SGM-SN Smart Grid four-wire meter eHZ

Smart mMe four-wire/two-wire eHZ connection available as mME version

Available as FNN basic meter for connection to smart metering systems

The system-compatible four-wire meter eHZ is the new basic module in an improved version for a smart metering system for measuring active electrical energy for private and commercial customers.

It can be used in the mME wired or w-MBus version as well as in the basic meter version in smart metering systems for connection to smart meter gateways.

The different versions give the user extensive freedom in the technical implementation of smart metering systems. The simple installation using plug-in technology with the option of uninterrupted replacement provides optimum support. The compact design fulfills the functions according to the industry standard FNN.

Product information

As a robust device, the SGM-SN has the following features:

Plug-in meter in housing according to eHZ standard
Flexible measurement via shunts with intrinsic immunity to high-frequency interference and external magnetic fields
Measured variables +A or -A with return stop, +A/-A bidirectional meter,|A| direction-independent
5(60) A, class A or B
External tariff control via rear interface in mME version
PIN-protected data display/output: Call-up via optical button according to FNN standard
Front optical interface for local data provision 9,600 baud
Rear optical MSB interface 9,600 baud in mME version
Multifunctional 2-line display for displaying metrological and historical data over 2 years
Robust, low-radiation power supply
Grid measured values and power quality parameters
Provision of TAF10 and TAF14 data for grid-related applications in the Smart Meter Gateway.
AC approval on all phases L1, L2, L3
Optional as w-MBus version with compact profile

Standard functions

In accordance with legal requirements, the meter acts as a reliable and safe measuring device for recording billing-relevant active energy quantities and grid-relevant measured values and parameters such as RMS values of conductor voltages/currents, power, phase angle and grid frequency.

The active energy is measured in both directions, whereby the following measurement types are available:

Measurement in one direction (+A or -A) with return stop
Measurement of the absolute amounts |A|: Direction-independent sum of the amounts in all conductors
Measurement in two directions +A and -A balancing across all phases

The current sensors used are robustly mounted, precise shunts, suitable for class accuracy B. The actual energy values in all conductors are managed internally and are available via the data interfaces. The measurement mode is set at the factory in accordance with metrological requirements.

The meter also provides the following “grid functions”:

Active power PL1 , PL2 , PL3 , calculated as mean value over 1 s, resolution 0.1 W
RMS values of the conductor voltages UL1 , UL2 , UL3, calculated as mean value over 1 s,
Accuracy 1 % of the measured value, resolution 0.1 V
RMS values of the conductor currents IL1 , IL2 , IL3, calculated as mean value over 1 s, resolution
0.1 A, accuracy 1 % of the measured value
Phase angle UL2 to UL1, UL3 to UL1, IL1 to UL1, IL2 to UL2, IL3 to UL3,
Accuracy/resolution 1 ° in relation to the fundamental frequency
Mains frequency fMains, accuracy 1 %, resolution 0.1 Hz

The daily, weekly, monthly and annual values of the active energy are recorded over a period of two years as historical data in the ring memory and displayed under PIN protection.

The optical interface on the front is used for the local provision of measured values and device information in accordance with SML/COSEM at one-second intervals. This function is also PIN-protected. The PIN is entered via the optical button on the front.

Depending on the version, the optical MSB interface on the rear is used for system communication at a baud rate of 9600 baud or 921600 baud.

The protocols used are HDLC in the link layer and SML/COSEM in the application layer. In the “intelligent measuring system” variant, communication is TLS-secured in accordance with BSI TR 03116-3.

As an option, the dual tariff function with external control is available in the mME version via the optical interface on the rear. The tariff registers in both energy directions and the current tariff are shown on the display.

Applications

With the versions 5(60)A, class A/B in accordance with MiD, MessEG and MessEV, the meter can be used as a stand-alone device (modern measuring device) or as a basic meter for all customer systems connected directly via four-wire and two-wire lines. Typical areas of application include domestic customers, customers with their own generation and feed-in to the public grid, residential complexes, small businesses and commercial premises.

In combination with an SMGw via the OKK, the SGM-SN forms the intelligent metering system that is also used in end customer systems with feed-in to the public grid. The Smart Grid four-wire meter eHz provides the required measured values for these grid-related tasks.