A novel power system defense plan to cope with 30% wind power penetration in the isolated Penghu system

In the plentiful wind resource on the Penghu Island, the capacity factor of the wind park is up to 47%. It is expected that more wind generating units will be integrated into this power system in the near future. However, many blackouts occurred at Penghu Island in the past and the present power protection scheme has not taken the influence of the wind generating units into consideration; therefore, it is necessary to revise the defense plan for Penghu´s power system. In this study, different generation/load patterns in different seasons are considered, followed with analyses on system steady-state and transient responses in some specific buses and important feeders. The accurate modeling on wind turbines and relay settings are performed by using the power system simulation program PSS/E. The original power defense scheme by only using under-frequency load shedding is examined, and a new protection scheme is proposed based on numerous contingency simulations, including islanding operation protection for some specific cases. It is expected that the reliability improvement of the Penghu system can be achieved by using the new defense scheme.