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ABB Distribution Protection Unit 1500R/2000R
Application Note AN-26
The DPU1500R/2000R internal logic and programmable outputs are flexible enough to provide single-pole tripping in
distribution applications where a group of three single-phase reclosers is used. This scheme requires that the loads
be single-phase connected line-to-neutral and provides the benefit of eliminating unnecessary interruptions of the
non-faulted phases.
Follow these steps to implement single-pole tripping on the DPU1500R/2000R:
1. Enable Multiple Device Trip Mode in the Configuration Settings.
2. Assign three of the programmable outputs to the Trip A, Trip B, and Trip C attributes.
3. Assign three programmable outputs to the Close attribute for the Phase A, Phase B, and Phase C reclosers.
When the DPU1500R/2000R is in Multiple Device Trip mode, it does not monitor the open-close positions of the
interrupting devices. The unit assumes the proper response of the interrupter if the fault current drops below 90% of
the pickup setting of each of the active overcurrent elements.
Operation Considerations
When set up for single-pole tripping, the DPU1500R/2000R operates as follows:
•
If simultaneous faults occur on two or more phases, the overcurrent trip timing is based on the highest phase
current, and all phases with current above pickup are tripped simultaneously.
•
If a fault on one phase results in a lockout condition, any subsequent trips on either of the other two phases result
in a lockout condition on that phase also. No reclosing occurs.
•
If one phase has tripped and is in its open interval timing, a trip on either of the other two phases moves the
reclosing program forward one step, and the open interval timing begins again. Both reclosers are closed
simultaneously at the end of this new open interval.
For example, Phase A has tripped and is in its open interval timing based on the 79-1 reclosing sequence. If a trip
occurs at this time on Phase C, the reclosing sequence immediately moves to 79-2 and the open interval timer
begins again.
13-18
Single-Pole Tripping
of Distribution Feeders
website:www.abb.com/papd
9/99
Applications Notes
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