Optimizing Electrical Protection for Medium Voltage Controller Lineup to Improve Liquids Pipelines Operation Reliability and Safety

2018 ◽  
Author(s):  
Ting Yu ◽  
Tushar Chaitanya
Keyword(s):  
Proximity Effect ◽  
Incident Energy ◽  
High Speed ◽  
Large Scale ◽  
Failure Modes ◽  
Partial Discharge ◽  
Light Detection ◽  
Medium Voltage ◽  
Voltage Controller ◽  
The Impact

MV (Medium Voltage) controller lineup electrical protection is crucial in protecting the equipment from large scale damage upon the occurrence of an electrical fault, reducing the time to restore power, thereby minimizing the impact to liquids pipelines operation. The paper discusses typical electrical failure modes that may occur in MV controller lineups, and demonstrates practical relaying engineering techniques that enable fast and effective fault clearing. Electrical faults in the MV controller lineup are often arcing type, commonly involve ground. Mitigating arc hazards in MV Class E2 controller lineups has traditionally been challenging without sacrificing the protection selectivity. As the paper demonstrates, a relaying scheme with the combined use of high-speed light-sensing and overcurrent detection will effectively mitigate the incident energy, while maintaining the protection selectivity for non-arcing overcurrent events. For new MV controller lineups, in addition to the “high-speed light detection and fault interruption”, zone-selective interlocking (ZSI) can also be a practical solution in improving relay protection speed, thus reduce the chance of severe arc flash occurrences. ZSI is particularly effective for fault occurrences on the line side of the phase CTs, busways or main incoming circuits. The ZSI scheme can be implemented on both Class E2 and circuit breaker (VCB) type MV controller lineups, however, with slightly different trip logic due to the limited fault clearing capability of the contactor. Although there are multiple contributing factors, the direct causes of electrical failures in MV controller lineup are commonly related to improper power cable installation and handling, potentially leading to premature insulation breakdown due mainly to the proximity effect and/or partial discharge. Inadequate cable separation and prolonged fault trip delay can increase the possibility of arcing fault occurrence. This can usually be mitigated through appropriate cable spacing, adequate conductor insulation, and optimized fault detection schemes. The paper provides overviews of the mechanisms of proximity effect and partial discharge propagation, and the modern relaying approaches for accurate fault type discrimination and facilitating fast fault interruption. Two case studies are provided in the paper as an aid in understanding the electrical fault mechanism originated from cable insulation failure, demonstrating the incident energy reduction before and after the implementation of high-speed light detection and fault interruption solutions on an existing MV controller lineup.

Research of Large-Scale Offshore Wind Farm Collection System Short Circuit Equivalent Network

2013 ◽  
Vol 448-453 ◽  
pp. 1732-1737
Author(s):  
Liu Bin ◽  
Hong Wei Cui ◽  
Li Xu ◽  
Kun Wang ◽  
Zhu Zhan ◽  
...  
Keyword(s):  
Large Scale ◽  
Wind Farm ◽  
Short Circuit ◽  
Short Circuit Current ◽  
System Optimization ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Collection System ◽  
Medium Voltage ◽  
The Impact

This paper analyses the characteristics of large-scale offshore wind farm collection network and the impact of the medium voltage collection system optimization,while from the electrical technology point,it proposes the short circuit current of the collection network computational model and algorithms,based on the principle of equivalent circuit.Taking a wind power coolection system planned for a certain offshore wind farm planning for example, the validity of the model and algorithm is verified.

CAN INFRASTRUCTURE DEVELOPMENT ALLEVIATE MULTIDIMENSIONAL POVERTY? — EVIDENCE FROM CHINA

2021 ◽  
pp. 1-34
Author(s):  
YONGBO GE ◽  
YUEXIAO ZHU ◽  
WENQIANG ZHANG ◽  
XIAORAN KONG
Keyword(s):  
Poverty Alleviation ◽  
Capital Accumulation ◽  
High Speed ◽  
Large Scale ◽  
Multidimensional Poverty ◽  
Infrastructure Development ◽  
Public Infrastructure ◽  
Regional Heterogeneity ◽  
The Impact ◽  
Insight Into

We investigate the impact of the construction of large-scale high-speed railways (HSRs) on regional multidimensional poverty in China. We find that the opening of HSRs can reduce this poverty indicator. This association is robust to a series of checks. Regarding the mechanisms, the opening of HSRs can improve regional accessibility, enhance local tourism, increase labor mobility and promote human capital accumulation, which alleviates multidimensional poverty. Further research indicates the regional heterogeneity of the effect. This research supplements poverty alleviation theory from the perspective of public infrastructure and offers insight into how multidimensional poverty arises and how it can be alleviated.

