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PUMP STATION ELECTRICAL DESIGN 40 Years Lessons Learned Maynard Wayne Robertson, PE, CEM TAUD Technology.

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Presentation on theme: "PUMP STATION ELECTRICAL DESIGN 40 Years Lessons Learned Maynard Wayne Robertson, PE, CEM TAUD Technology."— Presentation transcript:

1 PUMP STATION ELECTRICAL DESIGN 40 Years Lessons Learned Maynard Wayne Robertson, PE, CEM TAUD Technology Conference Gatlinburg, TN March 13, 2013

2 Pump Station Design Requirements Tennessee Dept. Environment & Conservation Environmental Protection Agency NFPA- 70- National Electrical Code Tennessee Fire Marshall- Electrical Inspections OSHA/TOSHA

3 TDEC Requirements General Design Requirements for Sewerage Works Key Chapters for Pump Stations; 1, 2, 14 Chapter 2. Section 2.5 Pump Stations Alarm System and totalizers on All stations All wet well wiring to be Class l, Division l, per NEC PS Capacity Greater Than MGD Requires Flow Meters Requires Back Up Power System

4 TDEC Requirements Chapter Requires to comply with All OSHA Rules. Work place safety. Chapter 2.7- Operability/ Reliability Do you need generator/backup power? Essentially EPA requirements. Reliability Class 1, Class 2, Class 3.

5 TDEC 2.5 Septicity Controls. I guess something that smells BAD. Do not make it smell worse. Setting controls for minimum time in wet well. Auto Pump Out (Timed pump start after low level contact made, low cost to reduce odor ) Electric Power Systems Chapter Design Criteria for Sewerage Works

6 National Electrical Code Latest Version NEC-2011 Next Version NEC-2014 Code revised on Three Year Cycle Version adopted in Tennessee NEC-2008

7 NFPA CHAPTER 70 National Electric Code / 70E work place safety NEC 2008 Used Statewide *Exceptions In Some Cities NEC E Work Place General Safety Requirements Installation Of Equipment Protection Of Electrical Equipment

8 NEC-2008 Organization Chapters: One thru Nine Articles Tables Appendix Chapters: One Thru Four Basic Wiring Requirements. Apply to all Wiring Installations. Chapters: Five thru Nine Special Conditions

9 NEC Chapters Chapter 1 – General Chapter 2 – Wiring and Protection Chapter 3- Wiring Methods and Materials Chapter 4 – Equipment for General Use Chapter 5 – Special Occupancies Chapter 6 – Special Equipment Chapter 7 – Special Conditions Chapter 8 – Communications Systems(Stands alone) Chapter 9 – Tables Annex A thru H ; Informational Only

10 Key NEC Articles for Sewer Pump Stations Articles: 200, 215, 220, 240, 250, 310, 312, Table , 400, 430, 445, 500 & 700. Note: Entire Code Applies Always!!

11 Tennessee State Fire Marshall Requires Electrical Inspection of all New and Modified Electrical Installations. Require Use of Listed Equipment- UL, etc. Current Enforcement NEC Authority Having Jurisdiction

12 EPA EPA Operability and Reliability Class 1 Standby Power nearly always required Class 2 Standby Power maybe Required Class 3 Normally not Required

13 Service Terms Service Service Entrance Metering Service Disconnect Service Type Overhead Underground Single or Three Phase Available fault Current

14 NEC Voltage Low Voltage = Less Than 600 Volts Single Phase 120/240 Volts Motors 5 HP or Less( 7.5 & 10.0 are manufactured) Three Phase 120/240 Volt Delta Connected 120/208 Volt Wye Connected 277/480 Volt Wye connected

15 Electrical Service Entrance Capacity for both pumps to operate Service disconnect rated for service entrance and capacity to allow second motor to start without tripping Service Equipment( Main Breaker and panel boards, etc.) rated for available fault current Fault Currents can be high at PS as result of large transformer and short wire runs Standard Interrupting capacity: 10,000, 22,000, 65,000amps Grounding and Bonding Adequate work space in front of electrical equipment For outdoor locations shield panels from sun and heat

16 Wiring Methods NEC Article 250 Grounding and Bonding Table Size of Equipment Ground Conductor Grounded Conductor Ground Wire Lightning protection Table /Table B(2)a, more than 3 conductors in raceway/conduit Conductors Rated at 75C Conductors Rated for Wet Location

17 Control Panels Correct NEMA Enclosure ( 3R, 4X, etc. ) Ventilation/Cooling Drains Labeled (UL, CSA) Alarms Control Transformer (Reduce line Noise) Instrumentation (Runtime, Volts, Amps, Calibration)

18 Motor Starters Manual Across the Line starters( NEMA SIZE 0, 1, 2, etc.) Part winding Auto transformer Soft Start VFD (6 pulse more noise and 12 pulse less noise) VFD noise may interfere with controls/SCADA

19 PHASE CONVERSION Single Phase Power to 3 Phase Power Phase Conversion Using VFD Size VFD Based On Single Phase Load Plus 15% 20Hp, 3P, 230V, FLA=54 Amp Based on single phase = 100 Amp Use 120 Amp VFD

20 Common WWPS Problems Corrosion, Corrosion, Corrosion!!!! Electrical Junction Boxes in Wet Wells Excessive Pumps starts/ Short run time Unlisted Electrical Equipment (Inspector Rejects) FAILURE TO DERATE CONDUCTORS in Conduit. (more than three) Lack of Phase Loss Protection Phase to Phase Voltage/excessive voltage difference. Poor Electrical Grounding No Isolation of sewer gas from control Panels thru use of junction boxes with double conduit seals. Complete failure less than 1 year. Circuit Breakers too small, Result excessive heat in Panel.

21 Common WWPS Problems NO Conduit Seals, Sewer Gas direct line to control Panel. Pump Rotation Wrong NEMA Class Enclosures Low Equipment Electrical withstand Ratings. VFD noise on Control circuits No GFIC Receptacles Generators/ transfer switches improperly wired/ Phase Reversed.

22 Checklist/Records Always use startup Checklist Voltage, Line to Line, Line to Ground, Phase to Phase Amperes Discharge Head Pumping Rate Photos Nameplate Data Terminals Tight

23 WWPS Life Cycle Cost Initial Cost Installation Commissioning Cost Maintenance and Repairs Cost ENERGY COST 90 PERCENT OF TOTAL High Efficiency Motors High Efficiency Pumps

24 Generators Correctly Sized to start second pump with all loads energized Portable /Permanent Transfer switches/ Manual or automatic Fuels/ Diesel, Natural Gas, Propane, Gasoline. Long Term maintenance cost

25 PUMP STATION ELECTRICAL DESIGN 40 Years Lessons Learned Maynard Wayne Robertson, PE, CEM TAUD Technology Conference Gatlinburg, TN March 13, 2013


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