Solar Power Generation Unit Research Articles

A new iterative mixed integer linear programming based real time energy efficient management of AC-DC distribution networks

In the smart grid era, AC-DC distribution networks are evolving for integrating massive amounts of distributed energy resources, especially battery associated solar power generation units, into distribution networks in most energy efficient ways. Performing real time energy management for such networks is challenging due to presence of different power electronic converters, grid-edge devices and voltage controlling equipment. Existing studies either focused on developing offline day ahead methods, or shortsighted greedy strategies by neglecting the offline beneficial attributes in real time optimization frameworks. On the contrary, this article proposes a novel real time AC-DC distribution network energy management portfolio by merging load control and conservation voltage reduction techniques to achieve energy efficient operation of the network by regulating the operation of the controllable resources. Initially, the overall optimization problem is developed as a mixed integer non-convex programming by modelling the offline benefits as time coupled stochastic expressions in real time optimization platform. The non-convex expressions are later simplified by adopting different linearization techniques and the entire energy management framework is revised as a simple mixed integer linear programming (MILP). The original problem is decoupled for each time step by simplifying the time coupled expressions using virtual queues and Lyapunov functions. Additionally, a new iterative MILP algorithm is proposed to solve the revised energy management problem with less computation complexity and time. Unlike the previous solution methods, the proposed algorithm initializes the variables by their median values and handles the infeasibilities by adding tangential cutting plane constraints and penalty variable minimization objective. Demonstrating on 33-bus AC-DC distribution network, the superiority of the proposed real time energy management process and iterative MILP algorithm is established after comparing with standard energy management portfolios and existing solution methods.© 2017 Elsevier Inc. All rights reserved.

Dynamic scheduling of market price-based combined heat–power-constrained renewable microgrid

Abstract In this paper, a market price-based combined heat–power dynamic dispatch model for a microgrid is presented. The microgrid comprises cogeneration units and wind and solar power-generation units. A battery and a heat storage tank are incorporated to optimally balance variations in heat-and-power load demands. The proposed model explores the impact of market prices of electricity, heat supply and load variability on the optimal schedule such that profit maximizes and emission, loss and waste heat are minimized. The Weibull probability distribution function is applied to characterize the uncertain renewable power variable in the model and to find the over- and under-scheduling costs. The problem is solved using an improved differential evolution algorithm in which a fuzzy membership module is appended to obtain a solution having the highest attainment for the selected multiple objectives. The results show that the proposed model can handle uncertain heat–power demand and price scenarios to produce feasible and optimal schedules with owner profits, heat utilization and renewable share varying between 10.55–115.97%, 72.51–90.39% and 26.82–38.05%, respectively.

Analysis of Solar Power Generation Performance Improvement Techniques

The performance of solar power generation systems broadly depends upon the effectiveness of the solar cell placed in the architecture. The performance of the solar cell may vary with respect to the heat generated over its surface. Hence different types of cooling methods are employed over the solar power generation system to improve its power efficiency. Apart from solar cell cooling method, different types of optimization techniques are also implemented to the solar power generation unit for extracting a good power output. The maximum power point tracking algorithm is one of the primary methods used for matching the generated power to reach the required power in the connected battery system. The paper analyzes the research attainments and limitations of the various cooling models employed for the solar power generation system to develop an efficient system in future.

Power Quality Improvement Using Modified ANFIS in Hybrid Miniature Solar Power Generation Units through Reduction of Total Harmonic Distortion

Power Quality Improvement Using Modified ANFIS in Hybrid Miniature Solar Power Generation Units through Reduction of Total Harmonic Distortion

Employing Battery Storage Systems to Improve Power System Survivability

This article presents the employment of battery storage systems (BSSs) to improve power system survivability. This application of BSSs is based on setting BSS charging/discharging as responses to integrating distributed generation units and/or adjusting load demands (load-side activities). The improvement of power system survivability is quantified by the survivability index <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Gamma$</tex-math></inline-formula> , which can exceed its boundary values due to load-side activities. The improvement of power system survivability is achieved by maintaining <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Gamma$</tex-math></inline-formula> within its boundary values post a load-side activity. The proposed approach to improve power system survivability is implemented and tested for the Barbados power system. Tests are conducted for integrating solar power generation units, and implementing demand response. Test results show that accurate BSS charging/discharging can maintain the index <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Gamma$</tex-math></inline-formula> within its boundary values post-load-side activities.

