Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
530 views
in General by (240k points)
closed by

A circuit breaker is rated as a 1450 A, 1,200 MVA, 33 kV, 3 s, 3-phase oil circuit breaker.

Find the breaking capacity.
1. 1,200 MVA
2. 33 kV
3. 3 s
4. 1,450 A

1 Answer

0 votes
by (238k points)
selected by
 
Best answer
Correct Answer - Option 1 : 1,200 MVA

Concept:

Breaking current: It expresses the highest number of short-circuit currents that the breakers are capable of breaking under specified conditions of transient recovery voltage and power frequency voltage. It is expressed in kA (RMS) at contact separation. The breaking capacities are divided into two types.

  • Symmetrical breaking capacity of a circuit breaker
  • Asymmetrical breaking capacity of a circuit breaker

Symmetrical breaking capacity \(= \sqrt 3 {V_{L}}{I_{B}}\)

Rated symmetrical breaking current \({I_B} = \frac{S}{{\sqrt 3 {V_L}}} \)

Making current of a circuit breaker is the peak value of the maximum current loop during sub transient condition including the DC component when the breaker closes.

Symmetrical making current = 2.55 × symmetrical breaking current

Calculation:

From the given data,

MVA rating = 1200 MVA

Symmetrical breaking capacity = 1200 MVA

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

...