1. Smart Meters in Power Systems
Sharief F Babikir
Department of Electrical and Electronic Engineering
University of Khartoum
August/2016

2. Outlines Transducers and Measurements Analogue and Digital Meters
IEC 60688
Smart Meters
Use in Power systems
PLC/GSM/GPRS

3. Transducers – theory and use
a device that converts variations in a physical quantity (pressure or brightness etc) into an electrical signal, or vice versa
microphones, loudspeakers, thermometers, position and pressure sensors, and antenna

4. Temperature Measurements:
R increases with temperature (Metals)
R decreases with temp (semiconductors)
Pressure measurements:
Piezoelectric effect: V = f(pressure)
Capacitive: C = f(pressure)
Optical properties depend on applied pressure
Photo sensors
LDR (light dependent resistance)
Photoelectric effect

5. Analogue measurement of Electrical Variables
Voltmeter/Ameter
The galvanometer coil of fine wire
Placed in a magnetic field
torque α current
Measure deflection
Determine V/I

6. Power and Energy Power per phase: Energy Power Factor f ???
Complicates things

7. Problems of analogue measurements
Relies on mechanical components
May require manual/visual inspection
Difficult to include in computations and control functions (analogue computers/ analogue controllers)
Data recording (Magnetic tapes, specialised readers etc).

8. Analogue PID Controller
Proportional + Integral +Derivative
Measurements at the sensor side
System is critically dependent on the sensor

9. Digital Measurements Uses a fraction of the signal (or amplified)
Uses a digital to analogue converter (ADC)
The data could be acquired by an intelligent agent.
Processors/microcontrollers are normally used

10. Transducers in Power Systems
Decisions in PS rely on the correct data
Data must be available in good time
PS is a Real Time system - late data is useless --
Accurate measurement devices needed
Robust and fast communication needed
Good controllers required
Fast relays and coordination required

11. Data Recoding in Power Systems
Real time data acquisition
Real time data recording
Playback and analysis

12. IEC-60688:
Name: ELECTRICAL MEASURING TRANSDUCERS FOR CONVERTING ac ELECTRICAL QUANTITIES TO ANALOGUE OR DIGITAL SIGNALS
Standard applicable to:
Current, Voltage, Active Power, Reactive Power, Power Factor, Phase Angle, Frequency
Defines the following:
Terminologies to be used, classes sensors, adjustments, errors and variations, accuracy,

13. Sample IEC specs

14. Consequences of ICE 60688
Stresses the need for calibration during development
Need for calibration of measurement sensors devices during the lifetime of the instrument
Compliance to variations due to environmental conditions
Defines the marking and labels

15. Smart Meters Records consumption of energy in intervals (e.g 1h)
Communicates that information to the utility for monitoring and billing
Enable two-way communication between the meter and the central system.
Gather data for remote reporting.
Advanced metering infrastructure (AMI) vs automatic meter reading (AMR)

16. Smart Meters and Communication:
Comms infrastructure needed
Role of service providers
Two way comms (utility <-> customer)

17. PLC and Smart Meters Uses existing network 3 voltage levels;
Low Voltage < 1 kV
Medium Voltage 1 kV – 100 kV and
High Voltage >100 kV.
The frequency levels:
Europe are decided by the CENELEC Standard EN
North America by FCC

18. PLC and Smart Meters: cont’d

19. PLC and Smart Meters: cont’d
Narrowband PLC
Frequency range: kHz
Data rates: 100s Kbps
Range: Several kilometres
Can be extended by the use of repeaters
Could be used in Smart Grids

20. PLC Communications (PLCC)
Provides the infrastructure and means to do:
Tele-protection
Tele-monitoring
Energy management
Fraud-detection
Load control
Demand response

21. Smart Meters: GSM and GPRS
GSM Modules at the meter side
Meter may regularly send the collected data to the monitoring station
Stations can poll the data from the SM

22. GSM/GPRS in Power Systems
Power Failure alerts:
Detect  Action  Alert/notify X
Interrogate meters and monitor status

23. Monitoring and Control via SMS
Meter has a GSM module
User sends SMS message (command and control)
Meter receives message
Meter processes the command
Meter notifies the user via SMS
Such energy meters in use in Sudan

24. Meter developments in SEDEC
Prepaid meters: Swiss, South African, Chinese
Sudanese Chinese factory
Development from scratch
Operational wired Meter + Screen available
Calibration and verification
Certification process underway

25. Thank you