scholarly journals Analysis of Permissibility of the Excitation Loss Mode of the Synchronous Generator in the Conditions of the Industrial Electrical Supply System

Author(s):  
Olga V. Gazizova ◽  
Alexandr P. Sokolov ◽  
Nikolay T. Patshin ◽  
Yulia N. Kondrashova

Modern operating conditions of large industrial enterprises require the provision of high reliability of power supply to consumers while reducing the cost of the electricity consumed. These requirements are ensured by the widespread introduction of own sources of electrical energy. These include combined heat and power plants, gas turbines, gas pistons and steam and gas power plants. At the same time, there is a significant complication of the industrial network configuration and possible emergency modes. One of the emergency modes in such networks is the loss of excitation of the synchronous generator. The admissibility of such a regime is specified by regulatory documents. In this situation, the generator goes into asynchronous mode and consumes reactive power from the network. The purpose of this work is to identify the admissibility of the synchronous generator operation for a certain time in the asynchronous mode as a result of the loss of excitation. An algorithm has been developed to calculate the transient electromechanical process of a synchronous generator taking into account the loss of machine excitation. Investigations have been carried out for various operating modes of an industrial power plant taking into account the initial generator load using the KATRAN software. The calculation results allow determining the generator load by active power at which the synchronous generator can operate in the asynchronous mode without excitation.

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.


Author(s):  
A. G. Zhuravlev ◽  
M. V. Isakov

The high importance of optimizing the operation of quarry transport is confirmed by the leading share of its costs in the total cost of mining. The current direction of optimization is the development and implementation of digital technologies for processing complex data on the parameters of transport vehicles. The solution of the above issues should be based on the results of scientific research on the collection and processing of information. Developed a set of techniques to perform experimental measurements of working parameters of mining dump trucks as part of a special unit experiments, and long monitoring measurements. A set of equipment for performing experimental measurements, as well as its installation on a dump truck is presented. The data of experimental measurements and a methodical approach to their analysis are presented. In particular, it shows the identification of operating modes of the power plant and the construction of the load diagram, the identification of elements of the transport cycle, etc. The approach to substantiation of innovative designs of power plants adapted to the conditions of a particular quarry is shown on the example of calculated schedules of energy consumption and reserve of recovery of braking energy. The proposed hardware-methodical complex is a research model for the development of methods for automated data collection and processing in the formation of elements of digital mining production.


Author(s):  
Anjana Jain ◽  
R. Saravanakumar ◽  
S. Shankar ◽  
V. Vanitha

Abstract The variable-speed Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) attracts the maximum power from wind, but voltage-regulation and frequency-control of the system in standalone operation is a challenging task A modern-control-based-tracking of power from wind for its best utilization is proposed in this paper for standalone PMSG based hybrid-WECS comprising Battery Energy Storage System (BESS). An Adaptive Synchronous Reference Frame Phase-Locked-Loop (SRF-PLL) based control scheme for load side bi-directional voltage source converter (VSC) is presented for the system. MATLAB/Simulink model is developed for simulation study for the proposed system and the effectiveness of the controller for bi-directional-converter is discussed under different operating conditions: like variable wind-velocity, sudden load variation, and load unbalancing. Converter control scheme enhances the power smoothening, supply-load power-matching. Also it is able to regulate the active & reactive power from PMSG-BESS hybrid system with control of fluctuations in voltage & frequency with respect to varying operating conditions. Proposed controller successfully offers reactive-power-compensation, harmonics-reduction, and power-balancing. The proposed scheme is based on proportional & integral (PI) controller. Also system is experimentally validated in the laboratory-environment and results are presented here.


2021 ◽  
Vol 13 (24) ◽  
pp. 13678
Author(s):  
Anton Petrochenkov ◽  
Aleksandr Romodin ◽  
Vladimir Kazantsev ◽  
Aleksey Sal’nikov ◽  
Sergey Bochkarev ◽  
...  

