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Response PaperApproval Standards for Electricity Meters Used for Trade

16 October 2017

Contents

Introduction.................................................................................................................1

The Outcomes.............................................................................................................1

Rationale.....................................................................................................................1

Summarised comments and responses......................................................................3Q 1 Scope of NMI R 46 / NMI M 6 -1.................................................................................................3

Q 2 Other metering types and applications........................................................................................3

Q 3 Other trusted international standards..........................................................................................4

Q 4 Impulse Voltage Requirements...................................................................................................5

Q 5 Approvals against different international standards.....................................................................6

Q 6 Minimum temperature range.......................................................................................................6

Q 7 Minimum temperature range - indoor..........................................................................................7

Q 8 Minimum temperature range - class............................................................................................7

Q 9 Storage periods for interval meters.............................................................................................8

Q 10 Mandatory markings.................................................................................................................. 8

Q 11 Authorised access..................................................................................................................... 9

Q 12 Other access for authorised persons.........................................................................................9

Q 13 Any other comments................................................................................................................10

Response Paper, Electricity Metering ii

IntroductionThis response paper provides outcomes and responses following the consultation conducted in 2015 on the pattern approval standards for electricity meters. The consultation sought feedback on the adoption of the International Organisation of Legal Metrology (OIML) recommendation OIML R 46. It also sought feedback on other applicable standards for electricity metering. NMI received 23 submissions. The consultation and public submissions are available here:

http://www.measurement.gov.au/measurementsystem/Pages/Approval-Standards-for-Electricity-Meters-Used-for-Trade.aspx

The OutcomesNMI will provide three pathways for the pattern approval of electricity meters:

Pathway 1: The current metrological and technical requirements of NMI M 6-1, with minor amendments and clarifications (see Note 1).

Pathway 2: The metrological and technical requirements of the Standards Australia adoption of International Electrotechnical Commission (IEC) standards AS-IEC 62052.11, 62053.21, and AS-IEC 62053.22 (see Note 2).

Pathway 3: NMI will adopt OIML R 46 without major modification as NMI R 46 (see Note 3).

Note 1: NMI will maintain the current flexibility with the Impulse Voltage test, accepting either the test specified in NMI M 6-1 or the test in OIML R 46. NMI M 6-1 will be updated in due course to clarify this and other issues such as marking requirements and temperature ranges.

Note 2: Any changes that NMI makes will only come in to effect following the completion of Standards Australia’s adoption process. It is anticipated this may occur at the end of 2017. NMI will continue to liaise with Standards Australia and participate in the EL-011 committee.

Note 3: The adoption of OIML R 46 under Pathway 3 is intended to support the acceptance of test results and certification under the future OIML Certification System (OIML-CS) that Australia may be a signatory to. (https://www.oiml.org/en/certificates/oiml-cs/general-information). The timeframe for the adoption of OIML R 46 will correspond with the implementation of OIML R 46 in OIML-CS from 2018.

RationaleNMI analysed the feedback and notes the following key points:

There was an identified need to provide flexibility and move away from a one-size-fits-all regulatory approach.

For instance, submissions advise that meters commonly used for sub-metering in other countries are designed to different standards than “utility-grade meters” which are typically larger.

Further, other submissions presented wide ranges of applications and technologies for electricity meters including with differing views on the appropriate and necessary requirements.

There was support to maintain some aspects of NMI M 6-1. In particular, there was support to maintain requirements for optical ports in the current NMI M 6-1 standard.

OIML R 46 would add regulatory burden, mainly associated with design changes for meters to comply with the new requirements. Estimates from the consultation submissions varied from no additional costs to $500k per meter type. A common estimate was $100k per meter type.

Response Paper, Electricity Metering 1

https://www.oiml.org/en/certificates/oiml-cs/general-information

https://www.oiml.org/en/certificates/oiml-cs/general-information



There was strong support from some submissions to align with IEC standards. These submissions referred to wide-spread international acceptance of IEC standards.

There are a number of technical and implementation issues with adopting OIML R 46:

Different descriptors for electrical current ratings which could require interpretation for consistent application of MPE classes.

Additional meter marking requirements with widely varying views on which are mandatory.

Introduction of environmental classes H1, H2 and H3. Further work may be needed to provide guidance on how to consistently interpret and apply these classes.

