1 / 25

Ben Kemink

Ben Kemink. Power Quality. What is the Quality of the Power Measurement?. Subjects Covered. Definition of Electrical Power. 2. The meaning of “T”. 3. Should we select the Voltage or the Current input channel for Synchronization?. 4. Is an Observation Time an alternative for “T”?.

mika
Download Presentation

Ben Kemink

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ben Kemink

  2. Power Quality • What is the Quality of the Power Measurement?

  3. Subjects Covered • Definition of Electrical Power 2. The meaning of “T” 3. Should we select the Voltage or the Current input channel for Synchronization? 4. Is an Observation Time an alternative for “T”?

  4. Power Quality Before discussing quality of power, lets have a look at how do we define the measurement of electrical power?

  5. Applied Voltage : u(t) = Upk.sin(t) • Resulting Current : i(t) = pk.sin(t+) CONSTANT AVERAGE=0 Traditional Amplitude=UrmsxIrms • p(t) = u(t) . i(t) = = ½ . Upk . Ipk . cos( ) - ½ . Upk . Ipk . cos(2t+ )

  6. Definition of Average Power The most difficult task for the power meter is to find the period time T correctly! Especially with distorted signals this can be very difficult.

  7. Vpk Ipk Amplitude=Urms x Irms Pavg Traditional 50Hz Tu Ti Tp

  8. Zero Crossing?

  9. The zero crossing lasts at least for one acquisition interval. An uncertainty caused by time resolution. Δt = resolution of Tperiod

  10. Current input channel is used for synchronization.

  11. What if the period is longer than the acquisition memory of the power meter?

  12. A too low Display Update Rate will not detect changes of short duration despite a high acquisition speed.

  13. Power Quality is first of all related to an accurate Power Measurement Factors that influence the total error for power are: • Amplitude • Frequency of the fundamental of the input signal • Crest Factor of the input signal (BW) • Crest Factor setting of the Power Meter • Power Factor • Temperature • Use of filters • Acquisition interval • Acquisition Clock Stability • Correct Detection of Period Time “T”

  14. There is enough energy. The challenge is how to control it! • For Example: If of 1 gram uranium all atoms split, the heat developed (energy) can make a water basin, 6 x 6 x 5 meter filled with water of 0 degrees Celsius, boil. Source: Van Barnsteen naar Kernchemie, Dr. K.K. Darrow

  15. Three ways to control Electrical Power 1. Thecurrentis manipulated. Example: Switched Power Supplies, Resistors. 2. Thevoltageis manipulated. Example: Pulse Width Modulated Power Inverters, Frequency Converters, Soft-starters, Thyristor Controlled Power Supplies, Inductive Cooking. • Boththe voltage and the currentare manipulated.Example: Electronic Ballasts for Lighting

  16. Voltage Current 1. Current Manipulation Example: Switching Power Supply

  17. Voltage Current 1. Current Manipulation example: Switching Power Supply, Voltage, Current & Power Harmonics Power

  18. 2. Voltage Manipulation example: Inductive Cooking

  19. 2. Voltage Manipulation example: 3-Phase Frequency Inverter Output

  20. 2. Voltage Manipulation example: Soft starter

  21. 3. Voltage & Current Manipulation example: Lighting Industry, electronic ballast WT1600

  22. 3. Voltage & Current Manipulation example: 50kHz Electronic Ballast for TL

  23. Summary • Today electric power consumption is controlled by high speed (switching) electronics. • Design engineers are very creative. • To limit the negative side effects for others, new regulations are issued frequently to set new guidelines for design. • The definition of the average electric power has not changed, but the selection of the true repetition time T (period) requires special attention. • The power meter should allow the user to select the appropriate synchronisation source for the measurement calculations.

  24. The power meter should allow the user to select the synchronisation source for the measurement calculations.

  25. THANK YOU QUESTIONS?

More Related