Application of Circuit-Breaker Standards in Short-Circuit Current Calculation for Generator Circuit-Breakers

2020 ◽  
Author(s):  
Priyanka Gugale ◽  
Mirko Palazzo
Keyword(s):  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Circuit Breakers ◽  
Generator Circuit ◽  
Current Calculation

scholarly journals Research on Application of ETAP in Ship electric propulsion system

2021 ◽  
Vol 252 ◽  
pp. 01031
Author(s):  
Kai Liu ◽  
Jing Chen
Keyword(s):  
Electric Propulsion ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Propulsion System ◽  
Selective Protection ◽  
Electric Propulsion System ◽  
Calculation Results ◽  
Research On Application ◽  
Current Calculation

This article takes a ship electric propulsion system as a specific example, using ETAP to establish a simulation model and short-circuit current calculation. Through the calculation results, the coordination setting of the circuit breaker and the comparison with the COMPASS calculation results are carried out, and finally the selective protection and coordination analysis of the power system are completed.

scholarly journals Fault Diagnosis Algorithm and Protection of Electric Power Systems in an Alternative Distribution System

2020 ◽  
Vol 1 (3) ◽  
pp. 8-16
Author(s):  
Oshin Ola Austin ◽  
Oluwasanmi Alonge ◽  
Ajayi Joseph Adeniyi
Keyword(s):  
Power Systems ◽  
Distribution System ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Research Work ◽  
Short Circuit Current ◽  
Phase System ◽  
Fault Current ◽  
Circuit Breakers ◽  
Protective Devices

In any power systems, protective devices will detect fault conditions and operate circuit breakers in order to disconnect the load from the fault current and limit loss of service due to failure. This fault may involve one or more phases and the ground, or may occur between two or more phases in a three-phase systems. In ground, fault’ or ‘earth fault, current flows into the earth. In a poly-phase system, a fault may affect each of the three phases equally which is a symmetrical fault. If only some phases are affected, the resulting ‘asymmetrical fault’ becomes more complicated to analyze due to the simplifying assumption of equal current magnitude in all the phases being no longer applicable. Therefore, the prospective short circuit current of the fault can be calculated for power systems analysis procedures. This will assist in the choice of protective devices like circuit breakers, current transformers and relays. This research work evaluated and analyzed the occurrence of faults in a distribution system. Fault currents were obtained and the maximum tripping time required for the protective devices to operate were determined. Hence, it was possible to select appropriate relay and circuit breaker for effective operation of a distribution

Generator Output Breaker Reliability/Availability Benefits

2006 ◽  
Author(s):  
Juan B. Ananos ◽  
Dieter Braun ◽  
Wolfgang Buck
Keyword(s):  
Short Circuit ◽  
Thermal Power ◽  
Circuit Breaker ◽  
Substantial Reduction ◽  
Circuit Breakers ◽  
Power Station ◽  
Power Stations ◽  
Generator Circuit ◽  
Fault Currents ◽  
Secondary Damage

The problem of operating power stations with the highest possible availability has become more and more important in recent years, the layout of a power station obviously has a decisive influence in this respect. The present paper is specifically concerned with the reliability assessment of large thermal power stations. It provides significant insights in the optimization of power stations layouts. The application of generator circuit-breakers for the switching of generators at their terminal voltage offers many advantages when compared with the unit connection such as lower first costs, simplified operational procedures and better fault protection. Modern SF6 generator circuit-breakers make it possible to interrupt all types of fault currents within four cycles. This rapid clearance of fault currents helps to avoid expensive secondary damage of power station equipment and consequently long down times for repair. Although they have a low probability of occurrence such outages have a substantial effect on the availability of a generating unit. It is obvious that long unavailability periods as e.g. in the case of disruptive faults on step-up transformers may affect the rate of return of investments related with power stations. With the recent successful certification of a generator circuit-breaker with a rated short-circuit breaking current of 200 kA SF6 generator circuit-breakers are now available for generating units up to 2000 MVA. Another recent development has been the integration of all the associated items of switchgear within the generator circuit-breaker enclosure as an option to their separate installation. This greatly improved functionality of generator switchgear also contributes to the realisation of simpler and more economic layouts of power stations. Beside a substantial reduction of the first costs this new solution, being fully factory assembled and tested, also makes possible considerable saving in time and expenditures for erection and commissioning.

scholarly journals A Digital-Controlled SiC-Based Solid State Circuit Breaker with Soft Switch-Off Method for DC Power System

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 837 ◽  
Author(s):  
Qin ◽  
Mo ◽  
Xun ◽  
Zhang ◽  
Dong
Keyword(s):  
Solid State ◽  
Field Effect Transistors ◽  
Cooling System ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Oxide Semiconductor ◽  
Circuit Breakers ◽  
Solid State Circuit ◽  
Protection Method

Due to the lower on-state resistance, direct current (DC) solid state circuit breakers (SSCBs) based on silicon-carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) can reduce on-state losses and the investment of the cooling system when compared to breakers based on silicon (Si) MOSFETs. However, SiC MOSFETs, with smaller die area and higher current density, lead to weaker short-circuit ability, shorter short-circuit withstand time and higher protection requirements. To improve the reliability and short-circuit capability of SiC-based DC solid state circuit breakers, the short-circuit fault mechanisms of Si MOSFETs and SiC MOSFETs are revealed. Combined with the desaturation detection (DESAT), a “soft turn-off” short-circuit protection method based on source parasitic inductor is proposed. When the DESAT protection is activated, the “soft turn-off” method can protect the MOSFET against short-circuit and overcurrent. The proposed SSCB, combined with the flexibility of the DSP, has the μs-scale ultrafast response time to overcurrent detection. Finally, the effectiveness of the proposed method is validated by the experimental platform. The method can reduce the voltage stress of the power device, and it can also suppress the short-circuit current.

