Polarity Check For The Current Input I; Measuring The Operating Time Of The Circuit Breaker - Siemens Siprotec 7VK61 Manual

Mounting and Commissioning
3.3 Commissioning
• Via binary input (No. 2906„>Sync. Start AR") initiate the measuring request. The synchronism check
must release closing (message „Sync. release", No. 2951). If not, check all voltage connections and
the corresponding parameters again carefully as described in Section 2.1.3.1.
• Open the VT mcb of the measuring point U
• Via binary input (No. 2906 „>Sync. Start AR") initiate the measuring request. No close release is given.
• Reclose the VT mcb of the measuring point U
Addresses 3515 to 3519 must be restored as they were changed for the test. If the allocation of the LEDs or
signal relays was changed for the test, this must also be restored.
3.3.9

Polarity check for the current input I

If the standard connection of the device is used whereby current input I
of current transformers (refer also to the connection circuit diagram in the Appendix A.3), then the correct po-
larity of the earth current path in general automatically results.
If, however, the current I
is necessary.
Otherwise the test is carried out with a disconnected trip circuit and primary load current. It must be noted that
during all simulations that do not exactly correspond with situations that may occur in practice, the non-sym-
metry of measured values may cause the measured value monitoring to pickup. This must therefore be ignored
during such tests.
DANGER!
Hazardous voltages during interruptions in secondary circuits of current transformers
Non-observance of the following measure will result in death, severe personal injury or substantial property
damage.
Short-circuit the current transformer secondary circuits before current connections to the device are opened.
Note
If parameters were changed for this test, they must be returned to their original state after completion of the test!
3.3.10

Measuring the Operating Time of the Circuit Breaker

Only for Synchronism Check
If the device is equipped with the function for synchronism and voltage check and it is applied, it is necessary
- under asynchronous system conditions - that the operating time of the circuit breaker is measured and set
correctly when closing. If the synchronism check function is not used or only for closing under synchronous
system conditions, this section is irrelevant.
For measuring the operating time a setup as shown in Figure 3-26 is recommended. The timer is set to a range
of 1 s and a graduation of 1 ms.
The circuit breaker is closed manually. At the same time the timer is started. After closing the circuit breaker
poles the voltage U
breaker closing time.
If the timer is not stopped due to an unfavourable closing moment, the attempt will be repeated.
224
is supplied by a separate summation CT, an additional direction check for this current
4
or U appears and the timer is stopped. The time displayed by the timer is the real circuit
sy1 sy2
(No. 361 „>FAIL:Feeder VT").
sy1
.
sy1
4
is connected in the starpoint of the set
4
C53000-G1176-C159-3, Release date 05.2009
SIPROTEC, 7VK61, Manual