Investigation of the dynamic performance of compensation devices for voltage stability during low voltages

The reactive power output of compensating devices must be compared at the minimum voltage that is accepted in the grid. This paper analyses the performance of flexible AC transmission system (FACTS) devices during low-voltage recovery transients for different fault conditions. Some critical interactions amongst FACTS devices during low-voltage conditions are also investigated. The reactive power control capabilities of dynamic compensating devices at post-fault conditions are compared. In addition, this paper addresses some general concerns towards high compensations in different grid topologies. Several cases are analysed using an IEEE benchmark test system composed of 16 machines and 69 buses, which is the reduced model of New England/New York interconnection. From the analyses, it can be concluded that high compensation can reduce the security limits under certain operating conditions; certain FACTS devices are beneficial for certain network configurations; and the FACTS device with a constant current source provides better performance during low-voltage conditions.