General Power Quality

GENERAL POWER QUALITY www.P3-Inc.com

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POWER QUALITY GOOD POWER BAD POWER

What is good Power?
What is Bad Power?

Conventional Industry Standard

IEEE Std 1100-2005 Conventional Industry Standard

What is good Power? IEEE is the most often quoted “Source” for definitions of Power IEEE stands for “Institute of Electrical and Electronic Engineers” IEEE defines Good Power as: Clean, pure power exhibits constant voltage and frequency, perfect sinusoidal waveshapes, and is free of harmonics, noise, and transients . Conventional Industry Standard

What is Bad Power? IEEE defines Bad Power as: Power that includes voltage variations, voltage swells, voltage sags, overvoltages and undervoltages, harmonics, transients, traveling waves, and power failures. Conventional Industry Standard

Over-voltages Under-voltages Sags Swells Harmonics Noise Transients Grounding The power quality BIG 8

Sags IEEE-1100 Swells IEEE-1100 Over-voltages IEEE-1100 Under-voltages IEEE-1100 Harmonics IEEE-519 and IEEE-1100 Noise IEEE-1100 Transients IEEE-C62.41 and IEEE 1100 Grounding IEEE-142 and IEEE 1100 The power quality BIG 8 Conventional Industry Standard

IEEE-1100-2.2.67: A… reduction in the ac voltage, at the power frequency, for durations from a 0.5 cycle to 1 Min. Voltage Sag Conventional Industry Standard

Voltage Sag Actual P 3 Power Quality Study

Voltage Swell IEEE 1100-2.2.78: An increase in… voltage or current at the power frequency for durations from 0.5 cycle to 1.0 min. Conventional Industry Standard

Voltage Swell Actual P 3 Power Quality Study

Over-voltages IEEE-1100-2.2.56: Increase in the ac voltage, at the power frequency, for a period of time greater than 1 min. Conventional Industry Standard

Actual P 3 Power Quality Study

Under-voltages IEEE 1100-2.2.56: Decrease in the ac voltage, at the power frequency, for a period of time greater than 1 min. Conventional Industry Standard

Actual P 3 Power Quality Study

Utility Standards Utility standards are defined by the various State Utility Boards. Most require the utility must adhere to this standard: 1. Voltage limits as stated by IEEE/ANSI C84.1 Conventional Industry Standard

IEEE/ANSI C84.1 Standard Voltage Voltage Range A Voltage Range B 120 114-126 110-127 120/240 114/228-126/252 110/220-127/254 208Y/120 197Y/114-218Y/126 191Y/110-220Y/127 480Y/277 456Y/263-504Y/291 440Y/254-508Y/293 13200Y 12870Y-13860Y 12504Y-13970Y “ Electrical supply systems shall be so designed and operated that most service voltages will be within the limits for range A” “ When…Range B… voltages occur, corrective measures shall be undertaken within a reasonable time to improve voltages to meet Range A requirements.” Conventional Industry Standard

IEEE-1100-2.2.83: A subcycle disturbance in the ac waveform that is evidenced by a sharp, brief discontinuity of the waveform. May be of either polarity and may be additive to, or subtractive from, the nominal waveform. Transient Conventional Industry Standard

Transient Actual P 3 Power Quality Study

Transient 8x20 µs Short Circuit Current TIME 3,000 10% 50% 20 µs 8 µs 0 90% Impulse / Combination wave Transient A M P E R E S

Transient 8x20 µs Impulse Location Category System Exposure Voltage (kV) Effective Impedance B1 B2 B3 C1 C2 C3 Low Medium High Low Medium High 2 4 6 6 10 20 2 2 2 2 2 2 Current (kA) 1 2 3 3 5 10 Peak Values Conventional Industry Standard

Transient peak r Voltage Waveform B3 — 0.5 µs, 100 kHz Ring Wave V peak T = 10 µs (f = 100 kHz) 60% of V 0.9 V peak 0.1 V peak 0.5 µs t Ring Wave Transient

