4,927 views
UPS design criteria and selection
An UPS system is an alternate or backup source of power with the electric utility company being the primary source. The UPS provides protection of load against line frequency variations, elimination of power line noise and voltage transients, voltage regulation, and uninterruptible power for critical loads during failures of normal utility source. An UPS can be considered a source of standby power or emergency power depending on the nature of the critical loads. The amount of power that the UPS must supply also depends on these specific needs.
These needs can include emergency lighting for evacuation, emergency perimeter lighting for security, orderly shut down of manufacturing or computer operations, continued operation of life support or critical medical equipment, safe operation of equipment during sags and brownouts, and a combination of the preceding needs.
The UPS selection process involves several steps as discussed briefly here.
Determine need
Prior to selecting the UPS it is necessary to determine the need. The types of loads may determine whether local, state, or federal laws mandate the incorporation of an UPS. An UPS may be needed for a variety of purposes such as lighting, startup power, transportation, mechanical utility systems, heating, refrigeration, production, fire protection, space conditioning, data processing, communication, life support, or signal circuits.
Some facilities need an UPS for more than one purpose. It is important to determine the acceptable delay between loss of primary power and availability of UPS power, the length of time that emergency or backup power is required, and the criticality of the load that the UPS must bear. All of these factors play into the sizing of the UPS and the selection of the type of the UPS.
Determine safety
It must be determined if the safety of the selected UPS is acceptable. The UPS may have safety issues such as hydrogen accumulation from batteries, or noise pollution from solid-state equipment or rotating equipment. These issues may be addressed through proper precautions or may require a selection of a different UPS.
Determine availability
The availability of the selected UPS must be acceptable. The criticality of the loads will determine the necessary availability of the UPS. The availability of an UPS may be improved by using different configurations to provide redundancy. It should be noted that the C4ISR facilities require a reliability level of 99.9999 percent.
Determine maintainability
The selected UPS must be maintainable. Maintenance of the unit is important in assuring the unit’s availability. If the unit is not properly cared for, the unit will be more likely to fail. Therefore, it is necessary that the maintenance be performed as required. If the skills and resources required for the maintenance of the unit are not available, it may be necessary to select a unit requiring less maintenance.
Determine if affordable
The selected UPS must be affordable. While this is the most limiting factor in the selection process, cost cannot be identified without knowing the other parameters. The pricing of the unit consists of the equipment cost as well as the operating and maintenance costs. Disposal costs of the unit should also be considered for when the unit reaches the end of its life.
Re-evaluate steps
If these criteria are not met, another UPS system must be selected and these steps re-evaluated.
.
Related articles
11,095 views
Galaxy 7000 UPS 250-500kVA by APC
Three-phase Galaxy 7000, 250 to 500 kVA (up to 4 MVA in parallel configurations), includes cutting-edge technologies for high-power applications.
Calling on over 40 years of experience in the Critical Power and Cooling Services division of Schneider Electric, the leader in complete, high-quality electrical power solutions, Galaxy 7000 offers optimised performance for data centers, infrastructure and industrial processes. The compact size, back-to-back or back-to-wall installation enables more room to be utilised for other equipments in the technical room than traditional UPS systems. The UPS can be upgraded to ensure available and secure power infrastructure for current as well as future demands.
Applications
Galaxy 7000 increases the productivity of these applications by providing continuity of service through secure supply solutions that are flexible, adaptable and upgradeable. Galaxy 7000 provides high-quality energy, compatible with all loads, with a very high level of availability. The variety of architectures meets the specific needs of each installation and allows easy upgrading. The communication capabilities and proactive services provided by Schneider Electric, the most complete and available worldwide, make for highly effective maintenance.
- Data Centers
The strategic and economic importance of data centers made it necessary to set up the ANSI/TIA site typology (TIER I to IV). It presents the necessary functions of the major components, including supply via UPSs, to ensure consistency and obtain a high level of overall availability.
.
Galaxy 7000, through its design and many possibilities for parallel connection, as well as its compatibility with STS (static transfer switch) systems, meets TIER IV requirements for fault-tolerant sites offering the highest level of availability (99.995%).
.
Combined with STS units, Galaxy 7000 can supply energy via two or three different channels for dual or triple-attach applications and also offers supervision, network administration and remote-control solutions. Galaxy 7000 is ideal for the large (over 500 square metre) data centers of banks, insurance companies, internet and colocation services, telecoms, etc. where 24/365 operation is mandatory and preventive maintenance and upgrades must not require system shutdown.
- Infrastructure and buildings
Service continuity is also required for infrastructure (airports, ports, tunnels) as well as the operation and technical monitoring (via SCADA and BMS systems) of shopping centres, hospitals, office buildings, etc. Galaxy 7000 is perfectly suited to the needs of these communicating, frequently upgraded applications thanks to its power ratings, extension possibilities and communication capabilities.
