1. 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

2. Water Wastewater (WWW) Challenges: Energy Usage
Demand for WWW
Age of infrastructure
Legislative compliance
Reduced financial resources
Energy efficiency awareness
Energy use
Process = 70%
Pumping = 16%

3. 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
What do you think is a good pumping efficiency? Any ideas?
Maybe 80%?

4. System Curve Uncertainty Results in Uncertain Pump Operation
- and higher costs
Has everyone seen this?
Good, help me with this!
First, how often to we operate at the specified operating point. Not often!
So when we do not have as much flow, we can cycle the pump on an off, inject a discharge valve or use a VFD.
Which one do you think I like?
If we use a discharge valve, the valve changes system curve upward and energy still is consumed similar to full flow.
If we use a VFD, it changes the pump curve and Al Gore is happy!

5. Pumping System Characteristics
Pump operating point
Duty point: rate of flow at certain head
Pump operating point: intersection of pump curve and system curve
Flow
Head
Static
head
Pump performance curve
System curve
Pump operating point
SUGGEST ADDING (BEP) TO THE SLIDE,
The rate of flow at a certain head is called the duty point. The pump performance curve is made up of many duty points.
The pump operating point is determined by the intersection of the system curve and the pump curve as shown in the Figure
The Best Efficiency Point (BEP) is the pumping capacity at maximum impeller diameter, in other words, at which the efficiency of the pump is highest. All points to the right or left of the BEP have a lower efficiency.
What the VFD does is change the pump curve only and decreases energy.
A discharge valve changes the system curve only
Example GPM pump at 45 psi, Do not need that flow very often
Lower flow to 200 GPM.
Thottle valve follows the pump curve to lower to 200 gpm.
VFD follows the system curve, huge energy savings.

6. Pumps System Overview and Fundamentals

7. Overview The pumping system: Pumps Motors, engines Piping
Components
End-use
Pumps
Motors, engines
Piping
Valves and fittings
Controls and instruments
Heat exchangers
Tanks
Others
Water treatment
Wastewater treatment
Water distribution
Power generation
Irrigation
Speaker Notes
Guys, I am just worrying about my little VFD turning the motor, etc. You are worrying about all this other stuff.
Describe the main components, including:
Pumps;
Prime movers: Electric motors, diesel engines, and air systems;
Piping (used to carry fluid);
Valves (used to control flow); and,
Other fittings, controls, and instruments.
Describe the end-use equipment, including heat exchangers, tanks, and hydraulic machines.
Highlight that other common systems components include filters, strainers, and heat exchangers. Any evaluation of a pumping system should consider the interaction between these components, and not just the pump itself. This is referred to as the systems approach to pumping system evaluation. The pump(s) and the system must be designed and treated as one entity, not only to ensure correct operation, but also to reap the benefits of energy-efficient pumping. 7

8. Overview, continued 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
Electric utility feeder
Transformer
Motor breaker/starter
Adjustable speed drive (electrical)
Speaker Notes
Highlight that the overall efficiency of the operation is the product of the efficiency of each incorporated energy component. For example, optimizing a single component may improve or reduce the overall efficiency depending of its effects on other components. Any effort made towards reducing energy consumption and cost must take into consideration the entire energy flow train.
<click to show arrows>Explain that there are other factors to consider in addition to efficiency. Reliability, for example, is a more important consideration in many industrial applications. These two factors are often complimentary for pumps themselves. Operating at or near a pump’s best efficiency point (BEP) will reduce damaging loads experienced and lead to increased reliability as a result.
Explain that systems are generally classified as closed or open:
Closed systems recirculate fluid around set paths and the frictional losses of system piping and equipment are the dominant loads.
Open systems have specified inputs and outputs, transferring fluids from one point to another and often have significant static head requirements due to elevation and tank pressurization needs.
Motor
Coupling
Pump
Fluid System
Served Process(es) 8

