PDF superior Estudio geológico estructural e inventario de deslizamientos de área tres de la Cuenca de Malacatos

Increasing flexibility of coal power plant by control system modifications

Increasing flexibility of coal power plant by control system modifications

Although the comprehensive control system modification is a general practice for coal power plants ramp improvement, one has to wonder about the achievable ramping rate without significant modifications. As mentioned before, much higher (32.5 °C) temperature variations could be allowed without compromising the boiler life expectancy. Nevertheless during more than 30 ramping tests, the temperature variations of this order were not possible because of the control system constrains. A significant ramp of around 5 MW/min was ob- served only once, caused incidentally by the engagement of additional coal feeder. Records of this event are shown on lower right diagram in fig. 4 starting around 05:25. Sudden start-up of the additional coal feeder (shown in the upper left diagram in fig. 4) causes thermal load over- shoot which is not compensated by the decrease in other five feeders. As can be seen from the upper right diagram in fig. 4, the temperature overshoot caused by this disturbance was not larger than 5 °C. These results lead to conclusion that even without complicated control sys- tem modifications and with just simple adjustments of the control system constraints (allow- ing thermal load overshot during fast load changes), significant ramping rate improvements can be accomplished. To confirm this thesis and asses maximal achievable ramping rates detailed one dimensional boiler model was used.
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The effect of coal-fired power-plant SO<sub>2</sub> and NO<sub>x</sub> control technologies on aerosol nucleation in the source plumes

The effect of coal-fired power-plant SO<sub>2</sub> and NO<sub>x</sub> control technologies on aerosol nucleation in the source plumes

pre-existing particles. Thus, large amounts of pre-existing aerosol will reduce the net number of particles formed in a plume both by reducing nucleation and condensa- tional growth rates and by increasing coagulation. Power-plant emissions in polluted- background regions likely generate fewer new particles than in clean regions (Stevens et al., 2012). Although not investigated in this paper, the emissions of primary ash par-

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Measurement and Control of Coal Pipe Temperature of Coal Mills of PF Boiler

Measurement and Control of Coal Pipe Temperature of Coal Mills of PF Boiler

As per schematic diagram of Fig. 3, planning and arrangements has been made to execute the project towards final outcome. We arranged all the equipments like Data logger, Temperature scanner, RTD, Signal cable, Junction box, Man power, etc. Once all the material, equipments available on site, one by one we installed, commissioned them as per our scheme. And after some working days we could measure and monitor coal pipe temperature value from remote in continuous basis. We prepared a graphical representation of all temperature value in our existing DCS system for plant operator so that in any time they can see the temperature value of all 32 numbers of coal pipe of eight coal mill at a glance. We discussed with both Operator people and other engineering departments for the alarm limit of those temperature value so that if any probability of coal pipe choking, happens it will give us early alert. After discussion we configured alarm for annunciator panel such that if any running Coal Mill pipe temperature goes low, below 60 ◦C it will flash an alarm called “Any coal mill pipe temperature low”. Thus we were able to execute the project and established automation for remote monitoring and measurement of coal pipe temperature of coal mill of PF boiler.
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The effect of coal-fired power-plant SO<sub>2</sub> and NO<sub>x</sub> control technologies on aerosol nucleation in the source plumes

The effect of coal-fired power-plant SO<sub>2</sub> and NO<sub>x</sub> control technologies on aerosol nucleation in the source plumes

quired from Texas Air Quality Studies (TexAQS) field cam- paigns near Houston, Texas during 2000 and 2006. The large-scale meteorological forcing of the SAM simulations are provided by vertical profiles of mean winds, tempera- ture, relative humidity and surface sensible heat, latent heat and momentum fluxes from the National Center for En- vironmental Prediction (NCEP) North American Regional Reanalysis (NARR) data (Mesinger et al., 2006). The re- analysis data were provided by the National Oceanic and Atmospheric Administration (NOAA)/Outstanding Accom- plishments in Research (OAR)/Earth System Research Lab- oratory (ESRL) Physical Sciences Division (PSD), Boul- der, Colorado, USA, from their website at http://www.esrl. noaa.gov/psd/. The NCEP NARR data has a spatial resolu- tion of 32 km by 32 km and 3-h time resolution. Although SAM resolves turbulent flows on spatial scales smaller than the NCEP NARR data, any systematic (non-turbulent) vari- ability in meteorology (e.g. flow around hills or buildings) will not be captured by the SAM model, and this could lead to uncertainties in the plume dispersion. Aerosol nucle- ation is calculated using the empirical activation nucleation scheme (Kulmala et al., 2006), where nucleation rates are equal to A[H 2 SO 4 ] and A = 10 −7 s −1 . Various nucleation
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Optimal Control Design of Static Synchronous Series Compensator for Damping Power System Oscillation

Optimal Control Design of Static Synchronous Series Compensator for Damping Power System Oscillation

It can be seen in Fig. 4 that, without the SSSC (k = 0), the maximum and the minimum rotor angle are around 124 and 3 degree, respectively. The damping of the system can be improved by using SSSC based optimal control. With the proposed method, the maximum and the minimum rotor angle are around 100 and 30 degree, respectively and the system can return to stable equilibrium point by 4 sec.