Impact of Renewable Energy Sources into Multi Area Multi-Source Load Frequency Control of Interrelated Power System

There is an increasing concentration in the influences of nonconventional power sources on power system process and management, as the application of these sources upsurges worldwide. Renewable energy technologies are one of the best technologies for generating electrical power with zero fuel cost, a clean environment, and are available almost throughout the year. Some of the widespread renewable energy sources are tidal energy, geothermal energy, wind energy, and solar energy. Among many renewable energy sources, wind and solar energy sources are more popular because they are easy to install and operate. Due to their high flexibility, wind and solar power generation units are easily integrated with conventional power generation systems. Traditional generating units primarily use synchronous generators that enable them to ensure the process during significant transient errors. If massive wind generation is faltered due to error, it may harm the power system’s operation and lead to the load frequency control issue. This work proposes binary moth flame optimizer (MFO) variants to mitigate the frequency constraint issue. Two different binary variants are implemented for improving the performance of MFO for discrete optimization problems. The proposed model was evaluated and compared with existing algorithms in terms of standard testing benchmarks and showed improved results in terms of average and standard deviation.

Study on the Development of Measurement Technology for Direct Current Power Systems in Insulation State Using AHRD Algorithm

In this study, an algorithm was developed to represent the insulation state of uninterruptible direct current power supply systems, including circuitry. The existing insulation monitoring system in uninterruptible state was only possible with attachment type devices, but there was no portable inspection equipment at the site. This algorithm is called asymmetric high resistance detection (AHRD), which can compensate for the shortcomings of existing pulse and passive measurement methods, like not being able to measure when both positive and negative electrodes are poorly insulated. The researchers then developed a device that uses this algorithm for the on-site testing of direct current power supply systems, such as solar power generation units and energy storage systems (ESSs). Conversion and estimation formulas were also developed and verified by analyzing the correlation between the measurement values and simulation results of the device’s sensor parameter settings. A standard power supply and standard resistance were used on the newly developed insulation meter to assess it using a lab test and a performance test. Its performance is verified through a comparative analysis between the newly developed insulation meter with the existing insulation monitoring device at an ESS site. Applying the technology proposed in this study at testing sites can enable the verification of the insulation state of circuitry and direct current power supply systems, thereby preventing accidents by ensuring electrical safety.

The Bamboo Greenhouse Technology For Hydroganic Plants with Independent Photovoltaic Energy in the Food Safety Program

