(WWW) Challenges: Energy Usage

Drives and Pump Optimization

Discussion on Pump Optimization Principles and “Need to

Know” Drive Technology

Smart Water for Smart Cities

Workshop

11:00am Tuesday May 20, 2014

Presented by Paul Krasko

Water Wastewater (WWW) Challenges:

Energy Usage

● Demand for WWW

● Age of infrastructure

● Legislative compliance

● Reduced financial resources

● Energy efficiency awareness

● Energy use

Schneider Electric | Jeff M. Miller | 2014 MWEA & AWWA-MO Joint Annual Meeting | 10:30 Monday March 31 st , 2014

Process = 70%

Pumping = 16%

2

Finnish Technical Research Center Report:

“Expert systems for diagnosis of the condition and performance of centrifugal pumps ”

Evaluation of 1690 pumps at 20 process plants:

● Average pumping efficiency is below 40%

● Over 10% of pumps run below 10% efficiency

● Major factors affecting pump efficiency

■ Throttled control valves

■ Pump over-sizing

● Seal leakage causes highest downtime and cost


3

System Curve Uncertainty

Results in Uncertain Pump Operation

- and higher costs


4

PUMPS SYSTEM OVERVIEW

AND FUNDAMENTALS


6

Overview

● The pumping system:

•

•

•

Components

•

•

•

•

• Pumps

Motors, engines

Piping

Valves and fittings

Controls and instruments

Heat exchangers

Tanks

Others


•

•

•

•

•

End-use

Water treatment

Wastewater treatment

Water distribution

Power generation

Irrigation

7

Overview, continued

Electric utility feeder

Transformer

Motor breaker/starter

System Approach

● Component optimization involves segregating components and analyzing in isolation

● System optimization involves studying how the group functions as one as well as how changing one component can help the efficiency of another

Adjustable speed drive

(electrical)

Motor Coupling Pump Fluid System

Served

Process(es)


8

Pump Fundamentals

There are two basic types of pumps:

1.

Centrifugal

2.

Positive

Displacement (PD)

● Use a rotating impeller to increase velocity of a liquid and its stationary components direct discharge flow to convert velocity to increased pressure

● Types include axial, mixed flow, and radial

● Move a set volume of liquid and pressure is obtained as the liquid is forced through the pump discharge into the system

● Types include piston, screw, sliding vane, and rotary lobe


9

Pump Fundamentals, continued

Centrifugal Pumps

• Impart energy to the liquid by increasing its speed in the impeller and then converting the speed to pressure through diffusion in the volute.


10

AC Motors - Variable Torque Applications

Variable Torque (VT)

%

Torque,

Flow,

& HP

100

50

(Amps)

Torque

Flow

HP

50 100

(Base)

%

Speed


11

Pump Fundamentals, continued

PD Pumps

● Impart energy by applying mechanical force directly to the liquid through a collapsing volume


12

Energy Efficiency in Pumps

• Load Characteristics

Water Wastewater Load Characteristics

Typical

Applications

Energy

Savings

Potential

Variable

Torque

Constant

Torque

Centrifugal Pumps and Blowers

Substantial

Potential – Largest of all VFD applications

Positive

Displacement

Pumps, Blowers,

Mixers, and

Chemical Feed

Pumps

Lowest Potential

Constant

Power

No applications

No Potential

The Main

Target priority)

( first The Next

Step ( second priority)


13

Pump Head Pressure

● Static head is the energy needed to overcome an elevation or pressure difference between the suction and discharge vessels.

● Frictional head loss increases by the square of the velocity change of the liquid in the pipe.

● In most cases:


14

Pump Head Pressure

Friction Head

Static Head

System Head Curve produced by US DOE PSAT Software


15

Pump Head Pressure

Friction Head

● May occur in pump systems due to hydraulic losses in:

• Piping

• Valves

• Fittings (e.g., elbows, tees)

• Equipment (e.g., heat exchangers)

● Which are used to control flow or pressure by:

• Automated flow and pressure control valves

• Orifices

• Manual throttling valves


16

VARIABLE FREQUENCY DRIVE

(VFD) BENEFITS WITH PUMPS


17

Energy Efficiency in Pumping Systems

• Motor costs


18

Energy Efficiency in Pumps

• Energy wastes

How your money is wasted !