. - Industrial processes
Operation in industrial environments requires equipment capable of maintaining processes, without failure, under difficult conditions, including dust, humidity, vibrations, major variations in temperature, etc. Due to its high electrical and mechanical level of performance, Galaxy 7000 meets these specific needs.
.
Technical files are available for all the applications specified by design offices, including Ni-Cad batteries for the chemical and petrochemical industries, high IP values, heavy-duty reinforced cabinets, dust filters, marine configurations, rated voltages up to 440 V, etc. The MGE UPS SYSTEMS design office, in conjunction with a specialised industrial organisation, can also handle uncommon conditions, e.g. outdoor installations, anti-vibration bases for marine applications, special paints with the corresponding labels, etc.
. - Colour
Light grey RAL 9023
Fig. 2. Applications such as data centers, infrastructure and industrial processes.
Strong Points
Galaxy 7000 design combines the best technology (double conversion) with the most recent innovations to supply high-quality power, available 24/365, to high-power applications, whatever the situation in the distribution system.
- Double conversion technology (VFI as per IEC 62040-3/EN 62040-3).
This is the only technology that insulates the load from the upstream network and completely regenerates the output voltage, thus providing high-quality, stable power.
- IGBT-based, PFC sinusoidal-current input rectifier. The rectifier draws sinusoidal current, without any reactive power, thus avoiding disturbances upstream by reducing harmonic reinjection.
• Very low current total harmonic distortion THDI, less than 5%.
• Input power factor (PF) greater than 0.99 from 50% load upwards.
.
These performance levels, combined with the three-phase input not requiring neutral, offer substantial savings in terms of cables and equipment.
Fig. 3. Three-phase, PFC sinusoidal-current rectifier, with DualPack IGBTs.
- Battery charger separated from the AC input. The chopper is supplied via the rectifier output and is thus protected against fluctuations on the AC input. Battery recharge is adjusted as a function of the temperature.
- A check on the phase sequence is run to protect the power system from the effects of incorrect connections.
- Wide input-voltage (250 to 470 V) and frequency (45 to 65 Hz) range. This is made possible by double-conversion technology and the PFC rectifier which is compatible with all sources and with disturbed distribution systems (voltages as low as 250 V for 30% load).
Fig. 4. Wide input-voltage range.
- Soft start. This system provides total compatibility with gensets through gradual start of the rectifier, in addition to a PF of 0.99. It makes it possible:
• when AC power is absent, to progressively transfer the load from the battery to the genset
• when the normal AC source returns to tolerances, to delay transfer from the battery to the rectifier, thus avoiding excessive variations on the AC source.
• in a parallel system, to set up sequential start-up of the inverters.
Fig. 5. Soft start walk-in ramp with time delay.
- Cold start on battery power if the AC source is absent or disturbed, even in parallel systems.
- High-quality output voltage (380, 400, 415 or440 V) for all types of loads with:
• THDU < 3%
• output PF = 09 for all types of load.
The range is suitable for the most recent non-linear and computer loads, called capacitive loads, with a leading PF close to 0.9 and a high crest factor.
- Output voltage adjustable to ± 3% of the rated value (in 0.5 V steps) to take into account voltage drops in long cables.
- Excellent response to load step changes, < 2% for 100 to 0% or 0 to 100% and return to the ± 1% tolerances within 100 ms.
- High current-limiting capacity for inverter short-circuits (2.5 In, 150 ms) to facilitate discrimination with downstream protective devices and accept high crest factors, 2.4:1 up to 3:1, depending on the voltage and power levels.
- Intelligent thermal-overload capacity curve for better performance. The curve is adjusted as a function of the ambient temperature, 1.5 In / 30 seconds, 1.25 In / 10 minutes.
Advanced management to extend battery life
Galaxy 7000 proposes backup times from 5 minutes to 2 hours with a rapid charger (recharge < 6 hours for 10-minute backup time). Backup time remains available due to digital battery management and the protection systems.
- The standard “DigiBat™” system monitors the battery to forward information and maximise performance. Based on a large number of parameters (percent load, temperature, battery type and age), DigiBat controls the battery charge voltage and continuously calculates:
• the real available backup time
• the remaining battery life (1).
.
DigiBat also offers:
• automatic entry of battery parameters
• test on battery status to preventively detect operating faults
• automatic battery discharge test at adjustable time intervals
• protection against deep discharge taking into account the discharge rate, with a circuit breaker to isolate the battery. The breaker opens automatically after double the specified backup time plus two hours (sleep mode to provide vital functions)
• limiting of the battery charge current (0.05 C10 to 0.1 C10)
• gradual alarm signalling the end of backup time
• numerous automatic tests.Fig. 10. Digibat.
