scholarly journals Methods of Current Limitation in Low Voltage (up to 1 kV) Electric Networks

2021 ◽  
Vol 64 (6) ◽  
pp. 492-504
Author(s):  
A. Yu. Kapustsinski ◽  
S. V. Kanstantsinava
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Electrical Network ◽  
Design Stage ◽  
Negative Consequences ◽  
Current Limitation ◽  
Advantages And Disadvantages ◽  
Current Limiting ◽  
Protection Devices ◽  
Short Circuit Currents

The article discusses and systematizes the causes of high values of short-circuit currents in electrical networks up to 1 kV and indicates their negative consequences. A brief analysis of some current limiting methods (both with and without additional investment) is given, which makes it possible to reduce the negative effects when significant short-circuit currents occur. The variants of the implementation of these current limiting methods recommended for study at the design stage or when replacing equipment that has exhausted its resource, are considered. The advantages and disadvantages of the methods of limiting short-circuit currents described in the article are indicated. Options for connecting equipment with low power consumption to nodes of the electrical network up to 1 kV with high values of short-circuit currents are also considered. Special attention is paid to current-limiting protection devices, a detailed description of the design of some of them is given, the advantages of their use in comparison with other current-limiting methods are indicated, the corresponding graphs of the limitation of the periodic component of the short-circuit current, shock short-circuit current and thermal pulse are presented. Based on the analysis of graphic materials, the issue of ensuring the selectivity of protections is considered. The degree of prevalence of equipment with the property of current limitation is determined. A method for determining selective current-limiting protection devices is given, viz. the method of energy selectivity, the corresponding graphs for determining energy selectivity are presented. The physics allowing to determine the degree of efficiency of limiting the short-circuit current is described. Recommendations on the use of current-limiting equipment are proposed.

Na and Cl Transport across the Isolated Anterior Intestine of the Plaice Pleuronectes Platessa

1981 ◽  
Vol 90 (1) ◽  
pp. 123-142
Author(s):  
M. M. P. RAMOS ◽  
J. C. ELLORY
Keyword(s):  
Chloride Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Negative Potential ◽  
Loop Diuretics ◽  
Significant Part ◽  
Cl Transport ◽  
Anterior Intestine ◽  
Short Circuit Currents ◽  
Na Uptake

1. The tissue was found to have a serosa negative potential, and short-circuit currents equivalent to the net Cl transport. 2. A significant part of the Cl uptake was Na dependent and a similar fraction of the Na uptake was Cl dependent. 3. Short-circuit current and uptake of both ions were inhibited by loop diuretics and analogues. 4. I80 and P.D. were abolished by ouabain. 5. The observations are consistent with the idea of a coupled NaCl entry into the cell, using the energy inherent in the Na gradient; Na being pumped out of the cells by the Na pump and followed electrically by Cl−. Net chloride transport and the serosa negative potential would be a consequence of the permselective properties of the junctions allowing Na but not Cl to recycle back to the mucosal solution.

Current Limiting Reactor's Reactance Value Selection Based on Short-Circuit Transient Analysis

2013 ◽  
Vol 722 ◽  
pp. 223-227
Author(s):  
Tie Ying Zhao ◽  
Yan Wen Wang
Keyword(s):  
Transient Process ◽  
Transient Analysis ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Engineering Calculation ◽  
Calculation Formula ◽  
Current Limiting ◽  
Current Change ◽  
Short Circuit Fault ◽  
A Current

Current limiting reactor can increase systems short circuit impedance so as to limit short circuit current. Current limiting reactor is directly involved in whole short circuit process when a short circuit fault occurs in a power system, which makes short-circuit current change more complex. Short circuit current level is affected by current limiting reactors parameters; a current limiting reactor with proper impedance value can maintain short-circuit current at an acceptable range. A short circuit transient process of a distributing network with current limiting reactor was analyzed, and the formula of current changing in short circuit transient process was deduced; according to the current changing formula, an engineering calculation formula of current limiting reactors impedance was derived. The case calculation shows that current limiting reactor meeting the need of the engineering calculation formula can reach the system current limiting requirement.

