Short-circuit current contribution of converter interfaced wind turbines and the impact on system protection

2013 ◽  
Author(s):  
Evangelos Farantatos ◽  
Ulas Karaagac ◽  
Hani Saad ◽  
Jean Mahseredjian
Keyword(s):  
Wind Turbines ◽  
Short Circuit ◽  
Short Circuit Current ◽  
System Protection ◽  
Current Contribution ◽  
The Impact

Short-Circuit Current Contribution of Doubly-Fed Wind Turbines according to IEC and IEEE Standards

2020 ◽  
pp. 1-1
Author(s):  
F. Jimenez-Buendia ◽  
A. Honrubia-Escribano ◽  
A. Lorenzo-Bonache ◽  
E. Artigao-Andicoberry ◽  
E. Gomez-Lazaro
Keyword(s):  
Wind Turbines ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Current Contribution ◽  
Ieee Standards ◽  
Doubly Fed

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.

Analytical and Experimental Studies on Induced Current Switching by a Fault-Proof Gas Insulated Earthing Switch

2010 ◽  
Vol 11 (5) ◽  
Author(s):  
Mandava Mohana Rao ◽  
Moutusi Paul ◽  
H.S. Jain
Keyword(s):  
Short Circuit ◽  
Experimental Studies ◽  
Short Circuit Current ◽  
Design Parameters ◽  
Induced Current ◽  
Current Switching ◽  
Test Circuit ◽  
Reliable Performance ◽  
Gas Insulated Substation ◽  
The Impact

Fault-proof earthing switches are one of the important modules of a gas insulated substation, as it enables make at 100 percent short circuit current, which is functionally different from maintenance earthing switches. The fault-proof earthing switch shall be designed to make and break electro-magnetically and electro-statically induced currents as per IEC-62271-102. The paper discusses the impact of “test circuit configurations and voltage” on test parameters for gas insulated fault-proof earthing switch utilizing simulation with PSCAD software. Authors record the development of a 145 kV gas insulated fault proof earthing switch by considering novel design features like minimum arcing/pre-arcing time, effective current transfer from arcing contact to ground terminal, etc. The development has been evaluated successfully for electro-magnetically and electro-statically induced current duties as per IEC. Finally, design parameters to be considered for ensuring reliable performance during induced current switching from fault-proof earthing switches are also discussed.

scholarly journals Improved Control Strategy of MMC–HVDC to Improve Frequency Support of AC System

2020 ◽  
Vol 10 (20) ◽  
pp. 7282
Author(s):  
Zicong Zhang ◽  
Junghun Lee ◽  
Gilsoo Jang
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Control Method ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Frequency Stability ◽  
Offshore Wind ◽  
Inertial Response ◽  
Control Evaluation ◽  
The Impact

With the continuous development of power electronics technology, variable-speed offshore wind turbines that penetrated the grid system caused the problem of inertia reduction. This study investigates the frequency stability of synchronous, offshore wind-farm integration through a modular-multilevel-converter high-voltage direct-current (MMC–HVDC) transmission system. When full-scale converter wind turbines (type 4) penetrate the AC grid, the AC system debilitates, and it becomes difficult to maintain the AC system frequency stability. In this paper, we present an improved inertial-response-control method to solve this problem. The mathematical model of the synchronous generator is based on the swing equation and is theoretically derived by establishing a MMC–HVDC. Based on the above model, the inertia constant is analyzed using a model that integrates the MMC–HVDC and offshore synchronous generator. With the new improved control method, a more sensitive and accurate inertia index can be obtained using the formula related to the effective short-circuit ratio of the AC system. Moreover, it is advantageous to provide a more accurate inertial control evaluation for AC systems under various conditions. Furthermore, the impact of the MMC–HVDC on system safety is assessed based on the capacitor time constant. This simulation was implemented using the PSCAD/EMTDC platform.

Effect of luminal acidity on the apical cation channel in rabbit esophageal epithelium

2007 ◽  
Vol 292 (3) ◽  
pp. G796-G805 ◽  
Author(s):  
N. A. Tobey ◽  
C. M. Argote ◽  
M. S. Awayda ◽  
X. C. Vanegas ◽  
R. C. Orlando
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Acid Reflux ◽  
Cation Channel ◽  
Esophageal Epithelium ◽  
Protective Function ◽  
Membrane Area ◽  
Luminal Ph ◽  
The Impact

Esophageal epithelial cells contain an apical cation channel that actively absorbs sodium ions (Na+). Since these channels are exposed in vivo to acid reflux, we sought the impact of high acidity on Na+channel function in Ussing-chambered rabbit epithelium. Serosal nystatin abolished short-circuit current ( Isc) and luminal pH titrated from pH 7.0 to pH ≥ 2.0 had no effect on Isc. Circuit analysis at pH 2.0 showed small, but significant, increases in apical and shunt resistances. At pH < 2.0, Iscincreased whereas resistance ( RT) decreased along with an increase in fluorescein flux. The change in Isc, but not RT, was reversible at pH 7.4. Reducing pH from 7.0 to 1.1 with H2SO4gave a similar pattern but higher Iscvalues, suggesting shunt permselectivity. A 10:1 Na+gradient after nystatin increased Iscby ∼4 μAmps/cm2and this declined at pH ≤ 3.5 until it reached ∼0.0 at pH 2.0. Impedance analysis on acid-exposed (non-nystatin treated) tissues showed compensatory changes in apical (increase) and basolateral (decrease) resistance at modest luminal acidity that were poorly reversible at pH 2.0 and associated with declines in capacitance, a reflection of lower apical membrane area. In esophageal epithelium apical cation channels transport Na+at gradients as low as 10:1 but do not transport H+at gradients of 100,000:1 (luminal pH 2.0). Luminal acid also inhibits Na+transport via the channels and abolishes it at pH 2.0. These effects on the channel may serve as a protective function for esophageal epithelium exposed to acid reflux.

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