Power Quality

Front 1

Manny tools designed to improve a power supplies quality are not only among the first to suffer from a lack of quality but are some times ______ the problems they are intended to resolve

Back 1

Contributors

Front 2

Companies have relied heavily on an increased use of _____? to achieve increase productivity

Back 2

Information technology

Front 3

List two characteristics of all IT devices

Back 3

Use power and are sensitive to fluctuations in the supply

Front 4

Companies invest in additional backup equipment which adds to the demand on the power supply and are sensitive to _____? in the system

Back 4

Fluctuations

Front 5

While IT devices can be made more efficient businesses ever-growing reliance on IT still results in a net ____? in the use of electrical power

Back 5

Increase

Front 6

Power quality disturbances may result from circumstances that exists _____? Or _____? a business's control

Back 6

Inside or outside

Front 7

What does a significant percentage of the work involved in maintaining a company's power supply involve

Back 7

Dealing with power equality phenomenons

Front 8

_____? of all computer problems and ____? of all data loss is associated with PQ phenomena can be traced back to the power line

Back 8

1/2 & 1/3

Front 9

From a business perspective what is considered a significant issues?

Back 9

Downtime the company experiences

Front 10

What can the underlying cause of most power quality problems be traced to?

Back 10

Simple rules of electrical circuits = generation transmission distribution system

Front 11

Voltage's and currents within a facility are generally not pure ___?

Back 11

Sine waves

Front 12

Harmonic currents are induced by loads that draw current in a ____? wave form

Back 12

Distorted

Front 13

Voltage's phasers or vectors are separated by ____? degree in a normal 3 phase power distribution system

Back 13

120°

Front 14

Putting electric Drive in front of a 3-phase motor to make an adjustable speed drive or a variable frequency drive Alters the phase angle to reflect a ____?

Back 14

Nonlinear distorted sine wave

Front 15

Current vectors will ___? Significantly when one phase conductors shorted either to ground or to another conductor

Back 15

Shift

Front 16

List the six categories of power quality phenomena

Back 16

RMS voltage variation, voltage transient, waveform Distortion, voltage fluctuations, imbalance, power frequency variation

Front 17

RMS voltage variations due to PQ phenomena are also referred to as ____ _____ _____

Back 17

Sags, swells , interruption

Front 18

A ____? Is a decrease from the nominal voltage supply level

Back 18

Sag

Front 19

A ____? Is an increase in the voltage level

Back 19

Swell

Front 20

List 3 causes of sag originating within a facility

Back 20

Load changes, electrical system faults, improper wiring

Front 21

Swells are frequently the result of a sudden ___? From fault protection

Back 21

Decrease

Front 22

Interruptions are usually the result of being ___? From the fault protection

Back 22

Downstream

Front 23

Voltage transients are usually categorized by the shape of the?

Back 23

Waveform

Front 24

____? transients add energy to the voltage waveform, while ____? transient subtract energy from the curb

Back 24

Positive/negative

Front 25

The PQ phenomena classification which encompasses harmonics inter-harmonic voltage fluctuations notching and DC off sets is waveform?

Back 25

Distortion

Front 26

The main source of harmonic current today are at the phase angle controlled ____? And ___?

Back 26

Rectifiers and inverters

Front 27

Three phase, full wave rectifier cause non-linear harmonic currents since the conduction of current takes place only when the transistor generator ___? allow it and not throughout the completed 60 hertz cycle

Back 27

Switches

Front 28

When are even numbered harmonics found in electrical systems?

Back 28

Unless there is current drawn on only one half of the sine wave

Front 29

Notching can be caused by switching semiconductor creating a brief ____? between two phases

Back 29

Short circuit

Front 30

When does imbalance in a three-phase system occur?

Back 30

When amplitude or phase angle of the voltage or current wave forms are not equal

Front 31

The use of proper personal protective equipment is intended to ___? or ___? injury

Back 31

Prevent or reduce injury

Front 32

What single activity was identified as being performed when an accident occurred?

Back 32

Troubleshooting (important to know)

Front 33

According to NFPA 70b, equipment should be D energize for inspections, test, repairs and other services. Such maintenance tasks can be performed when the equipment is energized provided ___? are made to allow maintenance to be performed ___?

Back 33

Provisions and safely

Front 34

According to NFPA 70b, switchboards, panel boards, industrial control panels, and motor control centers that are likely to require examination, adjustment, services, or maintenance while energize, should be ____? to warn qualified persons of potential electric arc flash hazards

Back 34

Field marked

Front 35

According to NFPA 70b, as a general rule no electrical apparatus should be worked on while it is?

Back 35

Energized

Front 36

What are the exceptions to the rule of working on D energized systems?

Back 36

Not feasible to turn off ( can't make voltage measurements, or can't turn on the main switch) or creates a greater hazard to work on the equipment by de-energizing