An integrated all frequency protection scheme is presented in this paper based on a review of the development of transient based protection and integrated protection. Integrating the conventional power frequency protection algorithms and the transient based protection algorithms, the proposed scheme divides the protection algorithms based on power frequency and transient measurement into three groups: the single end protection group, double or multiple end protection group and backup protection protection group. The single end protection group includes conventional distance protections based on power frequency measurement and boundary and positional protections based on high frequency transient measurement, and these protections are employed to form an instant tripping protection group based on single local end measurement. The double or multiple end protection group consists of conventional current differential protection and time synchronizing transient protection, and these protections are supported by communication link through interconnecting line. The backup protection group includes conventional directional protection and transient protection based on polarity comparison. Finallly, a protection scheme designed for the ultra long length of the half-wavelength transmission line is studied by integrating all frequency domain protection techniques.