Powerware SOLA 4000 manual Parallel-Redundant Systems, Parallel Systems

SOLA 4000 - General System Description

1 UPS Assembly

1.9 Parallel-Redundant Systems

A parallel UPS system consists of 2 to 8 single UPS units con- nected in parallel, sharing the load current equally. Each unit has an individual static bypass, thus ensuring also redundancy of the static bypasses in a redundant system, i.e. if one static bypass should fail, the bypass system will still be available.

There is no common electronic device for the parallel system. Each unit has its own parallel-operation electronics that controls all of its functions, thus ensuring perfect redundancy.

1.10 Parallel Systems

This is identical to the configuration in section 1.9 except that the rated load is normally equal to the rating of the UPS and there is therefore no redundant unit. UPS units of different kVA ratings may be connected in parallel in this configuration, proportionally sharing the load.

Note that the parallel configuration is identical to the parallel- redundant configuration if the load is reduced to a value such that the system minus one (or more) units is capable of supplying the reduced load. Therefore one (or more) units become redundant and the control is identical.

FIG. 1.8 - Parallel Operation - Block Diagram

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