Electricity Metering
Energy Management Branch – WPN08th February 2013
Overview of Topics
1. Introduction to electricity metering
2. Classification of electricity meters based on technology
3. Working principles, metering concepts
4. Net metering & Forward metering
5. Metering errors and meter tampers
Overview of Topics cont’d
6. Meter Testing, Meter Test Benches and Equipment
7. Distribution loss reduction through metering
3. Working principles and metering concepts
1. Voltage Coil – High impedance element
2. Current Coil – Low Impedance element
3. Stator – Concentrate and confines magnetic
filed
4. Aluminium rotor disk
5. Brake magnet
6. Spindle with worm gear
7. Display registers
Principle of Operation
Ferraris meter construction
Voltage element
Current element
Rotor
Disc speed proportional to power
p = u . i
u
i
u
i
x x
v = u • i •k
Voltage element
Current element
Disc
Metering unit 2
Metering unit 1 Metering unit 3
Electronic/ Static meters
Smart meters – block diagram
Measurement parameters of meters
• Active energy, kWh, MWh
• Reactive energy, kVarh, MVarh
• Apparent Energy, kVah, Mvah
• Maximum demand
(15-minute average Apparent/ Active power)
Power Triangle -
1.2 Metering Terminology cont’d
Four Quadrant energy measurement
Q 1 - Active energy import, pf laggingQ 2 - Active energy export, pf laggingQ 3 - Active energy export, pf leadingQ 2 - Active energy import, pf leading