Vts Implementation - GE MiCOM P40 Agile Technical Manual

P543i/P545i
following line energization (based on an All Poles Dead signal drop off). It must still be set in excess of any non-
fault based currents on line energisation (load, line charging current, transformer inrush current if applicable), but
below the level of current produced by a close-up three-phase fault.
If the line is closed where a three-phase VT failure is present, the overcurrent detector will not operate and a VTS
block will be applied. Closing onto a three-phase fault will result in operation of the overcurrent detector and
prevent a VTS block being applied.
3.4

VTS IMPLEMENTATION

VTS is implemented in the SUPERVISION column of the relevant settings group.
The following settings are relevant for VT Supervision:
VTS Mode: determines the mode of operation (Measured + MCB, Measured Only, MCB Only)
●
VTS Status: determines whether the VTS Operate output will be a blocking output or an alarm indication
●
only
VTS Reset Mode: determines whether the Reset is to be manual or automatic
●
● VTS Time Delay: determines the operating time delay
VTS I> Inhibit: inhibits VTS operation in the case of a phase overcurrent fault
●
● VTS I2> Inhibit: inhibits VTS operation in the case of a negative sequence overcurrent fault
For faults with I2 less than the setting VTS I2 Inhibit, VTS will be active and block the associated functions if
sufficient V2 is measured. VTS is only enabled during a live line condition (as indicated by the pole dead logic) to
prevent operation under dead system conditions.
Thresholds
The negative sequence thresholds used by the element are:
V2 = 10 V (fixed)
●
I2 = 0.05 to 0.5 In settable (default 0.05 In).
●
The phase voltage level detectors are:
Drop off = 10 V (fixed)
●
● Pickup = 30 V (fixed)
The sensitivity of the superimposed current elements is fixed at 0.1 In.
Fuse Fail
The device includes a setting (VT Connected ) in the CT AND VT RATIOS column, which determines whether there
are voltage transformers connected to it. If set to Yes, this setting has no effect.
If set to No it causes the VTS logic to set the VTS Slow Block and VTS Fast Block DDBs, but not raise any alarms. It
also disables the VTS function. This prevents the pole dead logic working incorrectly if there is no voltage or
current. It also blocks the distance, under voltage and other voltage-dependant functions. However, it does not
affect the CB open part of the logic.
A VTS condition can be raised by a mini circuit breaker (MCB) status input, by internal logic using IED
measurement, or both. The setting VTS Mode is used to select the method of indicating VT failure.
P54x1i-TM-EN-1
Chapter 18 - Supervision
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