LIVE Course for free

Rated by 1 million+ students
Get app now
0 votes
66 views
in General by (59.9k points)
closed by

A 500 MVA, 11KV synchronous generator has 0.2 p.u. synchronous reactance. The p.u. synchronous reactance on the base values of 100 MVA and 22 KV is


1. 0.16
2. 0.01
3. 4.0
4. 0.25

1 Answer

0 votes
by (110k points)
selected by
 
Best answer
Correct Answer - Option 2 : 0.01

Concept:

The relation between new per-unit value & old per unit value of reactance

\({({X_{pu}})_{new}}\; = {({X_{pu}})_{old}} \times {\left( {\frac{{k{V_{base}}}}{{k{V_{new}}}}} \right)^2} \times \;\left( {\frac{{MV{A_{new}}}}{{MV{A_{old}}}}} \right)\)

Also \({X_{pu}} = \frac{{{X_{Actual}}}}{{{X_{base}}}}\)

 \({X_{base}} = \frac{{kV_{base}^2}}{{MV{A_{base}}}}\)

Where,

(Xpu)new = New per unit value of reactance

(Xpu)old = Old per unit value of reactance

kVbase = Old base value of voltage

kVnew = New base value of voltage

MVAnew = New base value of power

MVAold = Old base value of power

Calculation:

Given that,

Xd(old) = 0.2 pu

MVA(new) = 100

MVA(old) = 500

KV(old) = 11

KV(new) = 22

∴ \({X_{d\left( {new} \right)}} = 0.2 \times \frac{{100}}{{500}} \times {\left( {\frac{{11}}{{22}}} \right)^2} = 0.01\;pu\)

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...