Voltage Stability Assessment Using Advanced Models of Thermal Generation Units for the P/V-Analysis

All transmission system operators (TSO) are encouraged to continuously monitor their transmission system to ensure a secure operation with all operational values within tolerable limits even in case of contingencies. Therefore the TSOs run an on-line steady state system security analysis using typically the (n-1)-criterion to determine the current and potential system states. In the conventional power flow analysis the maximum reactive power output of a unit does not depend on the voltage. This simplification, however, leads to overoptimistic results as the maximum reactive power capability decreases with the voltage. In this paper an advanced generation unit model is compared to the conventional model using the P/V-Analysis to determine the margins to different system states for a…