Basler Electric BE1-851 - Manual (Page 219)

High-Speed Reclose
Each reclose time delay can be set as low as 100 milliseconds. If the application requires a reclose time
delay of less than 250 milliseconds, it is recommended that the close logic expression be modified to
prevent mis-coordination between the TRIP and CLOSE outputs. A hold timer for each output relay is
provided to hold the output closed for approximately 200 milliseconds. This prevents the relay contacts
from opening before the breaker auxiliary contact interrupts the trip coil current. For high-speed reclosing,
the hold timer must be disabled so that the output contact follows the VO1 output expression. To modify
the logic, add the expression “reclose 79C AND NOT trip VO1” to the close logic. Examples 1 and 2 show
a close expression and hold disable setting for high-speed reclosing. Figure 8-18 illustrates this high-
speed reclose interlock logic scheme.
Example 1. Close expression: SL-VO2=79C*/VO1+101C
Example 2. Hold disable setting: SG-HOLD1=0
Figure 8-18. High-Speed Reclose Interlock Logic
Block Load Tap Changer
A block load tap changer output is not provided in any of the preprogrammed logic schemes. One of the
output relays can be programmed to operate when the recloser is running (79RNG) and wired to energize
a normally closed auxiliary relay. The 79RNG logic variable is high when any of the timers are timing and
low when the reclosing function is in a lockout or reset state.
Block Neutral and Negative-Sequence Protection
The neutral and negative-sequence overcurrent elements provide greater sensitivity to unbalanced faults
than the phase overcurrent elements because they can be set to pickup below balanced three phase
load. This can lead to a mis-operation during periods of load imbalance. The BE1-851 provides a neutral
and negative-sequence demand function that allows monitoring and alarming to prevent load imbalances.
9289900990 Rev R BE1-851 Application 8-63