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

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

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

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

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

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

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).

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

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

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

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

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,

Sample IEC 60688 specs

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

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)

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

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 50 065-1 North America by FCC

PLC and Smart Meters: cont’d

PLC and Smart Meters: cont’d Narrowband PLC Frequency range: 3-500 kHz Data rates: 100s Kbps Range: Several kilometres Can be extended by the use of repeaters Could be used in Smart Grids

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

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

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

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

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

Thank you