scholarly journals Analysis of Electromagnetic Processes Inside the Arc Interrupting System of a High-current Circuit Breaker

2017 ◽  
Vol 4 (2) ◽  
pp. 161-164 ◽  
Author(s):  
I. Murashov ◽  
V. Frolov ◽  
D. Ivanov ◽  
A. Kvashnin
Keyword(s):  
Mathematical Model ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Electric Arc ◽  
High Current ◽  
Electromagnetic Processes ◽  
Contact Position ◽  
Short Circuit Currents

Description of electromagnetic processes inside an arc interrupting system of high-current circuit breaker is presented in article. Non-stationary mathematical model of the circuit-breaker operation (short-circuit currents mode) is developed. The main regularities of the displacement of the electric arc inside an arc chute are established. The influence of the movable contact position on the conditions for the displacement of the electric arc is presented. Also, the influence of the arc chute material on the motion and interrupting of an electric arc (alternating and direct currents) is established.

scholarly journals Post-Arc Characteristics of High-Current Arcs in Vacuum Circuit-Breakers

2019 ◽  
Vol 6 (2) ◽  
pp. 170-174
Author(s):  
N. Wenzel ◽  
W. Haas
Keyword(s):  
Short Circuit ◽  
Early Period ◽  
Metal Vapor ◽  
Transverse Magnetic ◽  
High Current ◽  
Electric Resistance ◽  
Circuit Breakers ◽  
Arc Characteristics ◽  
Current Zero ◽  
Short Circuit Currents

The post-arc (PA) characteristics of vacuum arcs in transverse magnetic field contacts are studied for short-circuit currents of up to 123 kA peak and transient recovery voltages below 875 V. The measured PA currents are interpreted in terms of an Electric Resistance Model and the models of Andrews-Varey, Langmuir-Child, and Slepian-Schmelzle. Whereas in the late PA period, the calculations do not agree well with the measurements, the PA behavior is well described in the early period after current-zero. It is concluded that the PA discharge is amplified by ionization of metal vapor particles in the boundary sheath due to electron impact.

scholarly journals Development of a Method and Algorithm for Inhibiting an Automatic Transfer Switch of the Circuit Breaker for a Sustained Short-Circuit

2020 ◽  
Vol 220 ◽  
pp. 01011
Author(s):  
Igor Nikolaevich Fomin ◽  
Roman Pavlovich Belikov ◽  
Tatyana Anatolyevna Kudinova ◽  
Nailya Kamilevna Miftakhova
Keyword(s):  
Short Circuit ◽  
Circuit Breaker ◽  
Electrical Equipment ◽  
Ring Network ◽  
Circuit Breakers ◽  
Emergency Situations ◽  
Short Circuit Currents

Circuit breakers with automatic transfer switches (ATS) are designed in such a way that when the voltage disappears during a short-circuit (SC) in the ring network line, the ATS device is triggered. At the same time, its switch is turned on at short-circuit, then it is turned off with acceleration. Even a shortterm switching on of the automatic transfer switch for a sustained short-circuit leads to emergency situations [1,2]. The electrical equipment of the ring network spare line is exposed to high emergency short-circuit currents, and the consumers powered by the spare transformer are turned off. It is possible to minimize and eliminate the damages caused by the above mentioned cases by inhibiting the switching on of the circuitbreaker of the automatic transfer switch.

scholarly journals Investigation and Numerical Simulation of a High-Current AC Circuit Breaker

2019 ◽  
Vol 6 (3) ◽  
pp. 235-238
Author(s):  
I. Murashov ◽  
V. Frolov ◽  
A. Kvashnin ◽  
J. Valenta ◽  
D. Simek ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
High Speed ◽  
Circuit Breaker ◽  
Moving Mesh ◽  
Electrical Characteristics ◽  
High Current ◽  
Spectral Diagnostics ◽  
Current Voltage ◽  
Time Calculation

