scholarly journals Automatic Asynchronous Drive Efficiency Control with Soft-Starter Function

2021 ◽  
Vol 26 (2) ◽  
Author(s):  
Oleksandr R. Kovalov ◽  
Olha Yu. Nesterova ◽  
Valerii A. Borodai
Keyword(s):  
Automatic System ◽  
Capital Investment ◽  
Variable Load ◽  
Minimum Capital ◽  
Soft Starter ◽  
Start Up ◽  
Conversion System ◽  
Efficiency Control ◽  
Load Schedule ◽  
Step Control

Digital models of pulse-width voltage control system with step switching of power supply frequency and automatic control of induction motor are developed and built, the recommendations on the algorithm of their control and circuit solution for the implementation of smooth start modes, nominal and frequency-step control from low-power -variable load schedule are provided. The novelty of the work lies in the substantiated sequence and conditions of control and originality of the structure of the automatic system of smooth start-up and activation of the effective mode of the asynchronous drive. The introduction of the conversion system will create an automatic system of asynchronous drive, due to which it is possible to achieve energy conservation at all levels of the electromechanical system, with minimum capital investment.

Experimental Study On Preparation and Heat Transfer of Nickel-Based Ammonia LHP

2021 ◽  
Author(s):  
Wenjing Ning ◽  
Jun Ma ◽  
Cheng Jiang ◽  
Yingwen Cao ◽  
Chunsheng Guo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Pore Size ◽  
Thermal Load ◽  
Physical Property ◽  
Variable Load ◽  
Pressing Pressure ◽  
Cold Pressing ◽  
Porous Wick ◽  
Start Up

Abstract The loop heat pipe (LHP) is a passive heat sink used in aerospace and electronic devices. As the core component of the LHP, the physical property parameters of porous wick directly affect the overall performance of the LHP. In this paper, the performance of the porous wick is improved by adjusting the pore size, thereby improving the performance of the LHP. The nickel-based double-pore porous wicks are prepared by T225 nickel powder and NaCl particles, and the pore size of the porous wicks can be changed by different cold pressing pressures (30KN, 40KN, 50KN, 60KN). The effects of different cold pressing pressures on the porosity, permeability, and other physical property parameters are studied when the ratio of pore former is 20wt%. In the end, we select the cold pressing pressure of 30KN to prepare the porous wick of the LHP. Then the effects of constant load and variable load of the heat transfer performance under different placement angles are studied. The results show that the heat load range is 10W-100W, the minimum evaporator thermal resistance is 0.424K/W, and the minimum LHP thermal resistance is 0.598K/W. When ß=0°, there is a "backflow" phenomenon at the initial stage of low thermal load. With the increase of thermal load, the "backflow" duration decreases until it disappears, and the start-up time becomes shorter. The thermal resistances of the evaporator and LHP decrease and then increase. When ß= -90°, the LHP appears "reverse start-up" phenomenon.

Closed loop glycol systems—experience from BP's Shah Deniz gas export project and advances in technology

2008 ◽  
Vol 48 (1) ◽  
pp. 249
Author(s):  
Anthea Condilis ◽  
Jon Even Vale ◽  
Tor-Erik Stranna
Keyword(s):  
Capital Investment ◽  
Hydrate Formation ◽  
Careful Consideration ◽  
The Caspian Sea ◽  
Gas Field ◽  
Process Systems ◽  
Start Up ◽  
Regeneration Unit ◽  
Pre Treatment ◽  
Monoethylene Glycol

Aker Kværner Process Systems (AKPS) in Norway provided the monoethylene glycol (MEG) regeneration unit for BP’s Shah Deniz Gas Export Project. Design by AKPS began in 2003. The MEG unit was installed by May 2006 at the Sangachal Terminal outside Baku, Azerbaijan. MEG injection was selected to prevent hydrate formation in the pipelines conveying gas and condensate from the Shah Deniz gas field in the Caspian Sea to the onshore terminal. This MEG unit employs full stream reclamation, where reclamation (salts removal) is integrated into the reconcentration process (water removal). The commissioning of this MEG unit by BP was completed by November 2006 and the start-up phase was complete by May 2007. The chemistry of the MEG system was evaluated by AKPS during this period. Improved understanding of the chemistry has led to advances in the design of subsequent MEG units by AKPS. Two fundamental improvements are proposed for future MEG unit designs. One fundamental improvement is the use of a slip stream reclaimer for salts removal. Consequently, the reconcentration operation is not dependent on the operation of the reclaimer, greatly improving the availability and flexibility of the system. Another consequence of slip stream reclamation is the significant reduction in size of the reclaimer, and with this comes reduced capital investment and improved maintainability. The second fundamental improvement is the inclusion of pre-treatment operations for controlled precipitation and removal of low solubility salts originating from formation water and pipeline corrosion. Together with careful consideration of chemical additions to facilitate this precipitation, this design improvement is expected to prevent scaling in the downstream equipment. The function of the reclaimer is primarily to remove high solubility salts (chlorides). Improvements in the design of MEG regeneration units that are described above and the motives behind them are explored in detail.