9. Pump Fundamentals There are two basic types of pumps: Centrifugal
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
Positive Displacement (PD)
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
Speaker Notes
Describe the two most basic types of pumps, including:
Centrifugal pumps, which are the most common type of industrial pump and also offer the best opportunity for performance improvements. Most literature and training on pumping systems focuses on centrifugal pumps. In addition, 80-90% of industrial pumps are centrifugal pumps. Rely on a rotating, vaned disk attached to a driven shaft. The disk increases fluid velocity, which translates to increased pressure.
Positive Displacement (PD) pumps, which offers precise flow at higher pressure. The PD pump, unlike the Rotodynamic pump, moves a set volume of liquid and pressure is obtained as liquid is forced through the pump discharge into the system converting energy to pressure. The markets need for a broad range of pumping solutions has been the driver for the universe of technologies shown here for PD pumps. 9

10. 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.
Speaker Notes
Need to add moving graphic files to these slides They are from Module 1 Topic 2 page 4 of 31 and 15 of 31.
Describe rotodynamic pumps, which are constant head devices that impart the same amount of head to any liquid with the following two exceptions:
Increases in fluid viscosity; and,
Multi-phase fluids.
Further explain rotodynamic pumps by describing how:
An increase in viscosity will reduce the performance of rotodynamic pumps, causing reductions in efficiency, flow, and developed head.
Multiphase flows can also have adverse effects on rotodynamic pump performance. Liquid/gas mixtures lower the specific gravity of a solution but may also drastically reduce the flow rate through the pump due to the volume change of the vapor bubbles as they pass from the low pressure areas in the pump to the areas of higher pressure. Solid/liquid mixtures may have an opposite effect on the required pump power, depending on the specific gravity of the solids suspended in the flow.
Input power is used to increase velocity of fluid through rotation of impeller. When fluid exits the impeller, therefore velocity is reduced, increasing pressure. 10

11. AC Motors - Variable Torque Applications
Variable Torque (VT)
100 %
Torque,
Flow,
& HP
(Amps)
Torque
SUGGEST LABELING SLIDE WITH AFINITY LAWS STATED
Back to our infinity laws! 50
Flow HP
% Speed 50
100
(Base)

12. Pump Fundamentals, continued
PD Pumps
Impart energy by applying mechanical force directly to the liquid through a collapsing volume
Speaker Notes
Need to add moving graphic files to these slides They are from Module 1 Topic 2 page 4 of 31 and 15 of 31.
Describe the types of positive-displacement pumps, which are reciprocating, metering, and rotary pumps.
Explain how PD pumps will transport fluid from inlet to outlet, where input power is used to create the force to transport this volume against internal and system resistance. In addition, PD pumps create flow.
Explain how PD pumps may be found almost anywhere and everywhere but a generally accepted view is that over 90% go into applications within these top six industrial market segments. Specifically, in the following markets:
Oil and Gas;
Water and Wastewater Treatment;
Chemical;
Food, Beverage and Pharmaceutical.
Power; and,
General Industrial (Marine / Medical / OEM). 12

13. Energy Efficiency in Pumps
Load Characteristics
Water Wastewater Load Characteristics
Variable Torque
Constant Torque
Constant Power
Typical Applications
Centrifugal Pumps and Blowers
Positive Displacement Pumps, Blowers, Mixers, and Chemical Feed Pumps
No applications
Energy Savings Potential
Substantial Potential – Largest of all VFD applications
Lowest Potential
No Potential
CONSTANT TORQUE IS MENTIONED HERE, HOWEVER NOT THEREAFTER…….SHOULD CT BE DISCUSSED IN PRESENTATION?
The Main
Target ( first
priority)
The Next
Step ( second
priority)

14. 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:
Speaker Notes
Describe how friction effects the hydraulic design, where the the more fluid you pump, and the faster you pump it, will increase the friction losses. 14

15. Pump Head Pressure System Head Curve produced by US DOE PSAT Software
Static Head
Friction Head
Speaker Notes
System Head Curve produced by US DOE PSAT Software 15

16. 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
Speaker Notes
Describe friction and how it can an increase in friction can causes more energy to be used. 16

17. Variable frequency drive (vfd) benefits with Pumps

18. Energy Efficiency in Pumping Systems
Motor costs

19. 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
Do any of you still use valves?
Be honest!
Still one of the most common control methods in industry …..
with a considerable waste of energy

20. 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

21. VFD Benefits with Pumps
Physical laws for centrifugal loads
A motor running at 80% of full speed requires 51% of the electricity of a motor running at full speed.

