Synchronous modular meter

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The SyM 2 (Synchronous Modular Meter, formerly tLZ, renamed SyM 2 at the beginning of 2008 for legal reasons ) stands for a new generation of electricity load profile meters that is still in development. An essential feature is "isochronous mode". The specification was finalized and published in March 2008. The next development step is a field test with 2000 devices.

The SyM 2 was developed in a consortium of electricity suppliers ( EnBW , E.ON , RWE ) and several companies together with the Physikalisch-Technische Bundesanstalt (PTB). The development is scientifically supported by the Christian-Albrechts-Universität zu Kiel . In the meantime, the further development of SyM 2 takes place via the network technology / network operation forum in the VDE (FNN).

Overview

Unique counter values ​​even after a power failure (isochronous mode)

In conventional load profile counters, a real-time clock is built in, which jumps to a predefined start time after a power failure . If such an error occurs several times between two readings, the measured values cannot be used because there is no longer a correct time reference. In addition, the times of different counters diverge. For these reasons, the clocks must be set regularly.

There are different approaches to solving the problem. Some load profile meters use a real-time clock and synchronization procedures to avoid the error.

The SyM 2 has a (seconds) counter instead of the real-time clock. The reading of this meter grows strictly monotonously with every second and is used to clearly identify the (electricity) meter readings. After reading out the SyM 2 , this seconds index is linked to the absolute time. If there are (multiple) voltage interruptions in this counter, the sequence of the value blocks remains clear.

Modularity

The SyM 2 is divided into a basic device and various modules. The basic device only provides the basic functions of a meter, such as the part that requires verification. All other functions such as interfaces to other devices or communication units (e.g. GSM or GPRS module) can be plugged in as a module. This eliminates the need to develop your own device for every possible application, or to have to buy and stock it.

The base devices and modules from all manufacturers are compatible and the Smart Message Language was developed as part of the SyM 2 project, which is intended to replace the previous manufacturer-specific commands for querying meters. Ethernet IEEE 802.3u is used as the data interface .

Base unit

The basic device records electrical energy in all four quadrants, accumulated in counters and load profiles of

  • + A - Active energy, customer draws from the grid
  • -A - Active energy, customer delivers to grid
  • R1 - reactive energy quadrant I.
  • R2 - reactive energy quadrant II
  • R3 - reactive energy quadrant III
  • R4 - reactive energy quadrant IV

The counters are tariff-free. The load profiles are recorded as meter reading profiles with a registration period of 15 minutes.

The basic device is available in variants for

  • direct connection (3x230 / 400 V; maximum 100 A)
  • semi-indirect connection (3x230 / 400 V; maximum 2 A)
  • semi-indirect connection (3x230 / 400 V; maximum 6 A)
  • indirect connection (3x58 / 100 V; maximum 2 A)
  • indirect connection (3x58 / 100 V; maximum 6 A)

The basic device provides space for up to 4 modules via a top- hat rail . The modules are supplied with power via Power over Ethernet .

IW module

The module for pulse transmission (IW module) has 7 pulse outputs. They output a pulse frequency proportional to the power measured in + A, -A, R1, R2, R3 and R4 and the timing of the registration period.

KM module

The module for communication in wide area networks (KM module) connects the SyM 2 measuring device to one or more wide area networks. The supported networks are

A service interface is provided for emergency reading on site.

Field trial

The field trial from 2008 will cover the validation of the technological components. In addition, it is important to make reliable statements to assess the performance of the SyM 2 . Both the device system (base device and modules) and the newly created Smart Message Language protocol are tested . To carry out the field test with statistically usable results, a total of 2,000 counters are distributed among different companies.

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