1、 ANSI C12.20-2010 American National Standard for Electricity Meters 0.2 and 0.5 Accuracy Classes ANSI C12.20-2010 Revision of ANSI C12.20-2002 American National Standard for Electricity Meters 0.2 and 0.5 Accuracy Classes NOTICE OF ADOPTION ANSI C12.20 was adopted and is approved for use by the Depa
2、rtment of Defense (DoD). The National Electrical Manufacturers Association has furnished the clearance required by existing regulations. Copies of the document are stocked at the Standardization Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, for issue to DoD acti
3、vities only. All other requestors must obtain copies from NEMA. Secretariat: National Electrical Manufacturers Association Approved August 31, 2010 American National Standards Institute, Inc. ANSI C12.20-2010 NOTICE AND DISCLAIMER The information in this publication was considered technically sound
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13、nt. ANSI C12.20-2010 AMERICAN NATIONAL STANDARD Approval of an American National Standard requires verification by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the AN
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21、I C12.20-2010 This page intentionally left blank.ii ANSI C12.20-2010 Contents 1 SCOPE 1 2 DEFINITIONS 1 3 REFERENCES 1 4 REQUIREMENTS1 4.1 Mounting.1 4.2 Voltage and frequency1 4.3 Current classes and test amperes1 4.4 Form designations 2 4.5 Displays 2 4.5.1 Viewing requirements2 4.5.2 Size of digi
22、ts 2 4.5.3 Direction of energy flow.3 4.6 Provisions for testing of calibration.3 4.6.1 Test output that is proportional to energy3 4.6.2 Test mode3 4.6.3 Delivered and received energy .3 4.6.4 Other measurements.3 4.7 Nameplate 3 4.7.1 Nameplate additions3 4.7.2 Nameplate deletions3 5 ACCEPTABLE PE
23、RFORMANCE OF NEW TYPES OF ELECTRICITY METERING DEVICES AND ASSOCIATED EQUIPMENT 3 5.1 General.3 5.1.1 Acceptable meters.3 5.2 Selection of metering devices for approval tests4 5.3 Conditions of test4 5.4 Rules governing the acceptance of types 4 5.5 Performance requirements.4 5.5.1 Test conditions 4
24、 5.5.2 Loading for accuracy tests 4 5.5.3 List of type tests 5 5.5.4 Accuracy tests .7 5.5.4.1 Test number 1: No load .7 5.5.4.2 Test number 2: Starting load .7 5.5.4.3 Test number 3: Load performance 7 5.5.4.4 Test number 4: Effect of variation of power factor.7 5.5.4.5 Test number 5: Effect of var
25、iation of voltage.9 5.5.4.6 Test number 6: Effect of variation of frequency.11 5.5.4.7 Test number 7: Equality of current circuits for multi-element meters11 5.5.4.8 Test number 8: Internal meter losses12 5.5.4.9 Test number 9: Temperature rise12 5.5.4.10 Test number 10: Effect of register friction1
26、2 5.5.4.11 Test number 11: Effect of internal heating.12 5.5.4.12 Test number 12: Effect of tilt 14 5.5.4.13 Test number 13: Stability of performance14 5.5.4.14 Test number 14: Effect of polyphase loading 14 5.5.5 External influences 14 iii ANSI C12.20-2010 5.5.5.1 Performance verification14 5.5.5.2
27、 Test number 15: Insulation 15 5.5.5.3 Test number 16: Voltage interruptions test .15 5.5.5.4 Test number 17: Effect of high voltage line surges .15 5.5.5.5 Test number 18: Effect of external magnetic field .15 5.5.5.6 Test number 19: Effect of variation of ambient temperature .15 5.5.5.7 Test numbe
28、r 20: Effect of temporary overloads 17 5.5.5.8 Test number 21: Effect of current surge in ground conductor.17 5.5.5.9 Test number 22: Effect of superimposed signals 18 5.5.5.10 Test number 23: Effect of voltage variation-secondary time base.18 5.5.5.11 Test number 24: Effect of variation of ambient
29、temperature-secondary time base.18 5.5.5.12 Test number 25: Effect of electrical fast transient/burst test18 5.5.5.13 Test number 26: Effect of radio frequency interference 18 5.5.5.14 Test number 27: Radio frequency conducted and radiated emission test 18 5.5.5.15 Test number 28: Effect of electros
30、tatic discharge (ESD).18 5.5.5.16 Test number 29: Effect of storage temperature .18 5.5.5.17 Test number 30: Effect of operating temperature 18 5.5.5.18 Test number 31: Effect of relative humidity18 5.5.5.19 Test number 32: Mechanical shock .18 5.5.5.20 Test number 33: Transportation drop 18 5.5.5.2
31、1 Test number 34: Mechanical vibration.18 5.5.5.22 Test number 35: Transportation vibration18 5.5.5.23 Test number 36: Weather simulation test 19 5.5.5.24 Test number 37: Salt-spray test.19 5.5.5.25 Test number 38: Raintightness 19 6 STANDARDS FOR IN-SERVICE PERFORMANCE 19 7 REQUIREMENTS APPLICABLE
32、TO DETACHABLE WATTHOUR METERS .19 8 REQUIREMENTS APPLICABLE TO BOTTOM-CONNECTED ELECTRICITY METERS19 9 PROCEDURE FOR ASSIGNING FORM DESIGNATIONS19 ANNEX A 20 A.1 Foreword to Second Edition (2002)20 A.2 Foreword to First Edition (1998) .22 iv ANSI C12.20-2010 Foreword (This Foreword is not part of Am
33、erican National Standard C12.20-2010.) This American National Standard establishes acceptable performance criteria for electricity meters. Accuracy class designations, current class designations, voltage and frequency ratings, test current values, service connection arrangements, pertinent dimension