Transient Standard 0.5 µs - 100 kHz Ring Wave Location Category System Exposure Voltage (kV) Effective Impedance A1 A2 A3 B1 B2 B3 Low Medium High Low Medium High 2 4 6 2 4 6 30 30 30 12 12 12 Current (kA) .07 .13 .2 .17 .33 .5 Peak Values Conventional Industry Standard

IEEE 1100-2.2.49: Unwanted electrical signals that produce undesirable effects in the circuits of the control- systems in which they occur. Noise Conventional Industry Standard

Noise Actual P 3 Power Quality Study

Harmonics A harmonic is the term used for current flow on your facilities power system at frequencies other than 60Hertz.

Harmonics Low Harmonic Waveform Actual P 3 Power Quality Study

Harmonics Actual P 3 Power Quality Study

Harmonic Problems
Electrical and Electronic damage.
Overheating and less efficient transformers
Control System errors due to Electrical
noise caused by harmonics.
Blown Fuses for no APPARENT reason.
Nuisance tripping of Circuit Breakers.

Typical Harmonic frequencies: 3 x 60 = 180HZ 5 x 60 = 300HZ 7 x 60 = 420HZ 11 x 60 = 660HZ 13 x 60 = 780HZ

Power Factor

Power Factor
What is Power Factor?
What is a good Power Factor?
What is a Bad Power Factor?
What problems are caused by
a bad Power Factor
How to correct for a bad
Power Factor.

What is Power Factor?
Power Factor is the ratio of Active Power to Total Power
Active Power Total Power = Power Factor

Active Power
Active power is what we normally see as the electricity used in our facility.
Measured in kW (Kilowatts).
This is normally what the power company charges against.
Main Service Motor Control Center Sub- Power Panels Sub- Power Panels Lights Phones Computers Etc. kWh METER Motor Motor Motor

Total Power
Total power is what our equipment needs to be sized for in our facility.
Measured in KVA (Kilo-voltamps).
The power company may charge extra money (penalties) for a large KVA.
The large KVA is usually stated in Power Factor .
Total Power is a combination of Active Power
and something called Reactive Power .

Reactive Power Measured in Kvar
Reactive Power takes into consideration the energy needed
to build all the magnetic fields in a facility.
Your facilities equipment must be sized large enough to handle
the extra energy needed to produce these magnetic fields.
Magnetic fields are produced in ALL current carrying equipment
in a facility. This includes Switchboards, Panelboards, Busway,
wiring, all equipment, and especially MOTORS. Motors have
thousands of feet of wire which add greatly to a facilities
Reactive Power

Magnetic Fields Produced in your Facility
In a AC (Alternating Current) system, current flow changes
direction 60 times every second. This is called 60 Hertz (Hz).
Each time the current changes direction a magnetic field is
developed around ALL current carrying parts of a circuit.
This includes all the wire in your facility, all Motors
and all transformers.

0V 680V 680V Section of Wire Magnetic Field Produced around wire

Reactive Power
The energy needed to produce this Magnetic Field is real.
You don’t see it on your energy bill because the power is
given back to the circuit in each quarter cycle.
The extra current flow is there. Therefore, you and your
power company must size equipment large enough to handle
the extra energy needed to produce these magnetic fields.
This is why many Power Companies add an extra charge (penalty)
to facilities with a large amount of reactive power.

Remember… Total Power is a combination of Active Power and Reactive Power . This is how they combine : Active Power (kW) Reactive Power (kvar) Total Power (kva) Active Power (kW) 2 + Reactive Power (kvar) 2 = Total Power (kva) 2

As Reactive Power increases Active Power stays the same however Total Power increases greatly. Active Power (kW) Larger Reactive Power (kvar) Larger Total Power (kVA)

Remember
Power Factor is the ratio of Active Power to Total Power .
When Reactive Power is large Total Power increases.
With the formula below we now see that when Total Power
increases the Power Factor decreases.

