Schweitzer Engineering Laboratories SEL-351S - Angle Difference Example (Voltages Vp and Vs are “Slipping”)

Date Code 20010112 Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements 3-43
SEL-351S Instruction Manual
,IWKHVOLSIUHTXHQF\LVJUHDWHUWKDQ+]DQGEUHDNHUFORVHWLPHVHWWLQJ7&/26'WKH
$QJOH'LIIHUHQFH&DOFXODWRUWDNHVWKHEUHDNHUFORVHWLPHLQWRDFFRXQWZLWKEUHDNHUFORVHWLPH
VHWWLQJ7&/26'VHWLQF\FOHVVHH)LJXUH7KH$QJOH'LIIHUHQFH&DOFXODWRUFDOFXODWHVWKH
$QJOH'LIIHUHQFHEHWZHHQYROWDJHV9
3
DQG9
6
FRPSHQVDWHGZLWKWKHEUHDNHUFORVHWLPH
$QJOH'LIIHUHQFH ¢µ9
3
µ9
6
>I
3
I
6
[7&/26'[VHFRQGF\FOHV[
VOLSF\FOH@¢
Angle Difference Example (Voltages V
p
and V
s
are “Slipping”)
5HIHUWRERWWRPRI)LJXUH
)RUH[DPSOHLIWKHEUHDNHUFORVHWLPHLVF\FOHVVHW7&/26' 3UHVXPHWKHVOLS
IUHTXHQF\LVWKHH[DPSOHVOLSIUHTXHQF\FDOFXODWHGSUHYLRXVO\7KH$QJOH'LIIHUHQFH&DOFXODWRU
FDOFXODWHVWKHDQJOHGLIIHUHQFHEHWZHHQYROWDJHV9
3
DQG9
6
FRPSHQVDWHGZLWKWKHEUHDNHUFORVH
WLPH
$QJOH'LIIHUHQFH ¢µ9
3
µ9
6
>I
3
I
6
[7&/26'[VHFRQGF\FOHV[
VOLSF\FOH@¢
,QWHUPHGLDWHFDOFXODWLRQV
I
3
I
6
 +]+] +] VOLSF\FOHVVHFRQG
7&/26'[VHFRQGF\FOHV F\FOHV[VHFRQGF\FOHV VHFRQG
5HVXOWLQJLQ
$QJOH'LIIHUHQFH ¢µ9
3
µ9
6
>I
3
I
6
[7&/26'[VHFRQGF\FOHV[
VOLSF\FOH@¢
 ¢µ9
3
µ9
6
>[[@¢
 ¢µ9
3
µ9
6
¢
'XULQJWKHEUHDNHUFORVHWLPH7&/26'WKHYROWDJHDQJOHGLIIHUHQFHEHWZHHQYROWDJHV9
3
DQG
9
6
FKDQJHVE\GHJUHHV7KLVGHJUHHDQJOHFRPSHQVDWLRQLVDSSOLHGWRYROWDJH9
6
UHVXOWLQJLQ
GHULYHGYROWDJH9
6
DVVKRZQLQ)LJXUH
1RWH 7KHDQJOHFRPSHQVDWLRQLQ)LJXUHDSSHDUVPXFKJUHDWHUWKDQGHJUHHV)LJXUH
LVIRUJHQHUDOLOOXVWUDWLYHSXUSRVHVRQO\
7KHWRSRI)LJXUHVKRZVWKH$QJOH'LIIHUHQFHGHFUHDVLQJ
±9
6
LVDSSURDFKLQJ9
3
,GHDOO\
FLUFXLWEUHDNHUFORVLQJLVLQLWLDWHGZKHQ9
6
LVLQSKDVHZLWK9
3
$QJOH'LIIHUHQFH GHJUHHV
7KHQZKHQWKHFLUFXLWEUHDNHUPDLQFRQWDFWVILQDOO\FORVH9
6
LVLQSKDVHZLWK9
3
PLQLPL]LQJ
V\VWHPVKRFN
7KHERWWRPRI)LJXUHVKRZVWKH$QJOH'LIIHUHQFHLQFUHDVLQJ
±9
6
LVPRYLQJDZD\IURP
9
3
,GHDOO\FLUFXLWEUHDNHUFORVLQJLVLQLWLDWHGZKHQ9
6
LVLQSKDVHZLWK9
3
$QJOH
'LIIHUHQFH GHJUHHV7KHQZKHQWKHFLUFXLWEUHDNHUPDLQFRQWDFWVILQDOO\FORVH9
6
LVLQSKDVH
ZLWK9
3
%XWLQWKLVFDVH9
6
KDVDOUHDG\PRYHGSDVW9
3
,QRUGHUWRLQLWLDWHFLUFXLWEUHDNHU
FORVLQJZKHQ9
6
LVLQSKDVHZLWK9
3
$QJOH'LIIHUHQFH GHJUHHV9
6
KDVWRVOLSDURXQG
DQRWKHUUHYROXWLRQUHODWLYHWR9
3
