Answer / parag mohanty.

upper impedance is the impedance above which distance relay
will not operate and lower impedance is below which it will
not operate

Answer / bl meena

upper-above which not operate
lower-below which operate

Answer / srikrishna kumar

the operation of the relays depended upon the magnitude of
current or power in the protected circuit. however,there is
another group of relays in which the operation is governed
by the ratio of applied voltage to current in the protected
circuit. such relays are called distance or impedance
relays. in an impedance relay, the torque produced by a
current element is opposed by the torque produced by a
voltage element. the relay will operate when the ratio V/I
is less than a predetermined value.

In all analog voltmeters or ammeter showing some small size symbols. as well as a star and in star 2no. digit, resister symbol,and other. what is that's meaning ?

1 Answers  

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how the B-H loop obtain under the static condition

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why is the transmission voltage is multiple of 11?

4 Answers  

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I did oil BDV test of 1600 KVA trafo 20KV/400V as per IEC 156. Result is 1) 58 KV 2) 58 KV 3)40 KV 4) 50 KV 5) 58 KV 6) 18 KV. Avr is 47 KV. Can we say oil is still ok even in the 6th test BDV is 18 KV ?

1 Answers  

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TYPE'S OF BREKAR ,WHAT IS TRANSFORMAR & SAFTY. STARTER DOL & STAR DELTA STARTER.

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after applying C-License in how many days we get it?

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What happens when the power factor is leading and its disadvantages.

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how does a submersible pump work..?

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why induction motor speed is decress with increase in load? how synchronous motor speed is constant?

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when generator short circuit condition, the current how dissipates. or at short circuit voltage not available then current how can flow?

0 Answers   Power Grid,

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What are PLC leader logic program method

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How to find Cable size? Caterpillar generator produce (Two generators) 127*2=254 amp at 11 kv . What would be the cable size (XLPE) to supply 256 amp at 11 kv? Air or surrounding Temperature is 32 degree C. Cable will go under ground at 2.5 feet depth. Group Rating Factors is 3 cables. Clearance between cables is 7 cm. Soil Temperature (Ambient) 28o C Soil Thermal Resistivity is 1.2 K.m/W I would like to use 3 separate single core instead of using 3 core cable. Some says I should use three separate single core 120RM cables. Some says 70RM .some says 95. I m totally confused. Is there ant specific rule to determine cable size? What would be the LT cable size to flow 500 Amp current? Ifte My e mail address is ifte13@yahoo.com Anyone please send me the answer to my e mail address, i will be very glad.

1 Answers  

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