Siemens 7SR51 Device Manual page 308

Protection and Automation Functions
5.22 59 Overvoltage Protection – 3 Phase
Parameter Value
ph-ph
ph-N
Parameter: Element
•
Default setting: Disabled
This setting is used to allow the element to be switched on and off if it is not required. A separate setting
is provided for each element. This setting can be used to select the number of elements required.
Parameter: Pickup Option
•
Default setting: Any
This setting defines whether the element picks up if the required voltage conditions are detected on one
phase Any or if they must be detected on all 3 phases All.
Parameter Value
Any
All
Parameter: Setting
•
Default setting: 80 V
This is the operating voltage threshold of the element. The element will pickup if the voltage rises above
this value. This should be set to suit the individual application.
Parameter: Hysteresis
•
Default setting: 3 %
This sets the drop-off threshold. The element will pickup if the voltage rises above the 59-n Setting
and will reset when the voltage reduces to 59V-n Setting minus the 59-n Hysteresis.
The default setting of 3 % is generally enough to avoid chatter of the element but care may be required
for settings which result in a reset voltage close to the rated voltage as the element may not reset when
the primary system recovers voltage within the acceptable operating tolerance as the voltage is still
inside of the hysteresis window.
Parameter: Delay
•
Default setting: 0.1 s
This is the time delay setting for the DTL element. This should be set to suit the individual application.
308
Description
Select this setting to monitor the load voltage condi-
tions. For this setting the function will not pick up on
earth faults.
Select the phase to neutral setting where it is required
detect voltage unbalances and overvoltage conditions
caused by earth faults.
Description
This setting will allow detection during unbalanced
voltage conditions and will operate for the worst
phase. This is the appropriate setting for most appli-
cations
This setting is commonly used when the element is
used to detect loss of supply or for extra immunity
from unbalance deviations.
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019