Transcript Energy & Power Meters History

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)
APR2
2885 (50 - 400 Hz)
2533 (DC, 10Hz - 20kHz)
Digital Display Power Meters
Current Shunt Input
Traditional
Stable Loads
New Generation
Digital Sampling
Power Meters
Single Shot Power Meter
Un-Stable Loads
QUALITY
2
INNOVATION
FORESIGHT
2532(DC,20Hz-400kHz))
WT1600 (DC,0.5Hz-1MHz))
WT230 (DC,0.5Hz-100kHz))
WT3000 (DC, 0.1Hz-1MHz)
PZ4000 DC – 2MHz
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 kHz
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
u(t)
Voltage
input circuit
Analogue
multiplier
Low pass
filter
X
Current
input circuit
i(t)
p(t)=u(t).i(t)
RMS circuit
MEAN circuit
RMS circuit
T
Average power
QUALITY
7
INNOVATION
1
  u (t ).i(t ).dt
T0
FORESIGHT
T
1
Paverage   p(t).dt
T0
To A/D
converter
Analogue calculation, Digital Readout
Yokogawa 2533E
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)
A/D
1 N
Active Power   U( n ) .I( n )
N n 1
QUALITY
10
INNOVATION
FORESIGHT
DSP
Digital
Signal
Processing
To next
stage
Digital Calculations and Display: WT-Family and PZ
QUALITY
11
INNOVATION
FORESIGHT
Example of true digital type
Yokogawa 2531A
QUALITY
12
INNOVATION
FORESIGHT
DSP versus CPU
Measurement via DSP operation
 32-bit floating point operation
 80ns for WT2000
(250ms display update)
 50ns for WT1000
(100ms display update)
Measurement via CPU
computation
QUALITY
13
INNOVATION
FORESIGHT







Urms
Irms
W
VA
Var
PF

 Range conversion
 
 Scaling
Energy & Power Measurement Trend
1950s
1980s
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
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 circuit or IC
Digital IC
Fixed
coils
Moving
coil
V
V
A-D
A
A-D
DSP
LPF
A
V
A-D
A
A-D
A-D
DSP
A-D
Fixed
coil
Moving
coil
Fixed
coil
Pointer
of meter
Principle or
Electrodynamometer
Acquisition
method
Theme
QUALITY
14
INNOVATION
Accuracy
FORESIGHT
A-D
CPU
DSP
CPU
CPU
MEMORY
Feedback time division
multiplier system
CRT
MEMORY
DSP
DSP
Digital multiplier
Sampling A/D C
Feedback pulse width
modulation
Counting A/D C
Real time FFT analysis
Response
Isolation / Software
Sampling A/D C
Probing/ Calibration