The purpose of the study is to analyze the prospects for the development of loading methods for gas turbines as well as to develop a mathematical model that adequately describes the real operating conditions of the loading system at various loads and rotation speeds. A comparative analysis of the most common methods and technical means of loading the shafts of a free turbine at gas turbine plants intended for operation as part of gas pumping units is presented. Based on the results of the analysis, the expediency of using the loading model “Free Power Turbine Rotor–Hydraulic Brake” as a load simulation is shown. Recommendations for the creation of an automation system for the load testing of power plants have been developed. Mathematical models and Hardware-in-the-Loop simulation models of power plants have been developed and tested. One of the most important factors that predetermine the effectiveness of the loading principle is the possibility of software implementation of the loading means using software control systems that provide the specified loading parameters of the gas turbine.


Author(s):  
Lorenzo Cozzi ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Savino Depalo ◽  
Pio Astrua ◽  
...  

Abstract The overall fraction of the power produced by renewable sources in the energy market has significantly increased in recent years. The power output of most of these clean sources is intrinsically variable. At present day and most likely in the upcoming future, due to the lack of inexpensive and reliable large energy storage systems, conventional power plants burning fossil fuels will still be part of the energy horizon. In particular, power generators able to promptly support the grid stability, such as gas turbines, will retain a strategic role. This new energy scenario is pushing gas turbine producers to improve the flexibility of their turbomachines, increasing the need for reliable numerical tools adopted to design and validate the new products also in operating conditions far from the nominal one. Especially when dealing with axial compressors, i.e. machines experiencing intense adverse pressure gradients, complex flow structures and severe secondary flows, CFD modelling of offdesign operation can be a real challenge. In this work, a state-of-the art CFD framework for RANS analysis of axial compressors is presented. The various aspects involved in the whole setup are discussed, including boundary conditions, meshing strategies, mixing planes modelling, tip clearance treatment, shroud leakages and turbulence modelling. Some experiences about the choice of these aspects are provided, derived from a long-date practice on this kind of turbomachines. Numerical results are reported for different full-scale compressors of the Ansaldo Energia fleet, covering a wide range of operating conditions. Furthermore, details about the capability of the setup to predict compressor performance and surge-margin have been added to the work. In particular, the setup surge-margin prediction has been evaluated in an operating condition in which the turbomachine experiences experimental stall. Finally, thanks to several on-field data available at different corrected speeds for operating conditions ranging from minimum to full load, a comprehensive validation of the presented numerical framework is also included in the paper.


Author(s):  
V. I. Goldfarb ◽  
V. M. Spiridonov ◽  
N. S. Golubkov

Abstract Actuator rotation sometimes is required to transmit considerable torques at low speeds in a limited angular range. Such operating conditions are typical, for example, for the rotational drives of gas pipeline stop valves. These conditions are made worse by increased torques requried at the initial instant of motion when the torque is 1.3 to 1.5 times greater than the nominal torque, and by the range of operating temperatures of −60°C to +50°C. A number of gearboxes with a spiroid gear mesh were developed to satisfy these conditions for different torques (i.e. for different standard stop valves), with the steel spiroid pair case-hardened to 60–62 hardness Rc. A set of numerical studies had been conducted in order to choose gear design parameters and other elements of the gearbox. Experimental research performed using special testing rigs for definite operating modes showed high reliability and wear resistance of the drives developed and their high durability compared to known ones which is of great importance for given application domain.


Author(s):  
Cesar Celis ◽  
Sergio Peralta ◽  
Walter Galarza

Abstract The influence of different power augmentation techniques used in gas turbines on the performance of simple cycle type power plants is assessed in this work. A computational model and tool realistically describing the performance of a typical simple cycle type power plant at design and off-design point conditions is initially developed. This tool is complemented with different models of power augmentation technologies. Finally, the whole model including both power plant and power augmentation techniques is used to analyze a case study involving a particular power plant in Peru. The results from the simulations of the specific power plant indicate that power output can be increased through all the evaluated power augmentation technologies. These results show indeed that technologies based on absorption refrigeration systems produce the largest gains in terms of power output (7.1%) and thermal efficiency (0.7%). Such results confirm the suitability of these systems for simple cycle type power plant configurations operating under hot and humid operating conditions as those accounted for here. From an economic perspective, considering the net present value as the key parameter defining the feasibility of a project in this category, power augmentation techniques based on absorption cooling systems result also the most suitable ones for the studied power plant. Power augmentation techniques environmental implications are also quantified in terms of CO2 emissions.


