ABB RELION RET670, Applications Manual

Page: 796 / 1016

Wearing of the tap changer contacts
SEMOD159053-376 v4
Two counters, ContactLife and NoOfOperations are available within the Tap changer
control and supervision function, 6 binary inputs TCMYLTC or 32 binary inputs
TCLYLTC (84). They can be used as a guide for maintenance of the tap changer
mechanism. The ContactLife counter represents the remaining number of operations
(decremental counter) at rated load.
ContactLife ContactLife
n+1
n
Irated
Iload
a
æ ö
= - ç
÷
ç ÷
è ø
EQUATION1873 V2 EN-US
(Equation 512)
where n is the number of operations and α is an adjustable setting parameter,
CLFactor , with default value is set to 2. With this default setting an operation at rated
load (current measured on HV-side) decrements the ContactLife counter with 1.
The NoOfOperations counter simply counts the total number of operations
(incremental counter).
Both counters are stored in a non-volatile memory as well as, the times and dates of
their last reset. These dates are stored automatically when the command to reset the
counter is issued. It is therefore necessary to check that the IED internal time is correct
before these counters are reset. The counter value can be reset on the local HMI under
Main menu/Reset/Reset counters/TransformerTapControl(YLTC,84)/TCMYLTC:
1 or TCLYLTC:1/Reset Counter and ResetCLCounter
Both counters and their last reset dates are shown on the local HMI as service values
under
Main menu/Test/Function status/Control/TransformerTapControl(YLTC,
84)/TCMYLTC:x/TCLYLTC:x/CLCNT_VAL and Main menu/Test/Function status/
Control/TransformerTapControl (YLTC,84)/TCMYLTC:x/TCLYLTC:x/
CNT_VAL
15.4.3 Setting guidelines
SEMOD171503-1 v1
15.4.3.1 TR1ATCC or TR8ATCC general settings
SEMOD171501-4 v3
TrfId : The transformer identity is used to identify transformer individuals in a parallel
group. Thus, transformers that can be part of the same parallel group must have unique
identities. Moreover, all transformers that communicate over the same horizontal
communication (GOOSE) must have unique identities.
Xr2 : The reactance of the transformer in primary ohms referred to the LV side.
Section 15
1MRK 504 163-UUS A
Control
790 Transformer protection RET670 2.2 ANSI
Application manual