Parameter Value
Description
1 s to 60 s
The percentage operated state is retained when the current falls below setting for
a period of the set delay. Subsequent increase in current to above setting within
the set delay will allow operation to resume from the partially operated state
instead of 0.
Parameter:
VTS Action
•
Default setting:
Off
Voltage transformer failure can affect the directional decision and introduce an error. This setting selects
if operation of the
60VTS Voltage Transformer Supervision
element automatically affects the
operation of the element.
Parameter Value
Description
Off
The function element operates with no consideration
of the 60VTS element output status.
Inhibit
When a VT failure is determined by the 60VTS func-
tion operation of the function element is inhibited.
Clearance of a system fault will then rely on other
elements or devices.
Non-Dir
When a VT failure is determined by the 60VTS func-
tion the 51 element is switched to non-directional
operation. This does not require VT inputs. The
element will operate for overcurrent regardless of
current direction.
i
i
NOTE
During a VT failure the device may assess the direction incorrectly and the element may operate for faults
in the non-operate direction or not operate for faults in the operate direction.
Parameter:
81HB2 Inhibit
•
Default setting:
No
High levels of inrush currents into reactive components such as transformers when they are switched can
result in operation of overcurrent elements. The inrush current can be detected by a high percentage of
second harmonic current content by the 81HBL2 element. This can be configured to inhibit the overcur-
rent element automatically by configuration of this setting.
Parameter Value
Description
No
The element is not inhibited by operation of the
81HB2 element
Yes
The overcurrent element is inhibited by operation of
the 81HB2 element and automatically released when
the 81HB2 element resets.
Parameter:
79 Delayed Inhibit
•
Default setting:
No
The autoreclose scheme sequence may require that some selected protection elements are only used for
the first trip(s) of the sequence, typically instantaneous ungraded protection elements, before reverting
to graded protection.
This setting allows the delayed element to be inhibited during the delayed autoreclose shots and should
be left at the default setting of
Off
unless this is required.
Note that function elements are assigned as
Delayed Trips
in the
79 > 79PF
menu.
Protection and Automation Functions
5.15 51G Time-Delayed Earth Fault – Measured
Reyrolle 7SR5, Transformer Protection Device, Device Manual
251
C53000-G7040-C015-1, Edition 11.2019