When Total Power increases the Power Factor decreases.
Active Power Total Power = Power Factor 1000 kW 1050 kVA .95 Power Factor = 1000 kW 1500 kVA .6 Power Factor

= 1000 kW 1050 kVA .95 Power Factor = 1000 kW 1500 kVA .6 Power Factor
.95 to 1 is considered a good power factor.
Anything less than .9 can be considered a bad power factor .
Your Power Company may charge you or you may have internal
problems in your facility with Power Factors less than .9.

The best way solve a low Power Factor problem is to install
Power Factor Correction Capacitors.
These Power Factor Correction Capacitors capture the energy
from the collapsing magnetic field and give the energy back
on the next Quarter cycle.

Power Factor Capacitor Storage of Magnetic Fields Produced in your Facility Power Correction Capacitor 0V 680V 680V Section of Wire

Gaining capacity with Power Factor Capacitors If we increase Power Factor, what happens to KVA? = 1000 kW 1500 kVA .6 Power Factor = 1000 kW 1050 kVA .95 Power Factor

Gaining capacity with Power Factor Capacitors 1500 kVA on a 480 3 phase system is 1800 AMPS 1050 kVA on a 480 3 phase system is 1200 AMPS Could we use this gain of 600 amps? Absolutly!

Harmonics

What is a Harmonic? A harmonic is the term used for current flow on your facilities power system at frequencies other than 60Hertz.

What exactly is a Harmonic?

Linear use of power Volts Amps 0V 680V 680V 0A 200A 200A

Equipment that uses power in a linear fashion

Non-Linear use of power Volts Amps 0V 680V 680V 0A 200A 200A

Equipment that uses power in a NON-linear fashion Fluorescent Lights and Ballast's Copiers and other Office equipment Variable Frequency Drives All equipment that uses an AC to DC power supply Computers

3 x 60 = 180HZ 5 x 60 = 300HZ 7 x 60 = 420HZ 11 x 60 = 660HZ 13 x 60 = 780HZ Typical Non-Linear frequencies that cause problems:

Why does Non-Linear current flow cause problems In my facility?

0V 680V 680V Section of Wire Magnetic field produced around wire

Combination of Linear and Non-Linear power 0A 200A 200A Section of Wire

Harmonic Problems
Electrical and Electronic damage.
Overheating and less efficient transformers
Control System errors due to Electrical
noise caused by harmonics.
Blown Fuses for no APPARENT reason.
Nuisance tripping of Circuit Breakers.

IEEE 519-1992 -Current Maximum Harmonic Current Distortion I SC / I L TDD 1-20 5% 20-50 8% 50-100 12% 100-1000 15% 1000+ 20% I SC= Maximum short circuit current I L= Maximum demand load TDD= Total Demand Distortion Conventional Industry Standard

Example: Typical Office Building 1200A 208Y/120 service 30K AIC The Maximum IEEE Harmonic distortion is: 30,000 AIC / 960 = 31 31 on the IEEE chart is 8% Current Harmonics

IEEE 519,1992 -Voltage Maximum Harmonic Voltage Distortion Voltage THD 69kV and below 5% THD=Total Harmonic Distortion Conventional Industry Standard

Installation involving Harmonic Cancellation Transformers in a typical four-story office building 480 Volt Main Switchgear Total Harmonic Distortion 2.8% 1 st Floor Panel with regular transformer Total Harmonic Distortion 5.1% 2nd Floor Panel with regular transformer Total Harmonic Distortion 5.4% 3rd Floor Panel with regular transformer Total Harmonic Distortion 5.9% 4th Floor Panel with regular transformer Total Harmonic Distortion 7.7% Harmonic levels on each floor are above the IEEE 519 maximum allowed level of 5%. The 7.7% level on the forth floor resulted in a distorted voltage waveform.