scholarly journals Frequency and time fault diagnosis methods of power transformers

2018 ◽  
Vol 18 (4) ◽  
pp. 162-167 ◽  
Author(s):  
Miroslav Gutten ◽  
Daniel Korenciak ◽  
Matej Kucera ◽  
Richard Janura ◽  
Adam Glowacz ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
High Voltage ◽  
Impact Test ◽  
Power Transformer ◽  
Short Circuit ◽  
Small Deformation ◽  
Short Circuit Current ◽  
Diagnostic Methods ◽  
Response Analysis ◽  
Short Circuit Currents

Abstract The authors describe experimental and theoretical analyses of faults of power transformer winding. Faults were caused by mechanical effect of short-circuit currents. Measurements of transformer were carried out in high-voltage laboratory. Frequency and time diagnostic methods (method SFRA - Sweep Frequency Response Analysis, impact test) were used for the analyses. Coils of transformer windings were diagnosed by means of the SFRA method and the time impact test. The analyzed methods had a significant sensitivity to a relatively small deformation of coil. In the analysis a new technique for analyzing the effects of short-circuit currents is introduced. This technique is developed for high-voltage transformers (different types of power). The proposed analyses show that it is necessary to analyze the value of short-circuit current. Short-circuit current represents a danger for the operation of the power transformer. The proposed approach can be used for other types of transformers. Moreover, the presented techniques have a potential application for fault diagnosis of electrical equipment such as: transformers and electrical machines.

Optimal Transmission Switching With Short-Circuit Current Limitation Constraints

2016 ◽  
Vol 31 (2) ◽  
pp. 1278-1288 ◽  
Author(s):  
Zhifang Yang ◽  
Haiwang Zhong ◽  
Qing Xia ◽  
Chongqing Kang
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Current Limitation ◽  
Transmission Switching

Fault Current Limitation (FCL) and Voltage Dip Improvement Thanks to Distributed Static Series Compensator (DSSC)

2012 ◽  
Vol 260-261 ◽  
pp. 525-531 ◽  
Author(s):  
Salman Badkubi
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Fault Current ◽  
Additional Function ◽  
Power Flow Control ◽  
Current Limitation ◽  
Fault Currents ◽  
Voltage Dip

This paper presents the comprehensive implementation of Distributed Static Series Compensator (DSSC) to limit the fault currents in power systems. This is the first time that the limitation of fault currents with D-FACTS devices is addressed. DSSC is one of the D-FACTS families whichoperate in a similar manner as Static Synchronous Series Compensator (SSSC) but in smaller size, lower price and more capability. The effectiveness of the DSSC in fault current limitation is investigated through the series voltage effect upon the line. The short circuit current limitation strategy presented here exhibited that besides of the power flow control which is carried out by DSSC; it can also perform this additional function. In the following the potency of the DSSC in reduction of instantaneous voltage dip range during fault current limiting mode is clarified. Furthermore, it is disclosed that with performing more DSSC in the power system, the entire system voltage dip will be improved. In order to validate the claims, computer simulations using PSCAD/EMTDC are exploited.

An Optimal Evaluation Model for Grid Short-Circuit Current Limitation Measures

2013 ◽  
Vol 732-733 ◽  
pp. 782-788
Author(s):  
Jing Hao Chen ◽  
Wen Ying Liu ◽  
Wei Zheng ◽  
Chen Liang
Keyword(s):  
Evaluation System ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Fuzzy Comprehensive Evaluation ◽  
Current Limitation ◽  
Proposed Model ◽  
Comprehensive Evaluation Model ◽  
Optimal Evaluation

A model for optimally evaluating grid short-circuit current limitation measures is proposed. Based on the fuzzy comprehensive evaluation model, a comprehensive evaluation system is introduced to consider the limiting effect and economy of the limiting measures configure program, also the program's impact on system security is involved. A judgment matrix is constructed to determine the weights of different system layers. With fuzzy behavior indices and membership function being led into, the evaluation of configuration program is given. Taking Gansu power grid for example, the feasibility and practicality of the proposed model are verified by simulation results.

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