Siemens 7SR51 - Page 224

Parameter: Setting
•
Default setting: 0.5 x I
n
(0.5 ⋅ I
rated
)
This setting defines the operating current threshold of the element. The operation timing will then be
dependent on the selected delay setting.
This setting should be set to suit the individual application.
Parameter: Delay
•
Default setting: 0 s
This time delay setting should be set to suit the individual application.
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 60VTS operation does not affect the element and the
forward/reverse directional decision assessed from
the applied voltage is applied regardless of the 60VTS
state. 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.
Inhibit When 60VTS detects a VT failure the element is
immediately inhibited automatically and will not
operate. Tripping of a system fault will then rely on
other elements or devices.
Non-Dir When 60VTS detects a VT failure the element will
become non-directional and ignore the directional
decision. The element will operate for overcurrent
regardless of which direction the fault current is in.
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 earth fault element is not affected by operation
of the 81HBL2 element.
Yes The earth fault element is inhibited by when the
81HBL2 element is operated.
Protection and Automation Functions
5.13 50G Instantaneous Earth Fault – Measured
224 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019