After installation of only one Harmonic Cancellation Transformer on the 4th floor the following readings were logged: 480 Volt Main Switchgear Total Harmonic Distortion 1.7% 1 st Floor Panel with regular transformer Total Harmonic Distortion 4.0% 2nd Floor Panel with regular transformer Total Harmonic Distortion 4.3% 3rd Floor Panel with regular transformer Total Harmonic Distortion 4.8% 4th Floor Panel with new transformer Total Harmonic Distortion 3.2% New Harmonic Cancellation Transformer Total Harmonic Distortion on the 4th floor dropped from 7.7% to an acceptable IEEE519 level of 3.2%. This also had an effect on the rest of the building power lowering the Harmonic levels as shown.

Installation of Transformers that treat harmonics have
many benefits, however the two largest benefits are:
Elimination of harmonics that cause damage to or errors
with your sensitive equipment.
Energy savings from eliminating harmonics in your
facility.

Transient Voltages And Surge Suppression Devices

Surge Protection Devices are used to help stop
Voltage Spikes and Surges from destroying your
facilities Electrical and Electronic Equipment and
Data.
They used to be called Transient Voltage Surge
Suppressors “TVSS” units.
They are now called Surge Protection Devices
“ SPD’s”.

TVSS SPD Sept. 2009

Voltage Spikes and Surges are known as: Voltage Transients, or just Transients. +170V Normal 120 Volt 60Hz AC Voltage Sine Wave -170V 0V +170V 120 Volt 60Hz AC Voltage Sine Wave With Transients -170V 0V

SPD Lightning/Surge Arrestor UL 1449 3 rd ed. Addressed by ANSI/IEEE 1100 No longer addressed by UL Not addressed by ANSI/IEEE 1100 Proper Design will limit voltages to ANSI/IEEE 3.4.3 Levels No standard for limiting Voltages SPD Lightning Surge Arrestor Conventional Industry Standard

What causes these Transients? Lightning Strikes Power Line Problems Motors Fluorescent Lights and Ballasts Copiers and other office equipment Welders and other industrial equipment

The Source of the Transients are from two areas. Internal in your Facility Motors Ballasts Office Equipment Industrial Equipment External to your Facility Lightning Power Company Problems 80% 20% Conventional Industry Standard

GE ® Study on Transients Generated by Switching Results of switching off a 2-bulb, four foot fluorescent fixture 24 transients in excess of 1200 volts Source: General Electric Instrumentation and Computer Service Laboratory 2000 1000 -1000 0 Volts* No Protector ® 10:1 Probe -10 µsec +10 µsec * Voltage scale corrected for probe attenuation factor Time -2E-5 -20 µsec 2E-5 +20 µsec OE-5 0

IEEE example of Transients Generated by Capacitor Switching

IEEE example of Transients Generated by energizing a transformer

Transient caused by switching a 120 volt 1500 Watt plug in heater Actual P 3 Power Quality Study

IEEE example Transients caused by Harmonics

IEEE example Transients caused by Motor switching

T ransients Oscillatory Transient (Ring Wave) Impulse Transient Time (mS) -7500 -5000 -2500 0 2500 5000 7500 14 12 10 0 80 60 40 20 0 -1.5 -1.0 -.05 .00 .05 1.0 1.5 2.0 100 Time

Some problems caused by Transients in your facility:
Premature Equipment failure
Long term cumulative equipment damage
Power loss
Data losses and system resets
Catastrophic equipment failure
Immediate operation shutdown
Expensive equipment repair and
replacement costs

Problems with Equipment
Motor Windings
Premature or Complete Motor Failure

Contact Failure from lightning strike Problems with Equipment

Problems with Equipment

Integrated Circuit Schematic From Innovative Technology, Inc

Electron Microscopic Photo Catastrophic Cumulative From Innovative Technology, Inc

The Protection Circuit Switchgear Motor Control Centers Lights Phones Computers Etc. 480V Incoming Power Neutral Ground 6000V Voltage Spike 600V Maximum Clamp by SPD SPD

The SPD is designed to:
Limit the let through voltage so electrical
and electronic equipment is not damaged
Therefore, the SPD must:
Sense Over-voltages
Limit the let through voltage
Not interrupt Normal Service
Give an indication when it is not working

Common Components Component Strengths Weaknesses
High energy-handling capability
Readily available
Sub-nanosecond response time
Consistent clamping levels
Degradation
MOV