Whether the terms multi-tariff meter should be used interchangeably with multi-rate meter.

Clarification of device specific parameters.

NMI considers the outcomes provide the best balanced solution. It avoids additional regulatory burden and recognises Standards Australia’s adoption of metering standards in support of competitive metering.


Summarised comments and responsesThe rest of this paper address specific issues raised in the submissions received to this consultation.

Q 1 Scope of NMI R 46 / NMI M 6 -1What is the appropriate scope or applicability of NMI R 46 (and NMI M 6-1) for different metering types or applications in Australia? Please specify and explain why.

Table 1 summarises submission comments and NMI’s responses.

Table 1. Summary of submission on the scope of NMI R 46 / NMI M 6-1.

Submission Summary NMI response

There is general support for the need for standards applicable to the range of metering applications, including sub-meters and other non-standard metering applications. However, opinions vary on the scope for NMI R 46 / NMI M 6-1:

It should apply to all meter types and applications.

It should exclude sub-meters and other non-standard metering application. Other standards are appropriate/applicable.

The scope of NMI M 6 will continue to cover all active energy meters that are used for trade.

However, the option of using Standards Australia standards (Pathway 2 above) is expected to provide greater flexibility for sub-metering and non-standard metering applications.

Adoption could impact a range of other documents such as the National Electricity Rules, Chapter 7, and related Australian Standards because, for example, changes in designations of accuracy classes, and current parameters.

NMI has and will continue to liaise with other relevant bodies including AEMO and Standards Australia.

Q 2 Other metering types and applicationsAre there other metering types and applications that are not listed under ‘Scope’ above? If so, please specify.

Table 2 summarises submission comments and NMI’s responses.

Table 2. Summary of submission on other metering types and applications.


A range of applications were identified, including:

Meters built into solar and battery inverters that are used for billing.

Panel-mounted meters for industrial electrical cabinets.

Changes under the AEMC Power of Choice review”[1]

Growing use of “in kind payments”.

These applications are noted. The outcome of this consultation is to provide greater flexibility in the approval of all meters for trade, thereby supporting innovation in metering technology.

Under the National Measurement Act 1960 (Cth), the definition of ‘use for trade’ is not limited to traditional billing, but includes for the purpose of “determining the consideration in respect of a transaction”.


[1] AEMC website: http://www.aemc.gov.au/Major-Pages/Power-of-choice

Q 3 Other trusted international standardsAre there any other trusted Australian or international standards that would be appropriate as a pattern approval standard for different metering types or applications in Australia? If so, please specify.

NMI acknowledges the numerous standards that were identified in the submissions. Not all of these standards are considered by NMI as pattern approval standards for metering, but they all have broad relevance to the electricity industry.

Table 3 lists some of the directly relevant metering standards that were identified in the consultation.

Table 3. Metering Standards.

Metering Standards Comments

AS 62052.11:2005 (based on IEC)

Electricity metering equipment (AC) - General requirements, tests and test conditions - Metering equipment (IEC62052-11, Ed.1.0 (2003) MOD)

AS 62053.21-2005 (based on IEC)

Electricity metering equipment (AC) - Particular requirements - Static meters for active energy (classes 1 and 2) (IEC 62053-21 Ed.1.0 (2003) MOD)

AS 62053.22-2005 (based on IEC)

Electricity metering equipment (AC) - Particular requirements - Static meters for active energy (classes 0.2 S and 0.5 S)

These three Australian standards were developed by Standards Australia and are based on IEC standards.

They were the main industry standards taken into consideration when developing NMI M 6-1.

Once published, the next edition of these standards may be used for pattern approval purposes under Pathway 2 (above).

AS 62054.21-2006 (based on IEC)

Electricity metering (ac) - Tariff and load control - Particular requirements for time switches

The timing tests in this Australia standard, based on an IEC standard, are directly referenced by NMI M 6-1.

AS 1284.11-1995

Electricity metering - Single-phase multifunction watthour meters

This Australian standard specifies requirements and desirable features of meters. It does not specify error limits nor performance tests other than to refer to other standards.

