Energy Power Meters History Measurement Principle

Energy & Power Meters History & Measurement Principle Ben Kemink

History and Types of Energy & Power Meters 1960’s 70’s 80’s 90’s Current Transformer Input Electro-dynamic Wattmeter Traditional Stable Loads Torque Balanced Type Time Division Multiplier Type (50 - 60 Hz) APR 2 2885 (50 - 400 Hz) 2533 (DC, 10 Hz - 20 k. Hz) Digital Display Power Meters Traditional Current Shunt Input Stable Loads New Generation Digital Sampling Power Meters Single Shot Power Meter Un-Stable Loads QUALITY 2 INNOVATION FORESIGHT 2532(DC, 20 Hz-400 k. Hz)) WT 1600 (DC, 0. 5 Hz-1 MHz)) WT 230 (DC, 0. 5 Hz-100 k. Hz)) WT 3000 (DC, 0. 1 Hz-1 MHz) PZ 4000 DC – 2 MHz

Thermocouple WATT-meter The thermocouple generates a DC-voltage proportionally to the temperature difference of the junction and the reference point. A moving coil instrument is used to indicate the result. This instrument can be used to measure both DC and AC. Frequency bandwidth Current: up to approx. 10 MHz Voltage: up to approx. 100 k. Hz The heating-wire is very thin and easily burned out by an over-current. QUALITY 3 INNOVATION FORESIGHT

Electro-Dynamic WATT-meter If fixed coils are representing the load-current and the moving coil the voltage-representative current, we are directly measuring electric power. This instrument can measure DC and AC. Frequency bandwidth Current: up to approx. 1000 Hz Voltage: up to approx. 150 Hz QUALITY 4 INNOVATION FORESIGHT

Electro-Dynamic WATT-meter QUALITY 5 INNOVATION FORESIGHT

Thermal Watt Meter versus Electro-dynamic Meter i i QUALITY 6 INNOVATION FORESIGHT

Analogue Measurement, Digital Readout Voltage input circuit u(t) Analogue multiplier Low pass filter X Current input circuit i(t) p(t)=u(t). i(t) RMS circuit MEAN circuit RMS circuit Average power QUALITY 7 INNOVATION FORESIGHT To A/D converter

Analogue calculation, Digital Readout Yokogawa 2533 E QUALITY 8 INNOVATION FORESIGHT

Time-division multiplication principle QUALITY 9 INNOVATION FORESIGHT

Today: WT-Family en PZ Voltage input circuit Current input circuit u(t) i(t) Sampled Instantaneous voltage value U(n) A/D Sampled Instantaneous current I(n) DSP A/D Digital Signal Processing QUALITY 10 INNOVATION FORESIGHT To next stage

Digital Calculations and Display: WT-Family and PZ QUALITY 11 INNOVATION FORESIGHT

Example of true digital type Yokogawa 2531 A QUALITY 12 INNOVATION FORESIGHT

DSP versus CPU QUALITY 13 INNOVATION FORESIGHT

Energy & Power Measurement Trend 1950 s 1980 s Present time Near future Requirement Stability / Repeatability Accuracy / Bandwidth Real time / Analysis Efficiency / Control Background Boom of house appliances Boom of Inverter Harmonics / Flicker Ecology / Energy Object / Target Commercial frequency Static power / Analysis Transient power Sensing Coil CT, DC/CT Non inductive shunt High freq. probe/sensor Method Moving coil Analog circuit or IC Digital IC Fixed coils Moving coil V V A A-D A LPF V A-D A-D Fixed coil Moving coil Fixed coil Pointer of meter Principle or Electrodynamometer Acquisition Theme QUALITY 14 INNOVATION A-D CPU DSP MEMORY Feedback time division multiplier system Accuracy FORESIGHT DSP CPU CRT MEMORY DSP Digital multiplier Sampling A/D C Feedback pulse width modulation Counting A C /D method DSP Real time FFT analysis Response Isolation / Software Sampling A/D C Probing/ Calibration