4608
72
TRF1
0
Light/No load On
4609
72
TRF1
1
Light/No load Off
4610
72
TRF1
2
HV side inrush On
4611
72
TRF1
3
HV side inrush Off
4612
72
TRF1
4
LV side inrush On
4613
72
TRF1
5
LV side inrush Off
4614
72
TRF1
6
Load normal On
4615
72
TRF1
7
Load normal Off
4616
72
TRF1
8
Overloading On
4617
72
TRF1
9
Overloading Off
4618
72
TRF1
10
High overload On
4619
72
TRF1
11
High overload Off
4620
72
TRF1
12
Setting changes, calculating new trafo data
4621
72
TRF1
13
Calculation nished, possible restart
In the table below is presented the structure of TRF function register content. This information is
available in 12 last recorded events.
Table. 5.4.8. - 68. Register content.
Date & Time
Event
code
HVL1 current
HVL2
current
HVL3
current
LVL1
current
LVL2
current
LVL3
current
dd.mm.yyyy
hh:mm:ss.mss
4608-
4621
Descr.
HV side Phase L1
current xIn
HV side
Phase L2
current xIn
HV side
Phase L3
current xIn
LV side
Phase L1
current xIn
LV side
Phase L2
current xIn
LV side
Phase L3
current xIn
5.4.9. Transformer thermal overload protection TT> (49TR)
Thermal overload function for transformers (TOLT) is used for power transformers thermal capacity
monitoring and protection.
TOLT function constantly monitors phase TRMS currents (including harmonics up to 31
st
) instant
values and calculates the set thermal replica status in 5 ms cycles. TOLT function includes total
memory function of the load-current conditions according to IEC 60255-8
TOLT function is based into thermal replica, which represents the protected object or cable thermal
loading in relation to the current going through the object. Thermal replica includes the calculated
thermal capacity used in the “memory” since it is integral function which tells apart this function from
normal overcurrent function operating principle for the overload protection applications.
Thermal image for the TOLT function is calculated according to equation described below:
, where
θ
t%
= Thermal image status in percent of the maximum thermal capacity available
θ
t-1
= Thermal image status in previous calculation cycle (the memory of the function)
I
MAX
= Measured maximum of the three TRMS phase currents
AQ-T216
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
114