Alstom MiCOM P846, Technical Manual

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P846/EN ST/D Settings
(ST) 4-6
MiCOM P846
ST
Setting Range
Menu Text Default Setting
Min. Max.
Step Size
CVT Enabled Enabled Disabled/Enabled
To enable (activate) or disable (turn off) the potential transformer alarm function.
CVT Threshold 10% 1 100 0.1%
Sets a maximum threshold for the ratio of negative sequence voltage V2 over the sum of
positive and negative sequence voltages (V1 +V2). Exceeding this threshold for a fixed
period of time of 2 minutes will arm the CVT alarm.
Tie-line Factor Disabled Disabled/Enabled
To enable (activate) or disable (turn off) the tie-line factor. Enabled when the relay is
connected to a tie line, usually a short line that may have very low transit
Base Power 2.081G 0 5.000 G 1 W
Sets the nominal base power (SIL:surge impedance loading) of the line.
Line charging 20.81 M 0 5.000 G 1 Var
Sets the nominal line charging MVARs
The rest of the settings are discussed in the same order in which they are displayed in the
relay menu.
1.2.2 Supervision (VTS)
The VTS feature within the relay operates on detection of negative phase sequence (nps)
Setting Range
Menu Text Default Setting
Min. Max.
Step Size
SUPERVISION
GROUP 1
VT SUPERVISION Sub-heading
VTS Status Blocking Blocking, Indication
This setting determines whether the following operations will occur upon detection of VTS.
•
VTS set to provide alarm indication only.
•
Optional blocking of voltage dependent protection elements.
VTS Reset Mode Manual Manual, Auto
The VTS block will be latched after a user settable time delay ‘VTS Time Delay’. Once the
signal has latched then two methods of resetting are available. The first is manually via the
front panel interface (or remote communications) and secondly, when in ‘Auto’ mode,
provided the VTS condition has been removed and the 3 phase voltages have been
restored above the phase level detector settings for more than 240 ms.
VTS Time Delay 5 s 1 s 10 s 0.1 s
Setting that determines the operating time-delay of the element upon detection of a voltage
supervision condition.
VTS
Ι
> Inhibit 20 kA 160 A 64 kA 20 A
The setting is used to override a voltage supervision block in the event of a phase fault
occurring on the system that could trigger the voltage supervision logic. Default setting
and setting range specified here are for a primary CT ratio of 2000:1 A