Settings; Testing; Test Equipment 7Vp8300-0; Testing Of The 7Sn71 - Siemens 7SN71 Instruction Manual

Transient earth-fault relay 7SN71
3.4

Settings

The pick-up sensitivity is adjusted to the system load
and c.t. ratios by means of the three coding plugs on
the front panel of the 1 or 5 A connection. The setting
is based on the earth current I
Zero-sequence current I
0
Terminals for
Front plug withdrawn
for normal sensitivity, plug no.
for increased sensitivity, plug no.
If the marking on the plug is in vertical position, the
plug is withdrawn and effective. In the in-effective,
plugged-in position the marking is horizontal.
3.5

Testing

Function tests of the transient earth-fault relay, inclu
ding tests of the connection wiring (e.g. of the cubicle
terminals), can be carried out with test equipment
7VP8300-0.
3.5.1

Test equipment 7VP8300-0

Test equipment 7VP83 serves to test the transient
earth-fault relay 7TH2300-0 / 7SN70 and 7SN71.
The test equipment operates at 230 V AC.
Test current I and test voltage V
0
detection of the transient earth-fault are made avai
lable via the terminal sockets.
The connection of the test current/voltage and the
phase rotation of the current are effected by means
of pushbutton S1. Activation of the test current/vol
tage is indicated by LED H1.
Siemens AG March 1997
Instruction Manual
of the unearthed
E
(sec.)
for the directional
0
Operating instructions
Order No.: E50410-A0007-U501-A1-7691
system converted for the secondary side of the c.t.s.
The coding plugs are selected according to the follo
wing table.
<0.5 A <2.5 A
1 A 1 A
3 1
all 2
3.5.2

Testing of the 7SN71

All safety precautions which apply for work in electri
cal installations are to be observed during tests.
Before testing, the current and voltage inputs of the
test object must be isolated.
Otherwise, the accuracy of the test results can be
invalidated.
the test object ic connected to test equipment 7VP83
as shown in figure 3.3.
3
<5 A >5 A
5 A 5 A
3 1
all 2
3 - 3