Frequency control of power system with solar and wind power stations installed by flow control of HVDC interconnection line

In recent years, environmental problems are being serious and renewable energy has attracted attention as their solutions. However, the electricity generation using the renewable energy has a demerit that the output becomes unstable because of intermittent characteristics such as variations of wind speed or solar radiation intensity. Therefore, it can cause frequency fluctuations or voltage fluctuations in the power system. Various methods have been investigated and reported so far to control the frequency and voltage fluctuations. This paper presents a new control method to suppress the frequency fluctuations occurring due to a large amount of photovoltaic (PV) power generation and wind power generation, which is based on power flow control of High voltage direct current (HVDC) interconnection line and using a dead band in its frequency control system.