Optimal Installation Scheme of Surge Arrester on Distribution Network

2015 ◽  
Vol 1092-1093 ◽  
pp. 304-309
Author(s):  
Ao An Li ◽  
Feng Yue ◽  
Man Cheng Xi ◽  
Zhi Yi Jia ◽  
Jun Kang Ni ◽  
...  
Keyword(s):  
Distribution Network ◽  
Simulation Models ◽  
Lightning Stroke ◽  
Effective Measure ◽  
Lightning Strikes ◽  
Economical Efficiency ◽  
Surge Arresters ◽  
Distribution Line ◽  
Simulation Results ◽  
The Relationship

Surge arrester is an effective measure to protect distribution lines from lightning strikes. But high costs will be spent on the maintenance of a great many surge arresters in 10kV distribution line. Taking the relationship between reliability and economical efficiency into consideration, aiming at installation density of surge arrester, this paper established the effective simulation models of direct lightning stroke overvoltage and induced overvoltage by ATP-EMTP. Finally, this paper presented the optimal installation scheme of surge arrester on the basis of the simulation and analysis of the lightning withstand level. The simulation results provide references for the optimal installation scheme of surge arrester on the distribution network.

scholarly journals Evaluation of a Direct Lightning Strike to the 24 kV Distribution Lines in Thailand

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3193 ◽  
Author(s):  
Pornchai Sestasombut ◽  
Atthapol Ngaopitakkul
Keyword(s):  
Electromagnetic Transients ◽  
Lightning Strike ◽  
Significant Variable ◽  
Line System ◽  
Lightning Strikes ◽  
Underground Cables ◽  
Ground Resistance ◽  
Distribution Lines ◽  
Surge Arresters ◽  
Distribution Line

This paper evaluates the effect of a lightning strike directly on the 24 kV distribution lines in Thailand, where such strikes are one of the main causes of power outages. The voltage across the insulator, and the arrester energy absorbed due to the lightning, need to be analyzed for different grounding distances of the overhead ground wire, ground resistance, lightning impact positions, and lightning current waveforms. Analysis and simulations are conducted using the Alternative Transients Program/Electromagnetic Transients Program (ATP/EMTP) to find the energy absorbed by the arrester and the voltages across the insulator. The results indicate that when surge arresters are not installed, the voltage across the insulator at the end of the line is approximately 1.4 times that in the middle of the line. In addition, the ground resistance and grounding distance of the overhead ground wire affect the voltage across the insulator if the overhead ground wire is struck. When surge arresters are installed, a shorter grounding distance of the overhead ground wire and a lower ground resistance are not always desirable; this is because they reduce the back-flashover rate and the voltage across the insulator if lightning strikes the overhead ground wire. However, lightning strikes to the phase conductor result in high arrester energy and the possibility that the arrester will fail. Furthermore, the tail time of the lightning waveform is a significant variable when considering the energy absorbed by the arrester, whereas the front time is important for the voltage across the insulator. In case lightning strikes directly on the connected point between the overhead lines and the underground cables, the distribution line system is protected only by the lightning arrester at the connection point. The overvoltage at the connection point is lower than the basic impulse level at 24 kV of 125 kV, but the overvoltage at the end of the cable is still more than 125 kV in case the cable is longer than 400 m. When the distribution line system is protected by the lightning arrester at both the connection point and the end of the cable, it results in overvoltage throughout the cable is lower than the critical flashover of insulation. This method is the best way to reduce the failure rate of underground cables and equipment that are connected to the distribution line system.

Study on the Identification of Lightning Over-Voltage Based on ATP-EMTP

2014 ◽  
Vol 672-674 ◽  
pp. 799-802
Author(s):  
Xiao Gang Li ◽  
Li Xue Li ◽  
Yi Hui Zheng ◽  
Xin Wang ◽  
Jian You Yu ◽  
...  
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Transient Process ◽  
Transmission Lines ◽  
Weak Link ◽  
Simulation Models ◽  
Transmission Line Model ◽  
Lightning Stroke ◽  
Line Model ◽  
Simulation Results

Lightning overvoltage often leads to transmission lines trip, which is the weak link of power system. In this paper, 110-kV transmission line model is studied on the basis of the EMTP software. Several simulation models are established for back flashover lightning, induced lightning, shield failure. The transient process of lightning stroke is studied. According to the contrast of simulation results of three kinds of lightning, a set of discriminant basis to distinguish lightning on transmission line is put forward.