Study of Generator Source Short-Circuit Currents with Respect to Interrupting the Duty of Generator Circuit Breakers, EMTP Simulation, ANSI/IEEE and IEC Methods

2008 ◽  
Vol 9 (3) ◽  
Author(s):  
J. C Das
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Circuit Breakers ◽  
Time Constants ◽  
Method Of Calculation ◽  
Generator Circuit ◽  
Dc Component ◽  
Current Zero ◽  
Short Circuit Currents ◽  
A Current

Large generators have high effective X/R ratios and combined with other generator time constants and parameters, a current zero may not be obtained at the time of contact parting, i.e., the dc component of the short-circuit current at the contact parting time is higher than the peak ac component. This is well documented in the current literature. The paper presents calculations of the generator source short-circuit currents of a 234 MVA generator using ANSI/IEEE and IEC standards and EMTP simulation. The results are compared and the application of a generator breaker to meet the requirements of calculated duties are discussed. It shows considerable differences in the results, depending upon the method of calculation.

scholarly journals Impact of Momentary Cessation Voltage Level in Inverter-Based Resources on Increasing the Short Circuit Current

2019 ◽  
Vol 11 (4) ◽  
pp. 1153 ◽  
Author(s):  
Namki Choi ◽  
Bohyun Park ◽  
Hwanhee Cho ◽  
Byongjun Lee
Keyword(s):  
Power Systems ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Fault Current ◽  
Test Results ◽  
Voltage Level ◽  
Fault Currents ◽  
Current Calculation ◽  
The Impact

This study analyzed the impact of varying the momentary cessation (MC) voltage level on the short circuit current of inverter-based resources (IBRs). To analyze the impact of the IBR MC function on the short circuit current, this paper proposes an advanced IBR model for fault current calculation to reflect its fault characteristics and a scheme for analyzing the influence of MC on the short circuit current. Based on the proposed methods, the authors conducted case studies using planning data from the Korea Electric Power Corporation (KEPCO). The influence of MC was investigated on the IBRs located at the southwest side of the KEPCO systems by screening the fault currents while varying the MC voltage. This paper demonstrates that the minimum MC voltage level needed for the fault current not to exceed the circuit breaker (CB) capacity can be proposed through analyzing the impact of MC voltage level on the short circuit current. The test results based on the proposed scheme showed that the short circuit current to power systems could not violate CB capacity if IBRs adjusted the MC voltage level higher than the lowest MC voltage level.

scholarly journals A Novel Low Voltage Selective Circuit Breaker with Additional Current Path

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8179
Author(s):  
Bartosz Rozegnał ◽  
Paweł Albrechtowicz ◽  
Piotr Cisek
Keyword(s):  
Low Voltage ◽  
Supply Voltage ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Circuit Breakers ◽  
Current Path ◽  
Correct Reaction ◽  
The Subject ◽  
Selection Of

The subject of the article is a description of the operating principle of the new proposal of the selective circuit breaker, which is an extension of the existing selective devices. The solution proposed in the article allows one to increase the selectivity range of classic selective circuit breakers. In the case of networks with high values of short-circuit loop impedance, operating at reduced supply voltage, the proposed solution will not limit the short-circuit current too excessively as it is in the case of classic solutions. This advantage will allow for the correct reaction of the protections preceding them. The article presents the structure and analysis of the selection of parameters of the proposed solution. The results of simulation calculations have also been illustrated.

Protection Coordination of 33/11 kV Power Distribution Substation in Iraq

2021 ◽  
Vol 39 (5A) ◽  
pp. 723-737
Author(s):  
Yamur M. Obied ◽  
Thamir M. Abdul Wahhab
Keyword(s):  
Time Delay ◽  
Power System ◽  
Power Distribution ◽  
Software Package ◽  
Short Circuit ◽  
Distribution Network ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Earth Fault ◽  
Current Characteristics

The coordination between protective devices is the process of determining the most appropriate timing of power interruption during abnormal conditions in the power system. The aim of this work is to coordinate the protection of the 33/11 kV power distribution substation in Iraq using the CYME 7.1 software package. In this paper overcurrent and earth fault relays are simulated in two cases, with time delay setting and instantaneous setting, to obtain the Time Current Characteristics (TCC) curves for each Circuit Breaker (CB) relay of Al-Karama substation (2×31.5 MVA, 33/11 kV) in Babil distribution network. The short circuit current at each CB is calculated and accordingly, the protection coordination for Al-Karama substation has been simulated. The TCC curves have been obtained in two cases for overcurrent and earth fault relays; in a case with time delay setting and in the case with the instantaneous setting. The setting takes into consideration the short circuit current at the furthest point of the longest outgoing feeder and the shortest outgoing feeder.

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