Why Neutral Busbar CT & transformer neutral CT connected
with phase CT in Restricted Earth Fault?

Answer Posted / vinod g

In Restricted earth fault protection Three phase CT is
parralleling (shorting all S1 andshorting all S2 together)
and paralleel conection with Neutral Relay and CT. IN
Healthy conditon current in all the three phase will be
balanced and summation will be zero. During earth fault out
side CT area summation of phase CT currents and Neutral CT
zero, so relay will not pick up. When earth fault inside
the transformer the current in the CT will differ and Relay
will pick and trip the tranformer breaker,so it is clear
that REF is for Transformer Winding protection and Bushing
CT is normally using for phase CT

Is This Answer Correct ?    3 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

It is desired to flood light the front of a building 42 meters wide and 16 meters hig.Projectors of 30 degree beam spread and 1000 watt lamps giving 20 lumen/watt are availabl.If the desired level of illumination is 75 lumen/m and show a suitable scheme.Assume the cofficient of utilization, deprecitation factor and waste light factor are 0.4, 13 and 1.2 respectively.

2977


briefly explain principle of resistance welding

1417


Pl. share your experience about industrial-electronics repair of machine tool.

1454


What is order of the system?

709


how the aircraft outer body and inner body is separated ?

630






how much leakage current is allowed in MC61A L&T make relay?

3132


1. what is usage for power factor in industries?? 2.why we need to monitor power factor??

6748


in non technical way how can u define POWER FACTOR??

1374


Role of active and reactive Power sharing in between two synchronized Generators, Droop Setting role ?

1281


How convergengr of nr method is not dependent on selection of slack bus and how gauss siedel method depends?

1346


Differentiate between low pass, high pass and band pass filter?

624


if we apply 1000ADC instead of 100ADC or We apply 50ADC instead of 100ADC,What will be happened in the test result value.Pl explain

907


what is reactive power?, why its measured in VA ? is it transient behavior of system?

1794


if we run a 3 phase machine on two phase what will happend??? given answer with solid reason please

1598


what is the difference between changer, converter and transformer?

905