Eaton Power Xpert 9395 Installation And Operation Manual

Also see for Power Xpert 9395: Installation and operation manual Installation and operation manual Installation and operation manual Installation and operation manual Installation and operation manual

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Understanding UPS OperationEaton ® Power Xpert® 9395P-300 (300kVA, 300kW) UPS Installation and Operation Manual P-164000563—Rev 04 www.eaton.com/powerquality 6-216.4 Multiple UPS Distributed Bypass SystemDistributed bypass parallel operation extends the normal operation of 9395P-300 UPSs by offering increasedcapacity and/or redundant capability. The parallel system continues to maintain power to the critical loadsduring commercial electrical power brownout, blackout, overvoltage, undervoltage, and out-of-tolerancefrequency conditions.The output of the system is normally supplied by Uninterruptible Power Modules (UPMs) contained in eachUPS. Multiple UPMs are connected with their outputs in parallel (tied together) to provide a load level greaterthan the rating of one UPM, for redundancy, or both. The paralleled UPMs supply the output load with protectedpower as long as the load does not exceed the combined rating of the paralleled UPMs.The power system is redundant as long as one of the UPMs can be disconnected from the output bus and theremaining UPMs can continue to supply power to the load without exceeding their ratings.When the load is being supplied by the UPMs, the system output bus is continuously monitored for anovervoltage or undervoltage condition. If an out of limits condition is detected, the paralleled UPMs transfer theload to bypass using the UPS static switches.Communication is required between the UPSs for system metering and mode control. System levelcommunication and control are accomplished using a Controller Area Network (CAN). A single building alarmin each UPS, connected to the other UPSs in parallel and tied to the bypass contactor auxiliary contacts in eachUPS, are used for a secondary communication path. This arrangement ensures bypass control even if the CANbus is lost.The system is paralleled for redundancy (1+1) in a system where two UPMs are paralleled together and theload is less than the supporting capability of one of the UPMs. The system is paralleled for capacity (2+0) if bothUPMs in a system are required to support the load.A parallel capacity system can also be redundant (2+1), as long as there is always one or more UPMs onlinethan required to support the load.6.4.1 Multiple UPS Parallel System ModesSimilar to the single UPS system, the 9395P-300 UPS parallel system supports a critical load in five differentmodes of operation. The standard operation modes are:l In Normal mode, the paralleled UPMs supply the critical load with clean, filtered power. Each UPM batterycharger also provides charging current for the battery if needed.l In Energy Saver mode, commercial AC power is supplied directly to the critical load through the continuousstatic switch and transfers automatically to Online mode if an abnormal condition is detected. The EnergySaver mode requires a UPS with a continuous static switch. Energy Saver mode in a parallel systemoperates the same as it does in a single UPS system (see paragraph 6.2.3).l In Variable Module Management mode, the UPS operates as a traditional double-conversion UPS, butselectively shifts the load to fewer UPMs to increase the efficiency of the UPS. In a parallel system eachUPS will require at least one UPM to be in double-conversion mode at all times; otherwise, Variable ModuleManagement mode operates the same as it does in a single UPS system (see paragraph 6.2.4).l In Bypass mode, the critical load is directly supported by utility power through the bypass circuit in eachUPS.l In Battery mode, the battery provides DC power, which maintains UPM operation. The UPM batteriessupport the critical load.The UPSs continually monitor themselves and the incoming utility power and automatically switch betweenthese modes as required, without operator intervention, except when manually switching to Bypass mode. Thesophisticated detection and switching logic inside the UPSs ensures that operating mode changes areautomatic and transparent to the critical load, while internal monitoring systems indicate the current mode ofoperation. The UPSs switch operating modes in response to these system events: