electric-power-quality-ppt ( Chất Lượng Điện Năng )

Our Roadmap for this PQ Session Our Roadmap for this PQ Session • To arm you with some useful power quality design recommendations and ideas • Illustrate Power Quality solutions usin

WORKSHOP WORKSHOP

Electric Power Quality

Our Roadmap

for this PQ Session

Our Roadmap

for this PQ Session

• To arm you with some useful power

quality design recommendations

and ideas

• Illustrate Power Quality solutions using case studies

• Industry Trends

• To arm you with some useful power

quality design recommendations

and ideas

• Illustrate Power Quality solutions using case studies

• Industry Trends

1 IEEE 1100-1992

1 IEEE 1100-1992

• “The concept of powering and grounding

sensitive equipment in a manner that is

suitable to the operation of that equipment.”1

• “Within the industry, alternate definitions or

interpretations of power quality have been

used, reflecting different points of view.”2

• The definition of Power Quality cannot be

limited to the characteristics of the supply

power The definition must also include the requirements of the load.

• “The concept of powering and grounding

sensitive equipment in a manner that is

suitable to the operation of that equipment.”1

• “Within the industry, alternate definitions or interpretations of power quality have been

used, reflecting different points of view.”2

• The definition of Power Quality cannot be

limited to the characteristics of the supply

power The definition must also include the requirements of the load.

Power Quality Paradigms

Demand for Clean Power Fueled

by 225% Growth in Microprocessors

Demand for Clean Power Fueled

by 225% Growth in Microprocessors

• Increased sensitivity to disturbances

and poor grounding

• Effects of harmonics on distribution

Power Quality Solutions/Electronic Loads

Electronic Ballasts Variable Speed Drives Energy Efficient Motors Solid-State Motor Controls

Surge Suppressors Power-Conditioning Equipment

Electronic Ballasts Variable Speed Drives Energy Efficient Motors Solid-State Motor Controls

Programmable Logic Controls

Solution Strategy

Solution Strategy

Good Grounding Practices

Surge Solutions

Harmonic Solutions

Voltage Variation Solutions

Power Quality Design and

Application Considerations

Power Quality Design and

Application Considerations

• Ensure grounding system integrity

• Limit creation of power quality

problems

• Attenuate power quality problems

• Withstand poor power quality

• Ensure grounding system integrity

• Limit creation of power quality

problems

• Attenuate power quality problems

• Withstand poor power quality

• Related to Over Half

of All Power Quality Problems

• Related to Over Half

of All Power Quality Problems

Good Grounding Practices

Good Grounding Practices

Surge Solutions

Harmonic Solutions

Voltage Variation Solutions

Equipment GroundingGrounding

• Reasons for grounding

Equipment Grounding

and Power Quality

Equipment Grounding

and Power Quality

• National Electrical Code Article 250 also provides the baseline require-

ments to ensure proper operation

of sensitive equipment

• FIPS 94 provides additional methods that are typically needed to ensure reliable operation of electronic

of safety

“Who omitted the safety equipment ground?”

Equipment Grounding

and Power Quality

Equipment Grounding

and Power Quality

Separate the inherent noise from

• Minimize the influence or radiation

of radio frequency noise

• Provide a low impedance path

to ground for noise

• Avoid creating ground loops in the conductors that connect the frames

of functional components

• Minimize the influence or radiation

of radio frequency noise

• Provide a low impedance path

to ground for noise

GND N 120

Desktop Computer

Server

Communications Cable

GND N 120 Balun

Harmonic

Harmonic

Harmonic Distortion

Harmonics are multiples of the fundamental frequency

When added together result

in a distorted

When added together result

in a distorted waveform

Harmonic Frequencies

Harmonics

Surges and Noise

Surges and Noise Transmitted Radio

Frequency

Transmitted Radio

Frequency Harmonic

• Harmonics are low frequency waveform distortions

(< 1kHz)

• Transients are higher frequency events

(between 1 kHz and 1 MHz)

• Above 1MHz, the wires become transmitters

and radiate the noise at this frequency

• Harmonics are low frequency waveform distortions (< 1kHz)

• Transients are higher frequency events

(between 1 kHz and 1 MHz)

• Above 1MHz, the wires become transmitters

and radiate the noise at this frequency

Sources of Harmonics

• Harmonics are produced by the

operation of nonlinear loads

• General categories and common

types of nonlinear loads are

– Power electronic equipment

THD = 104%

Variable Frequency Drive

Amps

Amps Amps

Amps

Amps

Sources of HarmonicsHarmonics

Common Symptoms of Harmonics

• Heating caused by higher frequency

current components

• Insulation stress caused by higher

frequency voltage components

• Circuit malfunction caused

Common Symptoms of Harmonics

Harmonic Distortion Standards

Harmonic Voltage Distortion Limits

for Individual

Total Harmonic

Harmonic Distortion Standards

Maximum Harmonic Current Distortion

Corrective Actions

• Passive harmonic filters

• Active harmonic filters

• Passive harmonic filters

• Active harmonic filters

Design SolutionsHarmonics

• Low harmonic producing loads

such as

– Low harmonic drives

– MG sets

– 10% distortion lighting ballasts

• Low harmonic producing loads such as

– Low harmonic drives

– MG sets

– 10% distortion lighting ballasts

Harmonic Design Tip

Multi-Cycle Voltage Variations

• Sags are responsible for a majority of upsets and nuisance trips of sensitive electrical equipment

• Sags are responsible for a majority of upsets and nuisance trips of sensitive electrical equipment

Good Grounding Practices

Surge Solutions Harmonic

Solutions

Voltage Variations

• Interruption – complete loss of voltage

• Interruption – complete loss of voltage

Voltage Variation SymptomsVoltage

Voltage Variation Sources

• Supply side variations