Why is the diffrential protection in DG. What if the CT
polarity is reversed while connecting for the same type of
protection? How polarity can be made ok?

Answer Posted / parthasarathy c

Diffrential protection is used to protect internal fault
like winding faults,it is used to protect the the
equipments like Generator,Transformer and bus bars.

If CT polarity changed in Directional type releys it will
give trip command when normal operating condition.

Brfore giving connection we must read name plate details to
avoid polarity change.

Is This Answer Correct ?    17 Yes 2 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

The Q-facr o of a coil given as wL/R. what will be shape of Q versus frequency graph.

1549


What is the difference between Encoder and Resolver?

2883


Can we convert off line transformer to on line transformer

1474


if sf6 gas low in gis what will happen

379


how much UPS neutral erath leakage current.

3124






WHAT IS MEANT BY TV TERMINAL IN 500MVA TRANSFORMER?

1708


if we give 60 hz single phase supply to the transformer used in europe , than what will happen

1513


In hydel power plants, L.A's, S.C's are placed inside the control panel boards. what is the purpose? [already the total body was earthed to ground.]

1445


In PFI plant one stage capacitor connection is directly connected(with out megnetic contact controll). but why?

1877


draw the full wave and half wave circuit of 3 phase system and inverter circuit used in ups 

1917


how to Select Lighting arrester? What r the parameters to be considered for the selection of Lighting arrester ?

1191


Classify driling machines.

699


We have 750KVA DG set, we want to introduce REF relay with 1250/1A,CL PS,Current transformers.The lead distance of 2.5mm copper flexible cable from CT to relay is around 5mtrs.We would like to know the knee point votage(VK) & IM calculion for CT's

1446


Dear Brother can u tell the proper size selection of cable & the fault level calculation of braker, busbar etc. pls mail me at azeemk30@gmail.com

1432


Dear all, I just want to ask an expert on this forum for some insights. For the magnetic balance test, when applied voltage on a Delta-Star transformer e.g. Dyn11, the following relationships apply for HV side: 1.  H1-H2 = H2-H3 H3-H1 2.  H2-H3 = H3-H1 H1-H2 3.  H3-H1 = H1-H2 H2-H3 For the LV side also: 4.  X1-X0 = X2-X0 X3-X0 5.  X2-X0 = X3-X0 X1-X0 6.  X3-X0 = X1-X0 X2-X0 Is there a similar pattern for Y-d, Y-Y, D-d? And how about Y-z, D-z, Z-y transformers? I've tested a YNzn5 transformer and for LV side I don't see the pattern. In this particular case I got for LV side the following (see values below): H1-H0  H2-H0  H3-H0    X0-X1  X0-X2  X0-X3 128.0  119.9  7.2      29.2   13.3   15.8 70.7   128.4  59.2     23.4   22.0   3.6 7.2    120.1  128.1    13.4   29.3   15.8 What is the relationship here for LV? For row 1 I see the relationship, for row 3 I also see but it's shifted, but for row 2 I don't see such relationship. Any suggestions, answers, someone?

1362