scholarly journals Dynamic Model for Hydro-Turbine Generator Units Based on a Database Method for Guide Bearings

2013 ◽  
Vol 20 (3) ◽  
pp. 411-421 ◽  
Author(s):  
Yong Xu ◽  
Zhaohui Li ◽  
Xide Lai
Keyword(s):  
Dynamic Model ◽  
Power Plants ◽  
Operating Conditions ◽  
Radial Vibration ◽  
Turbine Generator ◽  
Hydro Power ◽  
Rotating Speed ◽  
Hydro Turbine ◽  
Machine Health Monitoring ◽  
Fault Mechanism

A suitable dynamic model of rotor system is of great significance not only for supplying knowledge of the fault mechanism, but also for assisting in machine health monitoring research. Many techniques have been developed for properly modeling the radial vibration of large hydro-turbine generator units. However, an applicable dynamic model has not yet been reported in literature due to the complexity of the boundary conditions and exciting forces. In this paper, a finite element (FE) rotor dynamic model of radial vibration taking account of operating conditions is proposed. A brief and practical database method is employed to model the guide bearing. Taking advantage of the method, rotating speed and bearing clearance can be considered in the model. A novel algorithm, which can take account of both transient and steady-state analysis, is proposed to solve the model. Dynamic response for rotor model of 125 MW hydro-turbine generator units in Gezhouba Power Station is simulated. Field data from Optimal Maintenance Information System for Hydro power plants (HOMIS) are analyzed compared with the simulation. Results illustrate the application value of the model in providing knowledge of the fault mechanism and in failure diagnosis.

Performance Analysis of a 565 MW Steam Power Plant

2011 ◽  
Author(s):  
R. Chacartegui ◽  
D. Sa´nchez ◽  
J. A. Becerra ◽  
A. Mun˜oz ◽  
T. Sa´nchez
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Operating Conditions ◽  
Feed Water ◽  
Water Heater ◽  
Turbine Generator ◽  
Steam Power ◽  
Steam Power Plant ◽  
Water Heaters ◽  
Steam Power Plants

In this work, a tool to predict the performance of fossil fuel steam power plants under variable operating conditions or under maintenance operations has been developed. This tool is based on the Spencer-Cotton-Cannon method for large steam turbine generator units. The tool has been validated by comparing the predicted results at different loads with real operating data of a 565 MW steam power plant, located in Southern Spain. The results obtained from the model show a good agreement with most of the power plant parameters. The simulation tool has been then used to predict the performance of a steam power plant in different operating conditions such as variable terminal temperature difference or drain cooler approach of the feed-water heaters, or under maintenance conditions like a feed-water heater out of service.

scholarly journals PROPROTOTYPE DESIGN OF WATER LEVEL CONTROL SYSTEM BASED ON PID CONTROLLER IN PLTMH

2020 ◽  
Vol 4 (2) ◽  
pp. 53
Author(s):  
Nyoman Budiastra ◽  
A.A Maharta Pemayun
Keyword(s):  
Water Flow ◽  
Pid Control ◽  
Power Plants ◽  
Flow Sensor ◽  
Level Control ◽  
Hydro Power ◽  
Rotating Speed ◽  
Supply Pipe ◽  
Hydro Power Plants ◽  
The Stability

Abstract— One of the development of technological innovations in the field of control systems in all aspects of life is needed to maintain the stability of the work of a system, PID control to maintain the speed of water flow in the supply pipe in order to maintain the rotating speed of turbines Micro Hydro Power Plants (PLTMH) is very necessary because to maintain the generator rotational speed remains stable. To maintain the stability of the water flow, a sluice gate is needed to regulate the flow of water that comes out of the reservoir to the stockpile, the sluice is called a valve that can be controlled with a microcontroller that will open and close in accordance with the data value of the Water Flow Sensor attached to the pipe. Simulation of Water Flow Sensor with PID control is used to simulate the MHP system with PID control by comparing the output if the PID value is changed.

Computational Model for Investigating the Influence of Unbalanced Magnetic Pull on the Radial Vibration of Large Hydro-Turbine Generators

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Yong Xu ◽  
Zhaohui Li
Keyword(s):  
Computational Model ◽  
Analytical Method ◽  
Analytical Methods ◽  
Electrical Machine ◽  
Radial Vibration ◽  
Turbine Generator ◽  
Hydro Turbine ◽  
Unbalanced Magnetic Pull ◽  
Turbine Generators ◽  
Rotor Model

A radial unbalanced magnetic pull (UMP) can be produced by an eccentric rotor and leads vibrations in large hydro-turbine generators. The influence of nonlinear UMP on the radial vibration of a large hydro-turbine generator is analyzed in this paper. The UMP is determined as a function of eccentricities and field currents by means of a simple analytical method instead of the finite element (FE) method. The analytical method employs the no-load characteristic curve of an electrical machine and saturation effects of the ferromagnetic materials are taken into consideration. FE rotor model of a large hydro-turbine generator unit, taking account of guide bearings, thrust bearing and periodic forces, is developed to investigate the influence of UMP on radial vibrations. The FE rotor model and the analytical method for UMP constitute the computational model. UMP is calculated under different rotor eccentricities and field currents by the proposed method. Comparing with other analytical methods, the effectiveness of the proposed method is verified. Dynamic responses of the FE model under different analytical methods for UMP are calculated to investigate the difference in vibration between different analytical methods. A simulated excitation test is performed and a comparative analysis between the calculated results and the field data is provided. The computational model is proved to be reasonable according to the analysis.

