


Vol 55, No 4 (2019)
- Year: 2019
- Articles: 8
- URL: https://journal-vniispk.ru/0003-701X/issue/view/8940
Direct Sunlight-to-Electricity Conversion
Studies of the PV Array Characteristics with Changing Array Surface Irradiance
Abstract
This paper presents a brief analysis of the photovoltaic (PV) modules that are currently commercially available. The most used calculation formulas and measurement procedures used for evaluating the power characteristics of photovoltaic PV modules are given. The possible causes of power losses of solar cells and modules are described, including losses caused by design features. The theoretical calculations and experimental results of measuring the characteristics of silicon PV arrays with changing surface irradiance are compared. The calculated and experimental dependences of the power output variation of the ISM-50 photovoltaic module with changing its tilt angle are presented. It is shown that there is a significant discrepancy between theoretical studies and experimental results. A hypothesis has been put forward about the dependence of a real decrease in power characteristics and refraction indices of PV array protective coatings. An adjustment factor is proposed taking into account the decrease in the solar radiation output on the silicon photocell surface when passing through the antireflective protective coatings of the PV module. The conclusions drawn from the results of this work indicate that the identified factors affecting the electricity generation by photovoltaic converters need to be considered.



Solar Power Plants
Analysis of Various Energy Supply Scenarios of Crimea with Allowance for Operating Modes of Solar Power Planta
Abstract
This paper considers the structure of the regional energy supply of Crimea and presents the characteristics of the main groups of regional electricity producers, including combined heat and power plants, mobile gas turbine power plants, renewable energy sources, and backup power sources. It is proposed, depending on the purpose of calculations in the context of the transportation problem under consideration, to use average actual rates for a given period with energy suppliers as tariffs (the calculation purpose is to reduce the electricity production and transportation cost), as well as conditional qualitative assessments, such as “fines” (the purpose is to improve the environmental friendliness and reliability of the system as a whole). The influence of the produced solar plant power on the operating modes of the Crimean energy system is assessed. The solar power production optimization technique that affects the reliability and quality of power supply is developed. Various energy supply scenarios for Crimea are generated, including peak and average power consumption modes with various options for solar activity, season, including and excluding energy sources under construction, and off-season repair of power sources. Based on the calculation data, the reliability of the regional energy system is estimated for various power supply scenarios, as well as the need to use an energy bridge for a power exchange with the mainland.



Studies of the Operation of a Solar Power Plant
Abstract
This article paper the results of studying the effect of atmospheric climatic factors on the operation of the photovoltaic modules of a power plant. The modes of operation of the solar power plant were studied depending on temperature parameters, as well as taking into account the wind load and other parameters. The change in the production of electric energy is shown for various results of the study of a serial photovoltaic module RS 250 with a power of 250 W, which is used for the generation of electric energy at some solar power plants in the south of Ukraine. The results make it possible to evaluate its performance in natural conditions depending on various climatic factors. The article describes the study of the operation of a wind power plant (WPP) with helical blades; this type of WPP allows using the kinetic energy of the wind flow more fully to convert it into mechanical energy of rotation of the wind turbine shaft. The coefficient of wind energy utilization by the rotor of a wind turbine with such a design is much higher than that of horizontal-axis wind turbines. Wind–solar power plants operating in parallel with the general power grid occupy quite large territories. In this case, as a rule, wind turbines are located in the north part of the plant, without interfering with the operation of the modules, while photovoltaic modules are located on the south side of the wind turbines, which minimizes the losses from shading by the tower, engine room, and wind turbine blades. All the studies described above allow installing additional generating capacities on wind and solar power plants, which will greatly increase the total production of the plant and the efficiency of the entire energy complex.



