SHORT CIRCUIT SHORT CIRCUIT STUDY IN STUDY IN

ELECTRICAL ELECTRICAL TECHNOLOGYTECHNOLOGY

Presented By:Presented By:

K.V.V.S.CHAKRADHARK.V.V.S.CHAKRADHAR

IV Year EEE, JBREC.IV Year EEE, JBREC.

CONTENTSCONTENTS ABSTRACTABSTRACT INTRODUCTIONINTRODUCTION WHAT IS SHORT CIRCUIT?WHAT IS SHORT CIRCUIT? SHORT CIRCUIT ANALYSISSHORT CIRCUIT ANALYSIS BENEFITS OF SHORT CIRCUIT STUDYBENEFITS OF SHORT CIRCUIT STUDY PREVENTIONS OF SHORT CIRCUITPREVENTIONS OF SHORT CIRCUIT RECENT SHORT CIRCUIT ACCIDENTS IN APRECENT SHORT CIRCUIT ACCIDENTS IN AP CONCLUSIONCONCLUSION

ABSTRACTABSTRACT Short Circuit (Fault Current) studies Short Circuit (Fault Current) studies

are required to insure that existing are required to insure that existing and new equipment ratings are and new equipment ratings are adequate to withstand the available adequate to withstand the available short circuit energy available at each short circuit energy available at each point in the electrical systempoint in the electrical system

Fault currents that exceed equipment Fault currents that exceed equipment ratings are capable of extensive ratings are capable of extensive equipment damage and are a serious equipment damage and are a serious threat to human lifethreat to human life

INTRODUCTIONINTRODUCTION

Fires from electrical cords or from wiring devices Fires from electrical cords or from wiring devices are increasing in these years.are increasing in these years.

The reason is supposed to be the The reason is supposed to be the increase of electrical power dissipation increase of electrical power dissipation for domestic use.for domestic use.

India has approximately 60000 fires a India has approximately 60000 fires a year.year.

These fire accidents are occurred due These fire accidents are occurred due to short circuit.to short circuit.

Year 1980 1981 1982 1983 1984 1985Total number of fires

59,885 59,865 63,272 58,833 59,674 55,763

Electric heater for cooking

  192 193 155 176 190

Electric room heater

363 457 539 511 637 503

Cable for lighting or telephone

800 881 930 944 972 978

Electrical equipments

502 445 471 447 453 489

Electrical appliances

        819 713

Wiring devices 398 459 468 450 428 507

Light including neon light

358 321 331 310   

Electric Iron 130 128 94 98   

Others 1,659 1,564 1,582 1,590    Note : Blank is due to the change of classification

WHAT IS SHORT WHAT IS SHORT CIRCUIT?CIRCUIT?

A short circuit is a fault.  It means there is A short circuit is a fault.  It means there is a very low resistance conducting path a very low resistance conducting path from one side of a component to the otherfrom one side of a component to the other

A A short circuitshort circuit in an in an electrical circuit is is one that allows a current to travel along a one that allows a current to travel along a different path from the one originally different path from the one originally intended.intended.

. The electrical opposite of a short circuit . The electrical opposite of a short circuit is an "open circuit", which is an infinite is an "open circuit", which is an infinite resistance between two nodes.resistance between two nodes.

A wire might have come loose which A wire might have come loose which connects two sides of a circuit togetherconnects two sides of a circuit together

Shorting out a single component which is in series with Shorting out a single component which is in series with othersothers

Shorting out a whole circuit

A diagram of the shorting circuit in transformer is below.

Figure shows Normal and short circuit conditions

Prevention of short Prevention of short circuitcircuit

When the cables of the electrical When the cables of the electrical appliances are worn out or it's not appliances are worn out or it's not connected properly a short circuit may connected properly a short circuit may occur.occur.

ALWAYS ENSURE THAT THE ALWAYS ENSURE THAT THE EQUIPMENT AND ANY TEST EQUIPMENT AND ANY TEST EQUIPMENT YOU ARE USING IS EQUIPMENT YOU ARE USING IS PROPERLY GROUNDED AND THAT THE PROPERLY GROUNDED AND THAT THE RUBBER MAT YOU ARE STANDING ON RUBBER MAT YOU ARE STANDING ON IS IN GOOD CONDITIONIS IN GOOD CONDITION

DISCOLORED OR LEAKING DISCOLORED OR LEAKING

TRANSFORMER  TRANSFORMER  BEFORE YOU ENERGIZE THE BEFORE YOU ENERGIZE THE

EQUIPMENT, LOOK FOR:  EQUIPMENT, LOOK FOR:  SHORTSSHORTS   LOOSE, BROKEN, OR CORRODED LOOSE, BROKEN, OR CORRODED

CONNECTION CONNECTION  DAMAGED RESISTORS OR DAMAGED RESISTORS OR

CAPACITORSCAPACITORS   ENERGIZE THE EQUIPMENT AND ENERGIZE THE EQUIPMENT AND

LOOK FOR: LOOK FOR: SMOKING PARTSSMOKING PARTS  

DAMAGES DAMAGES

Damage from short circuits can be Damage from short circuits can be reduced or prevented by reduced or prevented by employing employing fusesfuses, , circuit breakerscircuit breakers, or , or other other overload protectionoverload protection, which , which disconnect the power in reaction to disconnect the power in reaction to excessive current. Overload excessive current. Overload protection must be chosen according protection must be chosen according to the to the prospective short circuit prospective short circuit currentcurrent in a circuit. in a circuit.

Benefits of short circuit Benefits of short circuit study study

Reduce the risk a facility could face Reduce the risk a facility could face and help avoid catastrophic losses. and help avoid catastrophic losses.

Increase the safety and reliability of Increase the safety and reliability of the power system and related the power system and related equipment. equipment.

Evaluate the application of protective Evaluate the application of protective devices and equipment. devices and equipment.

Identify problem areas in the system. Identify problem areas in the system. Obtain recommended solutions.Obtain recommended solutions.

Conclusion Conclusion

Finally from this short circuit study, Finally from this short circuit study, We have to learn about short circuit We have to learn about short circuit And we can clarify from some And we can clarify from some doubtable question like, what is doubtable question like, what is short circuit?, how it happens?, short circuit?, how it happens?, when it happen?, why it happens?. when it happen?, why it happens?. And also learn prevention methods And also learn prevention methods of short circuit. We can know the of short circuit. We can know the advantages about short circuit study.advantages about short circuit study.

Recently, 23000 fire complaints a year Recently, 23000 fire complaints a year from all over state. There are lot of fire from all over state. There are lot of fire accidents are occurred due to these accidents are occurred due to these short circuit. To protect the buildings short circuit. To protect the buildings from these short circuit, we have to from these short circuit, we have to learn about this short circuit learn about this short circuit phenomenon. The main aim of study of phenomenon. The main aim of study of short circuit is protect the short circuit is protect the peoples/buildings from short circuited peoples/buildings from short circuited fire incidents.fire incidents.