Functions
2.2 Overcurrent Protection 50, 51, 50N, 51N
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008
67
51 Element (phases) with IEC or ANSI characteristics
Having set address
112
Charac. Phase
=
TOC IEC
or
TOC ANSI
when configuring the protection functions
(Section 2.1.1.2), the parameters for the inverse characteristics will also be available.
If address
112
Charac. Phase
was set to
TOC IEC
, you can select the desired IEC characteristic (
Normal
Inverse
,
Very Inverse
,
Extremely Inv.
or
Long Inverse
) at address
1211
51 IEC CURVE
. If
address
112
Charac. Phase
was set to
TOC ANSI
, you can select the desired ANSI characteristic (
Very
Inverse
,
Inverse
,
Short Inverse
,
Long Inverse
,
Moderately Inv.
,
Extremely Inv.
or
Definite Inv.
) at address
1212
51 ANSI CURVE
.
If the inverse time trip characteristic is selected, it must be noted that a safety factor of about 1.1 has already
been included between the pickup value and the setting value. This means that a pickup will only occur if a
current of about 1.1 times the setting value is present. If
Disk Emulation
was selected at address
1210
51
Drop-out
, reset will occur in accordance with the reset curve as described before.
The current value is set in address
1207
51 PICKUP
. The setting is mainly determined by the maximum an-
ticipated operating current. Pickup due to overload should never occur since in this mode the device operates
as fault protection with correspondingly short tripping times and not as overload protection.
The corresponding time multiplier for an IEC characteristic is set at address
1208
51 TIME DIAL
and in
address
1209
51 TIME DIAL
for an ANSI characteristic. It must be coordinated with the grading coordination
chart of the system.
The time multiplier can also be set to
∞
. In this case, the element will not trip after pickup. However, pickup, will
be signaled. If the 51 element is not required at all, address
112
Charac. Phase
should be set to
Definite
Time
during protective function configuration (see Section 2.1.1.2).
51N Element (ground) with IEC or ANSI Characteristics
Having set address
113
Charac. Ground
=
TOC IEC
when configuring the protection functions (Section
2.1.1), the parameters for the inverse characteristics will also be available. Specify in address
1311
51N IEC
CURVE
the desired IEC characteristic (
Normal Inverse
,
Very Inverse
,
Extremely Inv.
or
Long
Inverse
). If address
113
Charac. Ground
was set to
TOC ANSI
, you can select the desired ANSI
characteristic (
Very Inverse
,
Inverse
,
Short Inverse
,
Long Inverse
,
Moderately Inv.
,
Extremely Inv.
or
Definite Inv.
) at address
1312
51N ANSI CURVE
.
If the inverse time trip characteristic is selected, it must be noted that a safety factor of about 1.1 has already
been included between the pickup value and the setting value. This means that a pickup will only occur if a
current of about 1.1 times the setting value is present. If
Disk Emulation
was selected at address
1310
51
Drop-out
, reset will occur in accordance with the reset curve as described before.
The current value is set in address
1307
51N PICKUP
. The setting is mainly determined by the minimum an-
ticipated ground fault current.
The corresponding time multiplier for an IEC characteristic is set at address
1308
51N TIME DIAL
and in
address
1309
51N TIME DIAL
for an ANSI characteristic. This has to be coordinated with the grading coor-
dination chart of the network. For ground currents with grounded network, you can often set up a separate
grading coordination chart with shorter delay times.
The time multiplier can also be set to
∞
. In this case, the element will not trip after pickup. However, pickup, will
be signaled. If the
51N-TOC
element is not required at all, address
113
Charac. Ground
should be set to
Definite Time
during configuration of the protection functions (see Section 2.1.1).