Frequency control of power system including PV and wind farms by using output frequency band control of HVDC interconnection line

Due to serious environmental issues in recent years, renewable energy has been focused on all over the world to solve the issues. However, because of indirect characteristics such as variations of solar radiation intensity or wind speeds, the output of power generation utilizing renewable energy becomes unstable. As a result, frequency and voltage in the power system can fluctuate. To solve this problem, various methods to control the frequency variations have been studied and reported until now, one of which is based on High voltage direct current (HVDC) transmission line. This paper proposes a novel control scheme to reduce the frequency variations due to large penetrations of wind power and photovoltaic (PV) power, which is introduced to power flow control of HVDC transmission line with utilizing a notch-band pass filter in its frequency control system.