GE D90 Plus - Page 263

CHAPTER 7: PROTECTION GROUPED PROTECTION ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 253
Figure 215: Neutral directional overcurrent 1 scheme logic
Ground time overcurrent
This element can provide a required time-delay operating characteristic versus the applied
current or be used as a simple definite time element. The ground current input value is the
quantity measured by the ground input CT and is the fundamental phasor or RMS
magnitude. Two methods of resetting operation are available: “Timed” and
“Instantaneous.” When the element is blocked, the time accumulator resets according to
the reset characteristic. For example, if the element reset characteristic is set to
“Instantaneous” and the element is blocked, the time accumulator clears immediately.
NOTE
NOTE:
These elements measure the current that is connected to the ground channel of an AC
module. This channel can be equipped with a standard or sensitive input. The conversion
range of a standard channel is from 0.02 to 46 times the CT rating. The conversion range of
a sensitive channel is from 0.002 to 4.6 times the CT rating.
Select the Settings > Protection > Elements > Group 1 > Current > Ground TOC menu to
open the ground time overcurrent configuration window.
`
127(6
&XUUHQWSRODUL]LQJLVSRVVLEOHRQO\LQUHOD\VZLWKWKH
JURXQGFXUUHQWLQSXWVFRQQHFWHGWRDQDGHTXDWH
FXUUHQWSRODUL]LQJVRXUFH
*URXQGFXUUHQWFDQQRWEHXVHGIRUSRODUL]DWLRQ
DQGRSHUDWLRQVLPXOWDQHRXVO\
3RVLWLYHVHTXHQFHUHVWUDLQWLVQRWDSSOLHGZKHQ
,BLVOHVVWKDQSX
$&'5
$1'
$1'
$1'
$1'
$1'
$1'
$1'
25
25
25
25
6(77,1*
'LVDEOHG 
(QDEOHG 
)XQFWLRQ
6(77,1*
2II 
%ORFN
6(77,1*6
6RXUFH
3RODUL]LQJ9ROWDJH
2SHUDWLQJ&XUUHQW
0HDVXUHG9;
&DOFXODWHG9B
&DOFXODWHG,B
0HDVXUHG,*
6(77,1*
9ROWDJH
&XUUHQW
3RODUL]LQJ
'XDO
_,*_ SX
6(77,1*6
)RUZDUG3LFNXS
581
î_,B_² î_,B_ 3LFNXS
RU
_,*_ 3LFNXS
. 

2SHUDWLQJ&XUUHQW
3RVLWLYH6HTXHQFH5HVWUDLQW
9ROWDJH3RODUL]DWLRQ
6(77,1*6
)RUZDUG(&$
581
)RUZDUG/LPLW$QJOH
5HYHUVH/LPLW$QJOH
2IIVHW
)RUZDUG
5HYHUVH
&XUUHQW3RODUL]DWLRQ
581
)RUZDUG
5HYHUVH
6(77,1*6
5HYHUVH3LFNXS
581
î_,B_² î_,B_ 3LFNXS
RU
_,*_ 3LFNXS
. 

2SHUDWLQJ&XUUHQW
3RVLWLYH6HTXHQFH5HVWUDLQW
7,0(5
F\FOHV
F\FOHV
)/(;/2*,&23(5$1'
1(875$/',52&):'
)/(;/2*,&23(5$1'
1(875$/',52&5(9