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# ANSI Standards & Recent Updates That Affect Service Departments

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Understand contents of ANSI C12.20-2010 for 0.2 and 0.5 Accuracy Class Meters
Understand the Relationship of C12.20 to C12.1
Understand ANSI C12.20 Changes Planned for 2015 Edition and ANSI C12.1 changes planned for 2013
Understand new ANSI C12.29 for Field Testing and potential time frame
Discuss – Will this affect how we test in the field?
Presented at the North Carolina Electric Meter School. 6/2013

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• Blondel&apos;s theorem, named after its discoverer, French electrical engineer André Blondel, is the result of his attempt to simplify both the measurement of electrical energy and the validation of such measurements. The result is a simple rule that specifies the minimum number of watt-hour meters required to measure the consumption of energy in any system of electrical conductors. The theorem states that the power provided to a system of N conductors is equal to the algebraic sum of the power measured by N watt-meters. The N watt-meters are separately connected such that each one measures the current level in one of the N conductors and the potential level between that conductor and a common point. In a further simplification, if that common point is located on one of the conductors, that conductor&apos;s meter can be removed and only N-1 meters are required. An electrical energy meter is a watt-meter whose measurements are integrated over time, thus the theorem applies to watt-hour meters as well.[1] Blondel wrote a paper on his results that was delivered to the International Electric Congress held in Chicago in 1893. Although he was not present at the Congress, his paper is included in the published Proceedings.[2] Instead of using N-1 separate meters, the meters are combined into a single housing for commercial purposes such as measuring energy delivered to homes and businesses. Each pairing of a current measuring unit plus a potential measuring unit is then termed a stator or element. Thus, for example, a meter for a four wire service will include three elements. Blondel&apos;s Theorem simplifies the work of an electrical utility worker by specifying that an N wire service will be correctly measured by a N-1 element meter. Unfortunately, confusion arises for such workers due to the existence of meters that don&apos;t contain tidy pairings of single potential measuring units with single current measuring units. For example, a meter was previously used for four wire services containing two potential coils and three current coils and called a 2.5 element meter. Blondel Noncompliance Electric energy meters that meet the requirement of N-1 elements for an N wire service are often said to be Blondel Compliant. This label identifies the meter as one that will measure correctly under all conditions when correctly installed. However, a meter doesn&apos;t have to be Blondel compliant in order to provide suitably accurate measurements and industry practice often includes the use of such non compliant meters. The form 2S meter is extensively used in the metering of residential three wire services, despite being non compliant in such services. This common residential service consists of two 120 volt wires and one neutral wire. A Blondel compliant meter for such a service would need two elements (and a five jaw socket to accept such a meter), but the 2S meter is a single element meter. The 2S meter includes one potential measuring device (a coil or a voltmeter) and two current measuring devices. The current measuring devices provide a measurement equal to one half of the actual current value. The combination of a single potential coil and two so called half coils provides highly accurate metering under most conditions. The meter has been used since the early days of the electrical industry. The advantages were the lower cost of a single potential coil and the avoidance of interference between two elements driving a single disc in an induction meter. For line to line loads, the meter is Blondel compliant. Such loads are two wire loads and a single element meter suffices. The non compliance of the meter occurs in measuring line to neutral loads. The meter design approximates a two element measurement by combining a half current value with the potential value of the line to line connection. The line to line potential is exactly twice the line to neutral connection if the two line to neutral connections are exactly balanced. Twice the potential times half the current then approximates the actual power value with equality under balanced potential. In the case of line to line loads, two times the half current value times the potential value equals the actual power. Error is introduced if the two line to line potentials are not balanced and if the line to neutral loads are not equally distributed. That error is given by 0.5(V1-V2)(I1-I2) where V1 and I1 are the potential and current connected between one line and neutral and V2 and I2 are those connected between the other line and neutral.[1] Since the industry typically maintains five percent accuracy in potential, the error will be acceptably low if the loads aren&apos;t heavily unbalanced. This same meter has been modified or installed in modified sockets and used for two wire, 120 volt services (relabeled as 2W on the meter face). The modification places the two half coils in series such that a full coil is created. In such installations, the single element meter is Blondel compliant. There is also a three wire 240/480 volt version that is not Blondel compliant. Also in use are three phase meters that are not Blondel compliant, such as forms 14S and 15S, but they can be easily replaced by modern meters and can be considered obsolete.