22. VFD Benefits with Pumps
Physical laws for centrifugal loads
A motor running at 50% of full speed requires 12.5% of the electricity of a motor running at full speed.

23. VFD Benefits with Pumps
Physical laws for centrifugal loads
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
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

24. Efficiency of pumping systems

25. VFD Benefits with Pumps
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

26. Steps to obtain pump optimization

27. 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.)
Ladies and Gentlemen this is the tough one!

28. 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

29. 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

30. Considerations for Variable frequency drives for water and wastewater

31. VFD Topics Type(s) Enclosure/Environment/Packaging
Harmonics/Harmonic Mitigation IEEE 519
Accessibility
Sustainability
Data Bulletin
8800DB1302

32. 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

33. One of These…

34. Packaging…
NEMA UL Type 1/12
MCC
Enclosed
Altivar Plus

35. 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

36. 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%
Typical 6 pulse input current waveform.
Note the large 300 amp peak currents.
The large double humped current waveform significantly contributes to harmonic content.

37. 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%

38. 18 Pulse Drive Using the Same 6 Pulse Inverter…
STD 6 Pulse Inverter
18 pulse Diode Bridge
Line Reactor
Phase Shifting XFMR

39. 18-Pulse Power Converter Configuration
DC Bus connections to
Altivar 61/71 Drive

40. 18-Pulse Drives: What You Get
6-Pulse power converter (no line reactor)
18-Pulse power converter
The voltage and current waveforms comparison between a 6 pulse and 18 pulse units,
Clean power performance

41. Passive Harmonic Filter Drive Using the Same 6 Pulse Inverter…
STD 6 Pulse Drive
Passive Harmonic Filter

42. 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?

43. Data on side by side comparisons of 18 Pulse and Passive Harmonic Filter.

44. Results

45. Results

46. Accusine Used with One or Many 6 Pulse Drives…

47. 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

48. 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
hp, 460VAC
hp, 600VAC
Altivar 61
hp, 460VAC
hp, 600VAC

49. Drives System Center Product Offering
Altivar 61/71 Plus
Altivar 71
hp, 460VAC
hp, 600VAC
Altivar 61
hp, 460VAC
hp, 600VAC
Altivar 71
hp, 460VAC
hp, 600VAC
Altivar 61
hp, 460VAC
hp, 600VAC

50. Drives System Center Product Offering
Variable Torque
hp, 460VAC
hp, 600VAC
Constant Torque
hp, 460VAC
hp, 600VAC
Drives System Center Product Offering
Top mount ventilation
Schneider Electric Enclosure
Control transformer
Flexibility for control requirements with swiveling control panel
Altivar power converter
Easy maintenance – power converter mounted on rail system
Fused disconnect
Motor connection
Line contactor (optional)
DV/DT motor filter (optional)
Bottom entry
Standard 4” plinth (8” optional) for bottom entry

51. Drives System Center Product Offering
Variable Torque
hp, 460VAC
hp, 600VAC
Constant Torque
hp, 460VAC
hp, 600VAC
Incoming Cubicle
Inverter Cubicle
Outgoing Cubicle
Cooling Cubicle
Cubicle fans
Line reactor
Operator interface
Heat exchanger
Flexibility for control requirements with swiveling control panel
Mandatory start up by Schneider Electric Engineering
Cooling (deionized water) will ship seperately
Circuit breaker
Cooling pump
Line connection
Line reactor
Motor connection
Plinth

52. 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

53. Considerations for total cost of ownership (TCO) of your next pumping system

54. 3 Steps to the Most Efficient… Design and Operation
Energy efficiency management
Asset management
Energy cost management

55. 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.

56. 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 ).

57. 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.

58. Questions? Jeff Szwec <Insert Title>
US Drives, Softstarts and Drive Systems
8001 Knightdale Blvd.
Knightdale, NC
Office: | Mobile:

59. appendix

60. 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

61. Broad array of drive solutions
Passive Harmonic Filter
Drive in
MCC
18 Pulse Drive 61