4.2.3.2 Function block
A070663 V2 EN
Figure 159: Function block
4.2.3.3 Functionality
The transient/intermittent earth-fault protection function INTRPTEF is a function
designed for the protection and clearance of permanent and intermittent earth faults in
distribution and sub-transmission networks. Fault detection is done from the residual
current and residual voltage signals by monitoring the transients.
The operating time characteristics are according to definite time (DT).
The function contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.
4.2.3.4 Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of INTRPTEF can be described with a module diagram. All the
modules in the diagram are explained in the next sections.
BLK_EF
OPERATE
Io
Uo
BLOCK
START
Timer 2
t
Timer 1
Transient
detector
Fault
indication
logic
Level
detector
Blocking
logic
A070661 V4 EN
Figure 160: Functional module diagram
Level detector
The residual voltage can be selected from the Uo signal Sel setting. The options are
"Measured Uo" and "Calculated Uo". If "Measured Uo" is selected, the voltage ratio
Section 4 1MRS758755 A
Protection functions
316 REC615 and RER615
Technical Manual
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