“Ct And Vt Ratios” Column - GE P741 Technical Manual

P74x/EN ST/Na7
(ST) 4-24
Man Close Pulse
Defines the duration of the close pulse.
Man Trip Pulse
Defines the duration of the trip pulse.
Man Close Delay
This defines the delay time before the close pulse is executed.
87BB Trip Delay
Sets the differential busbar protection (87BB) tripping delay time (to allow a sequential
tripping of all feeders connected to the faulty zone). The trip relays outputs will be closed
even if the CU trip signal is released before the end of the timer.
ST
CB Superv Timer
Setting for the operating time delay of the phase Circuit Breaker Supervision: The CB
alarm status will be displayed If both 52A and 52B are detected more than "CB Superv.
Timer".
1.3.2 "CT and VT ratios" column (P742 / P743)
This column is visible when the "CT & VT ratios" setting ("Configuration" column) = "visible".
CT AND VT RATIOS
Phase CT Primary
Sets the phase Current Transformer input primary current rating.
Phase CT Sec'y
Sets the phase Current Transformer input secondary current rating.
RBPh / RBN
Sets the ratio between the phase lead burden and the neutral lead burden.
Power Parameters
Standard input
Sets the Current Transformer knee point voltage when the British standard has been
chosen.
BRITISH STANDARD
Knee voltage V
Sets the Current Transformer knee point voltage when the British standard has been
chosen.
IEC
Rated Burden VA
Sets the Current Transformer power when the IEC standard has been chosen.
IEC
Rated Burden Ohm
(calculated value)
Calculated value from the Rated Burden set in VA
Menu Text Default Setting
0.50s
0.50s
10.00s
0s
150ms
Menu Text Default Setting
1.000A
1.000A
1
British Standard
250/I V
n
k
25 VA
2
25 / I
n
Setting Range
Min.
0.10s
0.10s
0.01s
0s
10ms
Setting Range
Min.
1A
1
0.5
British Standard / IEC
100/I V
n
5 VA
Ω Ω
2
5 / I
n
Settings
MiCOM P741, P742, P743
Step Size
Max.
10.00s 0.01s
5.00s 0.01s
600.00s 0.01s
0.400s 5ms
400ms 5ms
Step Size
Max.
30kA 1
5 4
10 0.1
5000/I V 10/I V
n n
100 VA 1 VA
Ω Ω
2 2
100 / I 1 / I
n n