ABB RELION Series Technical Manual page 393

1MRS758755 A
REC615 and RER615
Technical Manual
GUID-B8FF033F-EB15-4D81-8C9F-E45A8F1A6FA8 V1 EN
Figure 201: Operation in "General EF" mode
Operation mode "Alarming EF" is applicable in all kinds of earth faults in unearthed
and compensated networks, where fault detection is only alarming. It is intended to
detect earth faults regardless of their type (transient, intermittent or restriking,
permanent, high or low ohmic). The setting Voltage start value defines the basic
sensitivity of the MFADPSDE function. In "Alarming EF" mode, the operate timer is
started during the following conditions.
• Earth fault is detected by the GFC
• Fault direction equals Directional mode setting
• Estimated stabilized fundamental frequency residual current exceeds the set Min
operate current level
The START output is activated once Start delay time has elapsed. OPERATE output is
not valid in the "Alarming EF" mode. Reset timer is started if any of the above three
Section 4
Protection functions
387