Car example :

…try to regulate the speed of your car

• keeping one foot on the accelerator

• the other on the brake.

Pump example :

… try to adjust the pump output

• running the motor at full speed

• control the flow with a throttle valve

Still one of the most common control methods in industry …..

with a considerable waste of energy


19

VFD Benefits with Pumps

• Physical laws for centrifugal loads

It’s pure physics:

Due to the laws that govern centrifugal pumps, the flow of water decreases directly with pump speed

Affinity laws of centrifugal loads:

Flow = f (motor speed)

Pressure = f (motor speed) 2

Power = f (motor speed) 3


20



A motor running at 80% of full speed requires 51% of the electricity of a motor running at full speed.


21



A motor running at 50% of full speed requires 12.5% of the electricity of a motor running at full speed.


22



• A small reduction in speed produces a significant reduction in power

• Relevant applications : Pumps

• The resisting torque of centrifugal pumps varies with the square of the speed : T = kN²

• Power is a cubed function P = kN³

EX 50HP 10Hrs/day, 250 days @$.08

With 15% average speed reduction

ATL = $7,460

VFD = $4,188

Savings = $3,272

Today, less than 10% of these motors are controlled with variable speed drives


23

EFFICIENCY OF PUMPING

SYSTEMS


24


Other Benefits

In addition to energy savings, using a VFD has many other advantages:

• Less mechanical stress on motor and system

• Less mechanical devices - Less maintenance

• Process regulation with PID regulators, load management functions

• Reduce noise, resonance avoidance

• Performance and flexibility, range settings, above base operations

• Easier installation and settings, drive mechanics

• Can be controlled with automation, communication networks


25

STEPS TO OBTAIN PUMP

OPTIMIZATION


26

Pump Optimization

Complete a detailed Pump Assessment

Pumps are usually consuming more energy than necessary:

• The pump is oversized and has to be throttled to deliver the right amount of flow. Energy is lost in the valve.

• Pumps that are not running close to their best efficiency points (BEP) operate at lower efficiency. Throttled pumps usually fall into this category.

• Pumps are running with by-pass, or recirculation, lines open.

• Pumps are running although they could be turned off.

• The pump is worn and the efficiency has deteriorated.

• The pump/system was installed or designed incorrectly (piping, base plate etc.)


27

Pump Optimization

Complete a detailed Pump Assessment

To determine whether these reasons apply, some basic information is needed:

• Actual system demand (flow and pressure)

• Operational flow rate as a function of time (the duration curve)

• Flow controls

• The pump curve

• Where the pump operates on the curve


28

Process Energy Optimization

Automation is the key

• Develop consistent and appropriate milestone and deliverable expectations

• Standardize program schedule tracking requirements

•

Establish key energy management performance metrics

•

Produce meaningful reports that allow for clear and concise decision-making

• Install additional monitoring equipment as needed


29

CONSIDERATIONS FOR

VARIABLE FREQUENCY

DRIVES FOR WATER AND

WASTEWATER


30

VFD Topics

●Type(s)

●Enclosure/Environment/Packaging

●Harmonics/Harmonic Mitigation IEEE 519

●Accessibility

●Sustainability

Data Bulletin

8800DB1302


31

VFD Considerations

●The industry has standardized on PWM 6 pulse drives.

• Where 6 pulse refers to the front end of the drive and a bridge of 6 diodes converting incoming AC to DC power.

• A DC bus (capacitor)

• Insulated Gate Bipolar Transistors (IGBT) as the output components

• The output of which generates a simulated RMS waveform with a constant V/Hz ratio


32

One of These…


33

Packaging…

NEMA UL

Type 1/12

Enclosed

Altivar Plus

MCC


34

Harmonics Mitigation

●This continues to be a big topic in Water and

Wastewater

• The motor loads on VFDs are a large percentage of the total load.

