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RESOLVING TRANSFORMER NOISE

AND ELECTRICAL HARMONICSPROBLEMS ASSOCIATED WITH DEEPWELL PUMPING SYSTEMS

Craig Patterson, Project Engineer, Meurer & Associates

Paul D. Goldfain, Associate Principal, Meurer & Associates

Robert Anderson, Electrical Engineer, The RMH Group

David Kaunisto, District Manager, East Cherry Creek ValleyWater & Sanitation District

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East Cherry Creek Valley

Water & Sanitation District

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East Cherry Creek Valley

Water & Sanitation DistrictApproximately 50,000 population

10-15 MGD yearly range

Water Supply

Arapahoe aquifer (1,500 - 1,800 deep)

Laramie-Fox Hills aquifer (1,800 2,300

deep)

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Deep Well Installation

Diagram480 Volts 480 Volts 2300 Volts

SUBMERSIBLE WELL

PUMP AND MOTOR

UTILITYTRANSFORMER

(XFMR)

VARIABLEFREQUENCY

DRIVE

(VFD)

STEP-UPTRANSFORMER

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Deep Well Installation

Diagram

480 Volts 480 Volts 2300 Volts

1-YEAR

10-YEAR

PUMPING WATER LEVEL (PWL)

PUMPING WATER LEVEL (PWL)

VFD

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Variable Speed Pumps

70 Hz

60 Hz

50 Hz

Head

3000

2000

0

Gallons Per Minute

0 200 400 600

10 Year PWL

1 Year PWL

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Discussion of Problem

Power Factor Power Factor is the percentage

difference between apparent and

actual power.

The Electric utility requires at least

95%.

P.S. SA-8 was 84%.

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Discussion of Problem

Power Factor The current lags the voltage because

of motor load.

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Discussion of Problem

Transformer Noise Complaints from neighbors

about transformer noise.

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Transformers

Step-up

Utility

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Physical Muffling of

Transformer Noise by Fence

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Goal

Equipment combination that will:

Provide adequate power factor

Reduce noise to acceptable level

Provide operating flexibility to

meet varying demands.

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Electrical Analysis

RMH Group analyzed the powersystems at several pump stations.

They determined that problem was

caused by voltage and currentharmonics generated in the VFDs.

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Variable-Frequency Drive

VFDs

Accusine

Active Filter

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Variable Frequency Drive

6-step VFD voltage source output

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Electrical Harmonics

Graph of harmonics

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Electrical HarmonicsGraph of harmonics

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Harmonic Current Distortion

Well SL-10 VFD operating without Accusine

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Transformer Vibration

Core

Base connected to box

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How Noisy Is It?decibels (dB)

Whisper 30

Light Traffic 40-50Vacuum Cleaner 70

Garbage Disposal 80

Circular Saw 100

Rock Concert 110-130Threshold of Pain 108-130

Jet Takeoff 140

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Decibels vs. Audible Noise

Decibels (dB)

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Equipment Tested 12-step or Pulse-Width Modulated VFD

More frequent pulsing reduces distortion.

Southwest Electric Quiet Transformers Larger core, rubber supports, sound proofing

MTE load filter (for PWM drive) Converts VFD output to sinusoidal wave

Accusine Active filter Senses current, then gates just the right amountof power through the filter to correct distortion.

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Transformer Vibration

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Harmonic Current Distortion

Well SL-10 VFD operating without Accusine

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Harmonic Current DistortionWell SL-10 VFD operating with Accusine

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Accusine Installation Diagram480 Volts 480 Volts 2300 Volts

SUBMERSIBLE WELL

PUMP AND MOTOR

UTILITYTRANSFORMER

(XFMR)

6-STEPVFD

STEP-UPTRANSFORMER

ACCUSINEACTIVE

FILTER

480 Volts

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MTE Load Filter

Installation Diagram480 Volts 480 Volts 2300 Volts

SUBMERSIBLE WELL

PUMP AND MOTOR

UTILITYTRANSFORMER

(XFMR)

PWM(VFD)

STEP-UPTRANSFORMER

MTELOAD

FILTER

480 Volts

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Equipment Tests P.S. SA-8/SL-8

6-Pulse VFD

Utility Transformer 72 dB

Step-up Transformer 68 dBSWE Quiet Step-up Transformer 60 dB

12-Pulse VFD with Phase-Shift Transformer

Utility Transformer 68 dBSWE Quiet Step-up Transformer 60 dB

TAPS Phasor Step-up Transformer 63 dB

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Equipment Tests P.S. SA-8/SL-8

Before: Utility Transformer 72 dB

After adding Accusine Active Filter and Quiet Xfmrs:

Step-up Transformer 68 dB

Utility Power Factor 84%

Utility Transformer 66 dB

SWE Quiet Step-up Transformer 60 dB

Utility Power Factor 97%

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Equipment Tests P.S. A-19/L-19

Installed MTE Output (Load) Filters

A-19 Step-up Transformer 64 dB

L-19 Step-up Transformer 69 dB

Utility Transformer 62 dB, Power Factor 99%

Well A-19 equipped with Toshiba PWM 12-pulse VFD

Well L-19 equipped with Toshiba PWM 6-pulse VFD

A-19 Step-up Transformer 81 dBL-19 Step-up Transformer 82 dB

Utility Transformer 69 dB

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Equipment Tests P.S. SA-1/SL-1Both wells equipped with Centrilift 6-step VFDs and SWE

Quiet transformers.

Without Accusine operating:SA-1 Step-up Transformer 57 dB

SL-1 Step-up Transformer 50 dB

Utility Transformer 66 dB, Power Factor 25%

With Accusine operating:

SA-1 Step-up Transformer 55 dB

SL-1 Step-up Transformer

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$Equipment Costs

$

6-pulse drive $18,000 - $22,000

12-pulse drive $22,000 $24,000

Regular Step-Up Xfmr SWE Quiet Xfmr130 KVA $7,600 130 KVA $13,000

260 KVA $11,300 260 KVA $17,600

PCS300 Accusine Active Filter $36,900 MTE Load Filter $4,500

Transportation and Installation Add 20 - 30%

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ResultsInstallation of Quiet transformers generally

reduced transformer noise by 1/2.

Installation of Accusine Active Filter corrected

power factor to better than 95%, and reduced utility

transformer noise.

Installation of MTE load filter on PWM drivesreduced transformer noise by almost 1/2.

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Questions?

Craig Patterson, Project Engineer, Meurer & Associates

Paul D. Goldfain, Associate Principal, Meurer & Associates

Robert Anderson, Electrical Engineer, The RMH Group

David Kaunisto, District Manager, East Cherry Creek Valley Water& Sanitation District

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PWM Wave

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PWM Output Wave Forms