scholarly journals Lightning Overvoltage Protection of Step-Up Transformer Inside a Nacelle of Onshore New-Generation Wind Turbines

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 322
Author(s):  
Petar Sarajcev ◽  
Antun Meglic ◽  
Ranko Goic
Keyword(s):  
Wind Turbines ◽  
Software Package ◽  
Transient Analysis ◽  
Medium Voltage ◽  
Electromagnetic Transient ◽  
Surge Arresters ◽  
Overvoltage Protection ◽  
New Generation ◽  
Insulation Coordination ◽  
Selection Of

This paper presents an electromagnetic transient analysis of lightning-initiated overvoltage stresses of the step-up transformers installed inside a nacelle of onshore, multi-megawatt, new-generation wind turbines. The increase in the wind turbine (WT) nominal power output, necessitated introducing the step-up transformer into the nacelle. A transformer installed inside a nacelle is subjected to completely different overvoltage stresses from those present if it were installed at the base of the WT tower. This has serious repercussions on its overvoltage protection (i.e., selection and installation of surge arresters) and insulation coordination. Furthermore, the overvoltage protection of medium-voltage cables (inside the tower) is also problematic when considering their length, proximity to the tower wall, and their screen grounding practices, and needs to be tackled in conjunction with that of the step-up transformer. This paper presents detailed models for the various components of the latest-generation WTs, intended for fast-front transient analysis and assembled within the EMTP software package. We further present the comprehensive results of the lightning-transient numerical simulations, covering both upward and downward (first and subsequent) strikes, their analysis, and recommendations for the optimal selection of medium-voltage surge arresters for the step-up transformers installed inside a nacelle.

Study on Electrical Characteristics of Metal-Oxide Surge Arresters in Medium Voltage Power System

2014 ◽  
Vol 960-961 ◽  
pp. 1073-1076
Author(s):  
Li Zhang ◽  
Kun Yang ◽  
Li Mei He
Keyword(s):  
Metal Oxide ◽  
Power System ◽  
Distribution System ◽  
Operating Voltage ◽  
Electrical Characteristics ◽  
Protection Level ◽  
Power Distribution System ◽  
Medium Voltage ◽  
Surge Arresters ◽  
Overvoltage Protection

The index system for electrical characteristics of metal-oxide surge arresters is proposed and established, which is based on rated voltage (Ur), continuous operating voltage (Uc), nominal discharge current (In), overvoltage protection and insulation coordination including lightning overvoltage protection level, operating overvoltage protection level and coordination coefficient (Ks). The study considers both selection and application of overvoltage protection devices for the electrical equipments in 3-35kV medium voltage power system, and comparatively calculates and analyzes the main parameters between two types metal-oxide surge arresters (without gaps and containing series gapped structures), and illustrates their technical features and puts forward suggestions on how to improve the effective utilization. The results of 10kV power distribution system are simulated to show that the conclusions are feasible and available in the practical engineering application.

scholarly journals Modelling 132 kV Substation for Surge Arrester Studies

2008 ◽  
Vol 9 (5) ◽  
Author(s):  
Mohd Zainal Abidin Ab Kadir ◽  
Hatta Mohamed Ariff ◽  
Aida Maria Azmi
Keyword(s):  
Cost Effectiveness ◽  
Power System ◽  
Transmission Line ◽  
Transient Analysis ◽  
Single Phase ◽  
Layout Design ◽  
Phase Line ◽  
Surge Arresters ◽  
Damage Modelling ◽  
Insulation Coordination

Insulation coordination models are an essential part of power system studies and are used to determine the performance of a transmission line or substation. This paper generalizes the guidelines and parameters to be used in modelling the substation and in performing the analysis on the prediction of the transformer damage. Modelling parameters and the substation layout design are based and adapted from 132/11 kV Simpang Renggam – Ayer Hitam substation in Johor Baharu, Malaysia, courtesy of the Tenaga Nasional Berhad (TNB). The model is based on the single phase line model, as was suggested by the IEEE, to be adequate to represent the substation in transient analysis simulation. Extensive analyses on the placement of the surge arresters at the substation and a prediction of the transformer damage are also presented. The results obtained from this analysis are then compared with the suggested Basic Lightning Insulation Level (BIL) by the TNB, according to the standards, for assessing the percentage of transformer damage and optimizing the substation performance in terms of its reliability and cost effectiveness.

Development of the algorithm for the selection of a wind generator-based autonomous power supply system

2019 ◽  
Vol 2 (1) ◽  
pp. 8-16 ◽  
Author(s):  
P. A. Khlyupin ◽  
G. N. Ispulaeva
Keyword(s):  
Wind Turbines ◽  
Power Supply ◽  
Alternative Energy ◽  
Power Supply System ◽  
Supply System ◽  
Power Generators ◽  
Energy Devices ◽  
Wind Generator ◽  
Alternative Energy Sources ◽  
Selection Of

Introduction: The co-authors provide an overview of the main types of wind turbines and power generators installed into wind energy devices, as well as advanced technological solutions. The co-authors have identified the principal strengths and weaknesses of existing wind power generators, if applied as alternative energy sources. The co-authors have proven the need to develop an algorithm for the selection of a wind generator-based autonomous power supply system in the course of designing windmill farms in Russia. Methods: The co-authors have analyzed several types of wind turbines and power generators. Results and discussions: The algorithm for the selection of a wind generator-based autonomous power supply system is presented as a first approximation. Conclusion: The emerging algorithm enables designers to develop an effective wind generator-based autonomous power supply system.

Bifluoride Ion Mediated SuFEx Trifluoromethylation of Sulfonyl Fluorides and Iminosulfur Oxydifluorides

2018 ◽  
Author(s):  
Christopher J. Smedley ◽  
Bing Gao ◽  
Suhua Li ◽  
Qinheng Zheng ◽  
Andrew Molino ◽  
...  
Keyword(s):  
Breast Cancer Cells ◽  
Catalytic Mechanism ◽  
Bioactive Molecules ◽  
Chromatographic Purification ◽  
Rapid Exchange ◽  
Nucleophilic Displacement ◽  
Sulfur Fluoride ◽  
Reactions With Nucleophiles ◽  
New Generation ◽  
Selection Of

Sulfur-Fluoride Exchange (SuFEx) is the new generation click chemistry transformation exploiting the unique properties of S-F bonds and their ability to undergo near-perfect reactions with nucleophiles. We report here the first SuFEx based protocol for the efficient synthesis of pharmaceutically important triflones and bis(trifluoromethyl)sulfur oxyimines from the corresponding sulfonyl fluorides and iminosulfur oxydifluorides, respectively. The new protocol involves the rapid exchange of the S-F bond with trifluoromethyltrimethylsilane (TMSCF<sub>3</sub>) upon activation with potassium bifluoride in anhydrous DMSO. The reaction tolerates a wide selection of substrates and proceeds under mild conditions without need for chromatographic purification. A tentative catalytic mechanism is proposed supported by DFT calculations, involving formation of the free trifluoromethyl anion followed by nucleophilic displacement of the S-F through a five-coordinate intermediate. The preparation of a benzothiazole derived bis(trifluoromethyl)sulfur oxyimine with cytotoxic selectivity for MCF7 breast cancer cells demonstrates the utility of this methodology for the late-stage functionalization of bioactive molecules.<br>

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