scholarly journals A Five-Level Current-Source Inverter for Grid-Connected or High-Power Three-Phase Wound-Field Synchronous Motor Drives

2016 ◽  
Vol 6 (5) ◽  
pp. 1139-1148
Author(s):  
S. Mohamadian ◽  
M. H. Khanzade
Keyword(s):  
Power Factor ◽  
High Power ◽  
Power Plants ◽  
Short Circuit ◽  
Current Source ◽  
Harmonic Distortion ◽  
Operating Conditions ◽  
Hydro Power ◽  
Torque Pulsations ◽  
Voltage Clamping

Simple converter structure, inherent short-circuit protection and regenerative capability are the most important advantages of current-source inverters (CSI’s) which have made them suitable for medium-voltage high-power drives. Usually in grid-connected gas turbine generators or pumped storage hydro power plants, efficient and reliable current-source load-commutated inverters (LCI’s) with thyristor switches are employed. Also, this type of CSI is widely used in very large drives with power ratings of tens of megawatts to supply wound-field synchronous motors (WFSM’s). However, LCI’s suffer from some disadvantages such as large torque pulsations, poor power factor, and start-up criticalities. In this paper, a novel multilevel-based CSI is proposed. The proposed converter consists of one LCI and one CSI bridge with self-turn-off switches along with a voltage clamping circuit. The CSI switches are forced commutated; hence, a voltage clamping circuit is employed to limit voltage spikes caused by current variations in inductive paths during commutation transients. Drastic reduction in harmonic distortion of stator current and improved fundamental power factor are achieved by the proposed topology. In addition, torque pulsations are reduced remarkably for normal and starting operating conditions. Comprehensive analysis of the proposed structure is presented and the design of converter components is elaborated.

scholarly journals Using MPC to Balance Intermittent Wind and Solar Power with Hydro Power in Microgrids

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 874
Author(s):  
Madhusudhan Pandey ◽  
Dietmar Winkler ◽  
Roshan Sharma ◽  
Bernt Lie
Keyword(s):  
Predictive Control ◽  
Power Plants ◽  
Parameter Sensitivity Analysis ◽  
Improve Performance ◽  
Hydro Power ◽  
Hydro Turbine ◽  
Wind Power Plants ◽  
Power Injection ◽  
Future Prediction ◽  
Valve Position

In a microgrid connected with both intermittent and dispatchable sources, intermittency caused by sources such as solar and wind power plants can be balanced by dispatching hydro power into the grid. Both intermittent generation and consumption are stochastic in nature, not known perfectly, and require future prediction. The stochastic generation and consumption will cause the grid frequency to drift away from a required range. To improve performance, operation should be optimized over some horizon, with the added problem that intermittent power varies randomly into the future. Optimal management of dynamic system over a future horizon with disturbances is often posed as a Model Predictive Control (MPC) problem. In this paper, we have employed an MPC scheme for generating a hydro-turbine valve signal for dispatching necessary hydro power to the intermittent grid and maintaining grid frequency. Parameter sensitivity analysis shows that grid frequency is mostly sensitive to the turbine valve signal. We have found that controller discretization time, grid frequency, and power injection into the grid are interrelated, and play an important role in maintaining the grid frequency within the thresholds. Results also indicate that the fluctuations in grid frequency are insignificant on the turbine valve position during power injection into the grid.

scholarly journals Numerical aided design of Pelton nozzle jet deflector

2021 ◽  
Vol 5 (2) ◽  
pp. 149-156
Author(s):  
Andrej Lipej ◽  
Boro Popovski
Keyword(s):  
Power Plants ◽  
Renewable Energy Sources ◽  
Fem Analysis ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Operating Conditions ◽  
Optimized Design ◽  
Small Hydropower ◽  
Hydro Power ◽  
Important Place

Hydro energy still occupies an important place among renewable energy sources. In special operating conditions, Pelton turbines are irreplaceable and can be used for extremely small hydropower plants and also large hydro power plants. Pelton turbines can operate with high head and relatively small flow rates. In many cases, the height differences of the water are very large. Sometimes it is necessary to stop the operation of the turbine very quickly and the consequences of water hammer can be very severe. The responsible part to minimize the consequences of this phenomena is jet deflector, which can be in two different technical designs. The steps for 3-D geometry definition, pre-processing and post-processing, flow modelling and FEM analysis are presented. In the paper is presented the new optimized design of push-out jet deflector shape. Optimization consider 3-D CFD analysis of free surface flow and stress analysis. The main goal of the research was to minimize the influence of all force components on the torque of deflector servomotor. The final results present the geometry of the deflector, with a significant reduction in the stresses and deformations. These have been achieved with a crucial reduction in the hydrodynamic force and torque.

Could biomass-fueled boilers be operated at higher steam temperatures? Part 3: Initial analysis of costs and benefits

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Superheated Steam ◽  
Black Liquor ◽  
Simulation Software ◽  
Operating Conditions ◽  
Costs And Benefits ◽  
Steam Generation ◽  
Fireside Corrosion ◽  
Corrosion Resistant

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

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.

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