Generator Auxiliary Systems

This chapter discusses the general nature of the five major auxiliary systems that may be in use in a particular generator: Lubricating‐oil system; hydrogen cooling system; seal‐oil system; stator cooling water system; and excitation system. In some plants, one may find an elaborate hydrogen cooling system panel where all hydrogen controls are located. The lubricating‐oil (lube‐oil) system provides oil for all of the turbine and generator bearings and also is the source of seal oil for the seal‐oil system. As a safety feature, there is often a second ac motor‐driven pump or a dc motor‐driven emergency seal‐oil pump provided. The excitation system also provides control and protective equipment that regulates the generator electrical output. The stator cooling water system (SCW) is used to provide a source of demineralized water to the generator stator winding for direct cooling of the stator winding and associated components.