Author(s):  
Paolo Chiesa

LNG regasification process needs a considerable quantity of thermal energy that is usually obtained by cooling sea water or by burning a fraction of the evaporated natural gas. These systems, though offering low cost and high reliability, are thermodynamically inefficient: they require energy for water pumping or fuel to provide heat and do not exploit the physical exergy related to the initial conditions of LNG to produce mechanical work. The present paper aims to assess the performances of various gas turbine based cycles which use the LNG regasification process as a low temperature heat sink for power cycles. In particular it will focus on the following configurations: • Closed loop gas cycles • Gas-gas combined cycles • Combined gas-organic Rankine cycles Two different sendout pressure (70 and 30 bar, corresponding respectively to the supply of long-distance pipelines or power plants based on heavy-duty gas turbines) are considered. Their performances are calculated and proper effectiveness indexes (e.g. thermal and exergetic efficiency) are introduced to carry out a comprehensive comparison among the systems considered. A simple economical analysis completes the discussion.


2020 ◽  
pp. 245-250
Author(s):  
А.В. Балакин ◽  
А.Н. Дядик ◽  
А.С. Кармазин ◽  
М.В. Ларионов ◽  
С.Н. Сурин

В статье представлена упрощенная имитационная модель, описывающая работу топливного процессора в составе воздухонезависимой энергетической установки. Рассмотрено блочное моделирование отдельных составляющих ВНЭУ, в частности, высокотемпературного реактора, блока очистки газа от серы и сажи, первого и второго блоков конверсии, сепаратора и регулирующего клапана. Имитационные модели отдельных элементов ВНЭУ позволяют рассчитывать динамические характеристики энергоустановки и создавать алгоритмы управления клапанами подачи водорода в переходных режимах. Теоретические зависимости для определения массовых расходов реагентов, температур и давлений приведены для идеальных газов с целью представления в среде LabVIEW с учетом полученных экспериментальных данных для проведения расчета маневров по регулированию давления на заданных режимах работы ВНЭУ при различных условиях ее работы. The article presents a simplified simulation model that describes the operation of the fuel processor as part of an air-independent power plant. Block modeling of the individual components of an air-independent power plant, in particular, a high-temperature reactor, a unit for cleaning gas from sulfur and soot, the first and second conversion units, a separator, and a control valve, is considered. Simulation models of individual elements of an air-independent power plant allow you to calculate the dynamic characteristics of a power plant and create algorithms for controlling hydrogen supply valves in transient conditions. Theoretical dependencies for determining the mass flow rates of reagents, temperatures and pressures are given for ideal gases for the purpose of presentation in the LabVIEW environment, taking into account the obtained experimental data for the calculation of maneuvers for regulating pressure at specified operating modes of an air-independent power plant under various operating conditions. The results of the work are described extremely accurately and informatively. The main theoretical and experimental results, actual data, discovered relationships and regularities are presented.


Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2377
Author(s):  
Edward Canepa ◽  
Alessandro Nilberto

The recent growing attention to energy saving and environmental protection issues has brought attention to the possibility of exploiting syngas from gasification of biomass and coal for the firing of industrial plants included in the, so called, Integrated Gasification Combined Cycle power plants. In order to improve knowledge on the employ of syngas in lean premixed turbulent flames, a large scale swirl stabilized gas-turbine burner has been operated with a simplified model of H2 enriched syngas from coal gasification. The experimental campaign has been performed at atmospheric pressure, with operating conditions derived from scaling the real gas turbines. The results are reported here and consist of OH-PLIF (OH Planar Laser Induced Fluorescence) measurements, carried out at decreasing equivalence of air/fuel ratio conditions and analysed together with the mean aerodynamic characterisation of the burner flow field in isothermal conditions obtained through LDV (Laser Doppler Velocimetry) and PIV (Particle Image Velocimetry) measurements. The OH concentration distributions have been analysed statistically in order to obtain information about the location of the most reactive zones, and an algorithm has been applied to the data in order to identify the flame fronts. In addition, the flame front locations have been successively interpreted statistically to obtain information about their main features and their dependence on the air to fuel ratio behaviour.


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