ABB RELION Series Technical Manual page 261

1MRS758755 A
REC615 and RER615
Technical Manual
There is also a calculation of the present time to operation with the present current.
This calculation is only performed if the final temperature is calculated to be above the
operation temperature:

Θ −
final
t τ ln
= − ⋅ 
operate

Θ
final

A070782 V2 EN
Caused by the thermal overload protection function, there can be a lockout to
reconnect the tripped circuit after operating. The lockout output BLK_CLOSE is
activated at the same time when the OPERATE output is activated and is not reset until
the device temperature has cooled down below the set value of the Reclose
temperature setting. The Maximum temperature value must be set at least two degrees
above the set value of Reclose temperature.
The time to lockout release is calculated, that is, the calculation of the cooling time to
a set value. The calculated temperature can be reset to its initial value (the Initial
temperature setting) via a control parameter that is located under the clear menu. This
is useful during testing when secondary injected current has given a calculated false
temperature level.
 Θ
ln
t
= − ⋅ τ 
lockout release _


A070783 V3 EN
Here the final temperature is equal to the set or measured ambient temperature.
In some applications, the measured current can involve a number of parallel lines. This
is often used for cable lines where one bay connects several parallel cables. By setting
the Current multiplier parameter to the number of parallel lines (cables), the actual
current on one line is used in the protection algorithm. To activate this option, the
ENA_MULT input must be activated.
The ambient temperature can be measured with the RTD measurement. The measured
temperature value is then connected, for example, from the AI_VAL3 output of the
X130 (RTD) function to the AMB_TEMP input of T1PTTR.
The Env temperature Set setting is used to define the ambient temperature if the
ambient temperature measurement value is not connected to the AMB_TEMP input.
The Env temperature Set setting is also used when the ambient temperature
measurement connected to T1PTTR is set to "Not in use" in the X130 (RTD) function.
The temperature calculation is initiated from the value defined with the Initial
temperature setting parameter. This is done in case the protection relay is powered up,
the function is turned "Off" and back "On" or reset through the Clear menu. The
temperature is also stored in the nonvolatile memory and restored in case the
protection relay is restarted.

Θ
operate


− Θ
n

− Θ  
final lockout release _


Θ − Θ
final n

Section 4
Protection functions
(Equation 8)
(Equation 9)
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