Wind Farm and Conventional Generation Protection
Figure 3 explains the philosophy of conventional generator protection and its protection zones. A large conventional generator is protected through the standard protection philosophy of unit generation protection scheme. In the above case it is easier to establish coordination among generator, transformer, and transmission protection because of limited or single unit of generation. Conventional generators even have the capability of supplying reactive power and the inertia is also an inherent capability. Because of the reactive support and having higher short-circuit strength, they have higher FRT capability and they can satisfy almost any FRT criteria established in any part of the world.
If wind farms are compared to conventional generators, they will require different and varied protection requirements. Since a single wind farm usually con- sists of several wind units and these units are connected together to collector bus through collector feeders. Reactive support is also a separate unit and is normally
connected to collector bus. The collector bus voltage is stepped up in order to connect to transmission system as shown in Fig. 4. In thisarrangement, protection requirements are different from normal conventional generator as each wind unit is provided with generator protection and also has the collector feeder protection. The coordination of transmission protection with entire unit protection configu- ration requires additional effort and care.