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UNINTERRUPTIBLE POWER SUPPLIES. JOHN LIGUORI CONSULTING ENGINEER MSEE, PE. PRESENTED TO THE IEEE LONG ISLAND CONSULTANT’S NETWORK 9/6/06. UNINTERRUPTIBLE POWER SUPPLIES.
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UNINTERRUPTIBLE POWER SUPPLIES JOHN LIGUORI CONSULTING ENGINEER MSEE, PE PRESENTED TO THE IEEE LONG ISLAND CONSULTANT’S NETWORK 9/6/06
UNINTERRUPTIBLE POWER SUPPLIES • THIS PRESENTATION IS FOR INFORMATIONAL AND EDUCATIONAL PURPOSES ONLY. IT DOES NOT CONTAIN ALL INFORMATION REQUIRED, AND IS NOT INTENDED TO BE USED FOR THE SPECIFICATION OR DESIGN OF UNINTERRUPTIBLE POWER SUPPLIES (UPS) OR UPS SYSTEMS.
UNINTERRUPTIBLE POWER SUPPLIESOUTLINE • INTRODUCTION • POWER DISTURBANCES • UNINTERRUPTIBLE POWER SUPPLIES • GENERAL DISCUSSION • SUMMARY • REFERENCES • QUESTIONS
INTRODUCTION • PURPOSE • WHAT IS AN UNINTERRUPTIBLE POWER SUPPLY? • WHY USE A UPS?
PURPOSE • THE PURPOSE OF THIS PRESENTATION IS TO DISCUSS THE DIFFERENT TYPES OF UNINTERRUPTIBLE POWER SUPPLIES AVAILABLE, WHAT THE UPS PROTECTS AGAINST, THE COMPONENTS OF A UPS, AND ISSUES REGARDING SELECTION AND SIZING. • THE DIFFERENT TYPES AND CAUSES OF POWER DISTURBANCES ARE DISCUSSED, AS WELL AS WHAT THE POWER UTILITY, THE ORIGINAL EQUIPMENT MANUFACTURER, AND YOU, CAN DO TO MINIMIZE THEIR EFFECT.
WHAT IS AN UNINTERRUPTIBLE POWER SUPPLY? • AN UNINTERRUPTIBLE POWER SUPPLY (UPS) IS A DEVICE THAT HAS AN ALTERNATE SOURCE OF ENERGY THAT CAN PROVIDE POWER WHEN THE PRIMARY POWER SOURCE IS TEMPORARILY DISABLED • THE SWITCHOVER TIME MUST BE SMALL ENOUGH TO NOT CAUSE A DISRUPTION IN THE OPERATION OF THE LOADS
WHY USE A UPS? • PROTECTS AGAINST MULTIPLE TYPES OF POWER DISTURBANCES • ONLY DEVICE THAT PROTECTS AGAINST AN OUTAGE • OFFERS PROTECTION AGAINST • EQUIPMENT NOT OPERATING PROPERLY • COMPUTER AND EQUIPMENT DAMAGE • DATA LOSS • TIME AND EXPENSE TO RECOVER BACK TO WHERE YOU WERE, IF EVEN POSSIBLE
POWER DISTURBANCES • CAUSES • TYPES • DURATION • RESULTING PROBLEMS • COMMENTS • WHAT THE POWER UTILITY CAN DO • WHAT THE ORIGINAL EQUIPMENT MANUFACTURER (OEM) CAN DO • WHAT YOU CAN DO • PROTECTIVE DEVICES
CAUSES OF POWER DISTURBANCES • STORM ACTIVITY – LIGHTNING, WIND, ICE • OBJECTS COMING IN CONTACT WITH POWER LINE AND TRIPPING BREAKER – TREE BRANCHES, ANIMALS, OTHER • UTILITY FAULT CLEARING • CONSTRUCTION ACTIVITY • ACCIDENTS – MOTOR VEHICLE, OTHER • EQUIPMENT FAILURE • OVERLOADING • LOAD SWITCHING • NON-LINEAR LOADS • POOR GROUNDING • ESD
