The deficiency of traditional relay protection is analyzed

and the concept of flexible operation features of relay protection is proposed. That is

operation features are determined with a variety of criteria according to the fault characteristics of protection objects. Compared with the operation features using a single criterion for relay protection

flexible operation features are suitable for cases of indistinct fault characteristics. The application occasions of the protection flexible operation features are described

including transformer excitation inrush current identification

distance protection oscillation block open conditions

the rapidity and accuracy of high resistance grounding fault

and so on. Finally

the application prospects of the relay protection flexible operation features are previewed.