3 Phase & 1 Phase UPS
Robert Lyga
Gamatronics
Agenda
• Module 1 – Modular UPS technology-3-Phase
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Basics of Modular UPS technology
Centralized vs Decentralized Battery
Planning for Capacity and Future Growth
N+1 Redundancy Methods – Modular UPS vs Single Size UPS
Reliability/Maintenance of Today’s Modular Systems
• Module 2 – Single Phase Technology
– Methods of achieving long run times
– Charging batteries in multiple battery packs
Basics of Modular UPS Technologies
Traditional UPS consists of single rectifier and
inverter sized for full capacity of UPS.
– System may not be upgradeable for future expansion
• Replacement with larger system required
• High cost of expansion
– System may need to be oversized today for correct size in
future
• Higher cost of UPS today
– Failure of the rectifier or inverter transfers the loads to
static bypass
• Lower reliability due to single points of failure
• Redundancy can be done but at a higher cost
80kVA
Rectifier
Inverter
~
=
~
• Lower efficiency and higher Cost of Operation while
undersized
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Basics of Modular UPS Technologies
• Today’s modular UPS system
– Can be configured from 10kVA to 100kVA
• 10kVA to 12kVA power modules
• UPS capacity based on the # of modules
• Modules can be added to increase capacity, redundancy, or
charging
– Each module contains rectifier and inverter
– Control system may be in each module or at system
level
• Module level control with master – slave relationship
Basics of Modular UPS Technologies
•
Modular UPS consists of multiple, smaller
rectifier/inverter modules.
–
System can be upgraded with addition of power modules as
loads grow
• System does not have to be replaced
• Lower cost of expansion
–
Customer purchases the correct size UPS today and the UPS
can grow as needed.
• Lower initial investment
• UPS can be operated at % load that give the best
efficiency and operating cost
–
One rectifier or inverter may fail without causing the UPS to
transfer the loads to static bypass
• Remaining modules may support the load
• Higher reliability due to lack of single point of failure
• Redundancy can be done at lower cost at the module
level
80kVA
Centralized vs Decentralized Battery
•
Centralized Battery
Centralized vs Decentralized Battery
• Centralized Battery
– Batteries are charge simultaneously by all modules, independent
of the integrity of the individual modules
– Backup time not affected by faulty module
– Optional addition of battery strings in parallel
– High reliability
– Charge current control and monitoring according to battery
capacity
– Operation unaffected by rectifier failure in one of the modules
Centralized vs Decentralized Battery
•
Decentralized Battery
Centralized vs Decentralized Battery
• Decentralized Battery
– End-of-discharge disconnection voltage is determined by the
weakest battery set.
– An inverter failure in one of the modules reduces the backup
time
– A rectifier failure in one of the modules excludes its battery set
as well as its inverter output.
– Over current condition may develop in the remaining battery sets
in case of a module failure
– Problematic maintenance of multiple battery sets (hundreds of
batteries per system!)
– Downgrade of battery reliability due to so many batteries that are
liable to fail
Planning for Capacity and Future Growth
• Planning for Capacity
– Determine the amount of load as normal
• Consider start surges and periodic loads as needed
– Select a UPS size based on current capacity requirements
– Select battery system to meet runtime needs.
– Determine the type of maintenance bypass required
Planning for Capacity and Future Growth
• Planning for Future Growth
– Select UPS chassis that is scalable to future needs
– Select battery system that is scalable or with proper over
current protection
– Size maintenance bypass to allow UPS growth
– Size wiring for future capacity
N+1 Redundancy Methods
• Single Size UPS
2 units of 80kVA
provide N+1 Redundancy
N+1 Redundancy Methods
• Single Size UPS
– High initial capital cost
• Must Purchase 2 large UPS system
– High installation cost
• Must install 2 systems
– Lower efficiency = higher operating cost
• Systems operating at 50% load
– 2X footprint
• Floor space may not be available
• Square foot cost
N+1 Redundancy Methods
• Modular UPS
10kVA
10kVA
10kVA
10kVA
10kVA
10kVA
10kVA
10kVA
+
80kVA
10kVA
8 x 10kVA for Capacity
plus 1 x 10kVA for N+1 Redundancy
N+1 Redundancy Methods
• Modular UPS
– Low initial capital cost
• Add one additional module for N+1 redundancy
– Lower installation cost
• Install a single UPS system
– Lower efficiency = higher operating cost
• All modules operating at higher % load
– Single UPS footprint
• Lower floor space costs
Reliability / Maintenance of Today’s
Modular Systems
• Reliability
– Scalability allows operation at optimal % load
– N+1 redundancy increases system reliability
• Maintenance
– Achieved on modular lever
– Lower MTTR
– Lower labor costs for repair
– Spare parts = spare module
Single Phase UPS Technologies
• Methods of achieving long runtimes
– Single battery systems with large wpc batteries
• Typical for larger single phase UPS
• May not be available for smaller UPS
• High initial cost
• Difficult to add incremental runtime
• May require a large charger
Single Phase UPS Technologies
• Methods of achieving long runtimes
– Multiple external battery packs (EBP)
• Typical for smaller UPS
• Use smaller wpc batteries in each pack
• Lower initial cost
• Can add incremental runtime
• Charging method dependant on system
Single Phase UPS Technologies
• Methods of achieving long runtimes
– Multiple external battery packs (EBP)
Single Phase UPS Technologies
• Charging batteries in multiple battery packs
– Single charger in UPS
• May be too small for total battery
• Battery packs may receive different charge voltage and current
– Chargers in each battery pack
• Charger sized correctly for the pack
• Each pack receives correct current and voltage
Single Phase UPS Technologies
• Charging batteries in multiple battery packs
– Chargers in each battery pack
Questions?
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