• Blondel&apos;s theorem, named after its discoverer, French electrical engineer André Blondel, is the result of his attempt to simplify both the measurement of electrical energy and the validation of such measurements. The result is a simple rule that specifies the minimum number of watt-hour meters required to measure the consumption of energy in any system of electrical conductors. The theorem states that the power provided to a system of N conductors is equal to the algebraic sum of the power measured by N watt-meters. The N watt-meters are separately connected such that each one measures the current level in one of the N conductors and the potential level between that conductor and a common point. In a further simplification, if that common point is located on one of the conductors, that conductor&apos;s meter can be removed and only N-1 meters are required. An electrical energy meter is a watt-meter whose measurements are integrated over time, thus the theorem applies to watt-hour meters as well.[1] Blondel wrote a paper on his results that was delivered to the International Electric Congress held in Chicago in 1893. Although he was not present at the Congress, his paper is included in the published Proceedings.[2] Instead of using N-1 separate meters, the meters are combined into a single housing for commercial purposes such as measuring energy delivered to homes and businesses. Each pairing of a current measuring unit plus a potential measuring unit is then termed a stator or element. Thus, for example, a meter for a four wire service will include three elements. Blondel&apos;s Theorem simplifies the work of an electrical utility worker by specifying that an N wire service will be correctly measured by a N-1 element meter. Unfortunately, confusion arises for such workers due to the existence of meters that don&apos;t contain tidy pairings of single potential measuring units with single current measuring units. For example, a meter was previously used for four wire services containing two potential coils and three current coils and called a 2.5 element meter. Blondel Noncompliance Electric energy meters that meet the requirement of N-1 elements for an N wire service are often said to be Blondel Compliant. This label identifies the meter as one that will measure correctly under all conditions when correctly installed. However, a meter doesn&apos;t have to be Blondel compliant in order to provide suitably accurate measurements and industry practice often includes the use of such non compliant meters. The form 2S meter is extensively used in the metering of residential three wire services, despite being non compliant in such services. This common residential service consists of two 120 volt wires and one neutral wire. A Blondel compliant meter for such a service would need two elements (and a five jaw socket to accept such a meter), but the 2S meter is a single element meter. The 2S meter includes one potential measuring device (a coil or a voltmeter) and two current measuring devices. The current measuring devices provide a measurement equal to one half of the actual current value. The combination of a single potential coil and two so called half coils provides highly accurate metering under most conditions. The meter has been used since the early days of the electrical industry. The advantages were the lower cost of a single potential coil and the avoidance of interference between two elements driving a single disc in an induction meter. For line to line loads, the meter is Blondel compliant. Such loads are two wire loads and a single element meter suffices. The non compliance of the meter occurs in measuring line to neutral loads. The meter design approximates a two element measurement by combining a half current value with the potential value of the line to line connection. The line to line potential is exactly twice the line to neutral connection if the two line to neutral connections are exactly balanced. Twice the potential times half the current then approximates the actual power value with equality under balanced potential. In the case of line to line loads, two times the half current value times the potential value equals the actual power. Error is introduced if the two line to line potentials are not balanced and if the line to neutral loads are not equally distributed. That error is given by 0.5(V1-V2)(I1-I2) where V1 and I1 are the potential and current connected between one line and neutral and V2 and I2 are those connected between the other line and neutral.[1] Since the industry typically maintains five percent accuracy in potential, the error will be acceptably low if the loads aren&apos;t heavily unbalanced. This same meter has been modified or installed in modified sockets and used for two wire, 120 volt services (relabeled as 2W on the meter face). The modification places the two half coils in series such that a full coil is created. In such installations, the single element meter is Blondel compliant. There is also a three wire 240/480 volt version that is not Blondel compliant. Also in use are three phase meters that are not Blondel compliant, such as forms 14S and 15S, but they can be easily replaced by modern meters and can be considered obsolete.
