BE1-951
Protection and Control
4-33
If the 60FL element trip logic is TRUE, and V block is enabled for negative sequence blocking<Q>, all
functions that use the negative sequence voltage (V
2
) are blocked. For more information on the 60FL
function, see the paragraphs later in this section.
If the target is enabled for the 47 element, the target reporting function will record a target when the trip
output is TRUE and the fault recording function trip logic expression is TRUE. See Section 6,
Reporting and
Alarm Functions, Fault Reporting Functions for more information about target reporting.
BESTlogic Settings for the Negative Sequence Overvoltage Element
Logic settings for the 47 function are made using the SL-47 (settings logic–negative sequence overvoltage)
command. The settings of this command determine whether the element is enabled or disabled. The SL
command also provides blocking control as determined by the logic expression assigned to the BLK input.
Negative sequence overvoltage logic settings are summarized in Table 4-25.
Table 4-25. Negative Sequence Overvoltage Logic Settings
Function
Range/Purpose
Default
mode
0 = Disabled
1 = Enable
0
BLK logic
Logic expression that disables function when
TRUE. A setting of 0 disables blocking.
0
SL-47 Command
Purpose:
Read or set the negative sequence overvoltage pickup level and time.
Syntax:
SL-47[=<mode>,<BLK logic>]
Comments:
See Table 4-25 for SL-47 settings information.
SL-47 Command Example
1.
Enable negative sequence voltage protection. Disable the 47 element when VO10 is TRUE or VO11 is
FALSE.
>SL-47=1,VO10+/VO11
Operating Settings for the Negative Sequence Overvoltage Element
Operating settings for the 47 function consist of pickup and time delay values. The pickup value determines
the level of voltage required for the element to start timing toward a trip. The unit of measure is secondary
volts PN. The time delay value determines the length of time between pickup and trip. Time delays can be
set in milliseconds, seconds, or cycles. The default is milliseconds if no unit of measure is specified. A time
setting of zero makes the element instantaneous with no intentional time delay. Negative sequence voltage
settings are made using the S<g>-47 command. These settings can also be viewed or changed at the front
panel HMI using screen 5.x.4.1, where x equals 1 for setting group 0, 2 for setting group 1, 3 for setting
group 2, or 4 for setting group 3. Negative sequence overvoltage operating settings are summarized in Table
4-26.