Compact Covered Distribution Lines Supported by Triangle Spacers: Configuration and Benefits

2009 ◽  
Vol 10 (2) ◽  
Author(s):  
Jinliang He ◽  
Shuiming Chen ◽  
Rong Zeng
Keyword(s):  
Distribution Network ◽  
Lightning Protection ◽  
Mechanical Theory ◽  
Movement Process ◽  
Distribution Lines ◽  
Distribution Line ◽  
Phase Conductors ◽  
Covered Conductors ◽  
The Relationship

Adopting covered conductors and compact configuration has become the tendency in the renovation of distribution network in China. Advantages of compact configuration are discussed in this paper, which can further save the passage of distribution line, and can easily realize multiple lines in a pole. The movement process of phase conductors is analyzed by the Chord Forced Equation of the mechanical theory to obtain the relationship between the phase spacing of triangle spacer and the span between two neighboring spacers. The suitable phase spacing and spacer span are presented for polymeric and composite spacers. The superiority of compact configuration against lightning protection comparing with traditional distribution lines was analyzed.

Effect of Ambient Temperature Zinc Oxide Surge Arrester Condition Monitoring

2014 ◽  
Vol 554 ◽  
pp. 573-577 ◽  
Author(s):  
Zulkurnain Abdul-Maleka ◽  
Amir Hesam Khavari ◽  
Nabipour Afrouzi Hadi ◽  
Saeed Vahabi-Mashak
Keyword(s):  
Experimental Data ◽  
Zinc Oxide ◽  
Surface Temperature ◽  
Ambient Temperature ◽  
Simulation Analysis ◽  
Simulation Software ◽  
Surge Arresters ◽  
Simulation Results ◽  
Comsol Simulation ◽  
The Relationship

Various methods have been developed to monitor surge arrester condition and predict the probable interruption which can be caused by the failure of surge arresters. This paper aims to carry out experimental and simulation work to find the relationship between the aging level, arrester surface temperature and ambient temperature. COMSOL simulation software was used for the modeling of 120kV rated gapless ZnO surge arresters. It is observed from both the simulation analysis and experimental data that the leakage current and temperature increase as a consequence of an increase in the applied voltage across the arrester. The thermal profile of the ZnO surge arrester changes depending on the aging level and the ambient temperature. The surface temperature simulation results compare well with the experimental results, for the case of varying aging levels.

TCAD Study of the Raised SiGe Source/Drain in 40nm PMOS

2015 ◽  
Vol 645-646 ◽  
pp. 70-74 ◽  
Author(s):  
Min Zhong ◽  
Yu Hang Zhao ◽  
Shou Mian Chen ◽  
Ming Li ◽  
Shao Hai Zeng ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Critical Role ◽  
Sige Layer ◽  
Strain Engineering ◽  
Effect Transistor ◽  
Simulation Results ◽  
Aided Design ◽  
The Relationship ◽  
Growth Experiments ◽  
Good Agreement

An embedded SiGe layer was applied in the source/drain areas (S/D) of a field-effect transistor to boost the performance in the p channels. Raised SiGe S/D plays a critical role in strain engineering. In this study, the relationship between the SiGe overfilling and the enhancement of channel stress was investigated. Systematic technology computer aided design (TCAD) simulations of the SiGe overfill height in a 40 nm PMOS were performed. The simulation results indicate that a moderate SiGe overfilling induces the highest stress in the channel. Corresponding epitaxial growth experiments were done and the obtained experimental data was in good agreement with the simulation results. The effect of the SiGe overfilling is briefly discussed. The results and conclusions presented within this paper might serve as useful references for the optimization of the embedded SiGe stressor for 40 nm logic technology node and beyond.

Hybrid Fluid Flow Simulation Combining Full Physics Simulation and Artificial Intelligence

2021 ◽  
Author(s):  
Mokhles Mezghani ◽  
Mustafa AlIbrahim ◽  
Majdi Baddourah
Keyword(s):  
Artificial Intelligence ◽  
Reservoir Simulation ◽  
History Matching ◽  
Hybrid Approach ◽  
Flow Simulation ◽  
Latin Hypercube Sampling ◽  
Simulation Models ◽  
Fine Scale ◽  
Simulation Results ◽  
Optimization Loop

