Smart meters and interfaces in Slovenia
Slovenia has widely deployed smart electricity meters in recent years, with nearly all consumers now using digital meters. These meters come with interfaces (like the P1 port) that allow real-time data access for consumers or third party devices.
Types of smart meters in Slovenia
Residential meters: the primary smart meters currently deployed for households in Slovenia are Iskraemeco AM550 models (equipped with G3-PLC communication). These were supplied in a 2020-2022 nationwide project covering most distribution operators like Elektro Ljubljana, Maribor, Celje, Primorska [1].
Multiple sources are providing documentation on how to read data from Iskraemeco AM550, leading me to believe that it is infact used [2, 3, 4, 5, 11].
Prior to the AM550 rollout, many Slovenian utilities had installed Landis+Gyr smart meters (Landis E450 series) [7].
Industrial/commercial meters: for larger consumers, utilities have deployed advanced 3-phase meters such as the Iskraemeco MT880 industrial meter [1]. These are used for high demand sites and support remote reading and control.
| Distribution Operator (DSO) | Smart Meter Models (Residential) | Notes |
|---|---|---|
Elektro Ljubljana |
Iskraemeco AM550 (since ~2020) |
Previously Landis+Gyr E350/E450 series (some still in use), iskraemeco.com, evsvet.eu |
Elektro Maribor |
Iskraemeco AM550 |
Previously Landis+Gyr E450 (ZCXi 120, ZMXi 320), elektro-maribor.si |
Elektro Celje |
Iskraemeco AM550 |
Previously Landis+Gyr E350/E450 (PLC-enabled models) |
Elektro Primorska |
Iskraemeco AM550 |
Previously Landis+Gyr E450 (similar to Celje) |
Elektro Gorenjska |
Likely Iskraemeco AM550 in recent installs |
Previously Landis+Gyr E450 (ZCX/ZMX series), elektro-gorenjska.si |
All these meters are advanced or ``AMI'' capable of remote reading. By law, 100% of household customers should have smart meters by the end of 2024 and indeed over 90% already did by early 2024 [9].
Interfaces on Smart Meters (P1 and others)
Modern smart meters in Slovenia come with a P1 interface (also called HAN - Home area network - port) intended for end user access. P1 port is usually an RJ12 socket on the meter [10]. Often labeled I1 on Iskraemeco meters, it provides read only serial data stream with real-time information such as current power, voltage per phase, tarrifs, … The P1 port on these meters adheres to standards derived from DSMR (dutch smart meter requirements) and IEC protocols. For example older DSMR-based P1 ports output data in a plain ASCII text, but newer meters in Slovenia use DLMS/COSEM binary protocol [11, 12].
Key characteristics of the P1 interface:
-
Physical connector: RJ12 6-pin female jack on the meter. A standard RJ12 male plug with 6-core cable is used to connect [10]. Pinout follows the DSMR standard and it includes +5V power output, a data line, data request pin and ground pins. Meter supplies power to connected device, which means that external reader can often be powered directly from the meters port. Pin assignment from Iskraemeco AM550:
pin1: 5V out pin2: data request pin3: data gnd pin4: not connected pin5: data out pin6: power gnd
-
Protocol and format: DLMS/COSEM protocol over P1 port encapsulated in HDLC. This is secure binary format and usually encrypted. P1 data must be decoded and decrypted. The data includes OBIS codes for energy readings, power etc but presented in COSEM DLMS format.
-
Optical port: besides P1 electrical port, most meters also have an optical IR port on the front. This is mainly used by the utility for configuration or manual reading with optical probe. It can output similar data but not convenient for continous monitoring by consumer. [12].
-
Other interfaces: RS-485, ethernet, wireless modules. In Slovenia the meters communicate with the utility via either PLC or cellular
Connectors and adapter devices for the P1 port
-
Direct P1 to USB cable: This is a cable with RJ12 connector on one end and USB on the other. It allows to plug directly from the meters P1 port to a computer or a raspberry pi. Price is around 15-30 eur.
-
Wi-Fi P1 reader (plug-in dongles): there are consumer friendly devices that plug into P1 port and send data over the wi-fi. Examples include HomeWizard Wi-Fi P1 meter [14]. Some users have reported that HomeWizard device works well with Iskra AM550 [15] is another device Reduxi P1 wifi [16] Lorawan device [17] Diy ESP32 SlimmeLezer ESPHome based P1 reader
Encryption
In slovenia each meter has unique encryption key AES encryption on the payload. When you connect the device you will receive a stream of hex data (HDLC frames). - Obtaining the key: by law and regulation in Slovenia, the end user is entitled to access their meters data [9], data needs to be accessible local or remote. Distributer should provide you with your key.
2 possible approaches are: 1. get key from the distributer, 2. get key from iskraemeco
key format is 32-character hex string (128-bit AES key)