Query on grounding of VT primary side

[kev2632]

Hi,

Is anyone able to explain to me why on this drawing where the withdrawable VTs are ? Why does the primary side of the VTs get grounded as well as the secondary side?

Thanks

 

[stevenal]

To provide a reference.

 

[kev2632]

To provide a reference.

Is it normal practice to do both sides of the VTs? As I've seen in some cases only the secondary side being done?

 

[waross]

Why does the primary side of the VTs get grounded as well as the secondary side?

So that you may determine the voltage to ground or neutral.
If you intend to measure the line to line voltage, grounding the primary side of the VT may be counterproductive to the point of immediate destruction.
(Check the interrupting capacity of the VT fuses against system ASCC before trying this.)
(PS; Don't try this at home. We are _untrained professionals.)