TYPES OF POWER DISTURBANCES • INTERRUPTION • SAG, UNDER VOLTAGE • SURGE, OVER VOLTAGE • VOLTAGE FLUCTUATION • FREQUENCY VARIATION • SPIKES / TRANSIENTS • IMPULSIVE • OSCILLATORY • WAVEFORM DISTORTION • DC OFFSET • HARMONICS • INTERHARMONICS • NOTCHING • NOISE • VOLTAGE IMBALANCE
DURATION OF POWER DISTURBANCES • INSTANTANEOUS - ½ CYCLE (8 1/3 ms) OR LESS • MOMENTARY - ½ CYCLE TO 3 SEC • TEMPORARY - 3 SEC TO 1 MIN • SUSTAINED - GREATER THAN 1 MINUTE
CLASSIFICATION OF PROBLEMS RESULTING FROMPOWER DISTURBANCES • DISRUPTIVE • EQUIPMENT DOES NOT OPERATE AS INTENDED • DISSIPATIVE • EQUIPMENT EXPERIENCES REPEATED STRESSES THAT LEAD TO FAILURE LATER FOR NO APPARENT REASON • DESTRUCTIVE • EQUIPMENT FAILS AT THE INSTANT THE DISTURBANCE OCCURS
PROBLEMS RESULTING FROMPOWER DISTURBANCES • DATA ERRORS • DATA LOSS • BLOWN FUSES • TRIPPED BREAKERS • INTERFERENCE WITH CONTROL OF LOADS • OVERLOADED NEUTRAL CONDUCTORS • MOTORS • HEATING • SPEED VARIATION • STALLING • AUDIBLE NOISE • VIBRATION • TRANSFORMERS • HEATING • AUDIBLE NOISE • VIBRATION
POWER DISTURBANCES - COMMENTS • NOT ONLY IS MODERN EQUIPMENT MORE SUSCEPTIBLE TO POWER DISTURBANCES, BUT THE EQUIPMENT ITSELF GENERATES MORE DISTURBANCES • ALL LOADS, FROM LARGE POWERFULL MOTORS AND INDUSTRIAL EQUIPMENT TO SMALL, SENSITIVE ELECTRONIC COMPONENTS, ARE CONNECTED TO THE SAME POWER GRID
WHAT THE POWER UTILITY CAN DO TO MINIMIZE THE EFFECT OF POWER DISTURBANCES • INSTALL STORM RESISTANT WIRING • USE INFRA RED SCANNING TO DETECT WEAK SPOTS IN POWER LINES • INSTALL REMOTE CONTROLLED RADIO SWITCHES TO RESTORE POWER QUICKLY • CLEAR TREE LIMBS AWAY FROM POWER LINES
WHAT THE OEM CAN DO TO MINIMIZE THE EFFECT OF POWER DISTURBANCES BUILD EQUIPMENT CONTAINING ONE OR MORE INTERNAL PROTECTIVE DEVICES • SURGE PROTECTIVE DEVICES • LINE FILTERS • ISOLATION TRANSFORMER • BATTERY OR CAPACITOR BACK UP TO INCREASE RIDE THROUGH TIME
WHAT YOU CAN DO TO MINIMIZE THE EFFECT OF POWER DISTURBANCES • BUY EQUIPMENT THAT HAS INTERNAL PROTECTIVE DEVICES • FOR EXAMPLE, BATTERY BACK UP FOR ANY APPLIANCE THAT CONTAINS A CLOCK • USE ONE OR MORE EXTERNAL PROTECTIVE DEVICES • SURGE PROTECTORS • LINE FILTERS • ISOLATION TRANSFORMER • VOLTAGE REGULATING LINE CONDITIONER • UPS
