Load Sharing in High-Reliability AC-DC and DC-DC Converter Power Systems

1994 ◽  
Author(s):  
A. S. Kislovski
Keyword(s):  
Power Systems ◽  
High Reliability ◽  
Load Sharing

Reliability analysis and state transfer scheduling optimization of degrading load-sharing system equipped with warm standby components

2021 ◽  
pp. 1748006X2110017
Author(s):  
Sheng-Jia Ruan ◽  
Yan-Hui Lin
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
High Reliability ◽  
Quadrature Rule ◽  
Load Sharing ◽  
Measurement Information ◽  
Model Parameters ◽  
Scheduling Optimization ◽  
State Transfer ◽  
Warm Standby

Standby redundancy can meet system safety requirements in industries with high reliability standards. To evaluate reliability of standby systems, failure dependency among components has to be considered especially when systems have load-sharing characteristics. In this paper, a reliability analysis and state transfer scheduling optimization framework is proposed for the load-sharing 1-out-of- N: G system equipped with M warm standby components and subject to continuous degradation process. First, the system reliability function considering multiple dependent components is derived in a recursive way. Then, a Monte Carlo method is developed and the closed Newton-Cotes quadrature rule is invoked for the system reliability quantification. Besides, likelihood functions are constructed based on the measurement information to estimate the model parameters of both active and standby components, whose degradation paths are modeled by the step-wise drifted Wiener processes. Finally, the system state transfer scheduling is optimized by the genetic algorithm to maximize the system reliability at mission time. The proposed methodology and its effectiveness are illustrated through a case study referring to a simplified aircraft hydraulic system.

scholarly journals A 4-stroke spark-ignition engine fuelled with low quality gas

2017 ◽  
Vol 168 (1) ◽  
pp. 122-124
Author(s):  
Marek BRZEŻAŃSKI ◽  
Michał MARECZEK ◽  
Marek SUTKOWSKI ◽  
Wojciech SMUGA
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
High Efficiency ◽  
High Reliability ◽  
Calorific Value ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
University Of Technology ◽  
Product Gas ◽  
Methane Number

Huge amount of by-products is still considered as waste and is simply disposed, for example by-product gas is usually flared. Political and social pressure to reduce air pollution and national needs for energy security make these waste fuels interesting for near-future power generation. Unfortunately most of these waste fuels, even when liquefied or gasified, have very low quality and can hardly be used in high-efficiency power systems. Among main challenges are low calorific value and composition fluctuation. Additionally very often there is a high content of sulphur, siloxanes, tars, etc., which have to be removed from the fuel. Modern 4-stroke gas engines designed for power generation applications provide very high efficiency, high reliability and availability. Unfortunately, these gas engines require high quality fuel with stable composition. Horus-Energia together with Cracow University of Technology developed a novel gas supply system HE-MUZG that can adapt to current gas quality and change engine settings accordingly.This article will present results from the HE-MUZG system tests on modern 4-stroke spark-ignition gas engine. Tests focus on low quality gas, such as gas with low calorific value, gas with very low methane number and gas with very big variations of calorific value. Test results compared with performance of that engine in the original configuration show huge improvements. Moreover the HE- MUZG system is easy to implement in commercial gensets.

Gas Turbine Power Systems for Military Tracked Vehicles

1983 ◽  
Author(s):  
Geoffrey D. Woodhouse
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Waste Heat ◽  
High Reliability ◽  
Turbine Engines ◽  
Tracked Vehicles ◽  
Turbine Engine ◽  
Response Characteristics ◽  
Air Inlet

