KR series
（
6
-
10kVA
）
user
’s manual
- 35 -
Picture 5.4-1 online drop out Parallel Unit
Caution
：
When the parallel system is working normally, it is better not to quit its output from
parallel system without shutting down parallel unit, otherwise the power system
will appear abnormal.
5.4.4 Online start-up Parallel System
When online launching one or more parallel unit is needed, just follow the
operation steps on Fig.5.4-2 After the new unit is operating stably, it will enter
parallel system automatically and achieve current sharing operation.
Fig.5.4-2 online Launch Parallel System
5.4.5 Redundancy and Expansion of Parallel System
1. Redundant Function
When using N+1 parallel redundant backup design, total output load should not be
large than N times of single machine rated output. When 1 single machine fails,
this single machine could launch and quit freely without affecting the operation of
parallel system, so it could improve the reliability of power system. When the
output exceeds above load, the overloaded single machine (exceed N/ (N+1) times
of single machine rated output) will alarm. For example, for double machines
backup power system, when the load of single machine exceeds 50%, it will alarm
the overloading.