Abstract Reservoir simulation is a key tool for predicting the dynamic behavior of the reservoir and optimizing its development. Fine scale CPU demanding simulation grids are necessary to improve the accuracy of the simulation results. We propose a hybrid modeling approach to minimize the weight of the full physics model by dynamically building and updating an artificial intelligence (AI) based model. The AI model can be used to quickly mimic the full physics (FP) model. The methodology that we propose consists of starting with running the FP model, an associated AI model is systematically updated using the newly performed FP runs. Once the mismatch between the two models is below a predefined cutoff the FP model is switch off and only the AI model is used. The FP model is switched on at the end of the exercise either to confirm the AI model decision and stop the study or to reject this decision (high mismatch between FP and AI model) and upgrade the AI model. The proposed workflow was applied to a synthetic reservoir model, where the objective is to match the average reservoir pressure. For this study, to better account for reservoir heterogeneity, fine scale simulation grid (approximately 50 million cells) is necessary to improve the accuracy of the reservoir simulation results. Reservoir simulation using FP model and 1024 CPUs requires approximately 14 hours. During this history matching exercise, six parameters have been selected to be part of the optimization loop. Therefore, a Latin Hypercube Sampling (LHS) using seven FP runs is used to initiate the hybrid approach and build the first AI model. During history matching, only the AI model is used. At the convergence of the optimization loop, a final FP model run is performed either to confirm the convergence for the FP model or to re iterate the same approach starting from the LHS around the converged solution. The following AI model will be updated using all the FP simulations done in the study. This approach allows the achievement of the history matching with very acceptable quality match, however with much less computational resources and CPU time. CPU intensive, multimillion-cell simulation models are commonly utilized in reservoir development. Completing a reservoir study in acceptable timeframe is a real challenge for such a situation. The development of new concepts/techniques is a real need to successfully complete a reservoir study. The hybrid approach that we are proposing is showing very promising results to handle such a challenge.

Dämpfungsschlitze in Kreissägeblättern*/Parametric FE analysis to identify the mode of action of damping slots in circular saw blades

2015 ◽  
Vol 105 (01-02) ◽  
pp. 41-46
Author(s):  
C. Birenbaum ◽  
U. Heisel ◽  
S. Weiland
Keyword(s):  
Finite Element Analysis ◽  
Thermal Expansion ◽  
Analytical Approach ◽  
Simulation Models ◽  
Fe Analysis ◽  
Element Analysis ◽  
Annular Plates ◽  
Circular Saw ◽  
Characteristic Modes ◽  
The Relationship

In Kreissägeblättern werden zur Verminderung von Schwingungen und zum Ausgleich thermischer Dehnungen sogenannte Dehnungs- und Dämpfungsschlitze eingebracht. Die Wirkungsweise der Schlitze auf die dynamischen Eigenschaften besteht einerseits in der Dämpfungswirkung sowie andererseits in der Modifikation der Schwingungseigenformen. Um Wirkmechanismen und Optimierungsmöglichkeiten zu identifizieren, werden in den hier vorgestellten Untersuchungen mithilfe der Finiten-Elemente-Methode (FEM) Analysen von Kreisscheiben mit einfachen Schlitzkonfigurationen durchgeführt. Hierdurch sollen Zusammenhänge einzelner Schlitzparameter mit den statischen und dynamischen Eigenschaften von Kreissägeblättern aufgezeigt werden. Zur Validierung des entwickelten Simulationsmodells dienen analytische Berechnungen.   To reduce vibrations and adjust for thermal expansion, so-called damping slots and expansion slots are applied to circular saw blades. The slots affect the dynamic behavior of the saw blades by damping the vibration and altering the characteristic modes and frequencies. An FE(Finite Element) analysis of annular plates with simple arrangements of damping and expansion slots is performed to identify the mechanisms and improvement opportunities. This allows determining the relationship between slot parameters and the static and dynamic qualities of circular saw blades. The developed simulation models are validated using an analytical approach.

scholarly journals DOA Estimation for Coprime Linear Array Based on MI-ESPRIT and Lookup Table

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3043 ◽  
Author(s):  
Weike Zhang ◽  
Xi Chen ◽  
Kaibo Cui ◽  
Tao Xie ◽  
Naichang Yuan
Keyword(s):  
Linear Array ◽  
Estimation Algorithm ◽  
Doa Estimation ◽  
Spatial Spectrum ◽  
Angle Measurement ◽  
Lookup Table ◽  
Signal Parameters ◽  
Estimation Precision ◽  
Simulation Results ◽  
The Relationship

In order to improve the angle measurement performance of a coprime linear array, this paper proposes a novel direction-of-arrival (DOA) estimation algorithm for a coprime linear array based on the multiple invariance estimation of signal parameters via rotational invariance techniques (MI-ESPRIT) and a lookup table method. The proposed algorithm does not require a spatial spectrum search and uses a lookup table to solve ambiguity, which reduces the computational complexity. To fully use the subarray elements, the DOA estimation precision is higher compared with existing algorithms. Moreover, the algorithm avoids the matching error when multiple signals exist by using the relationship between the signal subspace of two subarrays. Simulation results verify the effectiveness of the proposed algorithm.

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