AS 62053.23-2006 (based on IEC)

Electricity metering equipment (ac) - Particular requirements - Static meters for reactive energy (classes 2 and 3)

This Australian standard, based on an IEC standard, relates to reactive energy and is outside the current scope of Australian approval requirements. It may be considered in future work.


http://www.aemc.gov.au/Major-Pages/Power-of-choice

Metering Standards Comments

European legislation

Measuring Instrument Directive (2014/32/EU, previously 2004/22/EC)

The Measuring Instrument Directive (MID) is a European directive on measuring instruments. It specifies basic metering requirements and regulatory systems.

Approval against the MID is based upon assessment against technical standards recognised under the MID. These technical standards are based on IEC metering standards (see below). OIML R 46 was also drafted to operate under the MID.

OIML R 46 will be adopted as NMI R 46 and may be used for pattern approval purposes under Pathway 3 (above).

Q 4 Impulse Voltage RequirementsWhat are the appropriate impulse voltage requirements for different metering types or applications in Australia? Please specify and explain why.

Table 4 summarises the submission comments and NMI’s responses.

Table 4. Summary of submissions on impulse voltage requirements.


Submissions listed the following as the appropriate impulse voltage requirements:

As per IEC standards (6 kV)

As per OIML R 46 (10 kV)

As per NMI M 6-1 (12 kV)

Submissions also raised the need to specify the source impedance for the test in OIML R 46.

The submissions focussed on these three standards (IEC, OIML and NMI).

A fundamental challenge of developing or adopting a standard is to balance consistency against specific technology-specific or application-specific devices.

It is expected that the outcome of this consultation provides a balanced solution with greater flexibility by allowing compliance with any of these standards.


Q 5 Approvals against different international standardsAs a manufacturer/importer of electricity meters:

(a) How many electricity meter models do you have approved internationally against a different international standard?

(b) What additional costs would there be to comply with NMI R 46?


Table 5. Summary of submissions on approvals against different international standards.


OIML R 46 is generally viewed as a more onerous standard. Generally meters that are compliant with IEC would not be expected to be compliant with OIML R 46 without redesign or modification.

NMI acknowledges the importance of international harmonisation. At the same time, NMI is not aware of the mandatory adoption of OIML R 46 in any other country, though NMI understands that it is an option in Europe and being considered in other countries. Re-design for a single country is a valid concern.

The estimation of costs is a complex question. Submissions provided the following range of estimates:

Considering components, research and development, and lost opportunity costs associated with development changes, the estimated cost is $120k to $250k.

Design modification: $100k per model.

To modify existing products, we estimate over $500k per model. To replace some models, we estimate $1.5M per model.

Additional costs of $25k per meter.

Difficult to estimate engineering and in-house costs. Approval testing is typically over $30k.

NMI acknowledges the complexity, in estimating costs, and thanks all stakeholders for their submissions.

The cost estimates provided are significant and form part of the rationale for providing greater flexibility for the pattern approval of electricity meters as outlined above. It is expected that the outcome of this consultation will provide direct costs savings to industry.

Q 6 Minimum temperature rangeDo you support the proposed minimum temperature range of -10 °C to +55 °C?


Table 6. Summary of submissions on minimum temperature.


The majority of submissions supported the proposed temperature range.

The proposed temperature range will be included in a future amendment to NMI M 6.



From those submissions opposed, the rationale included:

Australian temperatures extending below and above this range; and

Temperature ranges should be specified by manufacturers.

The proposed temperature range is similar to accepted temperature ranges across different standards and categories of measuring instrument.

Manufacturers may select a wider range to meet customer needs. A minimum range supports reliance and confidence with the standard to support use of meters in expected environmental conditions in Australia.

Q 7 Minimum temperature range - indoorDo you support a reduced minimum upper temperature of +40 °C?


Table 7. Summary of submissions on minimum temperature range for indoor meters.


The majority of submissions do not support the proposal based on the following reasons

Indoor meters may be in metal boxes and similar high temperatures to outdoor.

Unnecessary compliance complexity.

Too low in a cabinet with other heat generating devices.

Recommend +45 °C to maintain alignment with IEC and Australian Standards for indoor meters.

The feedback suggests that the description ‘indoor’ does not in itself satisfactorily describe a condition that supports a reduced upper temperature rating.

Q 8 Minimum temperature range - classDo you support a reduced minimum upper temperature of +40 °C for meters of accuracy class C and D (corresponding to class 0.5 and class 0.2)?


Table 8. Summary of submissions on minimum temperature range for class C and D.


