ECE 576 POWER SYSTEM DYNAMICS AND STABILITY Lecture 15b Single-Machine Infinite-Bus System Professor Pete Sauer Department of Electrical and Computer Engineering © 2000 University of Illinois Board of Trustees, All Rights Reserved

Classical model Or, go back to the two-axis model and assume:

This is a pendulum model Neglect resistance and assume TCH = ∞ This is a pendulum model

This is a pendulum model Or This is a pendulum model

Response with K1=5, K2=10, K3=1.7 (appropriate units) Euler forward method with time step of 0.001 sec Initial angle -1 radian Initial speed 7.0 rad/sec

Phase portrait – Omega vs Delta

Response with K3=1.3 (appropriate units) – Delta converges to 30 degrees plus 720 degrees

Interesting result – increase the time step to be 0 Interesting result – increase the time step to be 0.003 sec – results in loss of damping!