The gas turbine engine has been examined as a power plant for military tracked vehicles for over 30 years. Advocates have stressed the potentially high power density and high reliability as factors in favor of the turbine. Several turbine engines have been evaluated experimentally in military tracked vehicles resulting in a better understanding of such aspects as response characteristics and air inlet filtration requirements. Moreover, although the small volume and light weight of aircraft derivative gas turbines have certain virtues, it generally has been concluded that some form of waste heat recuperation is essential to achieve an acceptable level of fuel consumption, despite the increased weight and volume incurred. The selection of the AVCO Lycoming AGT1500 recuperated gas turbine as the power unit for the U.S. Army new M1 “Abrams” main battle tank was a major milestone in the evolution of gas turbine engines for tank propulsion.

scholarly journals Modified Voltage Control Law for Low Frequency Railway Power Systems

2017 ◽  
Author(s):  
John Laury ◽  
Lars Abrahamsson ◽  
Math Bollen
Keyword(s):  
Power Systems ◽  
Reactive Power ◽  
Low Frequency ◽  
Voltage Control ◽  
Load Sharing ◽  
Alternative Methods ◽  
Control Law ◽  
Public Power ◽  
Negative Impacts ◽  
Railway Power Systems

In today’s Swedish and Norwegian low frequency railway power system the voltage at a converter is controlled such that its voltage will drop with increased reactive power output. However, for low frequency railways the influence of active power on voltage is larger compared to public power systems and alternative methods are interesting to investigate. This paper presents a modified voltage control law for increased load sharing between converter stations and reduce the risk for converter overload in low frequency railways power systems. The modified voltage control law is derived mathematically and tested with different droops for two case studies. The results confirms the increased load sharing between the converter stations. The results are analysed and discussed; ideas are presented to counteract some of the negative impacts of the modified voltage control law.

scholarly journals Development of high-performance KrF and Raman laser facilities for inertial confinement fusion and other applications

1993 ◽  
Vol 11 (2) ◽  
pp. 331-346 ◽  
Author(s):  
M.J. Shaw ◽  
B. Edwards ◽  
G.J. Hirst ◽  
C.J. Hooker ◽  
M.H. Key ◽  
...  
Keyword(s):  
Power Systems ◽  
Inertial Confinement Fusion ◽  
High Performance ◽  
Short Pulse ◽  
High Reliability ◽  
Laser System ◽  
Raman Laser ◽  
Current Status ◽  
Inertial Confinement ◽  
Laser Amplifiers

This article describes the current status of the KrF development programme based on the Sprite laser system at the Rutherford Appleton Laboratory. High reliability and high shot rate have been demonstrated. Using a unique KrF-pumped Raman laser architecture, beam brightness exceeding 2×1019 Wcm-2 sterad-1 giving a focussed intensity >5 ×1017 Wcm-2 has been achieved. The development of transform-limited short-pulse oscillators is shown to be of importance in avoiding spectral broadening in air propagation of high-intensity beams. Beam smoothing of KrF beams in a multiplexed configuration has been demonstrated for the first time. The technique of echelon-free induced spatial incoherence has been shown to produce smooth intensity distributions in the far field, which remain essentially unchanged on amplification. The development of pulsed-power systems capable of exciting multikilojoule laser amplifiers for the next phase of development, the Supersprite system, is briefly discussed.

scholarly journals Accuracy Improvement for the Determination of Parameters and Voltage Drops in Busbars, Considering the Networks Power Factor

2021 ◽  
pp. 37-52
Author(s):  
Mihail Kotsur ◽  
◽  
Yulia Yarymbash ◽  
Dmitry Bezverkhnya ◽  
Igor Kotsur ◽  
...  
Keyword(s):  
External Field ◽  
Power Systems ◽  
Power Factor ◽  
Voltage Drop ◽  
High Reliability ◽  
Accurate Estimation ◽  
Estimation Of Parameters ◽  
Voltage Drops ◽  
Network Power

