Siemens 7SJ85 - Settings; Information List; Application Example: High-Impedance Restricted Ground-Fault Protection; Description

Settings
Addr. Parameter C Setting Options Default Setting
Fast stage #
_:1 Fast stage #:Mode
•
off
•
on
•
test
off
_:2 Fast stage #:Operate &
flt.rec. blocked
•
no
•
yes
no
_:3 Fast stage #:Threshold 1 A @ 100 Irated 0.030 A to 35.000 A 10.000 A
5 A @ 100 Irated 0.15 A to 175.00 A 50.00 A
1 A @ 50 Irated 0.030 A to 35.000 A 10.000 A
5 A @ 50 Irated 0.15 A to 175.00 A 50.00 A
1 A @ 1.6 Irated 0.001 A to 1.600 A 10.000 A
5 A @ 1.6 Irated 0.005 A to 8.000 A 50.000 A
_:4 Fast stage #:Dropout
ratio
0.90 to 0.99 0.90
_:6 Fast stage #:Operate
delay
0.00 s to 60.00 s 0.00 s
Information List
No. Information Data Class
(Type)
Type
Fast stage #
_:81 Fast stage #:>Block stage SPS I
_:54 Fast stage #:Inactive SPS O
_:52 Fast stage #:Behavior ENS O
_:53 Fast stage #:Health ENS O
_:55 Fast stage #:Pickup ACD O
_:56 Fast stage #:Operate delay expired ACT O
_:57 Fast stage #:Operate ACT O
Application Example: High-Impedance Restricted Ground-Fault Protection
Description
With the high-impedance method, all current transformers operate in parallel at the limits of the protection
range on a common, relatively high-impedance resistor R, the voltage of which is measured.
The current transformers must be of the same type of construction and have at least one core of their own for
the High-impedance restricted ground-fault protection. Furthermore, they must have the same transfer ratio
and approximately the same knee-point voltage.
The high-impedance principle is especially suited for ground-fault detection in grounded networks at trans-
formers, generators, motors, and shunt reactors.
The left part of Figure 6-104 shows an application example for a grounded transformer winding or a grounded
motor/generator. The example at the right shows an ungrounded transformer winding or an ungrounded
motor/generator. In this example, it is assumed that the network is grounded at a different point.
6.12.6.3
6.12.6.4
6.12.7
6.12.7.1
Protection and Automation Functions
6.12 Overcurrent Protection, 1-Phase
SIPROTEC 5, Overcurrent Protection, Manual 535
C53000-G5040-C017-8, Edition 07.2017