Biology for Computer Engineers Course Handout.pptx
Calibration & Testing of Electronic Meters
1.
2. About PSPCL
Punjab State Power Corporation Limited (PSPCL)
is the electricity generating company of the
Government of Punjab state in India.
It was formerly known as Punjab State Electricity
Board (PSEB).
PSPCL was incorporated as company on 16-04-
2010 and was given the responsibility of operating
and maintenance of State's own generating
projects. The business of Generation of power of
erstwhile PSEB was transferred to PSPCL.
3. Electricity Meters
An electricity meter or energy meter is a device
that measures the amount of electric energy
consumed by a residence, business, or an
electrically powered device.
Electricity meters are typically calibrated in billing
units, the most common one being the kilowatt
hour [kWh]. Periodic readings of electricity meters
establish billing cycles and energy used during a
cycle
4. History of Electricity Meters
Samuel Gardiner takes out the first known patent
on an electric meter in 1872. This was a DC lamp-
hour meter that was a clock with an electromagnet
that started and stopped the mechanism.
Thomas Alva Edison, who introduced the first
electrical distribution systems for lighting using
direct current, held that electricity must be sold just
like gas – also used extensively for lighting at that
time. His “Electric meter” patented in 1881, used
the electrochemical effect of current.
5. Continued…
Oliver Blackburn Shallenberger developed an
induction type watthour meter for Westinghouse in
1894, which is reminiscent of modern day meters.
Shallenberger and an assistant accidently
discovered this. While working on an AC arc lamp,
a spring fell and they realized that the spring had
rotated. Shallenberger eventually discovered that
the changing electric fields induced a magnetic
field which caused the metal spring to rotate.
6. Types of Electricity Meters:
There are three types of meters that are currently in
the market:-
1. Electromechanical Meters
2. Electronic Meters
3. Smart Meters
7. 1. Electromechanical
Meters
The most common type of electricity
meter is the electromechanical
induction watt-hour meter.
The electromechanical induction
meter operates by counting the
revolutions of a non-magnetic, but
electrically conductive, metal disc
which is made to rotate at a speed
proportional to the power passing
through the meter. The number of
revolutions is thus proportional to the
energy usage.
8. 2. Electronic Meters
Electronic Energy Meter is based
on Digital Micro Technology (DMT)
and uses no moving parts.
In EEM the accurate functioning is
controlled by a specially designed
IC called ASIC (Application
Specified Integrated Circuit). ASIC
is constructed only for specific
applications using Embedded
System Technology.
9. 3. Smart Meters
A smart meter is usually an
electronic device that records
consumption of electric energy in
intervals of an hour or less and
communicates that information at
least daily back to the utility for
monitoring and billing purposes.
Smart meters enable two-way
communication between the meter
and the central system, preventing
tampering with the meter.
10. What is Calibration?
Calibration refers to a process of verifying the
performance of any instrument that measures,
sources or tests some parameters.
Electrical calibration involves the use of precise
devices, known as standard, that evaluate the
performance of key properties for other devices
called Units Under Tests (UUTs).
11. Why is Calibration
necessary?
To ensure readings from an instrument are
consistent with other measurements.
To determine the accuracy of the instrument
readings.
To establish the reliability of the instrument i.e. that
it can be trusted.
12. Calibration Process
A known amount of energy is simultaneously
supplied to a reference meter and to the unit under
test (UUT).
A reading from the reference meter is then
compared to a reading from the UUT and the error
is calculated.
14. NABL Accreditation
National Accreditation Board for Testing and
Calibration Laboratories (NABL) is an autonomous
body under the aegis of Department of Science &
Technology, Government of India.
NABL has been established with the objective to
provide Government, Industry Associations and
Industry in general with a scheme for third-party
assessment of the quality and technical
competence of testing and calibration laboratories.
15. Testing Bench
The testing benches are used to test and calibrate
both single and three-phase meters.
