A review of the generally accepted forms of relay protection for the synchronous generator and its excitation system is presented. This guide is primarily concerned with protection against faults and abnormal operating conditions for large hydraulic, steam, and combustion turbine generators.

This application guide for the relay protection of synchronous generators presents a review of the generally accepted forms of protection for the synchronous generator and its excitation system. It summarizes the use of relays and devices and serves as a guide for the selection of equipment to obtain adequate protection. The guide is primarily concerned with protection against faults and abnormal operating conditions for large hydraulic, steam, and combustion turbine generators. Basing generator protection on machine size is difficult because the desired protection may be determined more by the importance of the generator to the power system than by the size...

This Guide summarizes the use of relays and devices such that the reader may select the necessary equipment to provide adequate protection for AC generators from short circuits and abnormal operating conditions. Improved protection schemes have now been proven and multifunction relays now available provide the user more choices. These concepts need to be added to the Guide to maintain its completeness.