3.43
Date Code 20060320 Instruction Manual SEL-311C Relay
Distance, Out-of-Step, Overcurrent, Voltage, Synchronism Check, and Frequency Elements
Voltage Elements
27B = 1 (logical 1), if V
B
< pickup setting 27P
27B = 0 (logical 0), if V
B
≥ pickup setting 27P
27C = 1 (logical 1), if V
C
< pickup setting 27P
27C = 0 (logical 0), if V
C
≥ pickup setting 27P
3P27 = 1 (logical 1), if all three Relay Word bits 27A, 27B, and 27C
are asserted (27A = 1, 27B = 1, and 27C = 1)
3P27 = 0 (logical 0), if at least one of the Relay Word bits 27A, 27B,
or 27C is deasserted (e.g., 27A = 0)
EXAMPLE 3.2 Overvoltage Element Operation
Refer to Figure 3.27 (bottom of the figure).
Pickup setting 59P is compared to the magnitudes of the individual
phase voltages V
A
, V
B
, and V
C
. The logic outputs in Figure 3.27 are
the following Relay Word bits:
59A = 1 (logical 1), if V
A
> pickup setting 59P
59A = 0 (logical 0), if V
A
≤ pickup setting 59P
59B = 1 (logical 1), if V
B
> pickup setting 59P
59B = 0 (logical 0), if V
B
≤ pickup setting 59P
59C = 1 (logical 1), if V
C
> pickup setting 59P
59C = 0 (logical 0), if V
C
≤ pickup setting 59P
3P59 = 1 (logical 1), if all three Relay Word bits 59A, 59B, and 59C
are asserted (59A = 1, 59B = 1, and 59C = 1)
3P59 = 0 (logical 0), if at least one of the Relay Word bits 59A,
59B, or 59C is deasserted (e.g., 59A = 0)
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