ABB REF615 - Page 56

Three stages are offered for directional earth-fault protection. In addition, there is a
dedicated protection stage (INTRPTEF) either for transient based earth-fault
protection or for cable intermittent earth-fault protection in compensated networks.
A dedicated non-directional earth-fault protection block (EFHPTOC) is intended for
protection against double earth-fault situations in isolated or compensated networks.
This protection function uses the calculated residual current originating from the
phase currents.
The binary input 2 (X110:3-4) is intended for directional earth-fault protection
blocks’ Relay Characteristic Angle (RCA: 0°/-90°) or operation mode (I
0
Sinφ/
I
0
Cosφ) change. All operate signals are connected to the Master Trip and also to the
alarm LEDs. LED 2 is used for directional earth-fault and LED 3 for double earth-
fault protection operate indication.
A071320 V4 EN
Figure 19: Phase discontinuity, thermal overload and circuit breaker failure
protection
The phase discontinuity protection (PDNSPTOC1) provides protection for
interruptions in the normal three-phase load supply, for example, in downed
conductor situations. The thermal overload protection (T1PTTR1) provides
indication on overload situations. The operate signal of the phase discontinuity
protection is connected to the Master Trip and also to an alarm LED. LED 4 is used
for the phase discontinuity protection operate indication, the same as for negative
sequence overcurrent protection operate indication, and LED 5 is used for the thermal
overload protection alarm indication.
Section 3 1MRS756378 D
REF615 variants
50 REF615
Application Manual