MOV Degradation New MOV Fully Functional Slight degradation from use Total Degradation Less Peak Surge More Let Through Voltage

Many TVSS units DO NOT include ALL MODE PROTECTION Surge Protection Design Built for Endurance & Peak Surge Capacity Line to Ground 3 modes Neutral to Ground 1 mode Line to Neutral 3 modes Phase A B C N G 5 6 7 4 1 2 3 6 4 5 7

Sub-nanosecond response time
Reliable
Small energy-handling capability
Must use many to get adequate protection, therefore large enclosures
Transorb or Avalanche Diode

Filters ring wave transients
Provides EMI/RFI filtering
Effectiveness is frequency sensitive
May draw significant current at idle
Large values may upset operating system
Capacitor

IEEE Standard 1100- 3.4.3 states:
Electromechanical devices can generally tolerate voltages of several times their rating for short durations… solid-state devices can not tolerate more than twice their normal rating .
Therefore, voltages more than 240volts on a 120volt system cause damage to most modern electronic equipment.

When comparing SPD’s you must:
Check the let through (clamping) voltage
Determine which IEEE voltage was applied to the
SPD to determine the stated let through voltage.
At what point was the measurement taken on the
incoming waveform (90 Deg. Or 180 Deg.).
4. Where on the SPD was the measurement taken.

The two basic types of TVSS units

The new UL 1449 3 rd Edition Specification

Locations for SPD Types Type 1 Before service disconnect Type 2 (Type 1 permitted) After service disconnect Type 3 (Type 1 and 2 permitted) 30 feet of conductor between service disconnect and SPD Type 4 Component Level

Manufacturer chooses a current they want to test with:
Type 1 – 10kA or 20kA
Type 2 – 3kA, 5kA, 10kA or 20kA
Complete SPD is tested along with any required overcurrent devices (fuse or breaker)
Measured let through voltage for a 6000V 3000A surge is recorded
SPD is subjected to 15 surges at chosen current one minute apart with rated voltage applied between surges
Measured let through voltage for a 6000V and 3000A surge is recorded again – let through voltage must not deviate more than 10% from original voltage (this is brand new!)
Nominal Discharge Current - I n

Voltage Protection Rating is assigned to an SPD model by the NRTL from a table based on the average of the measured limiting voltage from 3 impulses of a 6000V/3000A Transient
Voltage Protection Rating “VPR”

VPR gives an indication of the quality of
construction and expected performance
VPR replaces the old “SVR” surge voltage rating
which only tested with 6000V 500A.
VPR ratings will be higher than the old SVR ratings
because VPR uses 6000V 3000A
Voltage Protection Rating “VPR”

The new UL 1449 3 rd Edition- Summary TVSS SPD Transient Voltage Surge Suppressor Surge Protection Device SVR VPR Surge Voltage Rating Voltage Protection Rating NDC- In Nominal Discharge Current Category A,B,C Type 1,2,3,4 Location A-1,2,3/B-1,2,3/C-1,2,3 Locations Out In

The new ANSI/IEEE C62.41 Standard

The new ANSI/IEEE C62.41 Standard 8x20 µs TIME 10% 50% 20 µs 8 µs 0 90% 0.5 µs, 100 kHz Ring Wave V peak T = 10 µs (f = 100 kHz) 90% peak 10% peak 0.5 µs peak 60% of V

ANSI/IEEE describes location categories
ANSI/IEEE also describes current and voltage levels that might be typical in these areas
A B C The new ANSI/IEEE C62.41 Standard

ANSI/IEEE Standard 1100 3.4.3 states:
Electromechanical devices can generally tolerate voltages of several times their rating for short durations… solid-state devices can not tolerate more than twice their normal rating .
Therefore, voltages more than 240volts on a 120volt system cause damage to most modern electronic equipment.

