| Title |
Performance Improvement of a PI Observer for Line Fault Detection of a Single Machine Infinite Bus System Under Model Uncertainty |
| Authors |
김준우(Jun Woo Kim) ; 양선직(Sun Jick Yang) ; 손영익(Young Ik Son) |
| DOI |
https://doi.org/10.5370/KIEE.2021.70.2.387 |
| Keywords |
Single-machine infinite bus system; Swing equation; PI observer; Model uncertainty; Recursive least square method |
| Abstract |
This paper proposes a method for improving disturbance estimation performance of a PI observer for line fault detection of the single?machine infinite bus (SMIB) power system under the model uncertainty. The SMIB model of the paper is described by an improved swing equation that reflects more realistic dynamic characteristics than the conventional one. The proposed method begins with the conventional swing equation and the PI observer for the exact disturbance estimation. Model uncertainty arising from the model difference is first estimated using the estimated equivalent disturbance by the PI observer during equilibrium operation. Next, the uncertain parameters are estimated by applying the Recursive Least Square algorithm to the modified swing equation by using the estimated term at the first step. The angular velocity and acceleration information for the RLS algorithm can be also estimated by the PI observer based on the modified swing equation. Finally, the estimated parameters are adopted to the proposed PI observer and its disturbance estimation performance can be improved effectively for the line fault detection. The performance of the proposed algorithm is verified by computer simulations of the improved SMIB power system model. |