10kV Grid Arc Grounding Over-Voltage Hazards and Countermeasures

2013 ◽  
Vol 392 ◽  
pp. 489-493
Author(s):  
Qing Hao Wang ◽  
Zi Jun Huang ◽  
Zhi Gang Li ◽  
Bo Fang ◽  
Gui Bin Hu
Keyword(s):  
Single Phase ◽  
Power Grid ◽  
Operation Mode ◽  
Scientific Basis ◽  
Neutral Point ◽  
Correct Selection ◽  
Capacitive Current ◽  
Current Test ◽  
Selection Of

Through the analysis of 2 single-phase grounding over voltage accidents caused by capacitive over current in 10 kV power grid in this paper, the causes and damages of arc grounding over voltage are illustrated, and the necessity of capacitive current test and effective methods are pointed out. The test and assessment to the 29 substations capacitor currents provides a scientific basis for the correct selection of the neutral point operation mode, and the strengths and weaknesses of the neutral Point grounding through the arc suppression circle and the mode trends of 10kV grid neutral grounding are demonstrated.

The Choice of 10 kV Neutral Point Operation Mode in Fushun Grid

2014 ◽  
Vol 543-547 ◽  
pp. 728-732
Author(s):  
Bo Liu ◽  
Qing Hao Wang ◽  
Chuan Zong Zhao ◽  
Xiao Shi ◽  
Yan Jun Pang ◽  
...  
Keyword(s):  
Operation Mode ◽  
Neutral Point ◽  
Test Method ◽  
Correct Selection ◽  
Power Network ◽  
Capacitive Current ◽  
Test And Evaluation ◽  
Arc Suppression Coil ◽  
Development Direction ◽  
Selection Of

This paper discusses that the capacitive current is a must of producing arc grounding overvoltage, and the method and necessary to restrain arc grounding over voltage. It also explains the concept of capacitive current and arc suppression coil, and the test method and significance of measuring capacitive current. Based on the comprehensive field test and evaluation of 29 substations, it provides the correct selection of neutral point operation mode and gives a development direction to 10 kV power network neutral point grounding method of Fushun grid.

Research of Installing Small Reactors on Neutral Points of 500 KV Autotransformers and the Analysis of Overvoltage

2010 ◽  
Vol 34-35 ◽  
pp. 1609-1613
Author(s):  
Yong Jian Li
Keyword(s):  
Single Phase ◽  
Short Circuit ◽  
Power Grid ◽  
Short Circuit Current ◽  
Neutral Point ◽  
Current Limitation ◽  
Three Phase ◽  
Insulation Coordination

Because of the extensive application of autotransformer in 500 kV power grid, the value of single-phase short-circuit current is generally greater than that of three-phase short-circuit current, or even greater than the maximum rated through current of the breaker. In order to reduce single-phase short-circuit current and avoid implement of bus split, this paper proposes to install small reactors on neutral points of 500 kV autotransformers. By analyzing and calculating the effect on short-circuit current limitation, the most suitable impedance value of small reactor is proposed. In addition，the overvoltage of the neutral point and insulation coordination are particularly discussed.

Analysis of Influence Factors and Rules of Transformer Neutral Point DC

2014 ◽  
Vol 1008-1009 ◽  
pp. 485-492
Author(s):  
Xiao Mao Wang ◽  
Ying Geng Xie ◽  
Yun Zhou ◽  
Cheng Jun Xia
Keyword(s):  
Power Grid ◽  
Operation Mode ◽  
Influence Factors ◽  
Calculation Model ◽  
Transmission System ◽  
Neutral Point ◽  
Regression Equations ◽  
Dc System ◽  
Analysis Theory ◽  
Grounding Electrode

When DC transmission system adopts monopole earth or bipolar imbalance operation mode, the DC grounding electrode will inject large amount of current into the earth, and then disturb the running of the power grid. In view of the influence which is created by DC transmission system in Guangdong power grid, this paper derived the mathematical expressions of the transformer neutral point current after creating a calculation model, and concluded the main influence factors; The subject applied the linear regressing analysis theory to calculate the regression equations of transformers so that the slope of the regressing equation can be used to estimate the influence scope of grounding DC. Finally it concludes that: transformer neutral point current and the power transmitted by DC system has positive correlation; For ±800kV DC Chu Sui, the transformers ,which is more than 80 km away from DC grounding electrode, will no longer be affected; The application of DC suppression devices will affect the neutral point current of the transformers nearby.

scholarly journals Topologies and Operation Modes of Rail Power Conditioners in AC Traction Grids: Review and Comprehensive Comparison

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2151 ◽  
Author(s):  
Mohamed Tanta ◽  
José Gabriel Pinto ◽  
Vitor Monteiro ◽  
Antonio P. Martins ◽  
Adriano S. Carvalho ◽  
...  
Keyword(s):  
Power Quality ◽  
Single Phase ◽  
Power Grid ◽  
Power Transformers ◽  
Correct Selection ◽  
Operation Modes ◽  
Three Phase ◽  
Different Types ◽  
Traction Substations ◽  
Comprehensive Comparison