16. Specifications of the Test Bench
Incoming Voltage: 3X230V/400V +/- 10%........65Hz
Outgoing Voltage: 30 to 300V ; 300VA
Outgoing Current: 0.0012 to 120A / 300VA
Maximum Voltage: 300V
Maximum Current: 120A
17. Parts of Test Bench:-
Scanner
Wires
Reference
Batteries
Emergency Measures
Software Used
18. 1. Scanner
The SH 11 model scanning head is designed for
detection of light emitting diodes (LED’s) of electronic
meters. The duration of optical impulse signals from
electric meters is detected and evaluated.
The precision optical lens is designed to make the
scanning head insensible to external light.
19. 2. Wires
Red 1- Phase 1 Incoming
Red 2- Phase 1 Outgoing
Yellow 1- Phase 2 Incoming
Yellow 2- Phase 2 Outgoing
Blue 1- Phase 3 Incoming
Blue 2- Phase 3 Outgoing
Neutral- For Earthing purposes
20. 3. Reference
The meter under test is
supplied with a known quantity
of the current being calibrated,
and the meter is interrogated in
order to ascertain the amount of
impulses that it has displays.
The amount of impulses is then
compared with the reference,
and the measurement error is
calculated.
21. 4. Batteries
These batteries are responsible for maintaining
constant voltage and current supply across the
test benches.
22. 5. Emergency Measures
A light lamp is attached on top of
the bench which signifies whether
the bench is working or not.
RED-ON ; GREEN-OFF
This button immediately cuts off the
power to the bench, in case of an
emergency.
23. 6. Software Used
CAMCAL for WINDOWS is a comprehensive
software package designed to fulfil the current
requirements of the modern meter testing
environment.
24. Procedure for testing a
meter
Mount the meters that are to be tested onto the
hooks present on the bench slots. Connect all the
wires according to the positions.
Now, align the impulse LED on the meter with the
SH-11 impulse scanner.
Turn on the bench and computer. On the desktop,
click on CAMCAL software which has been
installed as the compatible software to the bench.
In the software, add the meter by filling its
properties. Also, select the type of test you want to
perform on the meter.
25. Continued..
After confirming all the specifications of the meter
and of the test you want to run are, start the Test.
We can watch the progress of the test being run
on the window. The % errors present in all the
meter readings are shown alongside their slots.
The time remaining for the test to be completed is
also shown.
It gives us the specific details about the meter and
the % error that is present in the meter’s reading.
The data can be exported by clicking on the
Export button which will export the data to MS
Excel. Now, the results have been exported to the
MS Excel.
26. Some Tests that are conducted
on Meters
Scanner Test
100% Imax UPF
100% Ibasic UPF
75% Ibasic UPF
50% Ibasic UPF
25% Ibasic UPF
10% Ibasic UPF
5% Ibasic UPF
100% Ibasic 0.5 lag
100% Ibasic 0.8 lead
Dial Test
27. Tamper Testing and Security
Electric meters can be manipulated, thus causing
them to stop, under-register or even bypassing the
meter.
A common method of tampering on mechanical
disk meters is to attach magnets to the outside of
the meter.
Today, many power companies are installing
remote-reporting meters which are capable of
detect any tampering in electric meters, and
discover energy theft.
28. Tamper Tests
Voltage Failure
Current Failure
Voltage Unbalance
Current Unbalance
Mobile Tamper Test
Magnet Tampering
29. What is CMRI?
CMRI is the acronym of
Common Meter Reading
Instrument.
CMRI is used to
download the data of the
meter usage from the
meter, via a optical data
cable.
The data is stored in the
memory of CMRI which is
send to Lab where the
data is analysed and a
report is prepared.
30. Problems Faced
Intensive Heat in Summer
Late Delivery of Calibrated References
Excessive Amount of Meters
31. Solutions
Using Military Grade ICs
To be calibrated References should be sent to
Patiala
Setting up a new NABL Lab in Punjab