1. PRESENTED TO THE IEEE LONG ISLAND CONSULTANT’S NETWORK
UNINTERRUPTIBLE POWER SUPPLIES
JOHN LIGUORI
CONSULTING ENGINEER
MSEE, PE
PRESENTED TO THE IEEE LONG ISLAND CONSULTANT’S NETWORK
9/6/06

2. 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.

3. UNINTERRUPTIBLE POWER SUPPLIES OUTLINE
INTRODUCTION
POWER DISTURBANCES
UNINTERRUPTIBLE POWER SUPPLIES
GENERAL DISCUSSION
SUMMARY
REFERENCES
QUESTIONS

4. INTRODUCTION PURPOSE WHAT IS AN UNINTERRUPTIBLE POWER SUPPLY?
WHY USE A UPS?

5. 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.

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. CLASSIFICATION OF PROBLEMS RESULTING FROM POWER 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

13. PROBLEMS RESULTING FROM POWER 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. POWER DISTURBANCES AND PROTECTIVE DEVICES

20. UPS ARCHITECTURES WAVEFORMS INVERTER TECHNOLOGY COMPONENTS
SWITCHOVER TIME
ADVANTAGES / DIS-ADVANTAGES
SIZING
BATTERY SAFETY

21. UPS ARCHITECTURES
LINE INTERACTIVE
ON-LINE

22. BLOCK DIAGRAM LINE INTERACTIVE UPS
AUTOMATIC SWITCH
CRITICAL
LOAD
(AC)
AC SUPPLY
BATTERY CHARGER
INVERTER
DC TO AC
BATTERY
AC FAIL

23. BLOCK DIAGRAM ON-LINE UPS
AUTOMATIC SWITCH
CRITICAL
LOAD
(AC)
AC SUPPLY
CONVERTER AC TO DC
INVERTER
DC TO AC
BATTERY
INVERTER FAIL

24. BLOCK DIAGRAM LAPTOP COMPUTER POWER SUPPLY
CRITICAL
LOAD
(DC)
AC SUPPLY
CONVERTER AC TO DC
CONVERTER
DC TO DC
BATTERY

25. UPS WAVEFORMS
TRUE SINEWAVE
MODIFIED SINEWAVE
SQUARE WAVE

26. UPS WAVEFORMS

27. INVERTER TECHNOLOGY FOR TRUE SINEWAVE
PULSE WIDTH MODULATION - PWM
LINEAR AMPLIFIER
RESONANT INVERTER

28. BLOCK DIAGRAM PWM INVERTER
DC POWER
CRITICAL
LOAD
(AC)
HIGH FREQUENCY GENERATOR
PULSE WIDTH MODULATOR
BASE / GATE DRIVE
TRANSISTOR BRIDGE
TRANSFORMER
FILTER
REFERENCE SINEWAVE GENERATOR
COMPARISON
AMPLIFIER

29. BLOCK DIAGRAM LINEAR AMPLIFER INVERTER
DC POWER
CRITICAL
LOAD
(AC)
SINEWAVE OSCILLATOR
TRANSFORMER
OSCILLATOR
AMPLIFIER
COMPARISON
AMPLIFIER
POWER
AMPLIFIER

30. BLOCK DIAGRAM RESONANT INVERTER
DC POWER
CRITICAL
LOAD
(AC)
SQUARE WAVE GENERATOR
SWITCH DRIVE
TRANSISTOR SWITCHES
TRANSFORMER
LC RESONANT TANK FILTER
(OR FERRORESONANT)

31. UPS COMPONENTS CONVERTER - AC TO DC BATTERY INVERTER – DC TO AC
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

32. SWITCHOVER TIME A TYPICAL SWITCHOVER TIME 2 – 4 ms
ONE QUARTER CYCLE OR LESS
FOR SOME EQUIPMENT THIS IS NOT TOLERABLE

33. 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

34. 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

35. UPS SIZING – EXAMPLE SPREADSHEET

36. BATTERY SAFETY MAINTENANCE RISKS DISPOSAL 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

37. GENERAL DISCUSSION DOES A UPS OFFER COMPLETE PROTECTION?
DO YOU THINK “POWER DISTURBANCES WON’T HAPPEN TO YOU” ?
MISCELLANEOUS

38. DOES A UPS OFFER COMPLETE PROTECTION?
SOME POWER DISTURBANCES MAY EXCEED THE HANDLING CAPABILITY OF THE UPS
UPS FAILURE

39. 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

40. 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

41. SUMMARY THINGS 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

42. REFERENCES IEEE STANDARD 1100-2005 IEEE STANDARD 1159-1995
RECOMMENDED PRACTICE FOR POWERING AND GROUNDING SENSITIVE ELECTRONIC EQUIPMENT
IEEE STANDARD
RECOMMENDED PRACTICE FOR MONITORING ELECTRICAL POWER QUALITY

43. QUESTIONS