4674
73
TOLT1
2
Alarm2 On
4675
73
TOLT1
3
Alarm2 Off
4676
73
TOLT1
4
Inhibit On
4677
73
TOLT1
5
Inhibit Off
4678
73
TOLT1
6
Trip On
4679
73
TOLT1
7
Trip Off
4680
73
TOLT1
8
Block On
4681
73
TOLT1
9
Block Off
In the register of the TOLT function is recorded activated, blocked etc. “On” event process data. In the
table below is presented the structure of TOLT function register content. This information is available in
12 last recorded events for all provided instances separately.
Table. 5.4.9. - 78. Register content
Date & Time
Event code
Time to reach 100%
theta
Ref. T current
Active meas
current
T at the
moment
dd.mm.yyyy
hh:mm:ss.mss
4672- 4681 Descr.
seconds
xIn
xIn
%
Max temp rise allowed
Temp rise at the
moment
Hot Spot estimate
Hot spot max
all.
Trip delay rem
Used SG
deg
deg
deg
deg
s
1 - 8
5.4.10. Transformer differential Idb> Idi> I0dhv> I0dLv> (87T,87N)
Transformer differential function (DIF) is used for power transformer protection for two winding
transformers and in some extent for three winding and two winding transformers with double outputs
with summing application.
Power transformers are seen in the electric power generation, transmission, distribution and also
applications network in wide range considering of the power, voltage levels and usage purposes. Most
common use for transformer is as the name implies transform alternating voltage from one voltage level
to another. Common for all transformers is that they are crucial and one most important single
component in the network, because in many cases its failure will be seen in wide area. While
transformers do not have many moving parts (except tap changers), their electric and mechanical
properties are far from being simple.
Normal practice for transformer protection application design considers the usage of the transformer
as well as the power level transformed since the economical aspect comes more signi cant when the
transformer size increases. This means that the price of protection applied should be in line of the cost
of the transformer. For example, there is no point to install high level multifunction transformer IED into
few kVA distribution transformer which is feeding few farms in a rural area network as well as it is even
more pointless to leave few hundred MVA transmission transformer feeding entire cities protected only
with fuses.
When designing transformer protection, it should be considered which protection elements are
necessary to apply suf cient and “good enough” protection. Following table gives a rough idea about
protection methods and elements, which should be considered for each type of transformer, e.g.
protection design below these mentioned suggestions increase risk of having costly problems with
transformer.
Transformer
Risks
Protection
AQ-T216
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
122