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Analysis and optimization of pressure reducing and desuperheating system in thermal power plant

Analysis and optimization of pressure reducing and desuperheating system in thermal power plant

The lower the value for the cavitation index, the more likely cavitation will occur. As a rule of thumb, From the above equation it is clear that if the downstream pressure is lowered the cavitation index is increased and hence the cavitation is avoided in the application. Hence the pressure differential has to be low in order to avoid cavitation. So, the best possible solution is the staged pressure drop that can be achieved by using two valves in series.

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Financial Flexibility as a Phenomenon of Manifestation of Flexibility of the Financial System at the Micro-level

Financial Flexibility as a Phenomenon of Manifestation of Flexibility of the Financial System at the Micro-level

of Flexibility of the Financial System at the Micro-level The aricle considers inancial lexibility of economic subjects in the context of speciic features of manifestaion of this property at the micro-level of the inancial system. It generalises various theoreical approaches to understand- ing the essence of the inancial lexibility in the context of moives of its for- maion, sources and instruments of realisaion. It speciies criteria of inancial lexibility: manoeuvrability, eiciency and economy. It studies interrelaion between the inancial lexibility and inancial restricions at the micro-level and, consequently, factors that determine them: capital market imperfecion, development level and structure of the inancial system, cyclicity of economy, and company characterisics (including inancial architecture). The aricle describes their disinguishing features. It states that apart from maintaining the inancial lexibility during formaion of money reserves and debt load re- source the companies can be guided by other moives. It ofers classiicaion of types of inancial lexibility based on the sources and goals of formaion, inluence upon the inancial potenial, stages of reproducion of inancial re- sources, the instruments used, engaged elements of the inancial mechanism, stages of the business cycle and types of the used inancial resources. Key words: inancial lexibility, micro-level of the inancial system, inancial restricions, capital structure, inancial development, inancial market imper- fecion.
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Quality control of cast brake discs

Quality control of cast brake discs

Permanent and high quality products are essential for modern automotive industry. Investigations for improvement quality of vehicles elements are right materials selection and analysis of abrasive wear. Therefore, we can increase wear resistance materials and eliminate factors accelerating wear resistance. Brake disc operates in especially hard condition work. They must be resistant both against the thermal fatigue and abrasion wearing (at dry friction) as well as against seizing, corrosion and mechanical load [1].

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Markov approach to evaluate the availability simulation model for power generation system in a thermal power plant ,

Markov approach to evaluate the availability simulation model for power generation system in a thermal power plant ,

The availability simulation model (Av.) for power generation system has been developed for making the availability analysis, hence performance evaluation, using Markov concept has been carried out. Markov modeling is based on the assumption that a system and its components can be in different states. A Markov model is so-called state space model and describes the transitions of one state to another. The flow of states for the system under consideration has been described in a transition diagram, as shown in Figure 1, which is logical representation of all possible state’s probabilities encountered during the failure analysis of power generation system. Further, the mathematical analysis is done to derive and solve the various differential equations associated with the transition diagram for obtaining the expression of availability simulation model (Av.).
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Applying Human Factors Engineering Program to the Modernization Project of NPP Control Room in accordance with U.S.NRC and KTA Regulations

Applying Human Factors Engineering Program to the Modernization Project of NPP Control Room in accordance with U.S.NRC and KTA Regulations

Many nuclear power plants (NPP) in the world are approaching 20 to 30 years of operation. With license renewal, even these plants still have at least 30 to 40 more years of operation life (IAEA, 2004). Therefore, the application of new generations of digital equipment in modernization and upgrading the automation systems, plant control rooms and local control stations has resulted from a complex combination of factors, including the degradation and obsolescence of analog electronic systems, the difficulty obtaining spare parts for such systems and the improved performance of human-system interface (HSI) functionality (Galleti, 1996). Additionally, IAEA (2010) emphasizes other reasons for this modernization, such as the reduction of operations and maintenance costs, the safety enhancement and the improvement of competitiveness.
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Effects of Segregation on Granulated NPK Sieving – a  case study/  Efeitos da segregação na peneiração granulada de NPK - um estudo de caso

