9328900990 Rev L BE1-951 Protection and Control 4-73
Table 4-42. 60FL Element Blocking Settings
Mode
Input
Setting Explanation Default
DIS
When I Block is disabled, current tripping level is determined by the
sensing voltage level (51/27R operates normally).
I Block
ENA
When I Block is enabled and the 60FL logic is TRUE (voltage sensing is
lost), the current tripping level is controlled by the 51P function and the
27R function is inhibited. When I Block is enabled and the 60FL logic is
FALSE, the current tripping level is controlled by the 51/27R function.
ENA
DIS
Phase (P), Neutral (N), and Negative-Sequence (Q) voltage functions are
not automatically blocked when 60FL logic is TRUE.
P
All functions that use phase voltage are blocked when the 60FL logic is
TRUE. (27P, 59P, and 25)
N
All functions that use 3-phase residual voltage (3V
0
) measurements are
blocked when the 60FL logic is TRUE. (27X, 59X, 159X, - Mode 2)
V
Block
Q
All functions that use the negative-sequence voltage (V
2
) measurement
are blocked when the 60FL logic is TRUE. (47)
PNQ
Figure 4-68. Reporting and Alarms Screen, VT Monitor Tab
The directional tests are also supervised by the loss of potential function 60FL. If the 60FL bit is TRUE,
then voltage sensing was lost or is unreliable. Under this condition, positive, negative, and zero-sequence
directional tests are disabled and their bits are cleared. There is no user setting to enable or disable this
supervision. Current polarization is not affected by the 60FL since it does not rely on voltage sensing.
Similarly, zero-sequence voltage polarization can only be performed if 3P4W sensing is selected. The
following qualifiers are applied to the voltage polarized ground direction element based on the user
selected input quantity:
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