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9.5.2. more precise, the circuit-breakers
that lim the section affected the fault see the direction the fault current different ways (Relayl =forward and Relay2 backward).
Model 2234 Apparatus Scale
L2778
Doc. 14.
It should noted that activation the DBout3 output the relay3 will have effect the relay4, because the latter recording not an
out-of-phase (backward) fault current, but in-phase (forward) current with the power flow defined previously the user (Top Bottom). the above example, the circuit-breaker does not open with the l,
only the circuit-breaker with relay4 will open after time 100ms.
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.5 Protection "I"
The protection enabled/disabled from the menu.2).
In the case where zone selectivity "S" active, during the trip the relay for "I", the ZSO output signal activated any case guarantee correct
operation the relay the supply side (and the load side).
This function can activated through hand-held PR010/T unit via SD-Testbus2, SD-Pocket software through remote system via the system
bus. No.
The circuit-breakers (Relayl and Relay2) delim iting the section affected the fault are tripped with the selectivity tim ts, while the circuit-
breakers further away from the fault count down the time t7FW (Relay4) and t7BW (Relay3) without opening; this way, the system isolated,
in the time ts, exclude the part affected the fault.9. 2
Page No.
This protection goes when the closed, within time window ranging from 500ms and with threshold set customer, using
the same algorithm protection This protection can disabled and alternative protection "I".the power flow phase with the direction set the relay, the output DFout enabled (1).
If fault detected fault beyond the threshold I7) one the sections the system (Load A), the final circuit-breakers for the section
in question (Relayl and Relay2) comm unicate the presence the fault the connected circuit-breakers (Relay4 and Relay3) setting the
output signals DFout DBout depending the direction the current (DFoutl DB2out=On).2.6 Protection against closing sho rt-circuit "
The MCR can used protect the system from any closing short-circuit; operates only when Vaux PR120/V installed.
The function behaves exactly the same way the protection "S" (see par.2.
14.
The function can enabled from the menu the protection "I" page.
Vice versa, the power flow out phase, the output DBout enabled (1).9.
Note:
- With zone selectivity enabled, the direction the power flow cannot ascertained, the relay tripped considering the lesser the
programmed times between t7fw and t7bw, without enabling any outputs (DFout DBout).2.9.
The load where the fault has occurred, will disconnected, but loads and will continue powered normally.
14.2.
- The SdZ operates the basis the phase currents, not the neutral.
14.1 Start-up threshold "I"
The start-up function can selected.
The typical configuration the system circuit-breakers for which the SdZ likely used the sort ring illustrated the following
figure.
This function has one single fixed-time protection curve.
- If, for some reason, one the circuit-breakers required open does not so, specific function will activate the opening the first circuit-
breaker immediately upstream from it, after further 100ms approx
