Answer / monty

LBB called as a line breaker back up protection and it is used for the saftey of our equipment whenever fault occurs on line than the breaker of uper stream will be open if lower stream breaker will not operated.

Answer / tpfasil200

Local breaker backup or breaker fail relay(LBB)..It is used when the trip command is given and the breaker fails to open due to some mechanical problem. The protection is time delayed and initiated by all trip conditions.On LBB operation, busbar protection is initiated, as all the breakers connected to that particular bus to which the circuit is connected have to be tripped.I t also trips the tie breaker and sends a direct trip command to the other end breaker.

why do we have 230v a.c. as general voltage for domestic supply rather than others?

2 Answers  

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how electronic energy meter works?

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What is the difference between diesel generator engine with and without turbo charger with the same capacity?

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what effect will 10 milliampere current cause to human body

1 Answers   NPCIL,

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which bridge is used to measure frequency?

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i seen a 132kv/11kv transformer,and thier is a sugar factorys 10MW EXPORT PLANT,MY QUESTION IS THAT WHEN THEY EXPORT ELECTRICITY THEY USE THE SAME TRANSFORMER AND THE CONNECT IT TO 132/11KV TRANSFORMERS SECONDARY SIDE CAN ANY ONE EXPLAIN IT.. THE TRANSFORMER IS OF KIRLOSKAR MAKE AND IT HAS TAP CHANGER.

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L.A. (Lightening Arrester) is located at a place from where transmission line enters the transmitting substation. So L.A. (Lightening Arrester) is the first equipments which has to encounter with lightening, high voltage surges and switching surges. It has to absorb energy of lightening, high voltage surges, and switching surges. L.A. (Lightening Arrester) is made up of layers of semiconductors. If these layers can not tolerate energy released by lightening, high voltage surges, and switching surges the L.A. (Lightening Arrester) blasts.

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What is the deference between earth fault & earth leakage

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AVR is used for the Voltage regulation of the Generator using the feedback signal by exciting the field winding of the generator.But how the field winding will be excited & using what?

2 Answers   Alstom,

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How do I calculate/select Droop CT ratio for various capacity of generators?

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plz tell me about BACK emf and how it generates?

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What are the significant parts of dc generator?

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