The development of the city has made a lot of agricultural land turned into residential land and other urban facilities so that agricultural land becomes increasingly narrow so that it can weaken the food safety program. Another way is needed to utilize narrow land in an effort to develop agricultural products, namely by farming and maintaining fish hydroganic. Hydroganic comes from the words Hydro and Organic which are defined as organic cultivation systems by combining the hydro system and the organic system. The main source of nutrition from hydroganic is obtained from solid and liquid organic fertilizer and fish pond water that is treated as plant nutrition. The Hydroganic Technology Dissemination Program with independent electricity sources from solar power plants was carried out in Kampung Bunga Grangsil, Jambangan Village, Dampit District, Malang Regency. Communities that are the perpetrators of the activities are the Tourism Awareness Group Kampoeng Boenga Grangsil and the Syakura Arum Farmer Women's Group. The research method uses a descriptive qualitative method, beginning with the design, the creation of an Independent Energy Hydroganic Greenhouse and the planting of vegetables and fish stocking. Retrieval of data in the form of observations and documentation of photos and videos on activities: a) lectures and discussions; b) practice of making bamboo structures greenhouses; c) the practice of installing hydroganic plants; d) the practice of installing solar power plants; e) Hydroganic vegetable and fish growing practices. Through this program the construction of a tunnel-shaped greenhouse with bamboo structure has been carried out successfully, 2 (two) hydroganic farming facilities complete with fish ponds, 1 (one) solar power generation unit consisting of 4 solar panels each with a capacity of 100 wp with energy storage in the form of a 100 AH 12 V battery and a 1000 WH inverter in sunny conditions producing a minimum of 13.6 Amp, 18.8 V can meet the energy needs to drive the water circulation pump and greenhouse lighting lamps and the surrounding environment. Planting sla and mustard greens as well as spreading catfish and tilapia in mid-August 2019, lettuce vegetables can be harvested at the end of September 2019. The success that can be seen is that when farmers cannot grow vegetables in dry land, the vegetable plants in this hydroganic greenhouse remain fertile and healthy because water circulation occurs continuously. Tunnel-shaped greenhouse with bamboo structure using independent energy for hydropower farming is very practical, efficient and quick to build and can be planted with vegetables and spread fish throughout the year without pause is expected to be a prototype of modern agricultural and fishery facilities without relying on the rainy or dry season in the framework of the program increase national scale food safety. DOI: https://doi.org/10.26905/lw.v12i1.3676

Hydrogen as a battery for a rooftop household solar power generation unit

Decentralization of electrical power generation using rooftop solar units is projected to develop to not only mitigate power losses along transmission and distribution lines, but to control greenhouse gases emissions. Due to intermittency of solar energy, traditional batteries are used to store energy. However, batteries have several drawbacks such as limited lifespan, low storage capacity, uncontrolled discharge when not connected to a load and limited number of charge/discharge cycles. In this paper, the feasibility of using hydrogen as a battery is analyzed where hydrogen is produced by the extra diurnal generated electricity by a rooftop household solar power generation unit and utilized in a fuel cell system to generate the required electrical power at night. In the proposed design, two rooftop concentrated photovoltaic thermal (CPVT) systems coupled with an organic Rankine cycle (ORC) are used to generate electricity during 9.5 h per day and the extra power is utilized in an electrolyzer to produce hydrogen. Various working fluids (Isobutane, R134a, R245fa and R123) are used in the ORC system to analyze the maximum feasible power generation by this section. Under the operating conditions, the generated power by ORC as well as its efficiency are evaluated for various working fluids and the most efficient working fluid is selected. The required power for the compressor in the hydrogen storage process is calculated and the number of electrolyzer cells required for the hydrogen production system is determined. The results indicate that the hybrid CPVT-ORC system produces 2.378 kW of electricity at 160 suns. Supplying 65% of the produced electricity to an electrolyzer, 0.2606 kg of hydrogen is produced and stored for nightly use in a fuel cell system. This amount of hydrogen can generate the required electrical power at night while the efficiency of electrolyzer is more than 70%.

Integrating renewable energy in smart grid system: Architecture, virtualization and analysis

Abstract Renewable energy sources (RESs) and energy storage systems (ESSs) are the key technologies for smart grid applications and provide great opportunities to de-carbonize urban areas, regulate frequency, voltage deviations, and respond to severe time when the load exceeds the generation. Nevertheless, uncertainty and inherent intermittence of renewable power generation units impose severe stresses on power systems. Energy storage systems such as battery energy storage system enables the power grid to improve acceptability of intermittent renewable energy generation. To do so, a successful coordination between renewable power generation units, ESSs and the grid is required. Nonetheless, with the existing grid architecture, achieving the aforementioned targets is intangible. In this regard, coupling renewable energy systems with different generation characteristics and equipping the power systems with the battery storage systems require a smooth transition from the conventional power system to the smart grid. Indeed, this coordination requires not only robust but also innovative controls and models to promote the implementation of the next-generation grid architecture. In this context, the present research proposes a smart grid architecture depicting a smart grid consisting of the main grid and multiple embedded micro-grids. Moreover, a focus has been given to micro-grid systems by proposing a “Micro-grid Key Elements Model” (MKEM). The proposed model and architecture are tested and validated by virtualization. The implementation of the virtualized system integrates solar power generation units, battery energy storage systems with the proposed grid architecture. The virtualization of the proposed grid architecture addresses issues related to Photovoltaic (PV) penetration, back-feeding, and irregularity of supply. The simulation results show the effect of Renewable Energy (RE) integration into the grid and highlight the role of batteries that maintain the stability of the system.

