converter (VSC). The VSC regulates its currents to reduce the flow of the reactive component currents, negative sequence currents, and harmonics currents in the DG set. In this work, an adaptive algorithm is used to filter the nonlinear load currents and perturb and observe (P& O) based tracking algorithm is used to extract the maximum power from the solar PV array. A simulation study is carried out to show the effectiveness of this work and to validate the performance of the control algorithm.

Comparative investigation of performance evaluation, degradation causes, impact and corrective measures for ground mount and rooftop solar PV plants – A review

To address the static voltage stability issue and suppress the voltage fluctuation caused by the increasing integration of wind farms and solar photovoltaic (PV) power plants, a two-tier reactive power and voltage control strategy based on ARMA power forecasting models for wind and solar plants is proposed in this paper. Firstly, ARMA models are established to forecast the output of wind farms and solar PV plants. Secondly, the discrete equipment is pre-regulated based on the single-step prediction information from ARMA forecasting models according to the optimization result. Thirdly, a multi-objective optimization model is presented and solved by particle swarm optimization (PSO) according to the measured data and the proposed static voltage stability index. Finally, the IEEE14 bus system including a wind farm and solar PV plant is utilized to test the effectiveness of the proposed strategy. The results show that the proposed strategy can suppress voltage fluctuation and improve the static voltage stability under the condition of high penetration of renewables including wind and solar power.