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Power Quality and Harmonics
- 1. Prof. Mohsin A Mulla Assistant Professor, EE SITCOE Yadrav
- 2. ◦ Effects of power quality ◦ Power Quality definitions revisited ◦ What is needed for PQ monitoring ? ◦ GE Multilin’s solution PQMII EPM9000 series ◦ Summary Monitor and Analyze Power Disturbances, Disruptions & Harmonics
- 3. Power Quality issues cause business problems such as: ◦ Lost productivity, idle people and equipment ◦ Lost orders, good will, customers and profits ◦ Lost transactions and orders not being processed ◦ Revenue and accounting problems ◦ Customer and/or management dissatisfaction ◦ Overtime required to make up for lost work time According to Electric Light and Power Magazine, 30 to 40 Percent of All Business Downtime Is Related to Power Quality Problems.
- 5. ◦ The sensitivity of today’s electronic equipment makes it susceptible to power disturbances ◦ For some devices, a momentary disturbance can cause scrambled data interrupted communications a frozen mouse system crashes and equipment failure
- 6. ◦ Berkeley Lab Study Estimates $80 Billion Annual Cost of Power Interruptions … Research News, Berkeley Lab, February 2, 2005 ◦ $50 billon per year in the USA is lost as a results of power quality breakdowns …. Bank of America Report ◦ A manufacturing company lost more than $3 million one day last summer in Silicon Valley when the “lights went out.” … New York Times January 2000 ◦ “A voltage sag in a paper mill can waste a whole day of production - $250,000 loss” … Business Week, June 17,, 1996 ◦ Half of all computer problems and one-third of all data loss can be traced back to the power line … Contingency Planning Research, LAN Times
- 7. ◦ Lost production ◦ Scrap ◦ Costs to restart ◦ Labor costs ◦ Equipment damage and repair ◦ Other costs • High Cost Facilities o Semiconductor plants o Pharmaceuticals o Data centers • Medium Cost Facilities o Automotive manufacturing o Glass plants o Plastics & Chemicals o Textiles
- 8. IEEE Categories Std 1159-1995 Short Duration Variations Typical Duration Instantaneous Sag 0.5 – 30 cycles Momentary Sag 30 cycles – 3 sec Temporary Sag 3 sec – 1 min
- 9. IEEE Categories Std 1159-1995 Short Duration Variations Typical Duration Instantaneous Sag 0.5 – 30 cycles Momentary Sag 30 cycles – 3 sec. Temporary Sag 3 sec – 1 min. Instantaneous Swell 0.5 – 30 cycles Momentary Swell 30 cycles – 3 sec. Temporary Swell 3 sec – 1 min.
- 10. IEEE Categories Std 1159-1995 Short Duration Variations Typical Duration Instantaneous Sag 0.5 – 30 cycles Momentary Sag 30 cycles – 3 sec. Temporary Sag 3 sec – 1 min. Instantaneous Swell 0.5 – 30 cycles Momentary Swell 30 cycles – 3 sec. Temporary Swell 3 sec – 1 min. Momentary Interruptions 0.5 – 30 cycles Temporary Interruptions 30 cycles – 3 sec.
