4-32
Protection and Control
BE1-951
Figure 4-17. 47 Element
Table 4-24. Auxiliary Undervoltage and Overvoltage Operating Settings
Setting
Range
Increment
Unit of
Measure
Default
Pickup
0 = disabled
1 to 150
0.1 (for 0 - 99.9)
1.0 (for 100 - 300)
sec. volts
0
Time Delay
50 to 999 milliseconds
1
milliseconds
50
0.1 to 600 seconds
0.1 for 0.1 to 9.9
seconds
1.0 for 10 to 600
seconds
0 to 36,000 cycles (60 Hz)
7
cycles
0 to 30,000 cycles (50 Hz)
7
Time delays less than 10 cycles can be entered to the nearest 0.1 cycle from the front panel
HMI. All time delays can be entered to the nearest 0.01 cycle from the ASCII command interface.
Time delays entered in cycles are converted to milliseconds or seconds. Increment precision after
conversion is limited to that appropriate for each of those units of measure.
S<g>-59X/159X Command and S<g>-27X Command
Purpose:
Read or set protection settings for the auxiliary undervoltage function.
Syntax:
S<g>-27X[=<Pickup)>,<Time Delay>]
S<g>-<x>59X[=<Pickup)>,<Time Delay>]
Comments: g = setting group 0, 1, 2, or 3.
x = 1 for 159X and nothing for 59X. See Table 4-24 for setting definitions.
S<g>-<x>59X Command Example
1.
Set the group 1 neutral overvoltage pickup setting at 75 volts with a 50 millisecond time delay.
>S1-59X=75,50
47 Negative Sequence Overvoltage Protection
Figure 4-17 illustrates the inputs and outputs of the negative
sequence overvoltage element. Element operation is described
in the following paragraphs. Negative sequence Over voltage
protection is not available if VTP connection is single-phase.
The negative sequence overvoltage element has two outputs:
47PU (pickup) and 47T (trip). When the monitored negative
sequence voltage increases above the pickup setting, the
pickup output becomes TRUE and the element starts timing
toward a trip. The trip output becomes TRUE when the element
timer times out.
The Block (BLK) input is used to disable protection. A BESTlogic expression defines how the BLK input
functions. When this expression is TRUE, the element is disabled by forcing the outputs to logic 0 and
resetting the timer. This feature functions in a similar way to the torque control contact of an
electromechanical relay.
The 47 element is enabled or disabled by the Mode input. Two modes are available. Selecting Mode 0
disables protection. Mode 1 enables the 47 element. More information about logic mode selections is
provided in the
BESTlogic Settings for the Negative Sequence Overvoltage Element paragraphs.
The pickup setting determines the voltage pickup level of the element. Voltage pickup is based on PN. The
time delay setting controls how long it takes for the trip output to become TRUE after the pickup output
becomes TRUE. When the monitored voltage increases above the pickup threshold, the pickup output
(47PU) becomes TRUE and the timer starts. If the voltage remains above the pickup threshold for the
duration of the time delay setting, the trip output (47T) becomes TRUE. If the voltage decreases below the
dropout ratio of 98 percent, the timer is reset to zero.
