scholarly journals Development and Application of Live Replacement of Insulator Suspension Tool Components for Transmission Lines

2019 ◽  
Vol 136 ◽  
pp. 04010
Author(s):  
Ma Jun ◽  
Yu Liang ◽  
Shi Yonggang ◽  
Dong Gang ◽  
Gong Fuxing ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Operation Mode ◽  
Operation Time ◽  
Benefit Analysis ◽  
Lightning Strikes ◽  
The Stability ◽  
Insulation Performance ◽  
Tool Assembly

Transmission line insulators will reduce the insulation level and become low-value insulators because of lightning flashover. Toughened glass insulators are used in 500kV Tongfeng 1 and 2 lines in Tonghua area. Most umbrella skirts will break and fall off after lightning flashover, which greatly reduces the insulation performance. It needs to be replaced in time, but frequent blackouts will bring great losses and reduce the reliability of power supply. Aiming at the frequent lightning hazards and lightning strikes on transmission lines in Tonghua area, a tool assembly for live replacement of insulators for transmission lines is developed. Through the application of this tool, the live operation mode is adopted to eliminate such defects. The operation time can be arranged and implemented in a very timely manner, which avoids the threat of long-term defects, effectively reduces the outage time of equipment, enhances the stability of power grid, and greatly improves the reliability of power supply of lines. Finally, taking the live line insulator suspension tool as an example, the economic benefit analysis is given, and the feasibility and correctness of the tool are verified..

scholarly journals Lightning Performance of Unshielded 220kV Transmission Lines Equipped with Metal-oxide Arresters

2021 ◽  
Vol 242 ◽  
pp. 03009
Author(s):  
Pengkang Xie ◽  
Zhen Fang
Keyword(s):  
Metal Oxide ◽  
Simulation Model ◽  
Energy Absorption ◽  
Transmission Lines ◽  
Power Supply ◽  
Lightning Strike ◽  
Transmission Tower ◽  
Absorbed Energy ◽  
Lightning Strikes ◽  
Grounding Resistance

Overhead ground wires have been proved to be effective to protect conductors from direct lightning strikes, but breakouts of ground wires have been frequently reported. In order to prevent ground wire breakout incidents to happen, unshielded 220kV lines equipped with metal oxide arresters (MOAs) whole line have been proposed in this paper. After cancelling ground wire, lightning strike risk of transmission lines becomes much higher. In order to improve the anti-lightning abilities of unshielded transmission lines, it is necessary to obtain the lightning energy absorption ability of these MOAs. In this paper, simulation model of MOA equipped unshielded 220kV transmission line was built, the influences of lightning parameters, striking occurrence point and grounding resistance of transmission tower on the absorbed energy of MOAs were calculated, and the suggested energy absorption ability of MOA was given, which can give references for the improvement of power supply reliability of transmission lines.

scholarly journals Power Source Electronic Ballast for Electrodeless Fluorescent Lamps

Electronics ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 34
Author(s):  
F. Javier Diaz ◽  
Francisco J. Azcondo ◽  
Rosario Casanueva ◽  
Christian Brañas
Keyword(s):  
Operation Mode ◽  
Power Source ◽  
Voltage Source ◽  
Electronic Ballast ◽  
Long Term Stability ◽  
Resonant Inverter ◽  
Fluorescent Lamps ◽  
Power Mode ◽  
The Stability

This paper presents the design, control strategy and experimental results of a two-step, power factor correction stage (PFC) and resonant inverter (RI), electronic ballast proposal to supply 150 W electrodeless fluorescent lamps (EFL). The PFC acts as a controlled power source and provides mid and long-term stability to the system, while the stability of the current through the lamp is achieved with the RI. In addition, the power-mode control requires limitation of the output voltage. The dual operation mode of the PFC (voltage source mode and power source mode) enables an efficient soft resonant ignition and the implementation of simple dimming regulation.

scholarly journals Restoring normal network operation mode by automatically disabling network ATS

2020 ◽  
Vol 178 ◽  
pp. 01072
Author(s):  
A.V. Vinogradova ◽  
A.I. Psarev ◽  
A.V. Vinogradov ◽  
V.E. Bolshev ◽  
M. Jasinski ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Load Transfer ◽  
Power Transmission ◽  
Operation Mode ◽  
Power Transmission Lines ◽  
Initial State ◽  
Power Sources ◽  
Normal Network ◽  
Network Operation

Automatic sectionalizing and redundancy of power transmission lines is one of the conditions for network intellectualization and can significantly reduce the power supply interruption time for rural consumers. However, both sectionalizing and redundancy of power transmission lines in 0.4 kV electric networks are used extremely limitedly since there are no sufficiently effective methods and technical means for their implementation. This article presents a method to automatically deactivate the automatic load transfer switch when restoring the normal network operation mode. The paper considers the implementation of the method on the example of damage occurring in the network where power is supplied to consumers from two power sources using an automatic load transfer switch and two sectionalizing units. A device is developed which allows implementing the developed method of automatic load transfer switch deactivation. The device consists of sectionalizing unit, automatic load transfer switch, voltage presence sensor, power direction sensor, memory element, repeater element, element AND and 3 elements NOT. The work of the device is described. The proposed method for automatically disconnecting the automatic load transfer switch in order to return the consumers’ power supply circuit to its initial state solves the problem of eliminating unreasonable power supply interruptions for consumers.

