ABB Relion 650 Series Technical Manual page 205

1MRK 506 326-UUS B
Q = Q
n
EQUATION1168 V1 EN-US
where:
Q
n
Q
n-1
Q
final
Dt
t
The calculated component temperature is available as a real figure signal, TEMP.
When the component temperature reaches the set alarm level
ALARM is set. When the component temperature reaches the set trip level
signal TRIP is set.
There is also a calculation of the present time to operate with the present current. This calculation
is only performed if the final temperature is calculated to be above the operation temperature:
= - × ç
t
operate
EQUATION1169 V1 EN-US
The calculated time to trip is available as a real figure signal, TTRIP.
After a trip, caused by the thermal overload protection, there can be a lockout to reconnect the
tripped circuit. The output lockout signal LOCKOUT is activated when the device temperature is
above the set lockout release temperature setting
The time to lockout release is calculated that is, a calculation of the cooling time to a set value. The
thermal content of the function can be reset with input RESET.
t
lockout release _
EQUATION1170 V1 EN-US
The calculated time to reset of lockout is available as a real figure signal, TENRECL.
The protection has a reset input: RESET. By activating this input the calculated temperature is
reset to its default initial value. This is useful during testing when secondary injected current has
given a calculated "false" temperature level.
Line distance protection REL650
Technical manual
æ
( )
+ Q - Q ×
1
ç
- -
n 1 final n 1
è
is the calculated present temperature,
is the calculated temperature at the previous time step,
is the calculated final temperature with the actual current,
is the time step between calculation of the actual temperature and
is the set thermal time constant for the protected device (line or cable)
æ
Q - Q
t final operate
ln
ç
Q - Q
è
final n
æ
Q - Q
t
= - × ç final
ln
ç
Q
è
final
© Copyright 2011 ABB Power Grids. All rights reserved
D ö
t
-
-
t
e
÷
ø
ö
÷
÷
ø
ReclTemp .
ö
lockout release _
÷
÷
- Q
ø
n
Current protection
AlarmTemp the output signal
TripTemp the output
Section 6
(Equation 36)
(Equation 37)
(Equation 38)
199