Effects of Segregation on Granulated NPK Sieving – a case study/ Efeitos da segregação na peneiração granulada de NPK - um estudo de caso

Braz. J. of Develop., Curitiba, v. 5, n. 11, p.24824-24841 nov. 2019 ISSN 2525-8761 experiencing a higher feed rate from screens, impacting in the crushing efficiency thus increasing granulometry profile back to granulator from oversize discharge. The scalping screening system was producing 71.2% of the product between good product range (>2 mm to <4 mm – green highlight in Table 1), and that 25.6% of the mass fraction in the lower range of the granulometry (>1 mm to <2 mm) evidencing either that the recycle control was not playing any role in the granulation and that the screening system was working as a standard system, or particles were being broken in between two-surface screens and polishing screen. To cover all aspects of the production process, all the granulation parameters such as molar ratio in the pre-neutralizer, pH in different parts of the plant and moisture levels were investigated and showed to be under control and in normal ranges. The chain mills were checked for possible inefficiency, but no strong evidence could be identified that could impact on the process and still, the operators were not able to operate modulating control valve’s blade to reduce recycle particle size. It was necessary to have a more detailed sieve analysis using test sieves with opening of 4.00 mm, 2.86 mm, 2.50 mm, 2.00 mm, 1.18 mm, 1.00 mm, 0.50 mm. Samples were taken from both screening machines’ feed and product discharge ends for a better picture view of the situation. Results of sieve analysis of samples are shown in Table 2.
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Implementation of Self-Tuning Fuzzy PI Controller on DCS for Flow Control System

Implementation of Self-Tuning Fuzzy PI Controller on DCS for Flow Control System

Abstract —In case of changing a communication between field instruments and controller from analog signal into digital signal or of changing a model of plant, performance of controller is degraded because of the fixed controller parameters such as PID controller. To solve this problem, a self-tuning PID controller is proposed. One of a popular self- tuning method is self-tuning fuzzy. Many researchers have been presented the self-tuning fuzzy PID controller. In this paper, we present implementing of self-tuning fuzzy PI controller for flow control system. Both fuzzy and PI controller is implemented on distributed control system (DCS) as controller at which communication between field instruments and distributed control system is via both the analog input and output modules as analog signal in range of 4-20mA and digital signal as Profibus PA. The PI controller parameters, proportional gain and integral time, from auto-tuning method is used to control plant, flow control system, by using analog signal at which result shows that flow process variable reaches to flow set point. The same PI controller parameters is applied for PROFIBUS PA at which results shows that flow process variable oscillates because of effect of delay-time taken place from communication between field instruments and distributed control system.
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Protocol for Extreme Low Latency M2M Communication Networks

Protocol for Extreme Low Latency M2M Communication Networks

This dissertation focused on proposing an adaptation of the M2M H-NDMA protocol to provide URLLC for M2M services with power saving mechanisms. Chapter 2 char- acterized the existing enablers for URLLC as well as the significant access schemes and existing M2M MAC protocols, focusing on the characterization of the mission critical MACs. Chapter 3 described the new system and scenario considered in this dissertation for the M2M H-NDMA protocol and analyzed the changes needed to be made. With the new scenario of a DAS, it was found that the previous transmission power levels con- sidered in the previous version of the protocol were not adequate. Results showed that for guaranteeing reliability, the power gap should be, for a system up to 4BSs, of 20dB between NOMA power levels. Power control schemes were implemented, in order to try to reduce the delay and the EPUP, to comply to URLLC requirements. Results showed that the various power schemes tested performed similarly, and did not present a major improvement in delay or energy, although being able to guarantee reliability and a reason for it to happen could be due to the preamble overhead of the protocol. Finally, in this dissertation, the evolved M2M-HNDMA detailed algorithm was presented, along with a user guide to assist future users in the use of the simulator.
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Control of Hybrid System Using Multi-Input Inverter and  Maximum Power Point Tracking

Control of Hybrid System Using Multi-Input Inverter and Maximum Power Point Tracking

The dc/ac inverter will inject a sinusoidal current into the ac mains. The SPWM gate signals of switches M3 through M6 for producing sinusoidal ac current is generated by the DSP and the amplitude of the ac current is determined by the error signal of the measured dc bus voltage Vdc and Vdcref. If the measured dc bus voltage is lesser than the reference value, then the amplitude of the ac output current will be decreased in order to increase the dc bus voltage. On the other hand, if the dc bus voltage is higher than the reference one, then the amplitude of the ac output current will be decreased and at the same time, the dc bus voltage is regulated by the dc– ac inverter and the input-output power balance can be achieved.
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ANN BASED CONTROL PATTERNS ESTIMATOR FOR UPFC USED IN POWER FLOW PROBLEM

