Date Code 20020129
Differential, Restricted Earth Fault,
3-9
Overcurrent, Voltage, and Frequency Elements
SEL-387E Instruction Manual
Maximum Transformer Capacity, Three-Phase MVA (MVA)
Range
: OFF,
0.2–5000 MVA, in 0.1 MVA steps
Use the highest expected transformer rating, such as the FOA (Forced Oil and Air cooled) rating
or a higher emergency rating, when setting the maximum transformer capacity.
Internal Winding/CT Connection Compensation (ICOM)
Range:
Y, N
This Yes/No variable defines whether the input currents need any correction, either to
accommodate phase shifts in the transformer or CTs or to remove zero-sequence components
from the secondary currents. If this setting is Yes, the relay permits the user, in the next group of
settings, to define the amount of shift needed to properly align the secondary currents for the
differential calculation.
Connection Compensation (W1CTC through W3CTC)
Range:
0,
1,
…, 12
These settings define the amount of compensation the relay applies to each set of winding
currents to properly account for phase shifts in transformer winding connections and CT
connections. For example, this correction is needed if both wye and delta power transformer
windings are present, but all of the CTs are connected in wye. The effect of the compensation is
to create phase shift and removal of zero-sequence current components.
Line-to-Line Voltage, kV (VWDG1 through VWDG3)
Range
: 1–1000 kV, in 0.01 kV steps
Enter the nominal line-to-line transformer terminal voltages. If the transformer differential zone
includes a load tap-changer, assume that it is in the neutral position. The setting units are
kilovolts.
Current TAP (TAP1 through TAP3)
Range:
1 A:
0.1–31 A, secondary, in 0.01 A steps
5
A: 0.5–155 A, secondary, in 0.01 A steps
Note:
TAP
MAX
/TAP
MIN
must be less than or equal to 7.5
When a value is entered in the MVA setting (i.e., MVA is not set to “OFF”), the relay uses the
MVA, winding voltage, CT ratio, and CT connection settings you have entered and automatically
calculates the “TAPn” values.
You can also directly enter tap values. Set MVA = OFF, and enter the TAP1 through TAP3
values directly, along with the other pertinent settings.
Содержание SEL-387E
Страница 8: ......
Страница 10: ......
Страница 12: ......
Страница 50: ......
Страница 124: ......
Страница 176: ......
Страница 196: ......
Страница 198: ......
Страница 242: ......
Страница 270: ......
Страница 308: ......
Страница 422: ......
Страница 428: ......
Страница 432: ......
Страница 448: ......
Страница 450: ......
Страница 462: ......