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

Program implementing the conjugate gradient method, Write a program impleme...

Write a program implementing the conjugate gradient method (un-preconditioned). Solve the  matrix equation corresponding to a finite difference node-spacing, h = 0.02m in x and y d

Cost and profitability - proposed kpis, Cost and Profitability - Proposed K...

Cost and Profitability - Proposed KPIs  KPI  UOM  Measures   RepresentativeStandards  Aggregate Technical &  Commercial L

Automatic irrigation system on running solar power b, how to upload the pro...

how to upload the program on proteus software by using personal computer

Discuss the essentials of an oscillator, Q. Discuss the essentials of an os...

Q. Discuss the essentials of an oscillator? The essential components of an oscillator are (i) Tank Circuit: It consists of inductance coil(L) connected in parallel with ca

Determine the fault current and the bus voltages, The one line diagram of a...

The one line diagram of a simple three-bus power system is shown in the figure below.  Each generator is represented by an emf behind the transient reactance.  All impedances are e

Compute the worst voltage regulation, Q. The following data were obtained o...

Q. The following data were obtained on a 25- kVA, 2400:240-V, 60-Hz, single-phase distribution transformer: • Open-circuit test with meters on LV side: 240 V, 3.2 A, 165 W •

Principle of oscillation in an rc phase shift oscillator, Q. What is the ba...

Q. What is the basic principle of oscillation in an RC phase shift oscillator. With a neat sketch explain its working? For producing oscillations there must have positive feedb

Dual-ramp analog to digital converter, Q. Dual-ramp analog to digital conve...

Q. Dual-ramp analog to digital converter? Figure (a) shows the block diagram of a dual-ramp (dual-slope) A/D converter. After a start-of-conversion pulse, the counter is cleare

Solving electrical circuits, i need help solving an electrical circuit, usi...

i need help solving an electrical circuit, using kirchoffs laws, it a diamond shape with one voltage source

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