Stds for Electric energy meter

1. 1
Energy Metering Standards – A
Review,
• The Metering standards - minimum
performance standards
• Static Meters – Distinct standards
• IEC Vs ANSI – Essentially consistent in
intent
• Standards : Most Standards carry
historical burden

2. 2
IEC VS ANSI - SCOPE
• IEC 1036: Static watt-hour meters of
Class 1 &2
• ANSI 12.16: Solid State Electricity Meters
• Note: ANSI still mentions only Watt-hour
performance!

3. 3
IEC – ANSI- Display,
• IEC 1036 - No
Display Size. EDMI
meters digit height is
0.80 cm;
• IEC specifies
minimum 1500 hrs of
running at full load
before roll off.
• ANSI mentions the digit
size to be minimum
0.50 cm
• Minimum no. of digits is
4. This may cause a
rollover in less than
1000 hours

4. 4
IEC Vs ANSI- Detailed
Comparison
• Metrology Aspects
• Environmental Aspects
• Mechanical Tests
• Effect of External influences
• Over load behavour

5. 5
METROLOGY ASPECTS-
Starting Current
ANSI CLASS 20 Meter:
250 mA
IEC 5A meter: 50 mA
1 A meter: 10 mA
IEC METERS START TO REGISTER AT VERY
LIGHT LOADS. THIS MAY RESULT IN
BETTER REVENUES FOR THE UTILITY

6. 6
METROLOGY ASPECTS-
INFLUENCE QUANTITIES
Effect of
Variation of
Voltage
ANSI allows ±1%
error variation from
reference error
IEC allows ±0.2%
error variation
Effect of
variation of
Frequency
ANSI allows ±1%
error variation from
reference error
IEC allows ±0.2%
error variation
Equality of
Current Circuits
ANSI allows ±1%
error variation
IEC allows ±1%
error variation

7. 7
METROLOGY ASPECTS-
CONTD.
Load
Performance
ANSI : The
Worst Error is
2%
IEC687 : Worst
error of 1.0 %
Effect of
Variation of
Power Factor
ANSI allows the
worst errors of
2%
IEC 687 : Worst
Error of 1.0%
IEC METERS HAVE MORE STRINGENT TOLERANCE
THUS ALLOWING BETTER METROLOGICAL
PERFORMANCE.

8. 8
POWER CONSUMPTION AND
HEATING
Power Consumption ANSI:
Current Loss <1VA
Voltage Loss<10VA
IEC:Current Loss <1VA
Voltage Loss<10VA
Temperature Rise of
Meter Terminals
ANSI: <55°C IEC: <40°C , ensuring
longer terminal life.
Effect of Internal Heating
on Accuracy
ANSI:<±1.5% (condition
2-Max current applied for
1 hour)
IEC:<±0.2% (Max
current applied for at
least 1 hour)
IEC meters conform to more stringent performance parameters

9. 9
INSULATION TESTS
Impulse Voltage
test
ANSI specifies
a SINGLE
impulse of 6kV
IEC specifies 20
impulses of 6 kV
AC voltage test ANSI specifies
2.5kV r.m.s
IEC specifies
2kV r.m.s
While the impulse voltage test of IEC is very significantly stringent
, the AC Voltage test in ANSI specifies a marginally higher voltage.

10. 10
ENVIRONMENTAL ASPECTS
ANSI: Rain tightness
test as per ANSI/UL50-
1987(5)
IP-53 which exceeds ANSI requirement
because:-
1. IP53 has a higher water pressure 80-
100kPa compared to 34.5kPa of ANSI
2. IP53 has a shorter distance between the
spray head and the enclosure under
test.Distance is 300-500mm compare to
1400mm of ANSI
3. IP53 has a varying and greater angle at
which the water impacts with the enclosure
under test.Angle varies between vertical
and 60 degrees from vertical.ANSI specify
45 degrees from vertical (fixed)
4. IP53 also has dust tightedness