Design, Simulation and Testing of Overpack Encapsulation Vessels

2012 ◽  
Author(s):  
A. Towse ◽  
J. Dodds
Keyword(s):  
Pressure Vessel ◽  
High Speed ◽  
Failure Modes ◽  
Inner Product ◽  
Central Position ◽  
Video Footage ◽  
Rule Approach ◽  
The Moment ◽  
Explicit Dynamic ◽  
The Impact

The paper presents an overpack designed to contain nuclear product cans which may become pressurised or contaminated. The overpack provides a protective barrier to an inner product can, and due to the possibility of leakage of gas from the contents, the overpack must also function as a pressure vessel. Furthermore, the overpack is required to provide physical protection to the inner can and proof of containment was therefore necessary under a number of different impact scenarios, both pre-pressurised and also with the simulation of pressurisation at the moment of impact. Additionally, the inner product can was to be maintained in a central position during the deceleration at impact. This paper focuses on the analytical design and substantiation of the impact of the system which was performed using an explicit dynamic solver for a number of impact orientations. The design of the overpack to satisfy the relevant pressure vessel Code are not discussed in detail. The potential failure modes of the overpack during impact were assessed and design improvements made over a number of iterations. Following completion of the design and simulation phase, prototypes were built and tested to verify the engineering design and analysis. The testing showed that simulation driven design in conjunction with a pressure vessel design by rule approach was successful in creating a solution for the product can encapsulation. A comparison between the analytical simulation and high-speed video footage of the testing was also made.

scholarly journals Experimental Study on the Skidding Damage of a Cylindrical Roller Bearing

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4075 ◽  
Author(s):  
Qing Zhang ◽  
Jun Luo ◽  
Xiang-yu Xie ◽  
Jin Xu ◽  
Zhen-huan Ye
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Failure Modes ◽  
Roller Bearing ◽  
Weight Ratio ◽  
Operating Conditions ◽  
Roller Bearings ◽  
Light Load ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

As large-scale rotating machines develop toward high rotating speed and high power–weight ratio, skidding damage has become one of the major initial failure modes of cylindrical roller bearings. Therefore, understanding the skidding damage law is an effective way to ensure the safety of machines supported by cylindrical roller bearings. To realize the skidding damage, a high-speed rolling bearing test rig that can simulate the actual operating conditions of aviation bearings was used in this paper, and the skidding damage dynamic behaviors of cylindrical roller bearings were investigated. In addition, to ensure the accuracy of the obtained skidding damage mechanism, the cylindrical roller bearing was carefully inspected by microscopic analysis when the skidding damage occurred. Out results show that instantaneous increases in friction torque, vibration acceleration, and temperature are clearly observed when the skidding damage occurs in the cylindrical roller bearing. Furthermore, under the conditions of inadequate lubrication and light load, the critical speed of skidding damage is rather low. The major wear mechanisms of skidding damage include oxidation wear, abrasive wear, and delamination wear. The white layers are found locally in the inner ring and rollers under the actions of friction heat and shear force.

scholarly journals Stochastic Risk Assessment with a Lagrangian Solution for the Optimal Cost Allocation in High-Speed Rail Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jing Zuo ◽  
Jianwu Dang ◽  
Min Lyu
Keyword(s):  
Risk Assessment ◽  
High Speed ◽  
Large Scale ◽  
Cost Allocation ◽  
Optimal Allocation ◽  
High Speed Rail ◽  
Maintenance Costs ◽  
Optimal Cost ◽  
The Impact ◽  
Stochastic Risk

In large-scale high-speed rail networks (HSRNs), the occurrence of occasional malfunctions or accidents is unavoidable. The key issue considered in this study is the optimal allocation of the maintenance costs, based on the stochastic risk assessment for HSRNs. Inspired by the theoretical risk evaluation methods in the complex network, three major factors, including the local effects, global effects, and component self-effects are considered in the process of assessing the impact on the network components (nodes or lines). By introducing the component failure occurrence probability, which is considered to be an exponential function changing with the component maintenance costs, a feasible stochastic risk assessment model of the HSRNs together with the component impact assessment is proposed that can better unify the impact assessment of both the high-speed rail stations and railways. An optimal allocation algorithm based on a Lagrangian relaxation approach is designed. Correspondingly, the optimal cost allocation scheme can be determined using the algorithm to eliminate the various HSRN risks under the given costs. Furthermore, a real-world case study of the HSRNs in eastern China is illustrated. Compared with the genetic algorithm, the simulation shows that the approach can solve the optimal cost allocation problem to more effectively reduce the risks of large-scale HSRNs in practice.

scholarly journals Dynamic damage in carbon-fibre composites

2016 ◽  
Vol 374 (2071) ◽  
pp. 20160018 ◽  
Author(s):  
N. K. Bourne ◽  
S. Parry ◽  
D. Townsend ◽  
P. J. Withers ◽  
C. Soutis ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
High Speed ◽  
Failure Modes ◽  
Structural Integrity ◽  
High Speed Photography ◽  
Compression Phase ◽  
Impact Surface ◽  
Fibre Composites ◽  
The Impact ◽  
Carbon Fibre Composites

The Taylor test is used to determine damage evolution in carbon-fibre composites across a range of strain rates. The hierarchy of damage across the scales is key in determining the suite of operating mechanisms and high-speed diagnostics are used to determine states during dynamic loading. Experiments record the test response as a function of the orientation of the cylinder cut from the engineered multi-ply composite with high-speed photography and post-mortem target examination. The ensuing damage occurs during the shock compression phase but three other tensile loading modes operate during the test and these are explored. Experiment has shown that ply orientations respond to two components of release; longitudinal and radial as well as the hoop stresses generated in inelastic flow at the impact surface. The test is a discriminant not only of damage thresholds but of local failure modes and their kinetics. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

