The paper describes the issues of designing a relay (electrical) protection system for synchronous generators of different nominal powers, with an emphasis on generators with salient poles. The issues of selecting protection functions are analyzed with respect to the method of connecting the generator to the grid (distribution grid, transmission grid, generator busbars, block connection), the method of grounding the generator voltage level (and the method of grounding the incident grid), the generator nominal power, the design of the generator excitation system, the design of the stator winding (number of parallel branches, third harmonic level), etc. Different design variants are compared and analyzed: (i) differential protection of the generator-transformer block (with or without a tap, generator switch), (ii) ground-fault protection of the stator winding (overcurrent, overvoltage, based on the third harmonic, with voltage injection into the star point). The possibilities offered by the numerical relay device type REG650 from ABB are presented, with respect to the design of the relay protection system for synchronous generators.