Optimization the Arrangement of Power Cable Lines in Tunnel

2014 ◽  
Vol 678 ◽  
pp. 513-517
Author(s):  
Guang Hua He ◽  
Zhen Peng Zhang ◽  
Min Sheng Xie ◽  
Ying Xiong Wu ◽  
Dong Xing Yang ◽  
...  
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Layout Design ◽  
Power Cable ◽  
Cable Line ◽  
Force Peak ◽  
Cable Lines ◽  
Better Than ◽  
Peak Value

In order to optimized the power cable layout design in tunnel, and improved the operation ability of the cable line, this paper analyzed the cable rating and the short-circuit force under different arrangements. 220kV cable circuit was simulated in the tunnel with conditions of the flat and the trefoil arrangements. The temperature and the rating of the 220kV cable under the condition of the two arrangements were calculated in this paper. The short circuit force peak value and its direction of the cable line under short circuit current of 50kA under the condition of the two arrangements were simulated in this paper. The results show that, the cable rating in flat arrangement is better than in trefoil formation. The value and the direction of the short circuit force in tunnel are better in flat arrangement than in trefoil formation. So it is suggested that the flat arrangement is preferred when conditions permit.

Fluttering Amplitude Amplification by Utilizing Flapping Moment in Flutter-Driven Triboelectric Nanogenerator

2021 ◽  
Author(s):  
Yi Zhang ◽  
Ka Chung Chan ◽  
Sau Chung Fu ◽  
Christopher Yu Hang Chao
Keyword(s):  
Flow Velocity ◽  
High Speed ◽  
Aerodynamic Force ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Energy Output ◽  
Small Scale ◽  
Triboelectric Nanogenerator ◽  
Peak Value

Abstract Flutter-driven triboelectric nanogenerator (FTENG) is one of the most promising methods to harvest small-scale wind energy. Wind causes self-fluttering motion of a flag in the FTENG to generate electricity by contact electrification. A lot of studies have been conducted to enhance the energy output by increasing the surface charge density of the flag, but only a few researches tried to increase the converting efficiency by enlarging the flapping motion. In this study, we show that by simply replacing the rigid flagpole in the FTENG with a flexible flagpole, the energy conversion efficiency is augmented and the energy output is enhanced. It is found that when the flag flutters, the flagpole also undergoes aerodynamic force. The lift force generated from the fluttering flag applies a periodic rotational moment on the flagpole, and causes the flagpole to vibrate. The vibration of the flagpole, in turn amplifies the flutter of the flag. Both the fluttering dynamics of the flags with rigid and flexible flagpoles have been recorded by a high-speed camera. When the flag was held by a flexible flagpole, the fluttering amplitude and the contact area between the flag and electrode plates were increased. The energy enhancement increased as the flow velocity increased and the enhancement can be 113 times when the wind velocity is 10 m/s. The thickness of the flagpole was investigated. An optimal output of open-circuit voltage reaching 1128 V (peak-to-peak value) or 312.40 V (RMS value), and short-circuit current reaching 127.67 μA (peak-to-peak value) or 31.99 μA (RMS value) at 12.21 m/s flow velocity was achieved. This research presents a simple design to enhance the output performance of an FTENG by amplifying the fluttering amplitude. Based on the performance obtained in this study, the improved FTENG has the potential to apply in a smart city for driving electronic devices as a power source for IoT applications.

CFTR activation in human bronchial epithelial cells by novel benzoflavone and benzimidazolone compounds

2003 ◽  
Vol 285 (1) ◽  
pp. L180-L188 ◽  
Author(s):  
Emanuela Caci ◽  
Chiara Folli ◽  
Olga Zegarra-Moran ◽  
Tonghui Ma ◽  
Mark F. Springsteel ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
High Throughput Screening ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Bronchial Epithelial Cells ◽  
Human Bronchial Epithelial Cells ◽  
Thyroid Cells ◽  
Bronchial Epithelial ◽  
Rat Thyroid ◽  
Better Than