34、s, form designations, and environmental tests are covered. The existing C12.20 Standard has been revised with the intent to bring it up to date in an industry that is changing dramatically because of both technology and regulatory matters. This American National Standard establishes acceptable perfo
35、rmance criteria for electricity meters. The existing standard was broadened to allow three phase current and voltage sources as an optional test method to the existing single phase, series, parallel method. In memoriam to Glenn Mayfield and Ed Malemezian: both had a passion for standards and members
36、 of SC16 felt fortunate to know and learn from them. Suggestions for improvement to this standard are welcome. They should be sent to: National Electrical Manufacturers Association Vice President, Technical Services 1300 North 17th Street Suite 1752 Rosslyn, VA 22209 This standard was processed and
37、approved for submittal to ANSI by Accredited Standards Committee for Electricity Metering, C12. At the time the committee approved this standard, the C12 Committee had the following members: Herman Millican, Chairperson ANS C12/SC16 Tom Nelson, Chairperson ANS C12 Paul Orr, Secretary ANS C12 Main Co
38、mmittee Organization Represented: Name of Representative: Organization Represented: Name of Representative: General InterestAustin Energy H. Millican Center for Neighborhood Technology L. Kotewa EnerNex Corporation A. Snyder Future DOS R rated voltage 1%; rated frequency 1 Hz; test amperes 1%; and u
39、nity power factor (0 2). The meter shall be stabilized at ambient temperature before performance tests are made. The reference performance shall be as close as practical to zero error and in no case shall exceed 0.2% error for accuracy class 0.5 or exceed 0.1% error for accuracy class 0.2. In this f
40、irst version of ANSI C12.20 to specify that Polyphase loading may be used for calibration type tests, a meter may meet the requirements of tests 18 and 13 using either series-parallel loading or polyphase loading. The calibration type tests described in tests 18 and 13 shall all be performed using t
41、he same loading; that loading may be either series-parallel or polyphase. 5.5.2 Loading for accuracy tests Unless otherwise specified, accuracy tests may be done with either series-parallel loading or polyphase loading. For series-parallel loading, the meter shall be tested with the voltage circuit(
42、s) effectively in parallel and with the appropriate current circuit(s) energized effectively in series. For polyphase loading, the meter shall be tested with voltage and current phase angles similar to actual service installations as described below (polyphase loading). When polyphase loading is use
43、d, the appropriate loading will depend on the meter configuration. Calibration tests done with polyphase loading shall pass for Typical Loading configurations as shown in Table 3. Alternate Loading configurations are shown for information only. The internal meter connections for these Form Designati
44、ons are provided in ANSI C12.10. Table 3 Polyphase Service loading for use on Accuracy Tests Description Form Designations Typical Loading Alternate Loading Two Element, Self Contained 12S, 13S, 25S, 13A Three wire, Network Three wire, 3 ,delta Two Element, Transformer Rated 5S, 26S, 35S, 45S, 56S,
45、5A, 35A, 45A Three wire, 3 , delta Three wire, 1 Three Element, Self Contained 16S, 16A Four wire, wye Four wire, delta Three Element, Self Contained 17S Four wire, delta None Three Element, Transformer Rated 9S, 10S, 39S, 9A, 10A, 48A Four wire, wye Four wire, delta 4 ANSI C12.20-2010 Polyphase loa
46、ding may be either ABC or CBA phase sequence. For ABC phase sequence, the voltage and current phase angles for unity power factor are shown in Table 4. Table 5 shows phase angles for CBA phase sequence. Angles represent the amount that phasors lag the A Phase Voltage. Table 4 ABC Phase Sequence, Cur
47、rent the meter shall show no damage and shall operate correctly in accordance with the requirement of the standard. Any change in energy and power quantities shall be limited to 1 least significant digit displayed. 5.5.5.2 Test number 15: Insulation Refer to subclause 4.7.3.1 of ANSI C12.1-2008. 5.5
48、.5.3 Test number 16: Voltage interruptions test Refer to subclause 4.7.3.2 of ANSI C12.1-2008. 5.5.5.4 Test number 17: Effect of high voltage line surges Refer to subclause 4.7.3.3 of ANSI C12.1-2008. 5.5.5.5 Test number 18: Effect of external magnetic field Refer to subclause 4.7.3.4 of ANSI C12.1-
49、2008 except that Table 20 (below) is to be used in place of Table 21 in ANSI C12.1-2008. Table 20 Effect of external magnetic field Current In Amperes Current Class Condition 2 10 20 100 200 320 Position of Conductor From ANSI C12.1-2008 Maximum Deviation In % From Reference Performance Reference performance for conditions (1), (2), and (3) 0.025 0.25 0.25 1.5 3 5 Reference Condition (1) 0.025 0.25 0.25 1.5 3 5 Condition (1) in Paragraph 4.7.3.4 1.0 Condition (2) 0.025 0.25 0.25 1.5 3 5 Condition (2) in Paragraph 4.7.3.4 1.0 Condition (3) 0.025 0.25 0.25 1.5 3 5 Co
