I.L. 40-386.4
3-3
• Current Transformer Ratio:
RC = 1200/5 = 240
• Voltage Transformer Ratio:
RV = 600/1 = 600
Relay secondary ohmic impedances are:
Z
= Z
pri
x R
C
/R
V
Z1L
= Z2L = 15
∠
77˚
Z
0L
= 50
∠
73
°
x 240/600 = 20
∠
73
°
ohms
3.2.1
Ratio of Zero and Positive Sequence Impedances (ZR)
Z
0L
/Z
1L
= 20/6 = 3.33
Then REL 301/302 will automatically calculate the zero sequence current compensation factor
(k
0
) by using the value of “Z0L/Z1L”, “Ang Pos.”, “Ang Zero” and reference to equation 1 in
Section 2.2.1 i.e.,
NOTE:
The setting range of ZOL/ZIL has been expanded 0.1 - 7.0 to 0.1 - 10. Also the
setting ranges of Ang Pos. (Positive sequence line impedance angle) and Ang
Zero (Zero sequence line impedance angle) have been expanded from 40 -90 to
10 -90 as well. These changes were made to accommodate a wide variety of
system components and configurations. However, the selection of each set-
ting has to be carefully considered if the maximum fault current is 200 Amperes
(secondary or above).
If the maximum fault current is 200 Amperes (secondary) the following restric-
tions must be observed:
ZOL/ZIL less than or equal to 7.5
The setting difference of |Ang Pos| - |Ang Zero| = 50 or less
If the maximum fault current is less than 200 Amperes (secondary) these re-
strictions do not apply.
3.2.2
Zone-1 Distance Settings
A setting of 80% of the line impedance for Zone-1 reach is recommended, thus the Zone-1
phase and ground reach should be
“Zone-1 Ø” = 6 x 0.8 = “4.8 OHMS” and
“Zone-1 G” = 6 x 0.8 = “4.8 OHMS”
NOTE:
“Zone-1 Ø” and “Zone-1 G” can be set for different values if the application
requires.
As stated above, start with a setting of 80% of the line impedance for the Zone-1 reach setting.
Adjustment of the Zone-1 reach (line percentage) should be considered if any of the following
are true:
k
0
= Z
0L
Z
1L
–
(
)
/Z
1L
Z
OL
Z
1L
⁄
(
)
AngZero
AngPos
–
(
)
1
–
(
)
∠
=
Содержание REL 301
Страница 15: ......
Страница 24: ...I L 40 386 4 1 10 2682F39 Sheet 1 of 2 Sub 2 Figure 1 2 REL301 302 Layout Vertical ...
Страница 26: ......
Страница 27: ......
Страница 55: ...I L 40 386 4 2 27 Figure 2 8 Zone 1 Extension Scheme Figure 2 7 Zone 3 Trip Logic 1503B49 Sub 2 9662A64 Sub 1 ...
Страница 67: ...I L 40 386 4 2 39 Figure 2 31 REL302 Reversible Zone 3 Phase and Ground Reverse Block Logic 1503B55 Sub 2 ...
Страница 68: ......
Страница 69: ......
Страница 70: ......
Страница 71: ......
Страница 72: ......
Страница 73: ......
Страница 74: ......
Страница 91: ......