PROTECTIVE DEVICES OTHER THAN UPS • SURGE PROTECTIVE DEVICES – SPD’S PROTECTS AGAINST SPIKES OF LIMITED ENERGY • METAL OXIDE VARISTORS – MOV • DIODES • GAS TUBES • LCR FILTERS • HYBRIDS • LINE FILTERS FILTERS OUT HARMONICS, TRANSIENTS AND NOISE • ISOLATION TRANSFORMER ELIMINATES DC OFFSET AND NOISE • VOLTAGE REGULATING LINE CONDITIONER AUTOMATICALLY ADJUSTS FOR UNDER AND OVER VOLTAGES • CONSTANT VOLTAGE TRANSFORMER - CVT • MOTORIZED VARIAC
UPS • ARCHITECTURES • WAVEFORMS • INVERTER TECHNOLOGY • COMPONENTS • SWITCHOVER TIME • ADVANTAGES / DIS-ADVANTAGES • SIZING • BATTERY SAFETY
UPS ARCHITECTURES • LINE INTERACTIVE • ON-LINE
BLOCK DIAGRAMLINE INTERACTIVE UPS AUTOMATIC SWITCH CRITICAL LOAD (AC) AC SUPPLY BATTERY CHARGER INVERTER DC TO AC BATTERY AC FAIL
BLOCK DIAGRAMON-LINE UPS AUTOMATIC SWITCH CRITICAL LOAD (AC) AC SUPPLY CONVERTER AC TO DC INVERTER DC TO AC BATTERY INVERTER FAIL
BLOCK DIAGRAMLAPTOP COMPUTER POWER SUPPLY CRITICAL LOAD (DC) AC SUPPLY CONVERTER AC TO DC CONVERTER DC TO DC BATTERY
UPS WAVEFORMS • TRUE SINEWAVE • MODIFIED SINEWAVE • SQUARE WAVE
INVERTER TECHNOLOGY FOR TRUE SINEWAVE • PULSE WIDTH MODULATION - PWM • LINEAR AMPLIFIER • RESONANT INVERTER
BLOCK DIAGRAMPWM INVERTER DC POWER CRITICAL LOAD (AC) HIGH FREQUENCY GENERATOR PULSE WIDTH MODULATOR BASE / GATE DRIVE TRANSISTOR BRIDGE TRANSFORMER FILTER REFERENCE SINEWAVE GENERATOR COMPARISON AMPLIFIER
BLOCK DIAGRAMLINEAR AMPLIFER INVERTER DC POWER CRITICAL LOAD (AC) SINEWAVE OSCILLATOR TRANSFORMER OSCILLATOR AMPLIFIER COMPARISON AMPLIFIER POWER AMPLIFIER
BLOCK DIAGRAMRESONANT INVERTER DC POWER CRITICAL LOAD (AC) SQUARE WAVE GENERATOR SWITCH DRIVE TRANSISTOR SWITCHES TRANSFORMER LC RESONANT TANK FILTER (OR FERRORESONANT)
UPS COMPONENTS • CONVERTER - AC TO DC • SPD - PROTECTS AGAINST SPIKES AND TRANSIENTS • BATTERY • STORED ENERGY DEVICE - PROTECTS AGAINST INTERRUPTIONS • INVERTER – DC TO AC • WAVEFORM SYNTHESIS – PROTECTS AGAINST DC OFFSET AND INTERHARMONICS • FILTER – PROTECTS AGAINST HARMONICS, NOTCHING AND NOISE • VOLTAGE REGULATOR – PROTECTS AGAINST SAGS, SURGES AND FLUCTUATIONS • MONITOR AND CONTROL HARDWARE / SOFTWARE
SWITCHOVER TIME • A TYPICAL SWITCHOVER TIME 2 – 4 ms ONE QUARTER CYCLE OR LESS FOR SOME EQUIPMENT THIS IS NOT TOLERABLE
