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EQUATION1261 V2 EN-US
(Equation 24)
tPRCrvx, tTRCrvx, tCRCrvx: These parameters are used by the customer to create the inverse
reset time characteristic curve. For more information, refer to
Technical manual.
HarmRestrainx: Enables the block of step x from the harmonic restrain function (2nd
harmonic). This function should be used when there is a risk of an unwanted trip caused by
power transformer inrush currents. It can be set to
Off/On.
7.1.3.2
Setting example
GUID-20729467-24AB-42F0-9FD1-D2959028732E v1
Directional phase overcurrent protection, four steps can be used in different ways, depending
on the application where the protection is used. A general description is given below.
The operating current setting of the inverse time protection, or the lowest current step of the
definite time protection, must be defined so that the highest possible load current does not
cause protection operation. The protection reset current must also be considered so that a
short peak of overcurrent does not cause the operation of a protection even when the
overcurrent has ceased. This phenomenon is described in Figure
.
Operate current
Current (A)
The IED does not reset
Line phase current
Time (s)
Reset current
IEC05000203-en-2.vsd
IEC05000203 V4 EN-US
Figure 88: Operate and reset current for an overcurrent protection
The lowest setting value can be written according to Equation
Section 7
1MRK 505 370-UEN D
Current protection
148
Busbar protection REB670
Application manual
Summary of Contents for REB670 Series
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