Solar-driven high temperature hydrogen production via integrated spectrally split concentrated photovoltaics (SSCPV) and solar power tower

Hydrogen production can be achieved via combined concentrated photovoltaic (CPV) and concentrated solar power (CSP) in which concentrated radiation is spectrally split and then converted in a photovoltaic receiver and a thermal absorber. This study thus proposes an innovative solar process design integrating both thermal and quantum components of solar energy while providing a complete assessment of its global performance to demonstrate its practical interest. A stand-alone solar-to-hydrogen path was modeled and numerically simulated, which was both electrically and thermally supplied by a solar power generation unit to feed the electrolyzer power utilization unit with enhanced solar-to-hydrogen conversion efficiency. Following balance of plant (BoP), the heliostat field and cavity receiver were designed to match the entire system in which the receiver only intercepts a definite range of infrared wavelength while the rest is converted by separately insulated PV cells. Moreover, dichroic reflectors and optimum cutoff wavelength were applied to fulfill separate optimization and heat load reduction of each solar cell. Finally, the solid oxide electrolysis cell (SOEC) was designed to utilize the generated thermal and electrical power appropriately. In best case scenario, a solar-to-hydrogen conversion efficiency of 36.5% was achieved under 899 W/m2 direct normal irradiance (DNI) and 1000 suns concentration. The solar plant outputs at this operating point were 850 g/h H2 and 6754 g/h O2. Further improvement in efficiency can be achieved through alignment in regard to the site location and annual insolation variation.

Design and Control of a Small-Scale Isolated Concentrated Solar Power Generation Unit

Electricity generated by small-size concentrated solar power (CSP)-driven Rankine cycle (RC) is an increasingly explored alternative for powering isolated homes/small communities. In these units, solar energy is captured to raise the temperature of a heat transfer fluid (HTF). The hot HTF drives a low-temperature Rankine cycle to generate electricity for the household(s). Because the solar flux follows the diurnal transient cycle along with high variability in the power demand, very large inventory of the HTF is needed to store the solar energy and supply heat to the Rankine cycle, including when the solar flux is zero at night. There then is no steady state for the process and it must be designed for inherently transient operation over a very large operating window. Simultaneous design and control evaluation to ensure robust operation for such a large operating window is then essential. This work presents the same for a small scale 20 kW isolated CSP-RC power generation unit. Three enhancements to the ba...

Integration of humidification-dehumidification desalination and concentrated photovoltaic-thermal collectors: Energy and exergy-costing analysis

Water desalination by humidification-dehumidification-humidification (HDH) cycle is considered as a viable option for small-scale freshwater production in remote areas. When integrated with solar power generation units, this stand-alone co-generation system would become very attractive for reliable simultaneous freshwater and electrical power production. This study evaluates the performance of a co-generation unit based on integration of air-heated HDH desalination cycle with concentrated photovoltaic-thermal (CPVT) collectors. Mathematical model for integrated system under steady-state conditions has been presented. Exergy-costing method was applied to estimate the cost of system's products. The results show that the system would be able to produce 12m3 of freshwater and 960kWh of electricity per year for a site having 1.88MWh/yr solar irradiance. The unit cost for freshwater production and electrical power generation is estimated as 0.01 $/L and 0.289 $/kWh, respectively.