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9921
155
VJP1
1
Block Off
9922
155
VJP1
2
Trip On
9923
155
VJP1
3
Trip Off
9924
155
VJP1
4
Alarm On
9925
155
VJP1
5
Alarm Off
In the register of the VJP function, is recorded start, trip or blocked “On” event process data. In the
table below is presented the structure of VJP function register content. This information is available in
12 last recorded events for all provided instances separately.
Table. 5.4.20. - 160. Register content.
Date & Time
Event code
Fault type
Trip da meas /
dataset
Trip da meas /
dataset
Used
SG
dd.mm.yyyy
hh:mm:ss.mss
9920-9925
Descr.
L1(2), L2(3), L3(1)
and U4
Trip angle difference
Alarm angle
difference
1 - 8
5.4.21. Line thermal overload protection TF> (49F)
Line thermal overload function (TOLF) is used for cables and overhead lines thermal capacity
monitoring and protection. Also this function can be used for any single time constant application like
inductor chokes, certain types of transformers and any other static units which don’t have active
cooling in addition to the cables and overhead lines.
TOLF 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. TOLF function includes total
memory function of the load-current conditions according to IEC 60255-8
TOLF function is based on 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 TOLF function is calculated according to equation described below:
, where
q
t%
= Thermal image status in percent of the maximum thermal capacity available
q
t-1
= Thermal image status in previous calculation cycle (the memory of the function)
I
MAX
= Measured maximum of the three TRMS phase currents
I
N
= Current for the 100 % thermal capacity to be used (pick-up current in p.u., with this current
t
max
will be achieved in time τ x 5)
k
SF
= Loading factor (service factor) coef cient, maximum allowed load current in per unit value
depend of the protected object or cable/line installation
k
AMB
= Temperature correction factor either from linear approximation or settable 10 point
thermal capacity curve.
τ = Thermal time constant of the protected object (in minutes)
e = Euler’s number
t = Calculation time step in seconds (0.005s)
AQ-F255
Instruction manual
Version: 2.00
165
© Arcteq Relays Ltd