Parameter: Follower DTL
•
Default setting: 0 s
This setting allows an additional time to be added to that achieved by the selected characteristic curve. It
is applied as a DTL time after the operate state from the curve is achieved. With this setting, the whole
curve is shifted linearly on the time axis by this additional definite time.
This is traditionally used with recloser systems only and otherwise is recommended to be left at the
default setting of 0 s.
Parameter: Reset
•
Default setting: 0 s
The reset parameter is used to define whether the element pickup resets to 0 instantaneously when the
current falls below setting or a reset curve characteristic or fixed DTL is applied. This operation is signifi-
cant during intermittent faults where an induction disc device would be partially rotated when the fault
current is reapplied.
Parameter Value Description
IEC/ANSI Decaying This selection applies a resetting curve to the element pickup to provide emula-
tion of an induction disc device. The standard IEC curve is applied if the operating
Char is an IEC Characteristic and the ANSI reset curve is applied for an ANSI oper-
ating Char. Select this setting if the device is coordinated with electromechanical
devices or other devices which perform a disc emulation reset.
0 s Use this setting for instantaneous reset of the element. When the current falls
below setting the pickup will instantaneously reset completely and subsequent
increase in current above setting will restart the operation delay from 0.
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 function 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 function 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.
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.
Protection and Automation Functions
5.17 51 Time-Delayed Overcurrent – Phase
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 257
C53000-G7040-C014-1, Edition 11.2019
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