• Blondel&apos;s theorem, named after its discoverer, French electrical engineer André Blondel, is the result of his attempt to simplify both the measurement of electrical energy and the validation of such measurements. The result is a simple rule that specifies the minimum number of watt-hour meters required to measure the consumption of energy in any system of electrical conductors. The theorem states that the power provided to a system of N conductors is equal to the algebraic sum of the power measured by N watt-meters. The N watt-meters are separately connected such that each one measures the current level in one of the N conductors and the potential level between that conductor and a common point. In a further simplification, if that common point is located on one of the conductors, that conductor&apos;s meter can be removed and only N-1 meters are required. An electrical energy meter is a watt-meter whose measurements are integrated over time, thus the theorem applies to watt-hour meters as well.[1] Blondel wrote a paper on his results that was delivered to the International Electric Congress held in Chicago in 1893. Although he was not present at the Congress, his paper is included in the published Proceedings.[2] Instead of using N-1 separate meters, the meters are combined into a single housing for commercial purposes such as measuring energy delivered to homes and businesses. Each pairing of a current measuring unit plus a potential measuring unit is then termed a stator or element. Thus, for example, a meter for a four wire service will include three elements. Blondel&apos;s Theorem simplifies the work of an electrical utility worker by specifying that an N wire service will be correctly measured by a N-1 element meter. Unfortunately, confusion arises for such workers due to the existence of meters that don&apos;t contain tidy pairings of single potential measuring units with single current measuring units. For example, a meter was previously used for four wire services containing two potential coils and three current coils and called a 2.5 element meter. Blondel Noncompliance Electric energy meters that meet the requirement of N-1 elements for an N wire service are often said to be Blondel Compliant. This label identifies the meter as one that will measure correctly under all conditions when correctly installed. However, a meter doesn&apos;t have to be Blondel compliant in order to provide suitably accurate measurements and industry practice often includes the use of such non compliant meters. The form 2S meter is extensively used in the metering of residential three wire services, despite being non compliant in such services. This common residential service consists of two 120 volt wires and one neutral wire. A Blondel compliant meter for such a service would need two elements (and a five jaw socket to accept such a meter), but the 2S meter is a single element meter. The 2S meter includes one potential measuring device (a coil or a voltmeter) and two current measuring devices. The current measuring devices provide a measurement equal to one half of the actual current value. The combination of a single potential coil and two so called half coils provides highly accurate metering under most conditions. The meter has been used since the early days of the electrical industry. The advantages were the lower cost of a single potential coil and the avoidance of interference between two elements driving a single disc in an induction meter. For line to line loads, the meter is Blondel compliant. Such loads are two wire loads and a single element meter suffices. The non compliance of the meter occurs in measuring line to neutral loads. The meter design approximates a two element measurement by combining a half current value with the potential value of the line to line connection. The line to line potential is exactly twice the line to neutral connection if the two line to neutral connections are exactly balanced. Twice the potential times half the current then approximates the actual power value with equality under balanced potential. In the case of line to line loads, two times the half current value times the potential value equals the actual power. Error is introduced if the two line to line potentials are not balanced and if the line to neutral loads are not equally distributed. That error is given by 0.5(V1-V2)(I1-I2) where V1 and I1 are the potential and current connected between one line and neutral and V2 and I2 are those connected between the other line and neutral.[1] Since the industry typically maintains five percent accuracy in potential, the error will be acceptably low if the loads aren&apos;t heavily unbalanced. This same meter has been modified or installed in modified sockets and used for two wire, 120 volt services (relabeled as 2W on the meter face). The modification places the two half coils in series such that a full coil is created. In such installations, the single element meter is Blondel compliant. There is also a three wire 240/480 volt version that is not Blondel compliant. Also in use are three phase meters that are not Blondel compliant, such as forms 14S and 15S, but they can be easily replaced by modern meters and can be considered obsolete.
• ### ANSI Standards & Recent Updates That Affect Service Departments

1. 1. 10/02/2012 Slide 1ANSI Standards & RecentUpdates that AffectService DepartmentsPrepared by Tom Lawton, TESCOThe Eastern Specialty Companyfor the NC Electric Meter School 2013
2. 2. • Understand contents of ANSI C12.20-2010 for 0.2 and 0.5Accuracy Class Meters• Understand the Relationship of C12.20 to C12.1• Understand ANSI C12.20 Changes Planned for 2015 Editionand ANSI C12.1 changes planned for 2013• Understand new ANSI C12.29 for Field Testing and potentialtime frame• Discuss – Will this affect how we test in the field?Session Objectives
3. 3. Meter Testing for new and in-service kilowatt-hour meters, bothelectronic and electromechanical is specified in ANSI C12.1-2008,American National Standard for Electric Meters, Code for ElectricityMetering. Most utility commissions use this Standard as areference or the basis for their meter testing requirements.ANSI C12.20-2010, American National Standard for ElectricityMeters, 0.2 and 0.5 Accuracy Classes, provides different testtolerances and a few different or modified tests for higher accuracymeters. There is no reference made in C12.20 to field testing. Theonly mention of in-service testing refers back to Section 5 of C12.1.Current Meter Testing Standards
