Short Circuit Testing Methods for Generator Circuit Breakers with a Parallel Resistor

1985 ◽  
Vol PAS-104 (10) ◽  
pp. 2713-2720 ◽  
Author(s):  
L. Der Sluis ◽  
W. Van Der Linden
Keyword(s):  
Short Circuit ◽  
Testing Methods ◽  
Circuit Testing ◽  
Circuit Breakers ◽  
Generator Circuit

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.

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.

Prospective Transient Recovery Voltage Measurement of Short Circuit Testing Circuit by Reverse Current Injection

2019 ◽  
Vol 139 (8) ◽  
pp. 522-526
Author(s):  
Kyoya Nonaka ◽  
Tadashi Koshizuka ◽  
Eiichi Haginomori ◽  
Hisatoshi Ikeda ◽  
Takeshi Shinkai ◽  
...  
Keyword(s):  
Short Circuit ◽  
Reverse Current ◽  
Current Injection ◽  
Voltage Measurement ◽  
Circuit Testing ◽  
Transient Recovery Voltage ◽  
Recovery Voltage

Identification of Electrical Fire Melted Marks of Copper Wires by Electron Backscattered Diffraction (EBSD)

2014 ◽  
Vol 513-517 ◽  
pp. 281-285
Author(s):  
Cheng Sun ◽  
Min Ju Ding ◽  
Yong Feng Zhang ◽  
Xun Tan ◽  
Peng Wang ◽  
...  
Keyword(s):  
Copper Wire ◽  
Short Circuit ◽  
Testing Methods ◽  
Electron Backscattered Diffraction ◽  
Qualitative And Quantitative ◽  
Metallographic Method ◽  
Short Circuits ◽  
In Fire ◽  
Misorientation Of Grains ◽  
Electrical Apparatus

A variety of electrical apparatus used in daily life can cause fires because of internal or external factors. During cause identification of an electrical fire, the first short circuit melted marks of copper wire have been considered highly important because they are direct proofs. Additionally, overloaded short circuit caused by the overload of current due to excessive electrical usage can give rise to an electrical fire. Despite extensive research on the first short circuit in fire scenes, the overloaded short circuit remains difficult to be distinguished because of the limitation of commonly used testing methods. Conventional metallographic method is intuitionistic and simple, but may not provide detailed data of crystals such as misorientation of grains. Here a new method (electron backscattered diffraction, EBSD) is applied for identification of the first and overloaded short-circuited melted marks of copper wires in electrical fire scenes. Results show obvious morphological distinctions in melted marks of copper wires between the first and overloaded short circuits. Qualitative and Quantitative differences obtained from the contrast of the above two short circuit situations may assist for cause identification of electrical fires in the future.

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