Poznámky redaktora
9.
- This protection works the basis the phase currents, not the neutral current.
The general behavior summarized the table below.1 Start-up threshold "
The function can enabled from the menu (see description the protection menu 14.
(Example with power flow setting "Top Bottom").2 "D" (directional) zone selectivity
The Directional Zone Selectivity (SdZ function particularly useful ring and grid type systems where, addition the zone, essential
to define the direction the power flow that powers the fault.4.
Ifault (If) utputs status Inputs status trip
Value irection Fout out DFin Bin
lf either either either trip
lf Top Bottom either t
lf Top Bottom either
lf Bottom Top either 1
lf Bottom Top either t
Model 2234 Apparatus Scale
L 2778
Doc No- 2
Page No.4.9. 14.2).2.
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.4.2.
As the SdZ and the relays interact with each other, sending cutout signals via the outputs and reading them viathe inputs.
To define the zone and power flow, each relay has two inputs (DFin and DBin) and two outputs (Dfout and DBout), whichmust suitably
connected the other relays (see example below).9.result, the currents the circuit-breaker will defined "forward" "backward" their are phase out phase with the previously-
defined power flow (for the default setting, see par.
Note:
- With the directional protection activated, the direction the power cannot determined the relay takes effect considering shorter of
the programmed times between t7fw and t7bw.
In short:
Ifault (If) Power flow set
Top Bottom
Power flow set
Bottom Top
Value irection Trip Trip T
1, Either trip trip
1, High Low
|, Low High ^7RW *7FW
Example:
Once the power flow has been set "Top Bottom", the direction the figure alongside is:
positive reactive power "forward" direction;
negative reactive power "backward" direction;
If the preset trip times were t7FW= 200ms and t7BW= 400ms, this this case the
relay would have opened the circuit-breaker after t7FW= 200ms.4).
14.2. 14.5.2)
The function behaves exactly the same way the protection "S" (see par.
The SdZ can set alternative Zone Selectivity and and requires auxiliary power supply.
14.2
