Siemens SIPROTEC 7SJ62 Instruction Manual page 175

50N-2 Relay Ele-
ment
50N-1 Relay Ele-
ment
51N Relay Element
with IEC Curves
51N Relay Element
with ANSI Curves
7SJ62 Manual
C53000-G1140-C121-1
with phase protection. Because of this, relay coordination for ground faults is indepen-
dent of relay coordination for phase faults, and more sensitive settings can often be
applied to ground protection.
The pickup and delay of the 50N-2 relay element are set at addresses  1
3,&.83 and  1 '(/$< respectively. The same considerations apply for
these settings as did for 50-2 settings discussed earlier.
The delay set at address  is in addition to the 50N-2 element's pickup time. The
delay of the 50N-2 element may be set to ∞. The 50N-2 element will then pickup and
generate a message, but will never trip. If the 50N-2 element is not required at all, then
the pickup value should be set to ∞, thus preventing pickup, trip, and the generation
of a message.
The pickup value of the 50N-1 relay element (set at address  1 3,&.83)
should be set below the minimum anticipated ground fault current in the relay's zone
of protection.
If the 7SJ62 relay is used to protect transformers or motors with large inrush currents,
the energization stabilization feature may be used to prevent a false trip of the 50N-1
relay element. The configuration data for the energization stabilization feature is pro-
grammed at address block 22 (see Subsection 6.5.2).
The delay of the 50N-1 element is set at address  1 '(/$< and should be
based on system coordination requirements.
The delay set at address  is in addition to the 50N-1 element's pickup time. The
delay of the 50N-1 element may be set to ∞. The 50N-1 element will then pickup and
generate a message, but will never trip. If the 50N-1 element is not required at all, then
the pickup value should be set to ∞, thus preventing pickup, trip, and the generation
of a message.
Pickup of the 51N relay element will occur for currents greater than or equal to 110 %
of the 51N pickup value, and may or may not occur for currents between 100 % and
110 % of the 51 element's pickup value. Dropout of the 51N relay element occurs
when the current decreases to 95 % of the 51N element's pickup value.
The pickup value of the 51N element is set at address  1 3,&.83. As is the
case for the 50N-1 relay element, the pickup value of the 51N relay element should be
set below the minimum anticipated ground fault current in the relay's zone of protec-
tion.
The 51N element time multiplication factor is set at address  1 7,0( ',$/
and should be based on system coordination requirements.
The time multiplication factor may also be set to ∞. The 51N element will then pickup
and generate a message, but will never trip. If the 51N element is not required at all,
address  should be set to 'HILQLWH 7LPH 2QO\ during protective function con-
figuration (see Section 5.1).
Pickup of the 51N relay element will occur for currents greater than or equal to 110 %
of the 51N pickup value, and may or may not occur for currents between 100 % and
110 % of 51N pickup value. Dropout of the 51N relay element occurs when the current
decreases to 95 % of the 51N element's pickup value. If 'LVN (PXODWLRQ is selected
at address  1 5(6(7, then reset occurs according to the reset curve as de-
scribed in Subsection 6.2.1.2.
Functions
6-35