Improvement of system damping by using the differential feedback in the load frequency control

The power system stability mostly depends on the surplus kinetic energy which is stored in the generator during the fault period. The steam valve control is the most direct method to control the surplus kinetic energy. This paper proposes a new LFC scheme with a modified PID controller which improves the system damping. The proposed frequency controller is designed to guarantee the stability of frequency control for any change in the feedback gain of frequency deviation. The proposed LFC scheme adopts the nonwindup cutoff model for the steam valve position. It has been shown that the steam valve control is the most direct method to control the surplus kinetic energy stored in the generator during the fault period and control performance significantly depends on steam valve modeling. The proposed LFC scheme has been applied for two sample systems, 4-machine 10-bus and New England 39-bus systems.