Table of Contents
Advertisement
3-12
Protection Functions
857-UM001A-EN-P – July 2009
Four independent stages
There are four separately adjustable stages available: I
I
>>> and I
>>>>.
dir
dir
Inverse operation time
Stages I
> and I
>> can be configured for definite time or
dir
dir
inverse time characteristic. See chapter Error! Reference
source not found. for details of the available inverse delays.
Stages I
>>> and I
>>>> have definite time (DT) operation
dir
dir
delay. The device will show a scaleable graph of the configured
delay on the local panel display.
Inverse time limitation
The maximum measured secondary current is 50xI
the scope of inverse curves with high pick-up settings. See
"Inverse Time Operation" for more information.
Cold load and inrush current handling
See "Cold Load Pick-up and Inrush Current Detection" in Chapter 4.
Setting Groups
There are two settings groups available for each stage. Switching
between setting groups can be controlled by digital inputs, virtual
inputs (mimic display, communication, logic) and manually.
Figure 3.10 shows the functional block of the Idir> stage.
Figure 3.10 – Block Diagram of the three-phase Overcurrent Stage I
>, I
>>,
dir
dir
. This limits
N
>
dir
Advertisement
Table of Contents