ADVANTAGES / DIS-ADVANTAGES OF THE DIFFERENT UPS ARCHITECTURES • LINE INTERACTIVE ADVANTAGES • AC TO DC CONVERTER / BATTERY CHARGER DOES NOT HAVE TO PROVIDE FULL LOAD POWER (POTENTIALLY CHEAPER) • LESS STRESS ON DC TO AC INVERTER SINCE IT RUNS AT NO LOAD UNTIL UPS SWITCHES TO BATTERY POWER (POTENTIALLY CHEAPER) • ON-LINE ADVANTAGES • ZERO SWITCHOVER TIME FROM MAIN LINE TO BATTERY POWER • ALWAYS ISOLATED FROM POWER DISTURBANCES ON THE MAIN LINE
SIZING THE UPS • EQUIPMENT RATINGS FOR LOADS • OBTAIN RATINGS FROM NAMEPLATE OR SPEC SHEET • ENERGY USAGE MAY BE SPECIFIED IN VOLT AMPS (VA) OR WATTS (W) AND IN VALUES THAT ARE EITHER MAXIMUM OR NOMINAL • (VA) AND (W) ARE RELATED VIA THE POWER FACTOR • TOTAL UPS LOAD MUST NOT EXCEED THE UPS VOLT AMP (VA) RATING • TOTAL UPS LOAD MUST NOT EXCEED THE UPS WATT (W) RATING • OVERSIZE / DERATE TO ADD LIFE • RUNTIME CHARTS
BATTERY SAFETY • MAINTENANCE • INSPECT PERIODICALLY • REPLACE AS NEEDED • RISKS • ACID • ELECTRIC SHOCK • BURN • FLYING, MOLTEN METAL (EYES) • INJURIES RESULTING FROM CARRYING HEAVY BATTERY PACKS • DISPOSAL • DISPOSE OF PROPERLY • RECYCLE WHENEVER POSSIBLE
GENERAL DISCUSSION • DOES A UPS OFFER COMPLETE PROTECTION? • DO YOU THINK “POWER DISTURBANCES WON’T HAPPEN TO YOU” ? • MISCELLANEOUS
DOES A UPS OFFER COMPLETE PROTECTION? • SOME POWER DISTURBANCES MAY EXCEED THE HANDLING CAPABILITY OF THE UPS • UPS FAILURE
DO YOU THINK “POWER DISTURBANCES WON’T HAPPEN TO YOU” ? • POWER DISTURBANCES OCCUR FREQUENTLY, THOUGH MANY ARE SMALL AND WITHOUT CONSEQUENCE • AN ON-LINE UPS CAN PROTECT AGAINST MORE SIGNIFICANT POWER DISTURBANCES WHEN THEY DO OCCUR • THE COST OF NOT HAVING A UPS CAN EASILY EXCEED THE COST OF A UPS
MISCELLANEOUS • MANY RETAIL UPS FOR COMPUTER APPLICATIONS ARE LINE INTERACTIVE • MANUFACTURERS AND BUILDING CODES DO NOT ALLOW EXTENSION CORDS OR SURGE SUPPRESSORS TO BE USED WITH A UPS
SUMMARYTHINGS TO CONSIDER WHEN SPECIFYING A UPS • POWER QUALITY • ARCHITECTURE - LINE INTERACTIVE OR ON-LINE • WAVEFORM - SQUARE, MODIFIED SINE, TRUE SINE • IMMUNITY TO DISTURBANCES OTHER THAN OUTAGE • RUN TIME WITH AN OUTAGE • RELIABILITY • AUDIBLE NOISE • MONITOR AND CONTROL HARDWARE / SOFTWARE • LOCAL / REMOTE CONTROL • INITIAL COST • MAINTENANCE COST • WARRANTY
REFERENCES • IEEE STANDARD 1100-2005 RECOMMENDED PRACTICE FOR POWERING AND GROUNDING SENSITIVE ELECTRONIC EQUIPMENT • IEEE STANDARD 1159-1995 RECOMMENDED PRACTICE FOR MONITORING ELECTRICAL POWER QUALITY