Improvement of Methods for Predicting the Generation Capacity of Solar Power Plants: the Case of the Power Systems in the Republic of Crimea and City of Sevastopol
Abstract
The construction and operation of large solar power plants (SPPs) and the dependence of their production on light and other meteorological factors leads to a strong dependence of the operation modes of the Republic of Crimea and Sevastopol power system on meteorological factors. Today, given that the share of solar power plants is about 30% of the total installed capacity, it is necessary to solve the problems that have a great impact on the power system operating modes. With large output capacity of the solar power plant, the operator has to give commands to turn off the generating equipment of thermal power plants. In power systems with a large share of solar generation, it is necessary to solve this problem by improving the generated power predicting methods, as it will reduce the dependence of operating modes on weather factors and increase the reliability of the power system. The paper discusses the use of hybrid predicting methods that imply taking into account the possibility of the weather scenarios simulation, advanced cloud-based image processing technology, and close-to-real-time cloud motion surveillance cameras. There was an experimental software created that selects coefficients of set configuration time series. In combination with the conservative methods, it makes predicting the SPP Perovo output more accurate. Taken together, the chosen methods of predicting solar power generation capacity in the power system of the Republic of Crimea and Sevastopol ensure not only stability of the power system as a whole, but also the maximum efficiency of power plants, allow to accelerate the integration of solar power plants into the power system, and have positive effects on the environment.



A Device for Remote Monitoring of Solar Power Plant Parameters
Abstract
The need for application of a device for online remote monitoring of electrical parameters and the operability of photovoltaic converters of solar power plants is justified in the context of the problems encountered in the Sevastopol Solar Power Plant (S. Energy Sevastopol LLC) operation. A structural diagram of the device showing the connection and purpose of its main functional components is presented. The circuit is based on an ATmega 328p microcontroller, which transfers processed data from the sensors to the server by sending a GET request using a W5100 Wiznet Ethernet controller. Such a solution allows for a high data transfer rate—up to 25 Mbps—and provides a simple connection to the Internet independently from operating systems and external computers. The characteristics and performance analysis of galvanically isolated sensors used in the device are presented, such as a current sensor based on an Allegro ACS712 integrated current sensor, and a voltage sensor based on the transistor optocoupler. The results of the device operation illustrating the photovoltaic plant daily operation on a sunny fall day are provided. The device provides for continuous monitoring of the operation of the photovoltaic converters with long-term storage of measured values in graphical and numerical form, which makes it possible for operational and dispatching personnel to visually analyze the plant operation, monitor its performance, compare key performance indicators of various sections, and obtain production reports by periods with plotting of curves, as well as receive alarm signals.



Energy Security
The Use of Solar Power Plants to Provide Energy Security of the Crimean Region
Abstract
The electric power supply of the Crimean region and the city of Sevastopol requires the construction of thermal power plants and electricity supply from mainland Russia through the Strait of Kerch. Gas boiler houses are mainly used for the heat supply of the local cities, as well as solid and liquid fossil fuel heating stations. Under conditions of the energy and transit blockade of the peninsula, energy supplies for these facilities are becoming not only expensive, but also fraught with difficulty.



Renewable Energy Sources
Some Results of a Study of Wave Energy Converters at Sevastopol State University
Abstract
This paper is concerned with the issue of the efficiency of sea wave energy conversion. It is shown that the efficiency increases significantly if a low-damped mechanical oscillator, which is adapted to a wave power spectrum, is used as a primary converter. Two major types of oscillators are considered. The pendulum-type converter is found to be the most promising. A new schematic of a pendulum-type converter is suggested and briefly described. The converter consists of two oscillators adjusted to work in resonance mode. The first one includes a ballast-controlled floating platform pitching on sea waves. The second oscillator is a long sector-shaped pendulum located on the floating platform. The use of sea wave energy converters is promising in regard to the widespread use of renewable sources and elimination of the environmental impact of fossil fuel consumption in coastal regions. Various systems have been developed and projects implemented in this field.



An Offshore Wind-Power-Based Water Desalination Complex as a Response to an Emergency in Water Supply to Northern Crimea
Abstract
This paper is concerned with the problem of water shortage in northern Crimea. It shows that the Crimean Peninsula lacks access to fresh water from natural sources. For decades, water supply was provided mostly from the Dnieper River via the North Crimean Canal. An emergency situation arose in water supply in Crimea after the canal was shut down. It has been shown that seawater desalination from renewables is the only reliable way to tackle the problem. The work reviews perspective desalination methods, suggests a new schematic of a desalination complex based on Wind Energy Marine Units, and determines key parameters of the complex.


