Operation Of The Differential Protection From Ctx Input - Hitachi Relion REB670 Commissioning Manual

1MRK 505 372-UEN Rev. K
The connection of the test set to REB670 is greatly simplified if the RTXP 24 test switch is
included.When the test handle RTXH 24 is inserted in the test switch, the preparations for testing are
automatically carried out in the proper sequence, that is:
1. firstly blocking of the tripping circuits
2. then short-circuiting of the current circuits on the transformer side
3. then opening of current transformer circuits
4. then making IED terminals accessible from the terminals on the test plug handle.
If the REB670 is not provided with a test switch, the IED has to be tested in the proper way from
external circuit terminals. Make sure that the instrument transformers are isolated from the circuits
connected to the test set. The secondary phase terminals of the current transformers must be short-
circuited to neutral before the circuit is opened if any current can flow on the primary side.
The testing requires a good understanding of the protection functionality of the REB670. A testing
instruction is given for each type of protection function.
10.3.1.2

Operation of the differential protection from CTx input

Before the testing, prepare the IED for verification of settings as outlined in Section
and Section
The typical connection between the three-phase current test set and REB670 IEDs is shown in
Figure 12.
CTx
IEC01000112 V2 EN-US
Figure 12:
The testing will be explained from one general current input CTx (that is 1 ≤ x ≤ Nmax; where Nmax
is the maximum number of used CT inputs).
Follow the following test instructions to test the operation of the differential protection function for the
current input CTx:
Busbar protection REB670
Commissioning manual
Note that CT inputs for the REB670 are designed for a maximum continuous current
of four times rated value.
Note that the busbar differential protection functions are not included in the IED Test
Mode.
"Preparing for test" in this chapter.
REB 670 REB 670 REB 670
Typical test connection for CTx current input when COMBITEST RTXP 24 test
switch is delivered together with one-phase REB670 IED
© 2017 - 2022 Hitachi Energy. All rights reserved
6A
6B
7A
7B
6A
6B
7A
7B
6B
7B
Section 10
Testing functionality by secondary injection
SEMOD65865-3 v5
"Requirements"
3-Ph current
Test Set
L1 L2 L3 N
6A
7A
IEC01000112-2-en.vsd
73