Electric locomotives in AC traction power systems represent a huge single-phase non-linear load and, detrimentally, affect the power quality and the efficiency of the three-phase power grid. Nevertheless, along the last decades, power electronics are being used to mitigate power quality problems in the three-phase power grid. In particular, Rail Power Conditioner (RPC) helps to increase the loading capacity of traction substations and improve the power quality of three-phase power grids. As the main characteristics, an RPC can supply reactive power, suppress current harmonics and overcome currents imbalance of the three-phase power grid. On the other hand, the traction substations may be constituted by different types of power transformers. For instance, single-phase power transformers and open-delta (V/V) power transformers are widely used, while Scott power transformers are less frequently used, since they are more complex and expensive. In this framework, this work presents a review study of RPC topologies, including their operation modes, and a comprehensive comparison between the characteristics of the RPC topologies when using different types of AC traction substations and power transformers. This helps to ensure the correct selection of the RPC topology for a specific application, according to the main structure of the traction substation. Consequently, and based on the established review, it is possible to sort and allocate each RPC topology for limited or wider applications.

About the Selection of a Single-Phase Short-Circuit Current on Earth in the Network With Low-Ohm Resistive Grounding of the Neutral

2017 ◽  
pp. 34-41
Author(s):  
Andrei V. MAIOROV ◽  
◽  
Kirill A. OSINTSEV ◽  
Andrei V. SHUNTOV ◽  
◽  
...  
Keyword(s):  
Single Phase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Selection Of

The Long Road to Sustainability

2018 ◽  
Author(s):  
Alexander Gillespie
Keyword(s):  
Sustainable Development ◽  
Environmental Problem ◽  
Social Sustainability ◽  
Good News ◽  
Correct Selection ◽  
The Third ◽  
Positive Indicators ◽  
Laws And Policies ◽  
Developed World ◽  
Selection Of

This book examines the idea of sustainable development, made up of economic, social, and environmental parts over the period of human history. This work suggests humanity has been unsustainable in all three areas for most of its history, although in the last few hundred years the scale of unsustainability has increased, while, simultaneously, answers have started to emerge. This conclusion can be seen in two parts, namely the economic and social sides of sustainable development and then the environmental ones. This work suggests that, with the correct selection of tools, solid and positive foundations for the economic and social sides of sustainable development is possible as the world globalizes. This is not, however, a foregone conclusion. Despite a number of recent positive indicators in this area, there are still very large unanswered questions with existing mechanisms and other gaps in the international architecture which, if not fixed, could quickly make problems of economic and social sustainability worse, not better. With the third leg of sustainable development, that for the environment, the optimism is not as strong. The good news is that science, laws, and policies have evolved and expanded to the level that, in theory, there is no environmental problem which cannot be solved. In many areas, especially in the developed world, success is already easy to measure. Where it is not easy to measure, and pessimism creeps in, is in the developing world, which is now inheriting a scale and mixture of environmental difficulties which are simply unprecedented.

scholarly journals Simulation Verification of the Contact Parameter Influence on the Forces’ Course of Cereal Grain Impact against a Stiff Surface

2021 ◽  
Vol 11 (2) ◽  
pp. 466
Author(s):  
Włodzimierz Kęska ◽  
Jacek Marcinkiewicz ◽  
Łukasz Gierz ◽  
Żaneta Staszak ◽  
Jarosław Selech ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Decisive Role ◽  
Force Sensor ◽  
Contact Forces ◽  
Correct Selection ◽  
Contact Parameter ◽  
Cereal Grain ◽  
Wide Range ◽  
The Impact ◽  
Selection Of

The continuous development of computer technology has made it applicable in many scientific fields, including research into a wide range of processes in agricultural machines. It allows the simulation of very complex physical phenomena, including grain motion. A recently discovered discrete element method (DEM) is used for this purpose. It involves direct integration of equations of grain system motion under the action of various forces, the most important of which are contact forces. The method’s accuracy depends mainly on precisely developed mathematical models of contacts. The creation of such models requires empirical validation, an experiment that investigates the course of contact forces at the moment of the impact of the grains. To achieve this, specialised test stations equipped with force and speed sensors were developed. The correct selection of testing equipment and interpretation of results play a decisive role in this type of research. This paper focuses on the evaluation of the force sensor dynamic properties’ influence on the measurement accuracy of the course of the plant grain impact forces against a stiff surface. The issue was examined using the computer simulation method. A proprietary computer software with the main calculation module and data input procedures, which presents results in a graphic form, was used for calculations. From the simulation, graphs of the contact force and force signal from the sensor were obtained. This helped to clearly indicate the essence of the correct selection of parameters used in the tests of sensors, which should be characterised by high resonance frequency.

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