Siemens 7SJ85 - Page 1458

Characteristic curve: see Figure 12-14
Minimum time of the characteristic curve 0.00 s to 30.00 s Increments of 0.01 s
Knee-point time of the curve 0.00 s to 100.00 s Increments of 0.01 s
Maximum time of the characteristic curve 0.00 s to 200.00 s Increments of 0.01 s
Knee-point value 0.030 A to 35.000 A Increments of 0.001 A
Current at minimum time of the curve 0.030 A to 35.000 A Increments of 0.001 A
Time multiplier 0.05 to 1.50 Increments of 0.01
[dwdrloinkn-171013, 1, en_US]
Figure 12-14
Operate Curve of the Logarithmic Inverse Time with Knee-Point Characteristic (In the Example
of Threshold = 0.004 A)
Dropout
The greater dropout differential (= | pickup value – dropout value |) of the following 2 criteria
applies:
Dropout differential derived from the parameter
Dropout ratio
If this parameter is not available, a dropout ratio of 95 % applies for overcurrent and of 105 % for undercur-
rent functionality.
Minimum absolute dropout differential
Protection-class current transformer 15 mA sec. (I
rated
= 1 A) or
75 mA sec. (I
rated
= 5 A)
Instrument current transformer 0.5 mA sec. (I
rated
= 1 A) or
2.5 mA sec. (I
rated
= 5 A)
Technical Data
12.9 Directional Overcurrent Protection, Ground
1458 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017