Deterioration of Frequency Response in Low Inertia Networks due to Governor Dead-Bands

Renewable energy sources are increasingly replacing conventional fossil-fueled power plants in electric power systems around the world. As a result, the frequency excursions have become high due to the low synchronous inertia remaining in the system. An example is South Australia, where the generation mix heavily depends on renewable energy sources. Therefore, when South Australia is subjected to a non-credible contingency such as a network separation, the impact of governor dead-bands towards frequency stability can be significant. In this work, the influence of governor dead-bands on frequency nadir and quasi steady-state frequency is investigated. In turn, their effect towards the services, which are operating outside the normal operating frequency band, such as load shedding and frequency control services is discussed.