Schweitzer Engineering Laboratories SEL-351S - Overfrequency Element; Underfrequency Element; Frequency Element Operation; Overfrequency Element Operation

Date Code 20010112 Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements 3-49
SEL-351S Instruction Manual
Overfrequency Element
)RUH[DPSOHPDNHVHWWLQJV
1)5(4 +] QRPLQDOV\VWHPIUHTXHQF\LV+]
( HQDEOHIUHTXHQF\HOHPHQW
'3 +] IUHTXHQF\HOHPHQWSLFNXS
:LWKWKHVHVHWWLQJV '31)5(4
WKHRYHUIUHTXHQF\SDUWRIIUHTXHQF\HOHPHQWORJLFLVHQDEOHG'DQG'7RSHUDWHDV
RYHUIUHTXHQF\HOHPHQWV'LVXVHGLQWHVWLQJRQO\

Underfrequency Element
)RUH[DPSOHPDNHVHWWLQJV
1)5(4 +] QRPLQDOV\VWHPIUHTXHQF\LV+]
( HQDEOHIUHTXHQF\HOHPHQW
'3 +] IUHTXHQF\HOHPHQWSLFNXS
:LWKWKHVHVHWWLQJV '31)5(4
WKHXQGHUIUHTXHQF\SDUWRIIUHTXHQF\HOHPHQWORJLFLVHQDEOHG'DQG'7RSHUDWHDV
XQGHUIUHTXHQF\HOHPHQWV'LVXVHGLQWHVWLQJRQO\

Frequency Element Operation
5HIHUWR)LJXUH
Overfrequency Element Operation
:LWKWKHSUHYLRXVRYHUIUHTXHQF\HOHPHQWH[DPSOHVHWWLQJVLIV\VWHPIUHTXHQF\LVOHVVWKDQRU
HTXDOWR+]'3 +]IUHTXHQF\HOHPHQWRXWSXWV
'  ORJLFDO LQVWDQWDQHRXVHOHPHQW
'7  ORJLFDO WLPHGHOD\HGHOHPHQW
,IV\VWHPIUHTXHQF\LVJUHDWHUWKDQ
+]'3 +]IUHTXHQF\HOHPHQWRXWSXWV
'  ORJLFDO LQVWDQWDQHRXVHOHPHQW
'7  ORJLFDO WLPHGHOD\HGHOHPHQW
5HOD\:RUGELW'7DVVHUWVWRORJLFDORQO\DIWHUWLPHGHOD\''