4-34
Protection and Control
BE1-951
Figure 4-18. Typical 32 Element
Table 4-26. Negative Sequence Overvoltage Operating Settings
Setting
Range
Increment
Unit of
Measure
Default
Pickup
0 = disabled
10 to 300
0.1 (for 0.1 - 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)
9
cycles
0 to 30,000 cycles (50 Hz)
9
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>-47 Command
Purpose:
Read or set the negative sequence overvoltage pickup level and time delay.
Syntax:
S<g>-47[=<Pickup>,<Time Delay>]
Comments:
g = setting group 0, 1, 2, or 3. See Table 4-26 for S<g>47 setting definitions.
S<g>-47 Command Example
1.
Set the negative sequence overvoltage pickup setting at 50 volts with a time delay of 30 seconds for
all setting groups.
>S#-47=50,30
DIRECTIONAL POWER PROTECTION
32 Directional Power
Figure 4-18 illustrates the inputs and outputs of the Directional Power element. The BE1-951 provides one
such element: 32. Element operation is described in the following paragraphs.
The Directional Overpower element has two
outputs: PU (pickup) and T (trip). When monitored
power flow increases above the pickup setting in
the set direction (forward or reverse), the pickup
element becomes TRUE and the function begins
timing toward a trip. The trip output becomes true
when the element timer times out.
The Block (BLK) input is used to disable the 32
function. 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 to zero. This feature
functions in a similar way to the torque control contact of an electromechanical relay.
The 32 element is enabled or disabled by the Mode input. Two modes are available, Selecting Mode 0
disables the element. Mode 1 enables the element.
The 32 elements monitor three-phase power and compare it to the setting point. If total power is above the
set point in the set direction, the element will pick up. The element may be set as forward or reverse sensing.
The element will remain in the picked-up condition until power flow falls below the dropout ratio of 95% of
setting. The element is always calibrated to the equivalent three-phase power, even if the connection is
single-phase. For more information on the calibration and power calculations, refer to Section 3,
Input and
Output Functions, Power calculations.
