GE t60 Instruction Manual page 213

5 SETTINGS
Table 5–7: PHASE AND ZERO SEQUENCE COMPENSATION FOR TYPICAL VALUES OF
Φ
w
[ ] Grounding[
comp
240° lag
270° lag
p
[ ]
I w
A
p
[ ]
I w
B
p
[ ]
I w
C
300° lag
330° lag
p
[ ]
I w
A
p
[ ]
I w
B
p
[ ]
I w
C
In our example, the following phase and zero-sequence compensation equations would be used:
For Winding 1:
2 1
p
1 [ ] 1 [ ] 1 [ ]
-- - I -- - I
I = – –
A A B
3 3
For Winding 2:
1
p
[ ] 2 [ ]
I w = ------ - I
A A
3
g) MAGNITUDE, PHASE ANGLE, AND ZERO SEQUENCE COMPENSATION
Complete magnitude, phase angle, and zero sequence compensation is as follows:
c c
[ ] I [ ]
where: I w , w , and
A B
[ ]
M w = magnitude compensation factor for winding w (see previous sections)
p c
[ ] I [ ]
I w , w , and
A B
GE Multilin
w
] = "Not within zone"
p
[ ] [ ]
I w = I w
A C
p
[ ] [ ]
I w = I w
B A
p
[ ] [ ]
I w I w
=
C B
1 1
[ ] [ ]
------ - I ------ - I
= w – w
C B
3 3
1 1
[ ] [ ]
------ - I ------ - I
= w – w
A C
3 3
1 1
[ ] [ ]
------ - I w ------ - I w
= –
B A
3 3
p
[ ] [ ]
I w I w
= –
A B
p
[ ] [ ]
I w = – I w
B C
p
[ ] [ ]
I w = – I w
C A
1 1
[ ] [ ]
------ - I ------ - I
= w – w
A B
3 3
1 1
[ ] [ ]
------ - I w ------ - I w
= –
B C
3 3
1 1
[ ] [ ]
------ - I ------ - I
= w – w
C A
3 3
1 2 1
p
1 [ ] 1 [ ] 1 [ ]
-- - I -- - I -- - I
I = –
;
C B B
3 3 3
1 1
p
2 [ ] [ ] 2 [ ]
– ------ - I I w = ------ - I
;
B B B
3 3
c p
[ ] [ ] × [ ]
I w M w I w , where w
=
A A
c p
[ ] [ ] × [ ]
I w = M w I w , where w
B B
c p
[ ] [ ] × [ ]
I w M w I w , where w
=
C C
c
[ ]
I w = magnitude, phase and zero sequence compensated winding w phase currents
C
c
[ ]
I w = phase and zero sequence compensated winding w phase currents (see earlier)
C
T60 Transformer Protection System
w
Grounding[ ] = "Within zone"
2 1
p
[ ] [ ]
-- - I -- - I
I w = w –
A C
3 3
2 1
p
[ ] [ ]
I w -- - I w -- - I
= –
B A
3 3
2 1
p
[ ] [ ]
I w -- - I w -- - I
= –
C B
3 3
1
p
[ ] [ ]
------ - I
I w = w
A C
3
1
p
[ ] [ ]
------ - I
I w = w
B A
3
1
p
[ ] [ ]
I w ------ - I w
=
C B
3
2 1
p
[ ] [ ]
I w -- - I w -- - I
= – +
A B
3 3
2 1
p
[ ] [ ]
-- - I -- - I
I w = – w +
B C
3 3
2 1
p
[ ] [ ]
-- - I -- - I
I w = – w +
C A
3 3
1
p
[ ] [ ]
------ - I
I w = w
A A
3
1
p
[ ] [ ]
I w ------ - I w
=
B B
3
1
p
[ ] [ ]
------ - I
I w = w
C C
3
1 2
p
1 [ ] 1 [ ] 1 [ ]
-- - I -- - I
– I =
;
A C C C
3 3
1 1
p
2 [ ] [ ] 2 [ ]
– ------ - I I w = ------ - I
;
C C C
3 3
1 2 ... w , , ,
=
total
1 2 ... w , , ,
=
total
1 2 ... w , , ,
=
total
5.4 SYSTEM SETUP
Φ
comp
1
[ ] [ ]
-- - I
w – w
A B
3
1
[ ] [ ]
w -- - I w
–
B C
3
1
[ ] [ ]
w -- - I w
–
A C
3
1
[ ]
------ - I
– w
B
3
1
[ ]
------ - I
– w
C
3
1
[ ]
------ - I w
–
A
3
1
[ ] [ ]
w -- - I w
+
A C
3
1
[ ] [ ]
-- - I
w + w
A B
3
1
[ ] [ ]
-- - I
w + w
B C
3
1
[ ]
------ - I
– w
B
3
1
[ ]
------ - I w
–
C
3
1
[ ]
------ - I
– w
A
3
1 1
1 [ ] 1 [ ] 1 [ ]
-- - I -- - I
– –
(EQ 5.16)
A B
3 3
1
2 [ ]
– ------ - I
(EQ 5.17)
A
3
(EQ 5.18)
(EQ 5.19)
(EQ 5.20)
5-81
5