Sel SEL-351A - Accuracy; Voltage Element Operation; Undervoltage Element Operation Example

Date Code 20010307 Overcurrent, Voltage, Synchronism Check, and Frequency Elements 3-33
SEL-351A Instruction Manual

)LJXUH&KDQQHO969ROWDJH(OHPHQWV
Accuracy
3LFNXS 9DQGRIVHWWLQJ
7UDQVLHQW2YHUUHDFK RIVHWWLQJ
Voltage Element Operation
1RWHWKDWWKHYROWDJHHOHPHQWVLQ7DEOHDQG)LJXUHWKURXJK)LJXUHDUHD
FRPELQDWLRQRI³XQGHUYROWDJH´'HYLFHDQG³RYHUYROWDJH´'HYLFHW\SHHOHPHQWV
8QGHUYROWDJHHOHPHQWV'HYLFHDVVHUWZKHQWKHRSHUDWLQJYROWDJHJRHVEHORZ
WKHFRUUH
VSRQGLQJSLFNXSVHWWLQJ2YHUYROWDJHHOHPHQWV'HYLFHDVVHUWZKHQWKHRSHUDWLQJYROWDJH
JRHVDERYH
WKHFRUUHVSRQGLQJSLFNXSVHWWLQJ
Undervoltage Element Operation Example
5HIHUWR)LJXUHWRSRIWKHILJXUH
3LFNXSVHWWLQJ33LVFRPSDUHGWRWKHPDJQLWXGHVRIWKHLQGLYLGXDOSKDVHYROWDJHV9
$
9
%
DQG
9
&
7KHORJLFRXWSXWVLQ)LJXUHDUHWKHIROORZLQJ5HOD\:RUGELWV
$  ORJLFDOLI9
$
SLFNXSVHWWLQJ33
  ORJLFDOLI9
$
SLFNXSVHWWLQJ33
%  ORJLFDOLI9
%
SLFNXSVHWWLQJ33
  ORJLFDOLI9
%
SLFNXSVHWWLQJ33
&  ORJLFDOLI9
&
SLFNXSVHWWLQJ33
  ORJLFDOLI9
&
SLFNXSVHWWLQJ33
3  ORJLFDOLIDOOWKUHH5HOD\:RUGELWV$%DQG&DUHDVVHUWHG
$ % DQG& 
  ORJLFDOLIDWOHDVWRQHRIWKH5HOD\:RUGELWV$%RU&LV
GHDVVHUWHGHJ$ 