An overview of the protection that would be expected for a unit generator-transformer
system is summarized in Figure 18.16 and Table 18.3. The protective relays shown in Figure
18.16 and described in Table 18.3 are the minimum recommended protection for steam turbine
generators, hydro generators, and combustion turbine generators where the generator uses a
unit transformer for stepping up to transmission voltages. In most cases, the protections shown
apply equally to attended or unattended generating stations and for almost all ratings [7]. It is
assumed that high impedance grounding of the generator is used, with the grounding achieved