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

Show frequency response using pspice and probe, Q. Show Frequency response ...

Q. Show Frequency response using pspice and probe? PSpice is capable of performing transient circuit analysis, for which the request is given by the following statement: • T

Transfer characteristics of jfets, Q. Give the Shockley's equation for the ...

Q. Give the Shockley's equation for the transfer characteristics of JFET's? Where ID is the drain current and VGS is the voltage across gate and source. The squared term o

Accelerator and investment, Q. Accelerator and Investment? Accelerator,...

Q. Accelerator and Investment? Accelerator, Investment: Investment spending stimulates economic growth that consecutively stimulates further investment spending (as businesses

Power Engineering, A three-phase transposed line is composed of one ACSR co...

A three-phase transposed line is composed of one ACSR conductor per phase with flat horizontal spacing of 11 meters as shown in Figure (a). The conductors have a diameter of 3.625

What is the function of ct and p.t, Q. What is the function of CT and P.T a...

Q. What is the function of CT and P.T and where they are used? Ans: The full form of CT is Current transformer and is used for calculating of current. The full form of PT is

Calculate motor efficiency, 1. A self excited shunt generator supplies a lo...

1. A self excited shunt generator supplies a load of 12.5 kw at 125 volts. The field resistance is 25 ohms and the armature resistance is 0.2 ohms. The total voltage drop because o

Explain microprocessor development system, Explain Microprocessor developme...

Explain Microprocessor development system. Microprocessor development system: Computer systems consist of undergone many changes lately. Machines which once filled large area

Princeton and harvard microprocessor architectures, Question a) Explain...

Question a) Explain, with the aid of diagrams, the differences between the Princeton and Harvard microprocessor architectures. b) Describe why the principle of locality of r

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