Analysis of the start-up and variable load operation of a combined cycle power plant for off-grid mines

2017 ◽  
Vol 13 (3/4) ◽  
pp. 330 ◽  
Author(s):  
Alberto Romero ◽  
Ricardo Chacartegui ◽  
José Antonio Becerra ◽  
Monica Carvalho ◽  
Dean L. Millar
Keyword(s):  
Power Plant ◽  
Combined Cycle ◽  
Variable Load ◽  
Combined Cycle Power Plant ◽  
Start Up

Syndication in Venture Capital Investment in India: An Empirical Study

2017 ◽  
Vol 3 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Sarita Mishra ◽  
Dinabandhu Bag
Keyword(s):  
Venture Capital ◽  
Capital Investment ◽  
Control Mechanism ◽  
Fiscal Year ◽  
Venture Capital Investment ◽  
The Past ◽  
Efficient Management ◽  
Common Trend ◽  
Start Up ◽  
Start Ups

Indian economy witnessed high inflow of capital for start-ups in current fiscal year through venture capital (VC) investment. From different Indian VC deals, it is evident that VC investors prefer to invest jointly. In other words, joint investment or co-investment or syndication is a common trend in Indian VC industry. VCs adopt this strategy to minimise their future uncertainties as a part of the control mechanism. In this study, an attempt is made to find out different determinants of this syndication strategy. The samples taken in this study are retrieved from Venture Intelligence database for the period 2005–2014. The data are analysed through linear regression and binomial logistic regression. Two empirical models have been developed. The derived models validate different control variables and deal with specific characteristics to comprehend the rationale of syndication mechanism. The findings of the study indicate that the past experience and the number of industry exposure of a VC in IT and ITES industry are the major predictors for a syndication decision. Subsequently, the precautionary investment attributes like number of investment round, stage funding, etc. draw the interest of potential co-investors in a syndicated deal. Syndication mechanism benefits the VC investors through sharing of risk of investment in a start-up and preparing them for a successful exit. Extant literature supports the results as Indian VC investors prefer to share the risk profile of a start-up business and adopt different risk diversion mechanisms to attract co-investors in the deal. Furthermore, the joint investment by investors drag more funding amount and also create more human capital for efficient management of the investment in VC-backed portfolio.

Analysis of the start-up and variable load operation of a combined cycle power plant for off-grid mines

2017 ◽  
Vol 13 (3/4) ◽  
pp. 330 ◽  
Author(s):  
José Antonio Becerra ◽  
Monica Carvalho ◽  
Dean L. Millar ◽  
Ricardo Chacartegui ◽  
Alberto Romero
Keyword(s):  
Power Plant ◽  
Combined Cycle ◽  
Variable Load ◽  
Combined Cycle Power Plant ◽  
Start Up

scholarly journals Simulations of a flexible 100 kWel PEM Fuel Cell power plant for the provision of grid balancing services

2021 ◽  
Vol 238 ◽  
pp. 04003
Author(s):  
Elena Crespi ◽  
Giulio Guandalini ◽  
Stefano Campanari
Keyword(s):  
Fuel Cell ◽  
Power Plant ◽  
Power Plants ◽  
Maximum Load ◽  
Variable Load ◽  
Renewable Energy Resources ◽  
Continuous Growth ◽  
Warm Up ◽  
Start Up ◽  
Flexible Resources

The continuous growth of non-programmable renewable energy resources penetration leads to unpredictable oscillations of the net load faced by dispatchable power plants, hindering the reliability and stability of the electric grid and requiring additional flexible resources. The EU project GRASSHOPPER focuses on MW-scale Fuel Cell Power Plant (FCPP) based on low temperature PEM technology. The project aims to setup and demonstrate a 100 kWel PEM FCPP, flexible in power output and designed to provide grid support. This work presents a dynamic simulation model of the FCPP, developed to simulate plant flexible operation and identify the best management strategy, aiming at optimizing the efficiency while reducing the degradation rate. Cold start up simulations, according to a warm-up procedure limiting stack degradation, result in a time to operation equal to 26 minutes. A sensitivity analysis is performed to determine which parameters mostly influence the warm-up duration, showing that it is possible to reduce start-up time substantially (e.g. down to 3 minutes with component preheating). On the other hand, simulations at variable load along the entire range of operation (20-100 kWel), according to grid balancing requirements, show that the plant is able to ramp up and down between the minimum to the maximum load in about 40 seconds.

Generation and Control of Electricity in HTGR Helium Turbine Plant

2002 ◽  
Author(s):  
K. N. Pradeep Kumar ◽  
A. Tourlidakis ◽  
P. Pilidis
Keyword(s):  
South Africa ◽  
Power Plants ◽  
Transient Stability ◽  
Power Conversion ◽  
Engineering Project ◽  
Turbine Plant ◽  
Start Up ◽  
Conversion System ◽  
And Control ◽  
Operational Aspects

This paper analyses the operational aspects of a temperature Gas Reactor using direct Helium Cycle for power conversion. As an engineering project, the complexity in the operational aspects of HTGR’s is more severe than that of its design and installation. Its transient stability is achieved in a different manner compared to conventional power plants. An efficient and steady operation is a must for its successful realization. The paper looks into the start-up, shutdown and part load performance of helium power conversion system. The study is based on an ongoing developmental project in South Africa called Pebble Bed Modular Reactor (PBMR).

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