ANN BASED CONTROL PATTERNS ESTIMATOR FOR UPFC USED IN POWER FLOW PROBLEM

Basically, the UPFC control system can be divided functionally into two units concerning internal and external controls [1]. The internal control unit operates the two inverters so as to produce the commanded series injected voltage, and simultaneously draws the desired shunt real and reactive currents from the shunt inverter by controlling a proper output voltage at its AC terminals. On the other hand, the external control unit is responsible for generating the proper voltage commands for the internal control unit so as to regulate the controlled system variables, real and reactive power flows; to meet the desired values. However, the process in the external control unit is normally a tedious task; it takes a long time to solve a set of non-linear equations so as to get the input reference voltages requested by the internal control unit of the UPFC.
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J. Aerosp. Technol. Manag.  vol.7 número1

J. Aerosp. Technol. Manag. vol.7 número1

One of the biggest concerns of industry is the improvement of manufacturing eiciency in order to obtain minimization of production costs, maximization of production rate and maximization of production accuracy, etc.. In aeronautic industry, these are main concerns as well, especially with the prediction that the number of new airplanes will grow by more than 27.000 until 2025 compared to 2005 (Klocke et al., 2012). his prediction leads to an economic pressure on the aviation industry manufacturers, and the search for optimization in the manufacturing processes becomes necessary. For the aircraft components construction, several manufacturing processes are used, and machining stands between the most applied ones. According to Aurich et al. (2011), during machining process, high mechanical and thermal loads occur at the cutting tool, causing tool failure. Due to this, optimization at the cutting tool represents an advantageous possibility. Cutting tools have been optimized by improvements of cutting tool material, coating system and tool macrogeometry. however, cutting tools with higher qualities regarding material removal rates, chip removal of hard-to-machine materials and tool life are each day more requested.
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Analysis of natural radionuclides in coal, slag and ash in coal-fired power plants in Serbia

Analysis of natural radionuclides in coal, slag and ash in coal-fired power plants in Serbia

[2]. Combustion of coal thus enhances natural radiation in the vicinity of the coal- fired power plants by release of these radionuclides and their daughters into the surrounding ecosystem. Unlike most of the nuclear and hydroelectric power plants, coal- fired power plants in Serbia are generally located in areas which are thickly populated and hence, the environmental impact and health impact experienced by the neighboring population is significant.

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Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Optimisation of the turbine mixer’s performance during the preparations of the sand mix still remains an important issue as this mixer type is now in widespread use. Monitoring techniques of the system sand mixing include the analysis of electric power demand by the mixer’s drive based on measurements of power components. This study shows the operating characteristics of turbine mixers as the function of electric power demand by the drive system.

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Improved Predictive Power Control Algorithms to Increase CDMA System Capacity

Improved Predictive Power Control Algorithms to Increase CDMA System Capacity

CDMA power control is more important on the uplink direction compared to that on the downlink because uplink signals consist of all users from different locations (different path losses), while the downlink signals originate from the same base station and arrive at mobile stations with the same power level. Our previous study [2] shows that practical power control is imperfect in that it is affected by many factors; such as power updating rates and step size, channel estimation error, feedback transmission error, and feedback delay. This paper also shows that the effect of feedback delay on the performance of power control is the most serious. Therefore, prediction-based algorithms are employed to eliminate the effect of feedback delay. In a prediction-based algorithm, the channel state is predicted either through the measurement of signal strength or the signal-to-interference ratio (SIR) as the control parameter for power control algorithms.
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Analysis of Photovoltaic Fed Partially Isolated Three-Port Full Bridge Converter with the Centralised Controller

Analysis of Photovoltaic Fed Partially Isolated Three-Port Full Bridge Converter with the Centralised Controller

Abstract— In this paper analysis of an efficient topology of the three-port full bridge dc-dc converter is presented. This topology is promising with the view points of centralised control, compact design as it is capable of interfacing many numbers of ports with less number of switches, low cost, simple and fast power flow management with reduced conversion process. In a stand-alone system this topology is used to interface renewable energy sources and the load along with the energy storage device. Thus the proposed topology interfaces three ports: as one source port, one bidirectional storage port and an isolated output port. The key feature of this converter is that it performs buck-boost operation on the input port side to obtain power balance in the system with the centralised controller. The centralised controller was implemented by using proportional Integral (PI) controller. Such that it is used to track maximum power from the Photovoltaic (PV) system and to regulate output voltage by controlling the charging and the discharging characteristics of the battery. Zero voltage switching (ZVS) is also achieved in all the switches by using the energy stored in the leakage inductance of the transformer, output filter inductance and capacitance.
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