Answer / satya dev

1-Over current & earth fault relay for feedar Protection.

2-reverse power relay for Alternators ( if diffrent
sourcees are used- eg. transformer supply & DG supply)

3-Inverse/differetial relay for Busbar protection.

Answer / vel

over current and earth fault relays (2OL+1EL method)are
used for lv .

Answer / jagadisha.n bmsit

Different protection systems which is used in LV panels are:
1. Short circuit protection :- It is done by choosing set
point in sc protection relay which is present inside the CB's.

2. Thermal protection for Busbars/ cables:- Bec extreme
thermal point cause flash over

3. Over current protection

4.Protection provided by proper shielding & interlocks such
that operator & maintenance people can not accesses live parts

Answer / sachin

1.over current reley
2.earth fault reley
3.fase failure relay
3.fuse moniterning relay.

Answer / nagesh

current protection
1)over current
2)short ckt current
3)Instantanious current
Earth fault relay,
Negative phase sequence
Phase failure
If require
High temprature
High vibration
Safety (door switches)
MD over shoot(MD monitoring)

Answer / vinod

VCB,ACB,MCCB

I am having a DG set.The 415 V from Generator is step up to 460 v and then the same is used for Induction furnace. before Step up, I am connecting LT load to my factory use. When Induction furnace is in service from DG, when i try to start a motor, the generator is tripped.Please tell me the reason.

3 Answers  

we have one 75kw motor 380 volt 3ph amp134 please advise which size of cable required

2 Answers  

why hv current transformers have big size ?

5 Answers   RailTel, TCS,

how unidirectional torque is produced in DC motor?

0 Answers  

A 3-phase IM is supplied from 50 Hz system. It runs at speed of 1440 rpm and slip equal to 4 %. Calculate number of pole pairs. A 1 B 6 C 2 D 3

0 Answers  

2. Modify your design in question 1.a so that the circuit works according to the following function table X Y F 0 0 Clear 0 1 No Change 1 0 Parallel Loading 1 1 Count 3. Design a circuit that detects the pattern 010 in a serial input X considering: 3.a Overlapping 3.b No overlapping

0 Answers  

What is EHT(Abrebiation,Function,Voltage Regulation & how it works?

2 Answers   Adhunik,

which theorem is used to analyse fault a)thevinin b)Norton c)Superposition d)jordan

1 Answers   FFC, NTS,

why transformer rating in KVA or MVA instead of KW n MW??

3 Answers  

what is the mho relay

3 Answers  

In directional earth fault protection for generator, one core balance CT is for residual current, what other CT is for, which is placed on neutral?

2 Answers  

IN 6.6KV 3 phase switch gear .i will give 6.6kv to R phase only to earth in during H.v testing (through H.v KIT).what happen remaining phases.how much voltage get remaining phases.why? explain.

1 Answers