Presentation on theme: "PUMP STATION ELECTRICAL DESIGN"— Presentation transcript:
1 PUMP STATION ELECTRICAL DESIGN 40 Years Lessons LearnedMaynard Wayne Robertson, PE, CEMTAUD Technology ConferenceGatlinburg, TN March 13, 2013
2 Pump Station Design Requirements Tennessee Dept. Environment & ConservationEnvironmental Protection AgencyNFPA- 70- National Electrical CodeTennessee Fire Marshall- Electrical InspectionsOSHA/TOSHA
3 TDEC Requirements General Design Requirements for Sewerage Works Key Chapters for Pump Stations; 1, 2, 14Chapter 2. Section 2.5 Pump StationsAlarm System and totalizers on All stations2.6.3 All wet well wiring to be Class l, Division l, per NEC2.7.3 PS Capacity Greater Than MGDRequires Flow MetersRequires Back Up Power System
4 TDEC RequirementsChapter 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 TDEC2.5 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 lowlevel contact made, low cost to reduce odor )Electric Power SystemsChapterDesign Criteria for Sewerage Works
6 National Electrical Code Latest Version NEC-2011Next Version NEC-2014Code revised on Three Year CycleVersion 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-201170E Work Place General Safety RequirementsInstallation Of EquipmentProtection Of Electrical Equipment
8 NEC-2008 Organization Chapters: One thru Nine Articles Tables Appendix Chapters: One Thru FourBasic Wiring Requirements.Apply to all Wiring Installations.Chapters: Five thru NineSpecial Conditions
9 NEC Chapters Chapter 1 – General Chapter 2 – Wiring and Protection Chapter 3- Wiring Methods and MaterialsChapter 4 – Equipment for General UseChapter 5 – Special OccupanciesChapter 6 – Special EquipmentChapter 7 – Special ConditionsChapter 8 – Communications Systems(Stands alone)Chapter 9 – TablesAnnex A thru H ; Informational Only
11 Tennessee State Fire Marshall Requires Electrical Inspection of all New and Modified Electrical Installations.Require Use of Listed Equipment- UL, etc.Current Enforcement NECAuthority Having Jurisdiction
12 EPA EPA-430-99-74-001 Operability and Reliability Class 1 Standby Power nearly always requiredClass 2 Standby Power maybe RequiredClass 3 Normally not Required
13 Service Terms Service Service Entrance Metering Service Disconnect Service TypeOverheadUndergroundSingle or Three PhaseAvailable fault Current
14 NEC Voltage Low Voltage = Less Than 600 Volts Single Phase Motors 5 HP or Less( 7.5 & 10.0 are manufactured)Three Phase120/240 Volt Delta Connected120/208 Volt Wye Connected277/480 Volt Wye connected
15 Electrical Service Entrance Capacity for both pumps to operateService disconnect rated for service entrance and capacity to allow second motor to start without trippingService Equipment( Main Breaker and panel boards, etc.) rated for available fault currentFault Currents can be high at PS as result of large transformer and short wire runsStandard Interrupting capacity: 10,000, 22,000, 65,000ampsGrounding and BondingAdequate work space in front of electrical equipmentFor outdoor locations shield panels from sun and heat
16 Wiring Methods NEC Article 250 Grounding and Bonding Table Size of Equipment Ground ConductorGrounded ConductorGround WireLightning protectionTable /Table B(2)a, more than 3 conductors in raceway/conduitConductors Rated at 75CConductors Rated for Wet Location
17 Control Panels Correct NEMA Enclosure ( 3R, 4X, etc. ) Ventilation/CoolingDrainsLabeled (UL, CSA)AlarmsControl Transformer (Reduce line Noise)Instrumentation (Runtime, Volts, Amps, Calibration)
18 Motor StartersManualAcross the Line starters( NEMA SIZE 0, 1, 2, etc.)Part windingAuto transformerSoft StartVFD (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 VFDSize VFD Based On Single Phase Load Plus 15%20Hp, 3P, 230V, FLA=54 AmpBased on single phase = 100 AmpUse 120 Amp VFD
20 Common WWPS Problems Corrosion, Corrosion, Corrosion!!!! Electrical Junction Boxes in Wet WellsExcessive Pumps starts/ Short run timeUnlisted Electrical Equipment (Inspector Rejects)FAILURE TO DERATE CONDUCTORS in Conduit. (more than three)Lack of Phase Loss ProtectionPhase to Phase Voltage/excessive voltage difference.Poor Electrical GroundingNo 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 ProblemsNO Conduit Seals, Sewer Gas direct line to control Panel.Pump RotationWrong NEMA Class EnclosuresLow Equipment Electrical withstand Ratings.VFD noise on Control circuitsNo GFIC ReceptaclesGenerators/ transfer switches improperly wired/ Phase Reversed.
22 Checklist/Records Always use startup Checklist Voltage, Line to Line, Line to Ground, Phase to PhaseAmperesDischarge HeadPumping RatePhotosNameplate DataTerminals Tight
23 WWPS Life Cycle Cost Initial Cost Installation Commissioning Cost Maintenance and Repairs CostENERGY COST 90 PERCENT OF TOTALHigh Efficiency MotorsHigh Efficiency Pumps
24 GeneratorsCorrectly Sized to start second pump with all loads energizedPortable /PermanentTransfer switches/ Manual or automaticFuels/ Diesel, Natural Gas, Propane, Gasoline.Long Term maintenance cost
25 PUMP STATION ELECTRICAL DESIGN 40 Years Lessons LearnedMaynard Wayne Robertson, PE, CEMTAUD Technology ConferenceGatlinburg, TN March 13, 2013
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