scholarly journals Synthesis of flow‐compatible Ru-Me/Al2O3 catalysts and their application in hydrogenation of 1-iodo-4-nitrobenzene

2021 ◽  
Author(s):  
Michael Sebek ◽  
Hanan Atia ◽  
Norbert Steinfeldt
Keyword(s):  
Catalyst Deactivation ◽  
Operation Mode ◽  
Operation Time ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Impregnation Method ◽  
Flow Process ◽  
Ru Nanoparticles ◽  
Long Term Experiment

AbstractThe development of an active, selective, and long-term stable heterogeneous catalyst for the reductive hydrogenation of substituted nitrorarenes in continuous operation mode is still challenging. In this work, Ru based nanoparticles catalysts promoted with different transition metals (Zn, Co, Cu, Sn, or Fe) were supported on alumina spheres using spray wet impregnation method. The freshly prepared catalysts were characterized using complementary methods including scanning transmission electron microscopy (STEM) and temperature programmed reduction (TPR). The hydrogenation of 1-iodo-4-nitrobenzene served as model reaction to assess the catalytic performance of the prepared catalysts. The addition of the promotor affected the reducibility of Ru nanoparticles as well as the performance of the catalyst in the hydrogenation reaction. The highest yield of 4-iodoaniline (89 %) was obtained in a continuous flow process using Ru-Sn/Al2O3. The performance of this catalyst was also followed in a long-term experiment. With increasing operation time, a catalyst deactivation occurred which could only briefly compensate by an increase of the reaction temperature.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

Application of the method of mathematical modeling for forecasting channel deformations at the underwater crossing of the main pipeline

2020 ◽  
Vol 10 (6) ◽  
pp. 599-609
Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Roughness Coefficient ◽  
Computational Domain ◽  
Channel Deformations ◽  
Geological Surveys ◽  
Kuban River ◽  
The Stability ◽  
Protective Structures

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

Influence of internal and external risks on sustainability of financial system of Аltai krai

2018 ◽  
Vol 35 (4) ◽  
pp. 133-136
Author(s):  
R. N. Ibragimov
Keyword(s):  
Sustainable Development ◽  
Financial Stability ◽  
Management Strategy ◽  
Financial System ◽  
Risk Management Strategy ◽  
The Sustainable Development ◽  
The Stability ◽  
The Impact

The article examines the impact of internal and external risks on the stability of the financial system of the Altai Territory. Classification of internal and external risks of decline, affecting the sustainable development of the financial system, is presented. A risk management strategy is proposed that will allow monitoring of risks, thereby these measures will help reduce the loss of financial stability and ensure the long-term development of the economy of the region.

Study on Selective Leakage Protection System of Mine High Voltage Grid Based on Harmonic Phase Comparison

2015 ◽  
Vol 9 (1) ◽  
pp. 253-262
Author(s):  
Liu Zhongfu ◽  
Zhang Junxing ◽  
Shi Lixin ◽  
Yang Yaning
Keyword(s):  
High Voltage ◽  
Power Supply ◽  
Power Supply System ◽  
Supply System ◽  
Neutral Point ◽  
Arc Suppression Coil ◽  
Zero Sequence ◽  
Harmonic Extraction ◽  
Power Direction ◽  
The Stability

As for the wide application of arc suppression coil to the grounding in neutral point of mine high voltage grid, grid leakage fault rules and harmonic characteristics of the neutral point grounding system through arc suppression coil are analyzed, the selective leakage protection program “zero-sequence voltage starts, fifth harmonics of grid zerosequence voltage and zero-sequence current are extracted for phase comparison” is proposed, and corresponding fifth harmonic extraction circuit and power direction discrimination circuit are designed. The experimental results show that the protective principle applies not only to the neutral point insulated power supply system, but also to the power supply system in which neutral point passes arc suppression coil, which can solve selective leakage protection problems under different neutral grounding ways, improving the reliability of selective leakage and guaranteeing the stability of the action value.

scholarly journals Stress Drop, Seismogenic Index and Fault Cohesion of Fluid-Induced Earthquakes

2021 ◽  
Author(s):  
Serge A. Shapiro ◽  
Carsten Dinske
Keyword(s):  
Stress Drop ◽  
Induced Seismicity ◽  
Quantitative Characteristic ◽  
High Stress ◽  
Operation Time ◽  
Average Stress ◽  
Induced Earthquakes ◽  
Effective Stresses ◽  
Seismicity Rates

AbstractSometimes, a rather high stress drop characterizes earthquakes induced by underground fluid injections or productions. In addition, long-term fluid operations in the underground can influence a seismogenic reaction of the rock per unit volume of the fluid involved. The seismogenic index is a quantitative characteristic of such a reaction. We derive a relationship between the seismogenic index and stress drop. This relationship shows that the seismogenic index increases with the average stress drop of induced seismicity. Further, we formulate a simple and rather general phenomenological model of stress drop of induced earthquakes. This model shows that both a decrease of fault cohesion during the earthquake rupture process and an enhanced level of effective stresses could lead to high stress drop. Using these two formulations, we propose the following mechanism of increasing induced seismicity rates observed, e.g., by long-term gas production at Groningen. Pore pressure depletion can lead to a systematic increase of the average stress drop (and thus, of magnitudes) due to gradually destabilizing cohesive faults and due to a general increase of effective stresses. Consequently, elevated average stress drop increases seismogenic index. This can lead to seismic risk increasing with the operation time of an underground reservoir.

Sign in / Sign up

Export Citation Format

Share Document