IG-267-EN versión 01; 07/04/2017
72
Protection, metering and control models General Instructions
ekor.rpa
8.3.5. Checking and maintenance
The solution for facilities with ekor.rpa-110-p and
ekor.rpa-120-p units does not have a test terminal block in
the standard solution, with the option of making the checks
from primary only.
In this type of cubicles, the current transformers are installed
on the cable. This means special care must be taken, since
any incorrect installation of the transformers can result in
unwanted tripping which is not real. Incorrect installation is
not detected in the commissioning tests and must be taken
into account when installing.
The indications to be taken into account are detailed below:
1. The toroidal-core current transformers are installed on
the outgoing cables of the cubicle.
2. The earthing screen MUST go through the toroidal-
core current transformer when it comes out of the part
of cable remaining above the toroidal-core current
transformer. In this case, the twisted pair goes through
the inside of the transformers before it is connected to
the cubicle's earthing collector. The twisted pair must
not touch any metal part, such as the cable support
or other areas of the cable compartment, before it is
connected to the cubicle's earth.
3. The earthing screen must NOT go through the toroidal-
core current transformer when it comes out of the part
of the cable remaining under the toroidal-core current
transformer. In this case, the twisted pair is connected
directly to the earthing collector of the cubicle. If there
is no twisted pair for the earthing screen, because it is
connected at the other end (as in metering cubicles),
the twisted pair should also not go through the
toroidal-core current transformer.
1
Earth screen: It must pass through the inside of the current
transformers
Figure 8.12. Installation of toroidal-core current transformers
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