●Many consultants have standardized on designs by HP requiring line reactors or multipulse drives

(typically 18 pulse).

• There are multiple solutions

• One size does not fit all.

● Schneider Electric offers as standard…18 pulse

VFD, Passive Harmonic Filter and Active

Harmonic Mitigation


35

Harmonics Reduction

Typical AC drive

100HP

•

•

Typical 6 pulse AC drive without line reactor

• Input voltage: orange

•

•

•

Input current: cyan

Large current spikes due to capacitors charging

Peak currents = 300 amps

•

•

Harmonic current distortion

Large double humped current waveform significantly contributes to harmonic content.

Total Harmonic Distortion Current

THDI = 80%


36

Harmonics Reduction

AC drive with 3% line reactor

100HP

•

Typical 6 pulse AC drive

• With 3% line reactor

• Input voltage: orange

• Input current: cyan

• Lower current spikes due to

• capacitors charging

Peak currents = 190 amps

•

Harmonic current distortion

• Significant double humped current waveform reduced

Total Harmonic Distortion Current

THDI = 38%


37

18 Pulse Drive Using the Same 6 Pulse Inverter…

STD 6 Pulse Inverter

Line Reactor


18 pulse Diode

Bridge

Phase Shifting XFMR

38

18-Pulse Power Converter Configuration

A

B

C

Line

Reactor

8

9

7

1

A

Multipulse

Transformer

2

3

4

Rectifier Assembly

DC+

DC Bus connections to

Altivar 61/71

Drive

C B 6 5

DC-

Transformer

Tertiary


39

18-Pulse Drives: What You Get

6-Pulse power converter (no line reactor) 18-Pulse power converter


40

Passive Harmonic Filter Drive Using the Same 6

Pulse Inverter…

STD 6 Pulse Drive


Passive

Harmonic

Filter

41

Passive Harmonic Filter Drive

● Passive Harmonic Filter Mitigation provides as good or better than 18 pulse.

■ Better mitigation given voltage imbalance

● Footprint of drive is typically smaller than 18 pulse.

● Efficiency of drive is better than 18 pulse

■ Losses of 18 pulse bridge + Transformer + Line

Reactor > Passive Harmonic Filter

● Cost is typically lower than 18 pulse

● Output to the motor is identical.

What’s not to like?


42

Results


44

Results


45

Accusine Used with One or Many 6 Pulse Drives…


46

The Variable Frequency Drive for

WWW

• The Altivar ® 61 is our standard 6 pulse inverter for variable speed applications used in centrifugal pump and fan / blower applications offering the highest level of features, functions, and flexibility .

This same inverter is the heart of our configured enclosed applications, 18 Pulse Drives, Motor Control Centers and our new Passive Filter Packages.

All the Inverter parts, programming, troubleshooting, wiring, interfacing, etc. is common.


47

Drives System Center Product Offering

Altivar 61/71 Plus

Designed for rugged municipal process environments. Custom options to serve a wide range of applications.

•

•

•

• Growing sectors requiring high horsepower drives

NEMA Type 12 enclosure

•

•

Altivar 71

125-700hp, 460VAC

125-700hp, 600VAC

•

•

Altivar 61

125-900hp, 460VAC

125-800hp, 600VAC


48

Drives System Center Product Offering

Altivar 61/71 Plus

Altivar 71

 700-1800hp, 460VAC

 700-2100hp, 600VAC

Altivar 61

 900-2000hp, 460VAC

 800-2500hp, 600VAC

Altivar 71

 125-700hp, 460VAC

 125-700hp, 600VAC

Altivar 61

 125-900hp, 460VAC

 125-800hp, 600VAC


49

Variable Torque

125-900hp, 460VAC

125-800hp, 600VAC

Constant Torque

125-700hp, 460VAC

125-700hp, 600VAC

Drives System Center Product

Offering

Schneider

Electric

Enclosure

Flexibility for control requirements with swiveling control panel

Top mount ventilation

Control transformer

Altivar power converter

Easy maintenance

– power converter mounted on rail system

Fused disconnect

Motor connection

Line contactor

(optional)

Schneider Electric

Standard 4” plinth

(8” optional) for bottom entry

| Jeff M. Miller | 2014 MWEA & AWWA-MO Joint Annual Meeting | 10:30 Monday March 31 st , 2014

DV/DT motor filter

(optional)

Bottom entry

50

Other Drive/System Application

Considerations

• Enclosed drive or packaged drive short circuit current rating

• SE = 100k amps as standard

• Power loss ride through – especially for pump stations

• SE meets Semi F47 standards

• Communication capabilities

• SE offers Modbus Serial and 11 additional Protocols as options.

