current trasnsformer, Electrical Engineering

Assignment Help:
A 13.8 kV feed er circui t breaker has a 600:5 multira tio curr ent
transform er with charact eristics as show n in Figure 5.11. Th e max -
imum load on the feed er is 80 A pri mary. Phase time inve rse overcurrent
relays are connec ted to the CT secon daries. The relay burden
is 3.2 VA at the tap values selected, and the lead burden is 0.38 V.
a. If the 100:5 CT ratio is used, then a relay tap of 5 A is required in order
for the relay pickup to be 125% above the maximum load. With these,
determine the minimum primary current to just operate the relays.
b. For the select ion of part a what is the appro ximate maximu m
symme trical fault curr ent for whi ch the CTs will not saturate
(use the ANS I=IEEE knee point)?
c. If the 200:5 CT ratio is used so that the 2.5 A relay tap can be used,
determine the minimum primary current to just operate the relays.
13.8 kV
Bus Load bus
Equivalent
source
MVASC = 312.5
Z0 = 11.93 ?8 pu
On 100 MVA base
On 100 MVA base
X1 = X2 = j 0.42 pu
X0 = j 1.26 pu
X2 = 0.15 pu
X0 = 8
4 MVA load
@ 0.9 pf
@ 4 MVA
FIGURE P4.3
 2006 by Taylor & Francis Group, LLC.
d. Repeat part b for the selection of part c.
e. Which of thes e two CT and relay select ions would you recommend ?

Related Discussions:- current trasnsformer

Explain frequency response curve of a rc coupled amplifier, Q. Explain the...

Q. Explain the frequency response curve of a  RC coupled amplifier The frequency response curve of a typical RC coupled Amplifier is shown below: In mid frequency range

Status signals - pins and signals , Status Signals There are three st...

Status Signals There are three status  signals IO/M s and s 1 . All  these  signals  are output  signals. IO/ M - it is a status  signals  used to distinguish  whether  the

Digital switching switching in telecommunication, Name the switching scheme...

Name the switching schemes used in a digital exchange

Balanced budget laws, Balanced Budget Laws: Laws (usually passed by right-w...

Balanced Budget Laws: Laws (usually passed by right-wing governments) that require governments to run balanced budgets regardless of state of the overall economy. These lawshave th

Rrc rotate accumulator right instruction , RRC Rotate  Accumulator  Right...

RRC Rotate  Accumulator  Right Instruction This instruction also  rotates the contents of the  accumulator  toward right  by one bit. The  D 7   bit moves  to D 5   position a

What will the slipring voltage be in this case, A four-pole, three-phase, w...

A four-pole, three-phase, wound-rotor induction machine is to be used as a variable-frequency supply. The frequency of the supply connected to the stator is 60 Hz. (a) Let the r

Clampers., hint on clamping as a project topic

hint on clamping as a project topic

Induction heating - -stepper motor , Normal 0 false false f...

Normal 0 false false false EN-IN X-NONE X-NONE Induction Heating When alternating curren

Parabola by offset method, how many points are required to make an parabola...

how many points are required to make an parabola in offset method when vertical point has 4 points

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd