IG-150-EN version 04; 03/10/16
96
Protection functions. Description and settings
General instructions
ekor.rps
ECO
It is used in the permissive schemes (overreach, underreach
and directional unlocking).
The pilot protection instantaneous trip is the one
corresponding to the selected scheme.
The teleprotection signal is sent with either of the following
conditions:
1. According to the selected scheme
2. If the RTP is received and the fault is not detected either
forward or backward.
3. During a minimum programmable time or the breaker
is open. The ECO signal only provides a pulse of 50 ms.
Figure 4.31.
ECO logic
4.21. Thermal image
4.21.1. General description
This function calculates a temperature according to the
recent and present load conditions of the protected unit.
This temperature is visualized in the display in % with
respect to the trip value; when reaching the programmed
value an alarm relay is activated (if there is any programmed)
and when reaching the 100 % the thermal image trip relay
(if the unit is enabled) and the corresponding signaling
are activated. Once the unit has tripped by this unit, the
relay does not dropout while the calculated temperature is
above the 75 % and the rest of the locking conditions are
fulfilled. The calculated temperature can be reset through
the keyboard/display (accessing through “
↓
” to TEMP = 0?
and pushing “
↓
” during 2 seconds) or through console
command.
The time to trip is given by the following curves, which give
the time according to the ratio between the current and the
programmed rated current, and the programmed cooling
constant. According to the following formula (starting from
temperature 0):
Being
t: trip time
τ1
: cooling constant
I: average current
I
0
: programmed rated current
Once it has tripped, there is another programmable time
constant for the cooling.
Содержание ekor.rps
Страница 143: ......