Analysis of effects of synchronism conditions on power system operation

A power grid might be separated into several independent subsystems when the system suffers from major events. Conditions for parallel resynchronization operation of separated subsystems sometimes cannot be satisfied due to various problems. The main purpose of this paper is to analyze the effects of the differences between the frequencies, voltages, and/or phase angles of the two subsystems to be synchronously parallelized. Moreover, the allowed range of these differences and the methods for reducing these differences are studied. Also compared are the cases with two different points of parallel switching. The results are expected to be helpful with improving the system performance during parallel switching operation in order to recover the power system from emergency conditions.