Name
Type
Values (Range)
Unit
Description
TRESLO
INTEGER
-
-
Estimated time to reset of
the function (in min)
TTRIPCAL
INTEGER
0=Not Active
1=Long Time
2=Active
-
Calculated time status to
trip: not active/long time/
active
TRESCAL
INTEGER
0=Not Active
1=Long Time
2=Active
-
Calculated time status to
reset: not active/long
time/active
8.7.7
Operation principle
The sampled analog phase currents are pre-processed and for each phase current the
true RMS value of each phase current is derived. These phase current values are fed
to the protection function.
From the largest of the three phase currents a relative final temperature (heat content)
is calculated according to the expression:
2
final
ref
I
I
æ
ö
Q
= ç
÷
ç
÷
è
ø
EQUATION1171 V1 EN
(Equation 70)
where:
I
is the largest phase current
I
ref
is a given reference current
If this calculated relative temperature is larger than the relative temperature level
corresponding to the set operate (trip) current, then the start output signal START will
be activated.
The actual temperature at the actual execution cycle is calculated as:
If
final
n
Q
> Q
EQUATION1172 V1 EN
(Equation 71)
(
)
1
1
1
t
n
n
final
n
e
t
D
-
-
-
æ
ö
Q = Q + Q
- Q
× -
ç
÷
è
ø
EQUATION1173 V1 EN
(Equation 72)
If
final
n
Q
< Q
EQUATION1174 V1 EN
(Equation 73)
Table continues on next page
Section 8
1MRK502052-UEN B
Current protection
404
Technical manual
Summary of Contents for Relion REG670
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