Wind Energy Systems - Wind Energy Systems for Electric Power Generation - page 100

Fig. 5.20 Concept of an island grid with combined generation and storage
(Source: SMA)
contribute to power generation. Two capacitor banks are for the basic reactive load
compensation. A battery storage is provided which is coupled to the grid via a con-
verter The battery may be combined with the load controller. A passive filter com-
pletes the generation system.
The behaviour of simple concepts using frequency as controled variable is shown
in Fig. 5.21. The aim is to utilize the wind power wherever possible and to reduce the
operation time of the Diesels and save fuel. In the figure the congtroled frequency
interval is 49 < f < 51 Hz which is acceptable only in smaller stand-alone systems.
The operation management has to deal with frequent starts, synchronizations and
shut-downs. A priority switching scheme for consumers can be incorporated in the
system.
5.4.1.3 Combination with Other Renewable Power Sources
An extension of an island system as in Fig. 5.21, without Diesel generation but with
another renewable energy source such as photovoltaic (PV) generator, is shown in