Feature Element 51P Element 50P-1 Element 50P-2
*
at definite-time
characteristic
±2% of the set
operate time or ±25
ms
±2% of the set
operate time or ±25
ms
±2% of the set
operate time or ±25
ms
*
at IDMT characteristic
according to IEC 60255-
3: accuracy class index
E
5 or ±25 ms
*
at IDMT characteristic
according to
IEEE C37.112
±7% of the
calculated operate
time or ±25 ms
*
at RI-type characteristic ±7% of the
calculated operate
time or ±25 ms
*
at RD-type characteristic
(RXIDG)
±7% of the
calculated operate
time or ±25 ms
Operation accuracy
*
0.3...0.5 x I
n
±5% of the set
pickup value
*
0.5...5.0 x I
n
±3% of the set
pickup value
±3% of the set
pickup value
±3% of the set pickup
value
*
5.0...35.0 x I
n
±3% of the set
pickup value
±3% of the set pickup
value
a)
Because of the maximum measured current (50 × I
n
), the setting value 2.5 is used for the IDMT
calculation if the set value is greater than 2.5. This makes the operate time faster than the theoretical
IDMT curve. However, the element always pick up according to the set value.
b)
Resetting time of the trip signal.
Table 5.1.4.11.-2 Elements 51N and 50N
Feature Element 51N Element 50N
Set pickup value, 51N and
50N
*
at definite-time
characteristic
1.0...100% I
n
(CT) 5.0...800% I
n
(CT)
*
at IDMT characteristic 1.0...100% I
n
a)
(CT)
Pickup time, typical 60 ms 50 ms
Time/current characteristic
*
definite time
operate time, 51N TDLY and
50N TDLY
0.05...300 s 0.05...300 s
*
IDMT according to
IEC 60255-3
Extremely inverse
Very inverse
Normal inverse
Long-time inverse
time dial,51N TD IEC 0.05...1.00
*
Special type of IDMT
characteristic
RI-type inverse
RD-type inverse
time dial,51N TD IEC 0.05...1.00
*
IDMT according to
IEEE C37.112
Extremely inverse
Very inverse
Inverse
70
REF610REF610
Feeder Protection Relay
Technical Reference Manual - ANSI Version
1MRS755535
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