Activators of the CFTR Cl- channel may be useful for therapy of cystic fibrosis. Short-circuit current ( Isc) measurements were done on human bronchial epithelial cells to characterize the best flavone and benzimidazolone CFTR activators identified by lead-based combinatorial synthesis and high-throughput screening. The 7,8-benzoflavone UCcf-029 was a potent activator of Cl- transport, with activating potency (<1 μM) being much better than other flavones, such as apigenin. The benzimidazolone UCcf-853 gave similar Isc but with lower potency (5–20 μM). In combination, the effect induced by maximal UCcf-029 and UCcf-029, UCcf-853, and apigenin increased strongly with increasing basal CFTR activity: for example, Kd for activation by UCcf-029 decreased from >5 to <0.4 μM with increasing basal Isc from ∼4 μA/cm2 to ∼12 μA/cm2. This dependence was confirmed in permeabilized Fischer rat thyroid cells stably expressing CFTR. Our results demonstrate efficacy of novel CFTR activators in bronchial epithelia and provide evidence that activating potency depends on basal CFTR activity.

Ca-sensitive Na transport in sheep omasum

1999 ◽  
Vol 276 (6) ◽  
pp. G1331-G1344 ◽  
Author(s):  
Gerhard Schultheiss ◽  
Holger Martens
Keyword(s):  
Divalent Cations ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Voltage Divider ◽  
Close Correlation ◽  
Na Transport ◽  
Luminal Side ◽  
Flux Measurements ◽  
Voltage Divider Ratio ◽  
Peak Value

Na transport across a preparation of sheep omasum was studied. All tissues exhibited a serosa-positive short-circuit current ( I sc), with a range of 1–4 μeq ⋅ h−1 ⋅ cm−2. A Michaelis-Menten-type kinetic was found between the Na concentration and the I sc(Michaelis-Menten constant for transport of Na = 6.7 mM; maximal transport capacity of Na = 4.16 μeq ⋅ h−1 ⋅ cm−2). Mucosal amiloride (1 mM), phenamil (1 or 10 μ), or serosal aldosterone (1 μM for 6 h) did not change I sc. Removal of divalent cations (Ca and Mg) enhanced I sc considerably from 2.61 ± 0.24 to a peak value of 11.18 ± 1.1 μeq ⋅ h−1 ⋅ cm−2. The peak I sc(overshoot) immediately declined to a plateau I sc of ∼6–7 μeq ⋅ h−1 ⋅ cm−2. Na flux measurements showed a close correlation between changes in I sc and Na transport. Transepithelial studies demonstrated that K, Cs, Rb, and Li are transported, indicating putative nonselective cation channels, which are inhibited by divalent cations (including Ca, Mg, Sr, Ba) and by (trivalent) La. Intracellular microelectrode recordings from the luminal side clearly showed changes of voltage divider ratio when mucosal divalent cations were removed. The obtained data support the assumption of a distinct electrogenic Na transport mechanism in sheep omasum.

Analysis and calculation the thermal stress and short circuit force of the power cable line

2014 ◽  
Author(s):  
Zhen-peng Zhang ◽  
Nai-qiu Shu ◽  
Jian-kang Zhao ◽  
Wen-bin Rao ◽  
Shao-xin Meng ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Short Circuit ◽  
Power Cable ◽  
Cable Line

scholarly journals Safety Issues Referred to Induced Sheath Voltages in High-Voltage Power Cables—Case Study

2020 ◽  
Vol 10 (19) ◽  
pp. 6706
Author(s):  
Stanislaw Czapp ◽  
Krzysztof Dobrzynski
Keyword(s):  
High Voltage ◽  
Electric Shock ◽  
Short Circuit ◽  
Single Point ◽  
Power Cable ◽  
Power Cables ◽  
Power Losses ◽  
Cable Line ◽  
Low Level

