Test For High Impedance Protection; Testing The Reverse Interlocking Scheme; Direction Check With Load Current - Siemens siprotec SJ62 User Manual

3 Mounting and Commissioning
3.3.7

Test for High Impedance Protection

Polarity of Trans-
formers
3.3.8

Testing the Reverse Interlocking Scheme

(only if used)
3.3.9

Direction Check with Load Current

≥ 10 % of Load
Current
429
When the device is used for high-impedance protection, the current at I
equivalent to the fault current in the protected object. It is essential in this case that all
current transformers feeding the resistor whose current is measured at I
same polarity. The test currents used for this are through currents. Each CT must be
included in a measurement. The current at I
value of the single-phase time overcurrent protection.
Testing reverse interlocking is available if at least one of the binary inputs available is
configured for this purpose (e.g. presetting of binary input BI1 „>BLOCK 50-2" and
„>BLOCK 50N-2" to open circuit system). Tests can be performed with phase cur-
rents or ground current. For ground current the corresponding ground current settings
apply.
Please note that the blocking function can either be configured for the pickup current
connected (open circuit system) or the pickup current missing (closed circuit system).
For open circuit system the following tests are to be proceeded:
The feeder protection relays of all associated feeders must be in operation. At the be-
ginning no auxiliary voltage is fed to the reverse interlocking system.
A test current higher than the pickup values of 50-2 PICKUP and 50-1 PICKUP or
51 PICKUP is set. As a result of the missing blocking signal, the protection function
trips after (short) time delay 50-2 DELAY.
Caution!
Tests with currents that exceed more than 4 times the nominal device current
cause an overload of the input circuits.
Perform test only for a short time (see Technical Data, Section 4.1). Afterwards the
device has to cool off !
The auxiliary voltage for reverse interlocking is now switched to the line. The prece-
dent test is repeated, the result will be the same.
Subsequently, at each of the protection devices of the feeders, a pickup is simulated.
Meanwhile, another fault is simulated for the protection function of the infeed, as de-
scribed before. Tripping is performed within time 50-1 DELAY (longer time period)
(with definite time overcurrent protection) or according to characteristic (with inverse
time overcurrent protection).
These tests also check the proper functioning of the wiring for reverse interlocking.
The correct connection of the current and voltage transformers are tested via the pro-
tected line using the load current. For this purpose, connect the line. The load current
the line carries must be at least 0.1 · I
may never exceed half the pickup
N(S)
. The load current should be in-phase or
Nom
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
or I is
N NS
have the
N(S)