primePRIME (PoweRline Intelligent Metering Evolution) is a PLC (Power line communication) technology based on the ITU G.9904 specification. It uses OFDM (Orthogonal Frequency Division Multiplexing) technology to provide an efficient physical connectivity to elements that make up a smart grid, employing medium and low voltage power distribution networks that already exist.

PRIME technology has been developed by the PRIME Alliance and defined by ITU as an international standard.

PRIME version 1.4 (v1.4) represents an extension of version 1.3 (v.1.3). PRIME v1.4 includes PHY and MAC changes. Thanks to these modifications, a series of improvements (such as an increase in robustness, higher data transfer speeds, a bandwidth extension, more flexibility in band planning and IPv6 support for the convergence layer) have been introduced. Moreover, these developments are compatible with existing PRIME v1.3 devices.

The new version withstands broader frequency ranges, from the CENELEC-A band (lower than 95 kHz) up to 500 kHz. This means power networks around the world can make optimum use of PRIME technology. Increasing the bandwidth signal up to 500 kHz will likely provide high data transmission speeds (of up to 1 Mbps) to applications (for instance, on-board communications) and areas where these bandwidths are allowed (America and Asia).

PRIME v1.4 offers a reliable transmission mode. This helps improve the system’s performance when exposed to high energy impulsive noise, as well as when dealing with networks full of interference noise. Two new robust transmission modes are introduced: Robust DBPSK and Robust DQPSK. They add four repetitions of the OFDM symbol in the convolutional codifier, when compared to the existing PRIME v1.3.6. Message headers are now bigger and, together with longer preambles, allow for higher robustness when faced with impulsive noise. One of the characteristics that makes the PRIME robust mode unique is the number of repetitions at OFDM level, instead of at byte level (granting more time in the diversity domain).

Thanks to these improvements, PRIME v1.4 can be used in plenty of applications (and not only in those designed to measure power consumption using intelligent meters). This technology allows for connections to be established between IEC 61334-4-32, IPv4 and IPv6 devices. A few examples of where these applications are used include: medium-voltage scenarios, identification and mapping of the connection stage in intelligent meters, or remote control applications in low-voltage power lines.  

Adapting the PRIME MAC layer has been necessary to include these improvements. The changes made to the MAC layer make new developments compatible with previous PRIME versions. The main MAC-related feature stemming from this functionality (which derives from modifications in the physical layer) is the reduction of channel overloads. To achieve this, the size and flexibility of frames was increased and the number of control messages reduced.  

The addition of these new elements means that PRIME v1.4 devices have to be able to coexist with PRIME v1.3 devices in scenarios where both standards operate. The PRIME Alliance is committed to making any PRIME specification evolution compatible with previous versions of that same specification.

PRIME v1.4 has been designed so that it includes the latest state-of-the-art safety technologies. This is why it includes encryption mechanisms at the MAC level, allowing for data transfers to be carried out safely (even at the lowest protocol layers). Thanks to the two security profiles, the user gets optimum network safety and performance. PRIME uses an AES-COM of 128 bytes as an encrypted authentication method, as well as recognized standards for password generation, distribution and management.

PRIME v1.4 results from in-field experiences, gathered by devices whose design is based on previous PRIME versions.

All changes have been introduced after extensive data collection campaigns using devices that are already deployed and with the help of simulations. The latest technological alternatives have also been studied closely.

The PRIME specification has seen major revisions with the aim of improving the system’s performance. PRIME v1.4 can even be installed in networks with dire noise conditions.

Teldat PLC PRIME devices are ready to support PRIME v1.4 whenever the market and the power distribution companies ask for this technology to be deployed.


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Benjamin Garcia

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