ABB RELION Series Technical Manual page 292

Section 4
Protection functions
286
GUID-829C6CEB-19F0-4730-AC98-C5528C35A297 V2 EN
Figure 143: Definition of the relay characteristic angle, RCA=0 degrees in a
compensated network
Example 2
The "Phase angle" mode is selected, solidly earthed network (φRCA = +60 deg)
=> Characteristic angle = +60 deg
1MRS758755 A
REC615 and RER615
Technical Manual