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Earth Fault Protection


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:(

hi everybody

we have a 520kw dc motor (arm voltage 550v amps 1008) controlled by dc drive of siemens make.

The incoming supply of this drive is through transformer 3.3kv/550v .the neutral is unearthed.

 

can anyone suggest earth fault protection of motors and cables(dc /ac side).

ram

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  • 10 months later...

 

 

 

 

AC SIDE

 

EF protection for unearthed sys is tough, Now a days high sensitive CBCT 's are used to detect earth faults in such systems which measure cable capacitive disc. currents to the fault.

 

DC SIDE

 

Ground fault sensing cards are available , but i do not know whether those can be applied for DC drives.

 

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:(

hi everybody

we have a 520kw dc motor (arm voltage 550v amps 1008) controlled by dc drive of siemens make.

The incoming supply of this drive is through transformer 3.3kv/550v .the neutral is unearthed.

 

can anyone suggest earth fault protection of motors and cables(dc /ac side).

ram

 

for DC it require an instrument to detect +,- cable's current balancing,also a shunt trip is need for the motor's supply circuit breaker.

 

for AC it just need 3 nos CTs ,1 no earth fault IDMT,ciruit breaker of the AC side should provide a shunt trip.

 

 

for DC it require an instrument to detect +,- cable's current balancing,also a shunt trip is need for the motor's supply circuit breaker.

 

for AC it just need 3 nos CTs ,1 no earth fault IDMT,ciruit breaker of the AC side should provide a shunt trip.

 

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