The power systems must satisfy the requirements both for high reliability and efficiency. The main component of the shop power supply systems is a busbar. There have been certain engineering techniques for the estimation of parameters, voltage and power losses, characterized by having a high error. Other methods have had a significant calculation efficiency, but without allowing the voltage drop to be determined as a function of the network power factor. Therefore, the aim of this work was to develop an approach that allowed an accurate estimation of the parameters and voltage drop in trolleys, depending on the network power factor. This approach was based on the decomposition of the electromagnetic processes in a trolley busbar by connecting one phase to estimate both the resistance and reactance in the absence of the external field, and two phases to estimate the resistance and reactance in the presence of the external field. The most significant results were the determination of the resistances and reactance, depending on the frequency of the current harmonics and the distance between the phases of the busbar. The dependences were proposed to estimate the resistance and reactance for the corresponding phases and current harmonic. The analytical expression of the ratio between the voltage drop in trolleys and the power factor of the network was obtained. The testing data confirmed the high accuracy of the proposed approach. The significance of the results composed a more precise determination of the parameters and voltage drops in each phase of trolleys, irregardless of their location, number, shape, as well as the phase currents’ non-symmetry, wasting no time for the field simulation

scholarly journals Electrical Machines and Power Electronics for Starter-Generators in More Electric Aircrafts: A Technology Review

2019 ◽  
Author(s):  
Jonas Kristiansen Nøland ◽  
Matteo Leandro ◽  
Jon Are Suul ◽  
Marta Molinas ◽  
Robert Nilssen
Keyword(s):  
Power Systems ◽  
High Reliability ◽  
Power Conversion ◽  
Integrated System ◽  
Electrical Machines ◽  
Electronic Systems ◽  
Power Electronic ◽  
Electric Aircraft ◽  
Potential Benefits ◽  
Open Issues

<div>Safety-critical power conversion systems play a major role in the paradigm shift towards more electric aircraft (MEA) architectures. This paper reviews the electrical machines and their power electronic systems that are currently competing in the application of integrated starter-generators (S/Gs) in MEA power systems. Motivated by the strict requirements of sufficient electrical starting capability, super-high power density and ultra-high reliability, additional considerations on the overall system design are necessary, including the power electronic converters (PECs) and integrated thermal designs. These aspects are discussed not only in the light of their many benefits but also of the challenges introduced by the continuous advancements and emerging innovations in the power conversion technology. In achieving the MEA goals and capitalize on all potential benefits, optimization-based design approaches will be necessary, where the aggregation of electric machines, PECs and the aircraft grid is considered as an integrated system to be optimized. This review highlights the importance of these aspects and offers a view on future perspectives and open issues.</div>

scholarly journals Impact of Lightning Impulse on Electric Field Stress of Spacer in Single Phase Gas Insulated Busduct

2019 ◽  
Vol 8 (2S3) ◽  
pp. 837-842
Keyword(s):  
Electric Field ◽  
Power Systems ◽  
Triple Point ◽  
High Reliability ◽  
Moderate Pressure ◽  
Field Stress ◽  
Cone Type ◽  
Lightning Impulse ◽  
Reliable Power Supply ◽  
The Impact

During the last two decades, for reliable power supply, GIS have found a broad range of application in power systems because of their high reliability, easy maintenance, small space requirement, etc. Gas insulated sub-stations employs a superior dielectric gas, SF6 at moderate pressure for phase to phase and phase to ground insulation. Several troubles and system outages in GIS have been reported world-wide due to insulation failures which resulted in the intensification of electric field along the spacer surface and especially at the triple point electrode – spacer – gas. Hence, it was required to reduce the rate of insulation failure. In this work, Conventional cone type spacer geometry is taken for which field study has been done. Electric field stresses developed by the cone type spacer on the surface of the spacer and also at the triple junction is determined. It is found that the electric field stress at the surface of the spacer is maintained uniform, the electric field stress at the critical junctions formed by the conductor, solid insulator and SF6 gas is not maintained at minimum value. Metal inserts are considered as a means to reduce the stress at the triple point junction. The impact of Lightning Impulse on the Electric Field Stress along the spacer is carried and the reduction of stress is mitigated with the insertion of Metal Inserts.

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