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

Discuss the benefit and limitations of utilizing wind energy, a. Discuss th...

a. Discuss the benefits and limitations of utilizing wind energy for electricity generation. b. Draw the block diagram representation of a thermal power generation unit. Illustr

Communication systems/theory, have 18 multiple choice questions i need answ...

have 18 multiple choice questions i need answered by 9am cst and will pay Need ASAP

Find the initial current when switch is closed - capacitor, 1. In the circ...

1. In the circuit shown below, the capacitor initially has a voltage across it 4 Volts (at t = 0). a. Write down the expression for V C (t) when the switch is closed. b. Wr

States ohm''s law, States Ohm's law Ohm's law describes that the curren...

States Ohm's law Ohm's law describes that the current I flowing in a circuit is directly proportional to the applied voltage V and inversely proportional to the resistance R, g

Balanced score card and key performance indicators, Balanced Score Card and...

Balanced Score Card and Key Performance Indicators Every successful organization measures its performance across the subsequent parameters, for dissemination to all stakeholde

Describe abrasive grit size, Describe the effect of following parameters. ...

Describe the effect of following parameters. Abrasive grit size. Amplitude and frequency of vibration.

Explain the meaning of synchronous counters, Explain the meaning of Synchro...

Explain the meaning of Synchronous Counters? In the synchronous counters the clock inputs of all the flip-flops are connected together and are triggered by the input pulses, the

Can you explain twos complement division, Q. Can you explain twos Complemen...

Q. Can you explain twos Complement Division? 2's complement division is repeated 2's complement subtraction. The 2's complement of the divisor is calculated, and then added to

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