Smart Metering - Testing and Certification at the VDE Institute

The testing agency's range of tasks:

• Initial calibrations
• Recalibrations
• Calibration checks
• Special tests
• Extension of the calibration validity period (random sampling procedure)
• Acceptance tests

Testing equipment:

• Meter testing device with isolating current transformers
• Insulating test equipment
• Equipment for testing the influences of electromagnetic interference
• Climatic test chambers

Further development
The test results of the conformity test allow the meter manufacturers to pursue specific further development of their products, and can provide measuring point operators and energy suppliers with valuable information on their business processes.

For the technical implementation, the modular EDL concept was created in the VDE Network Technology/Network Operation forum (FNN). EDL stands for “Energie-Dienst-Leistung” (Energy Service) and provides energy suppliers with a platform that – while maintaining cost awareness – enables the implementation of requirements of the German Energy Management Act (EnWG).

Ensuring interoperability
By using the EDL specifications in the design of an electricity meter, the manufacturer can ensure that his product can be operated in the infrastructure of the energy supplier (interoperability).

To provide evidence of correct implementation in the design, the VDE Testing and Certification Institute offers conformity tests for the EDL system. Further system tests (including those for MUC) are in preparation.

Tested information security
The conformity test cases established by the expert group (MeKo) within FNN are implemented by VDE Institute in the TTCN-3 and represent the basis for testing the information security of EDL meters. The test setup consists of an EDL-capable meter whose information and measuring point operator interface is read and evaluated by a PC.

The VDE Institute performs tests and creates test reports based on these test cases. If desired, a VDE seal of quality can be issued if the results are favorable. Every single test case is evaluated and can be comprehensively analyzed thanks to extensive logging functions, which can furthermore be used in the acceptance test in the goods receiving department.

The following test points are required in the guideline and can be offered by the VDE.

• Magnetic DC fields, maximum strength
• Magnetic AC fields, maximum strength
• Failure in the neutral conductor
• Direct current component in the grid
• Direct voltage component in the grid
• Symmetrical high frequency currents 2 kHz to 150 kHz

The interference immunity test against symmetrical high frequency currents of 2 kHz to 150 kHz is specifically required by many network operators as a precondition for the use of a measuring device in the mains system.

CLC/TR 50579: AC electricity meter - testing accuracy, interference immunity and testing process for conducted interferences in the 2 kHz - 150 kHz frequency range.
This European technical report applies to brand-new, static electricity meters in households, businesses, or in the light industry for accuracy classes A, B and C for measuring electrical AC active energy in 50 Hz power grids.
Since the EN 50470 does not mention anything about the 2 kHz - 150 kHz frequency range, this technical report is suitable for closing this gap and substantiating that the electricity meter fulfills the basic requirements of the MID Directive.

EN 61000-4-19: Testing the interference immunity of AC grid connections against conducted, differential mode disturbances and disturbances from signaling in the range 2 kHz - 150 kHz
In the future, EN 61000-4-19 will be the basis for testing conducted, differential mode disturbances in the range 2 kHz - 150 kHz. This verification can already be tested and evaluated today at the VDE Institute while taking into account specific customer requirements.

Electromagnetic compatibility (EMC)
The VDE Institute offers you EMC testing of electronic meters and their auxiliary equipment as part of an approval test or during the development phase. Our modern and powerful systems provide excellent quality.                                                                                                                                                                                                                                                                                                            Take advantage of our expertise in statutory measuring and EMC to prove your product's increased reliability standards and measurement stability.

With its cutting edge test laboratory and long-time expertise in the field of service life tests, especially for electronic components, VDE Institute offers manufacturers and users a wide range of reliability test.

The benefits for you:

• Early detection of weak spots
• Quick reliability information thanks to statistical predictions
• Reduced consequential costs
• Enhanced level of quality

DIN EN 62059-31-1:2009-07 (IEC 62059-31-1)
In this accelerated reliability test, random samples are subjected to stress levels exceeding the intended operating conditions. The goal is to shorten the elapsed time until product failure, without subjecting them to new failure mechanisms.

