By effective data processing prior to the fault and optimization of the phase selection process， improvement has been made on the ability of the fault phase selector based on the fault component of compensation voltage to enable it to work better in the whole process of fault development， with the fault phase correctly indicated under different operation conditions when the power system is free from swing. Thus the inability of effectively maintaining the results of the fault phase selector based on the fault component of current and the lack of directionality are overcome using the maintaining and directional elements designed， increasing the rate of correct phase selection. The principle of synthetic fault phase selector based on the integration current is proposed and the incapability of normal operation of the fault phase selector based on stable electric components under abnormal operating conditions is resolved. A workable scheme for fault phase selection is described.