• Built in web server and diagnostic web displays with

Ethernet.

• Built in Bluetooth interface capability


52

CONSIDERATIONS FOR TOTAL

COST OF OWNERSHIP (TCO)

OF YOUR NEXT PUMPING

SYSTEM


53

3 Steps to the Most Efficient…

Design and Operation

1. Energy efficiency management

2. Asset management

3. Energy cost management


54

Step 1 Energy Efficiency Management

Scenario 1

Static head = 50% system head

Pump rated for the system

Scenario 2

Static head = 85% system head

Pump oversized for the system

Energy saved with variable vs. fixed speed drives at 100% and 60% flow, according to the static head and pump sizing. The operating point is represented as the intersection of the pump curve with the system curve.

st , 2014

55

Step 2 Asset Management

Newer Drive technology can significantly improve efficiency and life of your next pump system by operating close to Best Efficiency Point

(BEP ).


56

Step 3 Energy Cost Management

Knowing the breakdown of your electric utility costs may uncover opportunities for savings. Drives can assist to reduce all aspects of this cost.


57

Questions?

Jeff Szwec

<Insert Title>

US Drives, Softstarts and Drive Systems

8001 Knightdale Blvd.

Knightdale, NC 27545-9023

Office: 919.266.8360 | Mobile: 919.824.9114

Jeff.Szwec@Schneider-Electric.com

www.schnedier-electric.com


58

APPENDIX


59

VFD Application Considerations

● Keep motor lead lengths as short as possible

● VFD environment (0-40ºC), clean and non-condensing

● Enclosure rating (NEMA 1, NEMA 12, NEMA 3R)

● Ensure 3 metallic conduits are used (motor, power, and controls)

Be careful with underground runs!

● Dedicated ground wires from motor to VFD and from power source to VFD

● Use line reactors for harmonic distortion control and enhanced protection from AC line transients

● Size VFD based on amp rating (6-pole motors and up)

● Disconnect Issues

● Harmonic calculations


60

Drive in

MCC

Broad array of drive solutions

Passive

Harmonic

Filter

18 Pulse Drive


61

(WWW) Challenges: Energy Usage

Drives and Pump Optimization

PUMPS SYSTEM OVERVIEW

AND FUNDAMENTALS

VARIABLE FREQUENCY DRIVE

(VFD) BENEFITS WITH PUMPS

EFFICIENCY OF PUMPING

SYSTEMS

STEPS TO OBTAIN PUMP

OPTIMIZATION

CONSIDERATIONS FOR

VARIABLE FREQUENCY

DRIVES FOR WATER AND

WASTEWATER

CONSIDERATIONS FOR TOTAL

COST OF OWNERSHIP (TCO)

OF YOUR NEXT PUMPING

SYSTEM

APPENDIX

Related documents

Products

Support

(WWW) Challenges: Energy Usage

Drives and Pump Optimization

PUMPS SYSTEM OVERVIEW

AND FUNDAMENTALS

VARIABLE FREQUENCY DRIVE

(VFD) BENEFITS WITH PUMPS

EFFICIENCY OF PUMPING

SYSTEMS

STEPS TO OBTAIN PUMP

OPTIMIZATION

CONSIDERATIONS FOR

VARIABLE FREQUENCY

DRIVES FOR WATER AND

WASTEWATER

CONSIDERATIONS FOR TOTAL

COST OF OWNERSHIP (TCO)

OF YOUR NEXT PUMPING

SYSTEM

APPENDIX

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