Load currents and short-circuit currents in high-voltage power cable lines are sources of the induced voltages in the power cables’ concentric metallic sheaths. When power cables operate with single-point bonding, which is the simplest bonding arrangement, these induced voltages may introduce an electric shock hazard or may lead to damage of the cables’ outer non-metallic sheaths at the unearthed end of the power cable line. To avoid these aforementioned hazards, both-ends bonding of metallic sheaths is implemented but, unfortunately, it leads to increased power losses in the power cable line, due to the currents circulating through the sheaths. A remedy for the circulating currents is cross bonding—the most advanced bonding solution. Each solution has advantages and disadvantages. In practice, the decision referred to its selection should be preceded by a wide analysis. This paper presents a case study of the induced sheath voltages in a specific 110 kV power cable line. This power cable line is a specific one, due to the relatively low level of transferred power, much lower than the one resulting from the current-carrying capacity of the cables. In such a line, the induced voltages in normal operating conditions are on a very low level. Thus, no electric shock hazard exists and for this reason, the simplest arrangement—single-point bonding—was initially recommended at the project stage. However, a more advanced computer-based investigation has shown that in the case of the short-circuit conditions, induced voltages for this arrangement are at an unacceptably high level and risk of the outer non-metallic sheaths damage occurs. Moreover, the induced voltages during short circuits are unacceptable in some sections of the cable line even for both-ends bonding and cross bonding. The computer simulations enable to propose a simple practical solution for limiting these voltages. Recommended configurations of this power cable line—from the point of view of the induced sheath voltages and power losses—are indicated.

Effect of vasopressin on intracellular [Ca] and Na transport in cultured toad bladder cells

1988 ◽  
Vol 255 (5) ◽  
pp. F1015-F1024 ◽  
Author(s):  
S. M. Wong ◽  
H. S. Chase
Keyword(s):  
Ion Transport ◽  
Sodium Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Toad Bladder ◽  
Base Line ◽  
Intracellular Ca ◽  
Bladder Cells ◽  
Peak Value ◽  
Natriferic Action

Intracellular free [Ca] [( Ca]i) and transepithelial sodium transport were measured simultaneously in cultured toad bladder cells grown on collagen-coated filters. [Ca]i was measured with fura-2 and fluorescence microscopy while sodium transport was measured as the short-circuit current (Isc) with a voltage clamp. Following stimulation with vasopressin [Ca]i and Isc rose in parallel to maximal values within 10 min. [Ca]i increased from 65 +/- 5 to 123 +/- 12 nM and Isc, from 11 +/- 3 to 25 +/- 6 microA (n = 4). The vasopressin-induced rise in [Ca]i correlated significantly with the increase in Isc, suggesting that the rise in [Ca]i might be necessary for the increase in Isc. If so, then adenosine 3',5'-cyclic monophosphate (cAMP), which mimics the natriferic action of vasopressin, should also increase [Ca]i. Although cAMP increased [Ca]i to a peak value of 32 +/- 13% (P less than 0.05) above control at 10 min, the rise in Isc did not parallel the increase in [Ca]i. Isc peaked instead at 20 min, rising to 114 +/- 25% (P less than 0.05) over control, during which time [Ca]i returned to base line. This result suggested that a steady state increase in [Ca]i was not necessary for the natriferic action of cAMP. This notion was confirmed in experiments in which the vasopressin-induced increase in [Ca]i was prevented by bathing the tissue in a low-[Ca] buffer. Under these conditions, Isc increased 37 +/- 9% above control (P less than 0.05, n = 4) even though [Ca]i remained largely unchanged. Our results suggest that although vasopressin increases [Ca]i in toad bladder cells, the rise in [Ca]i does not seem to play a role in the natriferic response. These experiments also demonstrate the utility of making simultaneous measurements of ion transport and [Ca]i, which allow direct examination of calcium's role in mediating ion transport.

scholarly journals Study and identification of short-circuit currents at the complex distribution network SIDER EL Hadjar (ex ArceloMittal-Algerie)

2018 ◽  
Vol 8 (1) ◽  
pp. 24-31
Author(s):  
Benhamida Hakim ◽  
Mesbah Tarek
Keyword(s):  
Power Supply System ◽  
Short Circuit ◽  
Distribution Network ◽  
Short Circuit Current ◽  
Supply System ◽  
Electricity Distribution ◽  
Short Circuits ◽  
Short Circuit Currents ◽  
Complex Distribution ◽  
Peak Value