The article is devoted to the study of the high-current AC circuit breaker. The results of the study are presented for various configurations of the arc divider. The study includes methods of spectral diagnostics and high-speed camera shooting synchronized with the electrical characteristics of the circuit breaker (current, voltage) in time. The obtained results allow to determine the composition of the plasma and dynamics of changes in the composition of the discharge in time. Calculation of the plasma composition and properties is made according to the obtained data, which makes it possible to take into account the products of circuit breaker materials ablation in numerical simulation. Non-stationary two-dimensional mathematical model with a moving mesh is developed. The obtained results allow to correct and verify the developed mathematical model of the circuit breaker operation. The evaluation of the arc divider influence is presented in the article.

Short circuits currents comparison of 6 (10) kV and 20 kV.

2020 ◽  
Vol 14 (1) ◽  
pp. 21-26
Author(s):  
S. SKRYPNYK ◽  
◽  
A. SHEINA ◽  
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Supply ◽  
Short Circuit ◽  
Electric Arc ◽  
Electrical System ◽  
Three Phase ◽  
Short Circuits ◽  
Short Circuit Currents

Most failures in electrical installations are caused by short circuits (short circuits), which occur as a result of a failure in the electrical strength of the insulation of the conductive parts. A short circuit is an electrical connection of two points of an electric circuit with different values of potential, which is not provided by the design of the device, which interferes with its normal operation. Short circuits may result from a failure of the insulation of the current-carrying elements or the mechanical contact of the non- insulated elements. Also called a short circuit is a condition where the load resistance is less than the internal resistance of the power source. The reasons for such violations are various: aging of insulation, breakages of wires of overhead transmission lines, mechanical damages of isolation of cable lines at ground works, lightning strikes in the transmission line and others. Most often, short-circuits occur through transient resistance, such as through the resistance of an electric arc that occurs at the point of damage to the insulation. Sometimes there are metallic short circuits in which the resistance of the electric arc is very small. The study of short circuits in the power grid is a major step in the design of modern electrical networks. The research is conducted using computer software, first by modeling the system and then simulating errors. A malfunction usually leads to an increase in the current flowing in the lines, and failure to provide reliable protection can result in damage to the power unit. Thus, short-circuit calculations are the primary consideration when designing, upgrading, or expanding a power system. The three-phase short circuit is the least likely. However, in many cases, the three-phase short circuit is associated with the most severe consequences, as it causes the highest power imbalances on the shafts of the generators. The study of transients begins with the mode of three-phase closure due to its relative simplicity in comparison with other types of asymmetry. In most cases, the analysis and calculation of the transient regime of the electrical system involves the preparation of a calculated scheme of substitution, in which the parameters of its elements are determined in named or relative units. The electrical substitution circuitry is used to further study the transients in the power system. The definition of electrical and electromagnetic quantities in relative units is widely used in the theory of electric machines. This is because it significantly simplifies the theoretical calculations and gives the results a generalized view in the practical calculations of currents and residual voltages at the short circuit. By the relative value of any value is understood as its relation to another value of the same name, taken as the base. So, before presenting any quantities in relative units, we need to choose the basic units. In the electrical system with increased voltages, the overall load capacity of the network increases, which in turn makes it possible to supply high-quality electrical energy over a greater distance. In the process of comparing the type of transmission lines, it should be noted that the advantages of the cable transmission line. According to the results of the calculation of short-circuit currents, it can be concluded that in networks with a larger line cross-section and a higher voltage, the short-circuit currents are larger. Thus, during the transition of the electric networks to the higher voltage class of 20 kV, the currents of the KZ increased by 43% compared to the 6 kV electric network. This analysis shows that the importance of reliable power supply in the power supply system for high voltage classes must be high and have equipment to prevent emergencies. In the future, it is planned to develop a systematic calculation of short-circuit currents for a number of transmission lines and to conduct mathematical modeling in the system of applications for the study of transient processes at short circuits.

