MVR모드에서 AVR모드로의 절환에 의한 여자계 모델정수 결정

Identification of Excitation System Model Parameters from the Test of Switching from MVR Mode to AVR Mode

A simulation procedure was developed for identifying Yungnam unit 2 excitation model parameters to improve the accuracy of stability simulation of KEPCO. First, generator model parameters are derived by using modified load rejection technique from measured load rejection test. For identifying excitation model parameters, switch was changed from MVR mode to AVR mode in Yungnam unit 2 excitation system instead of applying to a small step to the voltage reference($V_{ref}$) because of saving time and efforts, assuming the test result would show coincided result with applying to a small step to the $V_{ref}$. However, it was found that the response of switching from MVR to AVR is greatly different from it of applying small signal to the $V_{ref}$. A simulation procedure was needed to take into accounts of real AVR component status before and after switching from MVR to AVR. This paper reports the procedure which duplicated the measured response and addresses the merits of this test on conventional AVR step test.