|Liebert® EXL™ UPS|
Multi-Module Distributed Bypass
Uninterruptible Power System
These specifications describe requirements for an Uninterruptible Power System (UPS) optimized for maximum efficiency. The UPS shall automatically maintain AC power to the critical load within specified tolerances and without interruption during failure or deterioration of the normal power source.
The manufacturer shall design and furnish all materials and equipment to be fully compatible with electrical, environmental and space conditions at the site. The UPS shall include all equipment required to properly interface the AC power source with the intended connected load and shall be designed for unattended operation.
The UPS and all associated equipment and components shall be manufactured in accordance with the following applicable standards:
UL Standard 1778, 5th Edition
CSA 22.2, No. 107.1
National Electrical Code (NFPA 70)
The UPS shall be UL-listed per UL Standard 1778, 5th Edition, Uninterruptible Power Supplies, and shall be certified to meet CSA requirements by an authorized certifying body.
The quality system for the engineering and manufacturing facility shall be certified to conform to quality system standard ISO 9001 for the design and manufacture of power protection systems for computers and other sensitive electronics.
The UPS shall be sized to provide a minimum of (625-1200)kW and a minimum of (625-1200)kVA output.
The UPS shall be able to power loads up to (625-1200)kVA with power factors between 0.7 lagging and 0.7 leading without derating.
Load voltage and bypass line voltage shall be 480VAC, three-phase, three-wire plus ground. Input voltage shall be 480VAC, three-phase, three-wire plus ground. The UPS shall not require or use an input neutral for normal operation. The design intent shall be to maintain reliability while delivering maximum efficiency as indicated in Section 1.3.5.E.
The AC input source shall be a solidly grounded wye service.
The battery shall support the UPS at 100% rated kW load for at least ____ minutes at 77°F (25°C) at startup.
The UPS shall have an active power factor-corrected, three-level IGBT converter/rectifier, capable of maintaining input power factor and input THDi within specifications without an additional input filter.
The UPS shall be of transformer-free design, requiring no internal transformer in the main power path for the basic operation of the module. Optional transformers in cabinets or otherwise external to the basic UPS module shall be permissible to provide isolation and/or voltage transformation.
Modes of Operation
The UPS shall operate as an on-line reverse transfer system in the following modes:
Normal: The critical AC load shall be continuously powered by the UPS inverter. The rectifier shall derive power from the utility AC source and supply DC power to the DC-DC converter, which in turn shall supply the inverter while simultaneously float charging the battery.
Emergency: Upon failure of utility AC power, the critical AC load shall be powered by the inverter, which, without any switching, obtains its power from the battery plant via the DC-DC converter. There shall be no interruption in power to the critical load upon failure or restoration of the utility AC source.
Recharge: Upon restoration of the utility AC source, the rectifier shall supply power to the output inverter and to the DC-DC converter, which shall simultaneously recharge the battery. This shall be an automatic function and shall cause no interruption to the critical AC load.
Bypass: If the UPS must be taken out of service for maintenance or repair, the static transfer switch shall transfer the load to the bypass source. The transfer process shall cause no interruption in power to the critical AC load.
Economizer Mode: The system control shall offer, via field upgrade, a method to increase maximum efficiency when conditions permit by automatically placing the load on the bypass source when the voltage and frequency of that source are within acceptable ranges. The load shall be transferred to the inverter automatically and without interruption should the bypass source be outside of the acceptable ranges. The UPS must maintain a constant float voltage to the batteries while in this mode.
Off-Battery: If the battery only is taken out of service for maintenance, it shall be disconnected from the DC DC converter by means of an external disconnect circuit breaker. The UPS shall continue to function and meet all of the specified steady-state performance criteria, except for the power outage backup time capability.
The solid-state power components, magnetics, electronic devices and overcurrent protection devices shall operate within the manufacturer’s recommended temperature while the UPS is operating at 100% critical load with the following conditions occurring simultaneously.
Any altitude within the specified operating range up to 3300 ft. (1000m) elevation
Any ambient temperature within the specified operating range of 32°F to 95°F (0°C to 35°C)
Any input voltage within the specified range, +10% to -20% of nominal
Full battery charging current shall be maintained down to -5% of nominal voltage at full kW load, or from +10% to -20% of nominal voltage at 90% kW load.
The UPS shall be capable of starting up a transformer load with a capacity equal to the UPS rating without transferring to bypass.
Range: +10%, -20% of nominal voltage at full kW load.
Frequency Range: ±5Hz
Rectifier Walk-In: 0% to 100% of full rated load over 1-30 seconds (adjustable)
Rectifier Start Delay: Programmable from 0-240 seconds before walk-in begins (adjustable).
Maximum Inrush Current: UPS inrush current not to exceed four times the rated input current for a maximum of 10 milliseconds.
Power Factor: Minimum 0.99 at full load with nominal input voltage.
Current Distortion: Reflected harmonics less than or equal to 5% THD at full load input current on a fully rated module in double-conversion mode.
Surge Protection: Sustains input surges without damage per criteria listed in ANSI C62.41, Category A3 and B3 (6kV).
Short Circuit Withstand Rating: Units shall carry a standard 65kA short-circuit current rating and shall have an optional 100kA rating. These ratings shall have been tested and verified as required for listing under UL 1778, 5th edition. A label shall be applied to the unit clearly indentifying this rating as required by the National Electrical Code.
Load Rating: 100% of load rating continuous at 95°F (35°C)
±1% RMS average for a balanced, three-phase load
±2% for 50% unbalanced load for line-to-line imbalances
Manual Voltage Adjustment Range: ±5% for line drop compensation
Synchronized to bypass: ± 0.1-5.0Hz in 0.1Hz steps
Synchronized to internal clock 0.1%
Free running frequency drift shall not exceed 0.1% during any 24-hour period.
Total frequency deviation, including short time fluctuations and drift, shall not exceed 0.1Hz from the rated frequency.
Efficiency (defined as output kW/input kW at 1.0 power factor load, measured at 25%, 50%, 75% and 100% of nominal load, with energy storage disconnected or at float, DC-DC converters running).
Balanced loads 120° ±1°
50% unbalanced loads 120° ±2°
Output Voltage Transients Under Step Loads (average of all three phases)
0-100% or 100-0%
Response Meets IEC 62040-3: 2010 Figure 2 Curve 1, Class 1
Meets ITIC and CBEMA Curve Requirements
Transient Voltage Deviation, RMS 6.5%
Step Load Transient Recovery (linear loads) ±2.5% of nominal at fifth cycle and beyond after transient
The system shall not transfer to bypass under the following conditions:
100% load step
Loss or return of AC input power, momentary sags, surges or spikes on the input to the UPS (all three phases or single phase)
Voltage Harmonic Distortion
Maximum 5% RMS total (linear load)
Maximum 7% RMS total for up to 100% non-linear load
Overload at full Output Voltage with ±1% Voltage Regulation
125% of full load for 2 minutes at 77°F (25°C) ambient
150% of full load for a minimum of 15 seconds at 77°F (25°C) ambient
Current Limit: 200% nominal current
Inverter only: 200% of normal full load current for 200 milliseconds (factory default) or 155% of normal full load current for <5 seconds (when bypass is not available). UPS performance shall be adjustable by certified factory service personnel based on an Output Current Limit setting.
Bypass available: 500% for not less than 10 cycles in inverter pulse-parallel operation when bypass is available.
The UPS chassis shall have an equipment ground terminal.