
PM 1000266 000 01 Device handbook SIRAX BM1200 14/44
Potential Transformer Primary Digit Edit
This screen will only appear following an edit of the Potential Transfor-
mer Primary Value.
If the scaling is not correct, pressing the key ʺDownʺwill return
to the “Potential Transformer Primary Value Edit” stage with the digits
flashing indicating that the multiplier (decimal point position) should
be selected.
Pressing the key ʺUPʺsets the displayed value and will advance
to the Potential Transformer secondary Value (See Section 7.2.1.3)
7.2.1.3 Potential Transformer Secondary Value
The value must be set to the nominal full scale secondary voltage
which will be obtained from the Transformer when the potential trans-
former (PT) primary is supplied with the voltage defined in 7.2.1.2
Potential Transformer Primary voltage.
The ratio of full scale primary to full scale secondary is defined as the
transformer ratio. The PT Secondary value can be set from 100VL-L to
480VL-L (according to input voltage range).
By pressing the key ʺUPʺaccepts the present value and advances
to the ʺCurrent Transformer Primary Value editʺmenu. (see section
7.2.1.4).
Pressing the key ʺDownʺwill enter the Potential Transformer
Secondary Value Editʺmode. Pressing the key ʺDownʺwill scroll
the value of the most significant digit from available range of PT
secondary value. Please refer the table below for dierent ranges.
Pressing the key ʺUPʺaccepts the present value at the cursor
position and advances the cursor to the next less significant digit.
Potential Transformer secondary ranges for various Input
Voltages
Input Voltage PT Secondary Settable Range
110 VL-L (63.5 VLN) 100 - 125 VL-L (57 - 72 VLN)
230 VL-L (133 VLN) 126 - 250 VL-L (73 - 144 VLN)
415 VL-L (239.6 VLN) 251 - 480 VL-L (145 - 277 VLN)
Potential Transformer Secondary Value Confirmation
This screen will only appear following an edit of the Potential Transfor-
mer Secondary Value.
If the scalling is not correct, pressing the key ʺDownʺwill return to
the “Potential Transformer Secondary Value Edit” menu.
Pressing the key ʺUPʺsets the displayed value and will advance
to the Current Transformer Primary Value. (See Section 7.2.1.4).
7.2.1.4 Current Transformer Primary Value
The nominal Full Scale Current that will be displayed as the Line
currents. This screen enables the user to display the Line currents
inclusive of any transformer ratios, the values displayed represent the
Current in Amps.
Pressing the key ʺUPʺaccepts the present value and advances to
the Current Transformer secondary Value (see section 7.2.1.5).
Pressing the key ʺDownʺwill enter the ʺCurrent Transformer
Primary Value Editʺmode.
This will scroll the value of the most significant digit from 0 through to
9, unless the presently displayed Current Transformer Primary Value
together with the Potential Transformer Primary Value results in a
maximum system power of greater than 3000 MVA (1000 MVA per
phase) in which case the digit range will be restricted, the value will
wrap.
Example: If primary value of PT is set as 1200 kVL-L (max value) then
primary value of Current is restricted to 1002 A.
Pressing the key ʺUPʺwill advance to the next less significant
digit. (*Denotes that decimal point will be flashing).
The “Maximum Power” restriction of 3000 MVA refers to 120% of no-
minal current and 120% of nominal voltage, i.e, 2083.3 MVA nominal
power per phase.
When the least significant digit has been set, pressing the key ʺ
UPʺwill advance to the ʺCurrent Transformer Primary Value Confirma-
tionʺstage.
The minimum value allowed is 1, the value will be forced to 1 if the
display contains zero when the key ʺUPʺis pressed.
Note: the flashing decimal point indicates the cursor position, a steady deci-
mal point will be present to identify the scaling of the number until the cursor
position coincides with the steady decimal point position. At this stage the
decimal point will flash.
When the least significant digit has been set, pressing the key ʺ
UPʺwill advance to the ʺPotential Transformer secondary Value
Confirmationʺstage.
Current Transformer Primary Value Confirmation
This screen will only appear following an edit of the Current Transfor-
mer Primary Value.