UPS Systems

IEEE 1100 Section 7 tells us: The correct UPS System can solve 7 of the 8 power problems that cause failure or malfunction of equipment in your facilities. Conventional Industry Standard

Conventional Industry Standard Overvoltage Undervoltage Sag Swell Transient Noise Long term outage Frequency variation Surge Protection Device Noise Filter Isolation Transformer Voltage Regulator Stand By Off Line UPS Line Interactive UPS Generator True On Line Double Conversion UPS N N N N Y ? N N N N N N N Y N N N N N N ? ? N N N N Y Y ? Y N N ? ? N N N N Y ? N N N N N N ? N Y Y N N N N ? ? Y Y Y Y Y Y ? Y

There are three basic types of Uninterruptible Power Supply systems available: 1. Stand by (Off line) 2. Line interactive (Off Line) 3. True On line Double Conversion

Equipment that needs uninterruptible power Power from normal power provider Batteries and DC to AC Inverter Stand By UPS System The stand by UPS system (sometimes called Off-line system) operates in the following manor: While the normal power provider is operational the equipment wired to the UPS system receives power from this normal power provider. When this normal power is lost (blackout) the UPS system activates (turns on) and supplies power to the equipment that needs uninterruptible power until the normal power returns. The way this UPS system creates power is by converting the DC power from batteries to AC via an inverter. The activation (turn on) time for the inverter and internal switch from normal power to inverter power is typically 8-16 milliseconds.

Equipment that needs uninterruptible power Power from normal power provider Batteries and DC to AC Inverter Stand By UPS System

Stand by (Off Line) UPS Benefits : Inexpensive Small Footprint Disadvantages : Not Designed for Critical Loads No Power Conditioning Load Exposed to Surges, Sags, and transients Not Generator Compatible Switching Necessary to go from Utility to battery Power. Discontinuous Power during Switch to Battery Less Battery Life (Used more often) Poor Maintainability without maintenance Bypass

Equipment that needs uninterruptible power Power from normal power provider Batteries and DC to AC Inverter Voltage Regulator Typically A Buck Boost Transformer Line Interactive UPS System Line interactive (Off Line) UPS systems add extra features that give us, at a minimum, two advantages over the Stand By UPS system. One, they usually include some type of voltage regulator between the normal power provider and your equipment that needs uninterruptible power and two, they have activation times around 4-8 milliseconds.

Line Interactive UPS Benefits : Less Costly than True on Line Technology Some Power conditioning Disadvantages : Not Designed for Critical Loads Limited Power Conditioning Load Exposed to Surges, Sags, and Transients Not always Generator compatible Less Battery Life (Used more often) Poor Maintainability without a maintenance bypass

Power from normal power provider Equipment that needs uninterruptible power AC to DC Rectifier Batteries DC DC to AC Inverter True On Line UPS system Double Conversion The On Line UPS is the best option when your equipment cannot loose power for even a split second. With an On Line system power is constant and there is no activation time. The On Line system uses batteries and a DC to AC inverter just like to other two units mentioned above, however, it also uses something called a rectifier. The addition of the rectifier along with the batteries and inverter enable the On Line UPS to give constant power to your equipment that needs uninterruptible power. The inverter that supplies power to your equipment is always on. The inverter gets its power from either the normal power provider (via the rectifier) or the batteries. With power to your equipment being supplied constantly from the inverter you receive clean regulated power at all times. In many cases this On Line technology is the only answer to your sensitive equipment power needs.

Power from normal power provider Equipment that needs uninterruptible power AC to DC Rectifier Batteries DC DC to AC Inverter True On Line UPS system Double Conversion

True On Line Double Conversion UPS Benefits : Designed for Critical Loads Superior Power Conditioning Isolates Load from Surges, Sags, and Transients Generator Compatible Extended Battery Times available with Full Time inverter Extended Battery Life (Only used during emergencies) Easy to Maintain with maintenance Bypass Switch Disadvantages : More Expensive than lessor technologies Bigger Footprint

The True On Line UPS is the best solution if the Uninterrupted operation of your equipment is critical .

General Power Quality

by Power Protection Products, Inc. on Feb 16, 2010

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