4. 4. • ANSI C12.20 establishes aspectsand acceptable performance criteriafor 0.2 and 0.5 percent accuracyclass meters meeting Blondel’sTheorem. This means that C12.20 isnot applicable for 2S meters.• Where there are differences betweenC12.20 and C12.1, ANSI StandardC12.20 takes precedence.Current ANSI C12.20 Requirements
5. 5. • Meter Requirements• Acceptable Performance of New Types of Electricity MeteringDevices and Associated Equipment• Refers back to C12.1 Section 4• Also has additional (and modified) tests specific to higher accuracyclass meters• Standards for In-Service Performance (refers to C12.1 Section 5)• No mention of Field Testing in ANSI C12.20 – 2010• The 2010 revision of the standard was broadened to allow threephase current and voltage sources as an optional test method to thesingle phase, series, parallel methodCurrent ANSI C12.20 Contents
6. 6. • In ANSI C12.1–2008 there is no mention of field testing• The In-Service section 5 of this standard was deemed in need ofstrengthening and ANSI C12 main committee decided there was aneed to look at field testing.• A draft of ANSI C12.1 – 2013 with a new section 5 is ready forapproval.• A Field Test Working Group was established to create a new ANSIstandard focusing on Field Testing (ANSI C12.29)• Both C12.1 and C12.20 will refer to this standard for field testingCurrent ANSI Field Testing Standards
7. 7. Current ANSI C12.1 Testing Requirements
8. 8. Current ANSI C12.20 Testing Requirements
9. 9. • Many State Utility Commissions require that new higher accuracy classelectric meters meet ANSI C12.1 and C12.20 requirements.• New meters are tested using all or a group of tests specified in ANSI C12.1and C12.20. These tests are typically performed by the meter vendors.• Meter vendors have different interpretations of certain ANSI tests and evenwhat “ANSI qualified” means.• Meter vendors often perform ANSI testing early in the development of ameter and certify future modifications to the meter by stating the updateddesign is similar to the old design in form and function.Current Meter Testing to Standards
10. 10. • More options for statistical models to use• More options for what to do if a group starts to perform poorly• Addresses the type of statistical testing available for ancillary devices (e.g.disconnect switches; communication devices).• Addresses the need to use statistical methods to determine as far inadvance as possible the potential failure modes and life expectancies of anynew technology being deployed to the field.ANSI C12.1 – 2013 Section 5Proposed Changes
11. 11. • The revised Section 5 for ANSI C12.1 will not specify any new field tests. The in-service testing required can be done in the field or in the meter shop as long as thebasic requirements of the tests are met.• The revised Section 5 tries to include ancillary devices including disconnect switchesincluded with the meter and external CT’s and PT’s.• This portion of the Standard focuses on the performance of the device as a group andnot the specfics of the test being performed.• ANSI C12 Main Committee has decided that this aspect of testing has beenoverlooked and has created a working group to address the “how-to” of field testing.A new standard, ANSI C12.29 is anticipated to be be drafted by this working groupand presented to the main committee of C12 for approval.• This working group has no time table to complete their work, but they are hoping tohave a draft ready for the Spring 2014 ANSI meeting (The main committee meetsevery 6 months in conjunction with the EEI TD&M conference.What do These Changes Mean forField Testing
12. 12. ANSI C12.29 will establish recommendedfield testing for metering devices and shouldeventually be referenced in C12.1 and C12.20.The new standard is expected to have threeSections:• Meter Testing• Instrument Transformer Testing• Site Wiring and Auxiliary DevicesNew ANSI C12.29 for Field TestingMetering Devices
13. 13. Meter Testing will be divided into threecategories based on where current andvoltage is supplied…• Using Customer Potential with CurrentSupplied by the Test Equipment• Using Customer Potential andCustomer Supplied Current• Using Potential and Current Suppliedby Test EquipmentNew ANSI C12.29 for Field TestingMetering Devices
14. 14. Instrument Transformer testing is anticipated to focus on:• Burden Testing - The theory and practicalapplication in the field• Ratio Testing - Practical application in thefield• Visual inspection of the CT’s and PT’sNew ANSI C12.29 for Field TestingMetering Devices
15. 15. Site Wiring and Auxiliary devices isanticipated to focus on:• Visual inspection• Continuity testing• Service Ground testing• Communication testing• Disconnect testing• Additional device testingNew ANSI C12.29 for Field TestingMetering Devices
16. 16. What the new Standard is not expected todo:• Mandate a new test or tests• Mandate the “right way” to do this test• Mandate the use of any equipment orspecific processesThis Standard is anticipated to be a “BestPractices” type of document and not anew set of requirements for UtilityMetering GroupsNew ANSI C12.29 for Field TestingMetering Devices
17. 17. Given the early stages for this Working Groupthis is all personal opinion and could changebefore the new Standard is completed.There is also no mandate that this Standardever has to come into existence. If theCommittee never presents a draft or if theANSI C12 main committee rejects the draftthere will be no C12.9 in the near future, andif approved, C12.1 and C12.20 do not haveto reference the new StandardNew ANSI C12.29 for Field TestingMetering Devices
18. 18. Where are ANSI and the voting members heading?Toward more comprehensive field testing that focuses on far more than justaccuracy testing. The members vision for the future of field testing is that utilitieswill perform the following checks when checking a metering installation in the fieldSite Verification…The New Field Testing• Meter Accuracy testing• Meter Communications Performance• Software and firmware verification• Setting verification• Functional testing• Disconnect/reconnect Functionality and as left setting• Tamper Verification• Site Audits appropriate to the type of meter
19. 19. Questions and DiscussionTom LawtonTESCO – The Eastern Specialty CompanyBristol, PA1-800-762-8211This presentation can also be found under MeterConferences and Schools on the TESCO web site:www.tesco-advent.com
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