- The B1000 battery monitoring or “Cellwatch” option monitors all battery strings 24/365 and displays a failure prediction for each block.
User-friendly interface for more dependable operation
Galaxy 7000 has a control and display interface offering intuitive functions. Based on graphs and pictograms, the interface can be set up in 19 languages including Chinese, Korean, Thai, Indonesian, Turkish and Greek. It includes a graphical display for time-stamped events and useful operating statistics. For operating personnel, that is an essential aspect in facilitating decisions. Simple and user-friendly, the interface enhances safety and comfort.
- Graphical display with HD, B&W touch screen (SVGA).
- Animated mimic panel.
- Menu keys and direct access to display functions.
- Buzzer.
- Remote supervision that can run under many BMS systems and network
supervisors via the communication cards. - Time-stamping of last 2500 events.
- On-line help to assist with the displayed messages.
- Multi-mode for parallel units (modular UPSs in parallel, parallel UPSs with SSC, frequency converters in parallel), i.e. it is possible to read the measurements of any unit on any unit, or to read system data.Fig. 11. HMI with display, LEDs, keys and mimic panel
Advanced communication
Galaxy 7000 offers the entire MGE UPS SYSTEMS range of communication systems designed to meet three essential needs.
- Inform on UPS operation and its environment, warn users, wherever they may be, concerning any potential and existing problems.
- Protect server data by automatic, clean shutdown of operating systems
- Actively supervise an entire set of UPSs.
These functions are carried out by hot-swappable communication cards running
under different protocols, depending on the environment in which Galaxy 7000 is
installed. - Standard relay card with programmable dry contacts (4 logic inputs and 6 logic
outputs). - INMC (Industrial Network Management Card) communication card with two
ports:
• JBus/ModBus RS485/RS232 protocol for communication with a BMS
• Ethernet 10/100 Mbps protocol using the Https standard (secure connection) for
supervision via the web.
Each UPS then has its own IP address making it possible for the user to:
• supervise and control the UPS via a simple browser (HTTP)
• interface with an SNMP administration system (HP Openview, etc.)
• communicate with shutdown modules installed on the protected servers
• set up external temperature and humidity monitoring (sensor environment)
• receive e-mail alarms. - NMTC (Network Management Teleservice Card) communication card with three
ports:
• JBus/ModBus RS232/RS485
• Ethernet 10/100 Mbps using the Https protocol.
The functions are identical to the INMC card, with in addition:
• a modem connection may be used to connect the UPS to the MGE Teleservice
centre for remote monitoring. - Life Cycle Monitoring software for optimised maintenance.
- Compatible with CPSOL software from Schneider Electric for complete
installation design.
Installation
Galaxy 7000 uses the latest technical and mechanical advances in terms of electrical components and power electronics. The greatly reduced number of components offers:
- an overall solution that is very compact, but high accessible for maintenance
- integration of many functions in a single cabinet. The batteries, installed in a
separate cabinet, can be hot-swapped (with the UPS supplying the load).
The UPS can be installed in both technical and computer rooms.
- The UPS can operate correctly back to the wall or back to back, but it is preferable to leave some space (> 600 mm) for easier maintenance.
- Leave one meter of free space in front of the UPS for door opening.
- At least 500 mm of clearance above the UPS is required.
Equipment and diagrams
Galaxy 7000 UPS units offer the following equipment and functions.
Standard configuration
- IGBT-based, PFC three-phase rectifier
- Phase-sequence check on input
- Chopper for battery charging, insulated from AC input, charge adjusted for ambient temperature
- Static switch (except parallel UPS units)
- Manual bypass (except parallel UPS units)
- Three-phase IGBT inverter with freefrequency PWM chopping
- Redundant ventilation for power components
- HMI with graphical interface, 19 languages, menu, function and ON/OFF keys
- Mimic panel with status LEDs
- Time-stamping of last 2500 events
- Battery protected against deep discharges by a circuit breaker
- Cold start on battery power
- Soft start with walk-in ramp and sequential start in parallel configurations
- EMC, level B
- Parallel connection of modular or parallel UPS units
- DigiBat digital battery monitoring and calculation of true backup time
- Programmable relay card, dry contacts, 4 logic inputs, 6 logic outputs
Options
- Connection through the top
- Isolation/voltage matching transformer
- Synchronisation module
- B1000 or Cellwatch battery-monitoring system for block by block management
- Lightning arrestor (built into the UPS cabinet)
- Backfeed protection
- Synchronisation module
- Multi-standard communication cards:
.- Jbus/Modbus + Ethernet 10/100
- Jbus/Modbus + Ethernet 10/100 + Modem
- 2 ports with dry contacts and/or remote shutdown - Battery circuit breaker unit
- Supervision and shutdown software:
- Enterprise Power Manager V.2
Electrical characteristics
.