- 11. IEEE Categories Std 1159-1995 Long Duration Variations Typical Duration Sustained interruptions > 1 min Under voltages > 1 min Over voltages > 1 min
- 12. IEEE Categories Std 1159-1995 Long Duration Variations Typical Duration Sustained interruptions > 1 min Under voltages > 1 min Over voltages > 1 min Voltage imbalance Steady state Waveform Distortion
- 13. IEEE Categories Std 1159-1995 Long Duration Variations Typical Duration Sustained interruptions > 1 min Under voltages > 1 min Over voltages > 1 min Voltage imbalance Steady state Waveform Distortion DC offset Steady state Harmonics Steady state Inter harmonics Steady state For Electric Utilities Control of Voltage and Prevention of Outages is Power Quality
- 14. Utility Sources ◦ Lightning ◦ PF Correction Equipment ◦ Faults ◦ Switching Internal Sources • Individual Loads –Lighting, Elevators, Coolers, HVAC • Uninterruptible Power Supplies • Variable Frequency Drives • Battery Chargers • Large Motors During Startup • Electronic Dimming Systems • Lighting Ballasts (esp. Electronic) • Arc Welders, and Other Arc Devices • Medical Equipment, e.g. MRIs and X-Ray Machines • Office Equipment and Computers • Wiring
- 15. Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics
- 16. Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring
- 17. Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring Intermittent lock-ups Lights flicker Garbled data Sags/Swell Source voltage variations Inrush/surge currents Inadequate wiring
- 18. Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring Intermittent lock-ups Lights flicker Garbled data Sags/Swell Source voltage variations Inrush/surge currents Inadequate wiring Component failure Dielectric breakdown Lock-ups Garbled data Wavy CRTs Impulses EMI/RFI Lightning Load switching Capacitor switching Static discharge Hand-held radios Loose wiring/arcing
- 19. Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring Intermittent lock-ups Lights flicker Garbled data Sags/Swell Source voltage variations Inrush/surge currents Inadequate wiring Component failure Dielectric breakdown Lock-ups Garbled data Wavy CRTs Impulses EMI/RFI Lightning Load switching Capacitor switching Static discharge Hand-held radios Loose wiring/arcing Overheated transformers and motors Voltage and current distortions Garbled data Lock-ups Harmonics Electronic loads SCR/rectifier
- 20. Source: EPRI, 1994 Spikes, 7% Sags, 56% Outages, 6% Swells, 31% Sags (Dips) Associated with system faults Switching of heavy loads Starting of large motors Swells System fault conditions Switching on a large capacitor bank Switching off a large load
- 21. Textile Industry Plastics Industry Glass Industry Process Industry Semiconductors $1k $10k $100k $1M $10M Losses per Voltage Sag Event Source: EPRI “The Economics of Custom Power”, IEEE T&D Show 2003
- 22. Momentary Outages create problems when computers and clocks reset, equipment stalls, and work stops.
- 23. High Speed Waveform Capture Is the Most Important PQ Troubleshooting Tool
- 24. Continuous PQ Monitoring Detects, Records, and Leads to the Prevention of PQ Problems • Power Quality monitoring provides a continuous “Health Check” of a facility’s power system … for example: o Harmonic interaction between loads and power conditioning equipment spotted o High Inrush currents from equipment startup detected o Transients from load switching are seen • It provides data to see, diagnose and avert looming problems – “like squeaky brakes on a car” o Trends can be detected o JIT equipment maintenance programs can be established • It acts like a “Black Box” on an airplane to tell you what, when, and where a Power Quality event occurred … to prevent it from reoccurring
- 25. PQ Monitors must detect and record the 7 types of PQ problems ◦ Transients ◦ Interruptions ◦ Sag/Under Voltage ◦ Swell/Over Voltage ◦ Waveform Distortion ◦ Voltage Fluctuations ◦ Frequency Variations These include Flicker and Compliance to ITI(CBEMA), IEEE and ISO Standards Plus they must … • Be easy to use • Be Suitable for continuously monitoring indoors and outdoors • Interface with standard PQ analysis Software…PQDif format • Be fast enough to capture high speed events that produce equipment problems • Have enough storage to save the waveforms you need • Have PQ analysis tools that produce usable, actionable recommendations
- 26. Source: AGA Brazil Meter: EPM9650 Period: Jan 2005 – Dec 2005 Continuous Monitoring of the Station for PQ Problems
- 27. Equipment Interrupting Voltage Sags as Recorded Damage Inducing Voltage Surges as Recorded ITI Acceptable Power Disturbance Envelope
- 33. GE Multilin provides the necessary tools for a successful PQ disturbance analysis and allows users to take remedial actions Accurate Measurement to determine actual state Examinations Remedial actionsRemedy Feels the pulse of the power system network Symptoms High resolution recordings for longer durations GE Communicator software Diagnosis
- 34. If You Can’t Measure it You Can’t Manage it If You Can Measure it You Can Manage it