Thytronic SME70, Manual

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13
SME70, SME70-C, SME70-M-Manual-04-2020
• V
0
Operation
The start of any 67N element becomes active when the following conditions are contemporaneously
active:
• The residual current fundamental component ( I
0
) overcomes the threshold
• The residual voltage fundamental component ( V
0
) or the negative sequence voltage ( V
i
) over-
comes the threshold
• The residual current phasor ( I
0
) is located inside the trip angular sector.
Each directional earth fault overcurrent elements can be enabled or disabled by setting ON or OFF
the 67NS1 Enable , 67NS2 Enable parameters inside the
Set \ 67
menu.
The setting in which both thresholds are disabled is indicated by a flashing LED 67N.
Depending on the type of fault the relays 51 and 67N and the LED 67N are driven.
• The trip of the 67NS1 threshold (60 ... 255°), with the 67NS2 threshold disabled, drives the relay 67N
and 67N LED
• The trip of the 67NS2 threshold (60 ... 120°), with the 67NS1 threshold disabled, drives the 51 and
67N relays and 67N LED
• A fault inside the 120...255° sector with the 67NS1 and 67NS2 threshold enabled, drives the 67N
relay and 67N LED
• A fault inside the 60...120° sector with the 67NS1 and 67NS2 threshold enabled, drives the 51 and
67N relays and 67N LED
Operate times:
• Duration of the fault not detected 0.04 s
• Duration of the fault detected (voltage present) 0.08 s
• Duration of the fault detected (voltage not present) 0.15 s
• Max operate time (voltage present) 0.15 s
• Max operate time (voltage not present) 0.17 s
67NS1 threshold
ENABLED
67NS2 threshold
DISABLED
Relay 67N ON
Relay 51 OFF
LED 67N ON
255°
60°
V
0,
V
i
120°
60°
NO TRIP
NO TRIP
TRIP
TRIP
67NS1 threshold
DISABLED
67NS2 threshold
ENABLED
Relay 67N ON
Relay 51 ON
LED 67N ON
255°
60°
120°
60°
NO TRIP
NO TRIP
TRIP
TRIP
67NS1 threshold
ENABLED
67NS2 threshold
ENABLED
Relay 67N ON
Relay 51 OFF with fault inside the 120...255° sector
Relay 51 ON with fault inside the 60...120° sector
LED 67N ON
255°
60°
120°
60°
NO TRIP
NO TRIP
TRIP
TRIP
V
0,
V
i
V
0,
V
i
V
0,
V
i
V
0,
V
i
V
0,
V
i
67N logic
Circuit breaker closing on fault
with voltage ON before fault
67N logic
Circuit breaker closing on fault
with voltage OFF before fault
40 ms
Fault
TRIP 67N
V
4
, V
8
, V
12
Circuit
breaker
CLOSED CLOSED
Voltage presence ON Voltage ON Voltage OFF
OPEN OPEN
≥80 ms
≤ 150 ms
40 ms ≥150 ms
≤ 170 ms