Ormazabal ekor.rpa Series, General Instructions Manual, Page: 32 / 116

IG-267-EN versión 01; 07/04/2017
32
Protection functions General Instructions
ekor
.rpa
4.5.2. Functionality
The broken conductor unit starts up when a series of
conditions are met, as detailed below, and is reset when any
of these conditions drops to 0. Tripping takes place if the
unit is started up for the time set.
The settings for the broken conductor unit are:
•
Enabling the unit
: Enable/disable the unit (ON/OFF).
•
Base current
: The magnitude to be used to calculate the
ratios. Can be I1 (direct sequence) or I
n
(primary rated
current of the current transformer). The I
n
value will vary
in accordance with the current transformers used.
•
Starting up the unit
: Start-up value of I2 (inverse
sequence)/Ib (base current) (from 0.05 to 0.5 p.u.).
•
Unit timing
: Unit tripping time (from 0.05 s to 600.00 s).
•
Minimum current threshold for phases
: Phase current
value, below which it is considered that the line is open.
Although the line is actually open, there may be current
flowing through this phase (through capacitive elements
of the lines, as this line continues to supply some stations
located before the broken conductor). Variable ranges in
accordance with current transformers used.
•
Maximum current threshold for neutral
: Maximum
ratio of Io (zero-sequence)/Ib (base current ) as of which
it is considered a single-phase fault rather than an
broken conductor (from 0.00 to 0.5 p.u.). If the setting
is 0.00, the 46BC unit does not make any zero-sequence
current check.
4.5.3. Block diagram
The broken conductor unit complies with the following
block diagram:
1
Input signal
2
Output signal
3
Settings
Figure 4.11. Block diagram