Correct AnswerB. Sparse matrix
Quick Explanation
Each power-system bus is directly connected to only a small fraction of all other buses. Therefore most off-diagonal elements of the bus-admittance matrix are zero, making YBUS a sparse matrix for a large network. Hence option B.
Detailed Explanation
Correct Answer
B — Sparse matrix
Concept and Reasoning
Each power-system bus is directly connected to only a small fraction of all other buses. Therefore most off-diagonal elements of the bus-admittance matrix are zero, making YBUS a sparse matrix for a large network. Hence option B.
Calculation / Key Relation
Yij=0 when buses i and j have no direct branch connection
Exam Takeaway
Large power-network YBUS is sparse because connectivity is local.
Common Mistake
Do not call YBUS full merely because every bus participates in the system solution.