The service life is assessed through record entries and examinations of the failures during the test. By determining the failure distribution and calculating service life models, it is possible to extrapolate the time to failure under the intended operating conditions. This process delivers quantitative results with its confidence limits and may be used to compare service life parameters of products that originate from different suppliers or from different lots of the same manufacturer.

DIN EN 62059-32-1:2012-10 (IEC 62059-32-1)
This draft standard represents the basis for assessing the metrological characteristics of an electricity meter under increased loads. The meter is operated for a longer period of time at the upper limits of operating temperature, voltage and current.

The change in the percentage measuring error of the test object at the beginning and at the end of the test serves as the acceptance criterion.

The VDE Institute also offers tailor-made tests such as climatic storage at elevated ambient temperature and humidity. Take advantage of our state-of-the-art meter testing equipment, which records changes in metrological characteristics under heightened climatic conditions.

Benefit from our experience in the field of statutory measuring to verify that your product meets increased reliability standards and measurement stability.

DIN EN 62059-41: 2007-01 (IEC 62059-41)
This standard provides methods for predicting the failure rate of electricity meters, which are assumed to be constant, based on the component stress process.

The result of the prediction can be used in the development phase to safeguard development decisions, relating to the type approval for safeguarding decisions regarding the certification period and in the operational phase to determine the required scope of maintenance to preserve the required availability.

The VDE testing system consists of software and a hardware module for exchanging messages with the meter. The software has a modular design and relies on tried-and-tested TTCN-3 technology for flexible use. It can be expanded to make it future-proof. To ensure that the strict requirements set for the LMN communication interface of the basic meter can be met, a special module was developed in collaboration with an external partner, capable of exchanging messages with a secured time base of 10 ns.

The test cases specified in the FNN are automatically executed by the VDE testing system software. In the process, the testing system takes control of an external electrical source system. The syntax and semantics of the exchanged communication protocols are checked and evaluated by the TTCN-3 software. Thus, the high degree of automation can significantly reduce the time it takes to test a basic meter with full recording of the test results for error Analysis.

Accompanying development tests of communication interfaces
In the age of the Internet of things (IoT), the requirements set for instrument communication technology are becoming increasingly higher. This trend can be observed especially in metering and metrology as well. Thus, in the future, energy meters should be capable of communicating with distribution grid operators and energy suppliers via a smart meter gateway in order to contribute to an intelligent power grid, the so-called smart grid.

Due to the standardization of the communication protocols used, software implementations must be planned, developed and tested for reliability in advance to prevent expensive errors in the subsequent operational field. The testing of the respective protocol implementation is an indispensable task that greatly benefits product quality if the communication remote terminal is an independent entity.

To optimally support manufacturers in this field during development, the VDE Testing and Certification Institute has comprehensively expanded its expertise in testing communication protocols. Specifically, communication protocols are supported in various application fields – for example, smart metering, smart home and e-mobility, where the VDE Institute relies on TTCN-3, the standardized technology for communication tests.

The following requirements must be met for the gateway according to calibration law:

• The calibration directive with annex 20
• PTB Specifications 50.7
• PTB specifications 20.1, section 2 “auxiliary Equipment”

For the requirements set forth in PTB A20.1, the VDE Institute, as an accredited test laboratory according to DIN EN ISO 17025, offers all tests for the environmental and EMC requirements according to DIN EN 62052-11.

These include, among others:

• Electrostatic discharges
• Electromagnetic RF fields
• Rapid transient disturbances
• Conducted interference induced by high-frequency fields
• Surge voltages
• Damped vibrations
• Radio frequency interference
• IP protection
• Impact and vibration tests
• Clearance and creepage distances

Combine these tests with the Institute’s other test services as well, such as electrical safety according to EN 50428 or the EN 60669 series of Standards.