Sel 411L - Fault Type Identification Selection Logic; Figure 3.83 Level 2 Watchdog Monitor Diagram; Table 3.71 Fault Type Identification Logic Settings; Table 3.72 FIDS Relay Word Bits

P.3.141
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
Fault Type Identification Selection Logic
Fault Type Identification Selection Logic
The Fault Identification Logic is enabled by the Group Setting EFID. This
logic identifies the faulted phase(s) for all faults involving ground by
comparing the angle between I
0
and I
2
. Without 87L protection enabled, the
logic uses the locally measured I
0
and I
2
quantities. When the relay is
configured for 87L protection and operating in master mode, the logic uses the
differential I
0
and I
2
currents as indicated by the 87FIDEN Relay Word bit
(total current method), resulting in improved fault identification performance,
specifically for high-resistive double-line-to-ground faults.
For cases where only zero-sequence current flows through the relay terminal
(that is, no negative-sequence current and no positive-sequence current), the
fault type identification selection (FIDS) logic uses single-phase undervoltage
elements for faulted phase selection.
The FIDS logic is not active during an SPO (single pole open) condition (i.e.,
when SPO equals logical 1) unless 87L protection is enabled. When an 87L-
enabled relay is operating in master mode and an SPO condition is present, the
relay continues to run the total current FIDS logic. Setting EFID should be set
equal to N only when the relay is applied in high-resistance grounded
transmission systems. These systems can challenge the operation of the FIDS
logic for phase-phase-ground faults. Setting EFID equal to N disables the
FIDS logic, thereby removing FIDS supervision of phase distance elements.
For all other applications, EFID must be set equal to Y to ensure proper
operation of the phase and ground-distance elements.
Figure 3.83 Level 2 Watchdog Monitor Diagram
Table 3.71 Fault Type Identification Logic Settings
Name Description Range Default
EFID Enable Fault Identification logic Y, N Y
Ta b l e 3.72 F I D S Re l ay Wo r d Bi t s
Name Description
FIDEN FIDS logic enabled
87FIDEN Differential (total current) fault identification enabled
FSA A-phase-to-ground fault or B-phase to C-phase-to-ground fault selected
FSB B-phase-to-ground fault or C-phase to A-phase-to-ground fault selected
FSC C-phase-to-ground fault or A-phase to B-phase-to-ground fault selected
FTSAG A-phase-to-ground fault (total current method)
FTSBG B-phase-to-ground fault (total current method)
FTSCG C-phase-to-ground fault (total current method)
FTSLG Single-phase-to-ground fault detected (total current method)
FTDLG Double-line-to-ground fault detected
FTSABG ABG fault (total current)
FTSBCG BCG fault (total current)
FTSCAG CAG fault (total current)
NOTE: FTDLG will assert during
single pole open (SPO) conditions.
FTSABG
FTSBCG
FTSCAG
FTDLG