WHY IS RESTRICTED EARTH FUALT PROTECTION NEEDED?? WHY CANT
DEIFFERENTIAL PROTECTION SUFFICE???
- 14 Answers
- 25515 Views
- I also Faced
- E-Mail Answers
Answer Posted / guest
whats the basic concept is to provide accurate protection
against fault for the system!
for alternator:
to do so we need to consider the extreme part from top of
the phase to neutral (as potential near neutral and earth is
low the most chances of such fault is to occur near the
neutral). now if the fault occurs near the neutral point,
the covered winding between the fault point and neutral
produce small magnitude of the fault current;
to measure that small signal current we require extreme
sensitive relay system!
if we use such then it ll also detect the unnecessary faults
such as inaccuracy of C.T or saturation of C.T etc. to avoid
malfunction: this is the reason why we protect only 80 to 85
% of winding and left 15% of winding from neutral side
unprotected!
so only the differential protection is not suffice!!
REF: to protect this remaining 15% we need other type of
earth fault protection scheme(neutral connected through
resistor or neutral connected via transformer)! (restricted
earth fault protection is designed to 15% of rated phase
current)
| Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
how to copy from plc ge fanuc versamax series,all input and output, adress, and printout.
hi frnz,can somebody give me any project work? i am a 2nd year student & interested in practical works...plz give me some projects
What are books to be referred for KPTCL exam?
HOE WE CAN IMPROOVE BY USE OF CAPACITOR
Draw a circuit diagram in which if button is open we can use socket and bulb as a series test circit and if button is close than simple we can use socket as any load purpose.
how can service sitting be setted for MCCB?Example for sittings IR (CURRENT RATING),IS(CURRENT STARTING)IO (current operating
What is the difference between solid grounding and impedance grounding?
which type of amplifiers are used in multimete?
What is the gross weight to copper ratio in slip ring induction motor of 4000 HP,6.6 kv, 372amp, 992 rpm GE motor.
i have done diploma and btech in EE and live in Chandigarh so kindly help me how can i make my competency certificate in my area.
what is earth fault relay 64T, why it is used in main Incomer and neutral CT of Transformer.
xpression 'document.FrmQF.myemail' [
1. Design a counter which counts 0, 4, 8, 2, 6, and repeats using: 1.a using JK flip flops 1.b using T flip flops 1.c using D flip flops
What is safety of Ht panel
Please nybody say, weather the result of Bharat Oman is declared or not? Probable date of declare???????