Modelling the Impact of Magnetic Storms on Planetary Environments

2021 ◽  
Author(s):  
Souvik Roy ◽  
Dibyendu Nandy
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Flux Rope ◽  
Magnetic Storms ◽  
Helicity Injection ◽  
Magnetic Flux Ropes ◽  
Planetary Environments ◽  
The Impact ◽  
Host Stars ◽  
Atmospheric Mass

<p>Coronal mass ejections (CMEs), large scale transient eruptions observed in the Sun, are thought to also be spawned by other magnetically active stars. The magnetic flux ropes intrinsic to these storms, and associated high-speed plasma ejecta perturb planetary environments creating hazardous conditions. To understand the physics of CME impact and consequent perturbations in planetary environments, we use 3D compressible magnetohydrodynamic simulation of a star-planet module (CESSI-SPIM) developed at CESSI, IISER Kolkata based on the PLUTO code architecture.  We explore magnetohydrodynamic processes such as the formation of a bow-shock, magnetopause, magnetotail, planet-bound current sheets and atmospheric mass loss as a consequence of magnetic-storm-planetary interactions. Specifically, we utilize a realistic, twisted flux rope model for our CME, which leads to interesting dynamics related to helicity injection into the magnetosphere. Such studies will help us understand how energetic magnetic storms from host stars impact magnetospheres and atmospheres with implications for planetary and exoplanetary habitability.</p>

Deformation, heating and melting of solids in high-speed friction

1961 ◽  
Vol 260 (1303) ◽  
pp. 433-458 ◽  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Frictional Heating ◽  
Vertical Axis ◽  
High Viscosity ◽  
Molten Material ◽  
General Behaviour ◽  
Low Viscosity ◽  
Heavy Loads ◽  
The Impact

An experimental study has been made of the effects of frictional heating on the deformation of solids rubbing at very high speeds and at reasonably heavy loads. A new method for measuring the friction under these conditions is described. A steel ball, rapidly spinning round its vertical axis, is allowed to fall a short distance and to bounce off an inclined flat solid surface. The friction of steel on various solids in a vacuum of ca . 10 -4 mm Hg, at sliding speeds up to 700 m/s, is determined from the measured direction of the ball’s horizontal velocity after the impact. In addition, separate piezo-electric measurements are made of the load and the friction force. Again the coefficient of friction is found to decrease with increasing sliding speed. The general behaviour is similar to that observed at light loads but there are important differences. With heavy loads the deformation of the solids appears to be primarily plastic. Within a very short time after being brought into contact with a fast-moving surface, solids with a sufficiently low melting point melt on a large scale so that a continuous film of molten material is developed over the area of contact. The resistance to motion is determined primarily by this liquid film so that it may now increase as the speed rises. The heating due to the shearing of this film causes the solid to melt away rapidly, and as a result the wear rate of such solids usually becomes great at high sliding speeds. Certain polymers, however, exhibit a greater wear resistance than metals and other solids which possess a low viscosity in the molten state. Calculations indicate that in these polymers, owing to their high viscosity, the temperature of the sheared film may be considerably higher than the melting temperature. As a consequence, a larger proportion of the heat developed by the shearing may be absorbed in the already molten material, and less heat will be available for further melting. Gas liberated by thermal decomposition may also reduce the friction and wear.

The deformation of solids by liquid impact at supersonic speeds

1961 ◽  
Vol 263 (1315) ◽  
pp. 433-450 ◽  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Impact Load ◽  
Turbine Blades ◽  
Stress Waves ◽  
Liquid Jet ◽  
High Speeds ◽  
Liquid Impact ◽  
The Impact ◽  
Very High

A study has been made of the deformation of solids at high rates of strain which are produced by the impact of a small cylinder or jet of liquid on the surface of the solid. A method is developed for projecting this jet against the solid at velocities up to 1200 m/s. The subsequent deformation of the solid under impact and the behaviour of the liquid is observed by high-speed photographic methods. The magnitude and duration of the impact load are also measured by using a piezo-electric transducer. The mode of deformation of the solid has been investigated for plastic, elastic and brittle materials. There is evidence that the liquid jet, on impact, behaves initially in a compressible manner. Part of the deformation is due to these compressible effects and part to the shearing action of the liquid flowing at very high speeds across the surface. If the head of the jet has an appropriate shape (e.g. wedge shaped) the velocity of flow across the surface may be much greater than the velocity of approach. It is found that there are five general types of deformation produced in the solid. There are (i) circumferential surface fractures, (ii) subsurface flow and fractures, (iii) large-scale plastic deformation, (iv) shear deformation around the periphery of the impact zone, and (v) fracture due to the reflexion and interference of stress waves. The predominating mode of deformation depends primarily on the mechanical properties of the solid and on the velocity of impact. The observations have a bearing on the practical problem of the erosion of aircraft flying at high speed through rain and on the erosion of turbine blades.

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