Current modeling in a bus packet of a high-current system

2020 ◽  
pp. 40-44
Author(s):  
T.A. Novozhilov ◽  
A.N. Novozhilov ◽  
D.M. Rahimberdinova
Keyword(s):  
Mathematical Model ◽  
Single Phase ◽  
Current System ◽  
Short Circuit ◽  
High Current ◽  
Furnace Transformer ◽  
Simulation Error ◽  
Flexible Connections ◽  
Split Winding ◽  
Secondary Winding

A graphoanalytic method for determining the highcurrent system resistances and a mathematical model of a single-phase furnace transformer with a split secondary winding are developed for modeling currents in a transformer and a high-current system bus package in case of short circuit and opening of flexible connections. Experiments have proved the adequacy of the proposed method. The simulation error does not exceed 10 %. Keywords: single-phase transformer, split winding, short circuit, high-current system, opening, resistance, mathematical model, modeling. [email protected]

SWITCHING AND LIGHTNING OVERVOLTAGES AND THE REQUIRED WITHSTAND VOLTAGE BETWEEEN THE OPEN CONTACTS OF 245 KV CIRCUIT BREAKERS

2016 ◽  
Vol 63 (0) ◽  
pp. 43-60 ◽  
Author(s):  
Janusz BANDEL ◽  
Artur HEJDUK ◽  
Andrzej DZIERŻYŃSKI ◽  
Piotr KORYCKI ◽  
Henryk SIBILSKI
Keyword(s):  
Short Circuit ◽  
Circuit Breaker ◽  
Dielectric Strength ◽  
Electrical Insulation ◽  
Power Engineering ◽  
Circuit Breakers ◽  
Short Circuit Currents ◽  
Very High ◽  
Single Break

This paper deals with the surges generated in the network during switching operations and lightning surges. The level of both kinds of surge was compared with the required dielectric strength between the open contacts of 245 kV circuit breakers. Overvoltages greater than the electrical withstand voltage of the circuit breaker can cause arc ignition between the circuit breaker’s open contacts and power engineering service s have reported such cases. The results of such failures can be very serious. This is a problem especially for single-break circuit breakers, in which the stresses on the electrical insulation between the open contacts of the breaker are very high. A method for selecting lightning arresters to lower the overvoltages is proposed. The switching of short-circuit currents by a circuit breaker may cause a weakening of the circuit breaker chamber’s insulation and reduce its electrical withstand and durability.

scholarly journals О способе увеличения предельно допустимого уровня ударных токов короткого замыкания в электрических контактах

2019 ◽  
Vol 89 (4) ◽  
pp. 614
Author(s):  
А.М. Чалый ◽  
В.А. Дмитриев ◽  
М.А. Павлейно ◽  
О.М. Павлейно ◽  
М.С. Сафонов
Keyword(s):  
Heat Release ◽  
Short Circuit ◽  
Electrical Equipment ◽  
Electrical Contacts ◽  
Recrystallization Temperature ◽  
High Current ◽  
Maximum Permissible Level ◽  
Impulsive Heating ◽  
Pass Through ◽  
Short Circuit Currents

AbstractCurrent passing through electrical contacts causes additional heat release due to the presence of a contact resistance. Heat release in contacts may be considerable. In high-current contacts of high-voltage electrical equipment, the problem of overheating gets worse when fault short-circuit currents pass through the contacts. The maximum permissible level of these currents is limited by heating contact areas to their melting point. Welds due to melting of contacts lead to their failure as a rule. A way of considerably raising maximum permissible short-circuit currents has been suggested. Its idea is impulsive preheating of contacts to a temperature higher than the recrystallization temperature of the contact material. The efficiency of this approach has been confirmed experimentally. Numerical simulation of impulsive heating has been conducted. The results have helped us elaborate recommendations for selecting parameters of a train of current pulses that, acting on a contact, may greatly improve its stability against short-circuit currents.

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