11. 11
ENVIRONMENTAL ASPECTS
PROTECTION
AGAINST
PENETRATION OF
DUST
NO ANSI TEST
SPECIFIED
IEC TEST AS PER
IEC529 FOR IP51
ETC.
DRY HEAT TEST NO ANSI TEST
SPECIFIED
IEC-68-2-2 +55ºC±
2ºC for 72 hours
COLD TEST NO ANSI TEST
SPECIFIED
IEC 68-2-1 -20ºC±
3ºC for 72 hours
DAMP HEAT
CYCLIC TEST
NO ANSI TEST
SPECIFIED
IEC 68-2-30 +40ºC±
2ºC for 6 cycles

12. 12
WEATHER SIMULATION TEST
IN ANSI
• TEST METHOD REFERS TO ASTM G23 , METHOD 1;
• ASTM G23 DESCRIBES EQUIPMENT FOR LIGHT
EXPOSURE APPARATUS FOR NON METTALIC
MATERIALS;

13. 13
WEATHER SIMULATION TEST
IN ANSI
• MOST METERS ARE NOW MADE OF UV RESISTANT, FLAME
RETARDANT POLYCARBONATE- WHICH ARE WATER
IMPERMEABLE. HENCE TESTING THE SAME MATERIAL ON
METERS IS REDUNDANT.
• A MEA TOU METER INSTALLED IN A STEEL CABINET WILL
NEVER EVER TO BE EXPOSED TO THE CONDITIONS
MENTIONED IN THE ANSI WEATHER SIMULATION TEST;
• BESIDES IEC ENVIRONMENTAL TESTS ARE MORE VARIED IN
CONDITIONS AND TEST THE METER IN REAL LIFE
CONDITIONS;
• IEC ENVIRONMENTAL TESTS ARE MORE THAN ADEQUATE
FOR ANY INSTALLATION OF TOU METER AT MEA;

14. 14
ANSI SALT SPRAY TEST
• THE TEST IS SIMILAR TO THE THE
SALT MIST TEST MENTIONED IN IEC.
• ANSI SPECIFIES THE TEST DURATION
AS 25 HOURS;
• EDMI GENIUS METERS HAS PASSED
THIS TEST FOR 168 HOURS ;

15. 15
MECHANICAL TESTS
Spring Hammer
Test
ANSI:No Test
Specified
IEC Mentions test as
per IEC 817 Kinetic
energy of 0.22Nm
±0.05Nm
Shock Test ANSI:No Test
Specified
IEC 68-2-27 Peak
Acceleration=147m/s²
for 11ms
Vibration Test ANSI:No Test
Specified
IEC 68-2-6 Frequency
range 10Hz-150Hz
Resistance to Heat
& Fire
ANSI:No Test
Specified
IEC 695-2-1 650ºC ±
10ºC for 30s ± 1s

16. 16
EXTERNAL INFLUENCES
High Voltage Line Surge
Test
ANSI: 6kV IEC :6kV
Effect of External
Magnetic Fields on
Accuracy
ANSI: ±1.0% IEC <1%
Effect of Variation of
Ambient Temp. on
accuracy
ANSI: ± 4% IEC: ± 1%
IEC METERS HAVE MORE STRINGENT PERFORMANCE PARAMETERS

17. 17
Temporary Overload & other
issues
Effects on
Accuracy
ANSI states the
limits of error
variation as
<±1.5%
IEC specifies
this limit as
<±0.05%
Electrostatic
Discharge
Immunity
ANSI TEST
LEVEL: 7.5kV
IEC TEST
LEVEL: 15kV

18. 18
METERS AND HARMONICS
• ANSI 12.16 does not specify any test for
the meters performance under harmonic
conditions
• IEC mentions adequate tests by injection
of harmonics , thus specifying the
performance parameters for Energy
meters in real life conditions

19. 19
CONCLUSION
• IEC standard : More stringent in all
aspects of measurement performance –
This can help to improve energy
registration;

20. 20
CONCLUSION
• IEC :- realistically covers all aspects of
Environmental tests adequately to meet
MEA’s requirement – specially for three
phase TOU meter housed in a steel
cabinet. IEC standards are more than
match the ANSI requirements;
• IEC based meters should be accepted as
fully suitable for MEA’s requirements.

21. 21
THANK YOU
Presented By
Arun Sehgal
EDMI ASIA PTE. LTD.