The majority of submissions do not support the proposal based on a number of reasons including:

Class C meters will be installed in similar conditions to class B meters and exposed to the same extreme environmental conditions.

The feedback suggest that class C and D is not an appropriate condition for a reduced upper temperature rating.


Q 9 Storage periods for interval metersDo you support the proposal of manufacturer-specified storage period capabilities for interval meters in Australia?


Table 9. Summary of submissions on storage periods for interval meters.


The majority of submissions supported the proposal.

Storage periods for interval meters is relevant for metrology. It does not affect the way the meter determines the measurement but it affects the availability of the measurement to affected parties.

However the intention is to not impose a greater burden on manufacturers to specify detailed capabilities. Instead, NMI will allow flexibility for different capabilities. A minimum or range of capabilities could be specified by a manufacturer.

Manufacturers need to be aware of other regulatory, market or customer requirements, including AEMC requirements.

Q 10 Mandatory markingsDo you support all of the proposed mandatory markings? If not, please specify and explain why?


Table 10. Summary of submissions on mandatory markings.


Avoid overlapping and duplication with

established Australian Standards

MID or IEC requirements

NMI agrees that unnecessary overlap or duplication should be avoided where possible. The greater flexibility provided regarding the use of standards for pattern approval addresses this issue.

Various submissions raised issues regarding the benefit and practicality of requiring physical markings in all cases. In particular Practical problem of mandatory markings on smaller devices.

The practicalities of physical markings is recognised as an important issue.

NMI will provide some flexibility at the approval stage to manage this for smaller devices.

Electronic storage may be considered an acceptable solution for some markings. NMI can provide some flexibility at the approval stage to manage this.

This more flexible approach will be formalised in a future amendment to NMI M 6.


Q 11 Authorised accessAre there existing authorisation systems that NMI could utilise to implement authorised access? Please specify.


Table 11. Summary of submissions on authorised access.


Several submissions proposed that only NMI appointed verifiers should have this authorised access. NMI intends to maintain this arrangement.

National legislation should support designs that promote batteries as a replaceable item, installed in a manner allowing replacement without impacting metrology components.

There is no restriction under the legislation provided that a manufacturer can demonstrate that replacing the battery has no impact on metrological performance.

Q 12 Other access for authorised personsWhat other access, besides for battery replacement, should NMI also consider allowing for authorised persons? Please specify.


Table 12. Summary of submissions on other access for authorised access.


Some applications don’t need special authorisation for installation and maintenance.

NMI does not require authorisation for installers – authorisation is required if the metrological parameters are access affecting the metrological performance of the meter. It is expected that meters are designed to enable installation without impacting the metrological parameters.

Firmware updates on meters can be performed without requiring meter reverification.

Firmware updates may, or may not, be metrologically significant. Changes are permitted without verification if they do not impact metrology.


Q 13 Any other commentsDo you have any other comments on the proposed requirements of NMI R 46? Please specify.


Table 13. Summary of submissions on authorised access.

Submission Comments NMI response

Various comments were provided relating to the adoption of standard or standards:

The proposed requirements of NMI R 46 appear to be stricter than IEC requirements.

Support the adoption of the IEC pathway.

Support alignment with European MID requirements.

Consider commercial and practical burdens, not only the best “technical solution”.

The outcome of this consultation hopefully addresses the issues raised this provided comments, primarily:

NMI R 46 would be more onerous and requires further clarifications.

Alignment with IEC and European MID in the sense that Standards Australia adoptions of IEC standards become a pathway for approval in Australia.

Removal of a one-size-fits-all approach.

Pattern approval testing could be based on Australian Standards (which are based on IEC standards).

NMI will provide a pathway for pattern approval via IEC standards adopted by Standards Australia and a future adoption of OIML R 46 (in addition to maintaining NMI M 6).

Various proposed extensions for OIML R 46 testing and requirements:

Industry use of varh values for billing. Consider extent of standard to cover measurement types used for billing.

Specification for internal supply switches (supply contactors)

Currently NMI does not regulate electrical measurement types other than active energy kWh. Any extension to include reactive energy or other non-active measurements would need to be considered as a separate process.

There are specifications for internal supply switches in the IEC 62052.31 safety standard. Standards Australia have an active project to adopt this standard.


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