Parameter: VTS Inhibit
•
Default setting: No
This setting defines the effect of a Voltage Transformer Failure on the operation of each 27/59
element. If a VT failure is detected by the separate VTS element, the 27/59 element will be automatically
blocked if this setting is set to Inhibit. If this setting is set to Off, the 27-59-n element will be unaf-
fected by the VTS element operation and the 27/59-n element may operate on the erroneous voltage
caused by the VT fuse failure which has been correctly identified by VTS. It is generally recommended
that setting to Inhibit is beneficial.
Settings Example
2-Stage Overvoltage Protection
This example considers a 2-stage overvoltage protection application. Settings are applied to detect a condition
of 5 % increase in voltage compared to nominal, this condition may indicate a voltage control failure. A 20 %
increase in voltage is detected more quickly to allow remedial actions such as a network reconfiguration or
trip.
•
First stage
To detect a +5 % deviation in the voltage compared to the expected 63.5 V phase to neutral secondary
nominal voltage connected to the V4 input allowing for a voltage controller which would be expected to
correct this deviation in less than 2 seconds.
Threshold = 63.5 ⋅ 1.05 = 66.675 V
Time delay must be greater than 2 seconds. Choose 3 s.
Choose a suitable element: 59Vx-1
•
Second stage
To detect a +20 % deviation in the voltage compared to the expected 63.5 V phase to neutral secondary
nominal voltage connected to the voltage inputs allowing only for transient conditions and fault clear-
ance and meeting the customers’ expectations for disconnection which will allow 1000 ms.
Threshold = 63.5 ⋅ 1.2 = 76.2 V
Time delay specified as 1000 ms.
Choose a suitable element: 59Vx-2
Element
Setting Values
59-1 59-1 Element Enabled
59-1 59-1 Setting 67 V
59-1 59-1 Hysteresis 3 %
59-1 59-1 Delay 3 s
59-2 59-2 Element Enabled
59-2 59-2 Setting 76.5 V
59-2 59-2 Hysteresis 3 %
59-2 59-2 Delay 1 s
Settings Menu
Functions > Function Config
Parameter Range Settings
Default Gn1 Gn2 Gn3 Gn4
59 Overvoltage Enabled
Disabled
Disabled
5.22.5
Protection and Automation Functions
5.22 59 Overvoltage Protection – 3 Phase
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 309
C53000-G7040-C014-1, Edition 11.2019
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