Because of an upcoming modernisation of the electricity distribution network in the SIDER EL HADJAR steel complex, a new calculation of the short-circuit current must be taken into account. The objectives are to determine the precise values of the currents of maximum and minimum fault by each start 225 kV, 63 kV and 15 kV of the distribution network to ensure the reliability of the existing system, and to validate the sizing of the 63 kV bus bar follows the increase of the load of the transformer station P4 by replacing the 70 MVA transformer with a 120 MVA transformer and comparing the results to the old computation. The calculation of short-circuit currents is a key step in qualifying the equipment to withstand the thermal and electromagnetic effects. So, to appreciate the reliability of numerical computation of the currents of short circuits requires modelling and simulations with software NEPLAN V5. Keywords: Initial short-circuit current, power supply system (SIDER EL HADJAR), IEC 60909-0, peak value of short-circuit current, NEPLA software.    

scholarly journals COOLING TIME OF ELECTRICAL ENGINERRING SYSTEM ELEMENT AFTER SHORT CIRCUIT IN DISTRIBUTION NETWORK OF THE SHIP REPAIR PLANT

2018 ◽  
pp. 115-124
Author(s):  
Aleksej Vladimirovich Melikov ◽  
Natalya Mikhailovna Veselova ◽  
Dmitriy Dmitrievich Nekhoroshev
Keyword(s):  
Short Circuit ◽  
Distribution Network ◽  
Short Circuit Current ◽  
Cooling Time ◽  
Thermal Calculation ◽  
Power Cable ◽  
Electrical System ◽  
Definition Of ◽  
Ship Repair

In the event of a short circuit in the element of electrical system of distribution network of the ship repair plant, the current passes through the cable core; further, it goes through the fault site into the screen and its grounding devices. The protection gets activated and cuts off the line. The cable is heated up to 250°С when the short-circuit current passes along its intact segment. After eliminating the accident caused by short-circuit current the line is re-connected to the network, but only if the cable is cooled to a temperature of 60°С. In this regard, there arises the problem how to determine the cooling time of an element of an electrical system after a short circuit. The article presents the step-by-step calculation of time after which it is possible to recycle a single cable lying underground at a certain temperature of the environment. As an example, there has been chosen a power cable of ABC type that is most often used when laying wiring in the ground. The main purpose of the chosen cable is to transmit electric power in electric lines with operational power 1.6 and 10kV. There has been developed the program for automatic definition of the cable cooling time after a short circuit. It will be useful for the thermal calculation of both a single cable laid in the ground and for several elements of the electrical system in distribution network of the ship repair plant. The program is based upon procedural programming, each procedure being a certain step in solving the problem. It has been proved that input of initial data takes much less time than efforts to solve the problem in-situ. Using the program doesn’t require special skills.

scholarly journals PARTICULARITIES OF MAGNETIC FIELD SHIELDING FOR UNDERGROUND CABLE LINE BY COMPOSITE FILL-UP SOIL WITH MAGNETIC PROPERTIES

2021 ◽  
Vol 2021 (58) ◽  
pp. 14-22
Author(s):  
I.M. Kucheriava ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Three Dimensional ◽  
3D Models ◽  
Power Cable ◽  
Appreciable Effect ◽  
Cable Line ◽  
Small Height ◽  
Underground Power Cable ◽  
Cable Lines

The computations of the magnetic field generated by high-voltage (330 kV) underground power cable line with special fill-up soil having different dimensions (bulk) are carried out by the two- and three-dimensional computer models. The supplementary soil above the cables is the composite material with effective magnetic properties and serves as a magnetic shield. The computer results obtained by 2D and 3D models are compared. The efficiency of magnetic field shielding depending on the magnetic permeability, width, and height of the fill-up soil is studied. As revealed, there is the optimal small soil height for the best magnetic field mitigation on the top of the ground directly over the cable line. In addition, the width of the magnetic soil has an appreciable effect on shielding efficiency. The shielding of underground single-circuit three-phase power cable lines is efficient only when using the magnetic fill-up soil (or ordinary external screen made of magnetic materials) with enough small height. References 14, figures 7.

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