ZIV METERING

PRIME Evolution towards 1.4

• In 2010 Spain starts its first deployment of PRIME 1.3.6 SmartMeters
• The initial deployment concludes in 2018 with 15 million meters deployed

Legal
Mandate

Proof of
Concept

Prototypes

Laboratory

Testing

Massive

Roll-out

End of

Roll-out

2007

2008

2010

2009

2011

2017

• In 2025 begins the renewal of meters due to a 15-year useful life limit and new regulatory
  milestones
• During this time there has been an evolution of the PRIME Technology to its PRIME 1.4
  version
• This new version includes significant improvements that address previous limitations of
  the technology:
  • PHY Layer improvements
  • MAC Layer improvements
• This new PRIME 1.4 version presents new opportunities as well as challenges and impacts
  the future deployment

• Robust modes: 4 times repetition of the same signal, Preamble, header
  and payload
• Improve against narrow band interference and impulsive noise. More
  reliable communications
• 
  

• Repeat the original preamble 4 times (sign inversion)
• From 2.048ms chirp to 8.192ms
• Preamble power increased 4dB above the payload
• Noise rejection: Robustness
• More precise synchronization (key for OFDM)

• There is a cyclic shift in frequency for each repetition
• Interleaver distributes the information across all subcarriers

• Robust modes added for both DBPSK and DQPSK modulations (Higher bit density)

• Type BC Frame: Mechanism to
  avoid collisions in a mixed
  network (1.4 and 1.3.6 devices
  using CENELEC-A Band)

• Type B Frame: Header is
  optimized. Only one
  symbol before repetition
  (4 in 1.4 vs 2 in 1.3.6)

• PRIME Alliance technical group simulations
• Gaussian white noise, up to 4dB
• Notched channels, up to 6dB
• Impulsive noise, up to 14.5dB
• 
  
• 
  

• Saturated spectrum vs Less congested. Better communications
• Higher frequencies: Reduce noise, increase impedance and attenuation

• PRIME 1.3.6
  • Control traffic to maintain the subnet is >60% of the total traffic
  • Once a switch starts switching multicast for a group it never stops
• PRIME 1.4 fixes some of these issues:
  • Multicast switching management has been moved to the BN so only switches
    that actually have to repeat traffic repeat it
  • Time values of several concepts has been increased all through the Spec
    • Examples: Alive times, commands, promotion needs...
    • 
      

• Frame has been adapted and now have configurable larger lengths
  • 276 symbols 276, 552, 828 or 1104 symbols
  • Less CFP/BCN slot less sync points better CSMA/CA
  • 
    

• PRIME 1.3.6 has no specific mechanism to determine which modulation to use in point-to-
  point communications
• PRIME 1.4 introduces a Robust communication management:
  • Each generic MAC PDU has RM information
    • Allows having updated information with no bandwidth loss
    • Clear information on which encoding could be used with the last received power
  • New Alive mechanism is used to manage robustness
    • Packet level RM has an issue: going from non robust to robust mode is not well
      handled
    • Alive makes sure the robustness will be increased if needed because it now includes
      a link level ACK

• PRIME 1.3.6 defines security but is incomplete and not working,
  security relies on upper layers
• PRIME 1.4 security is written from the scratch
  • AES-128-CCM for data
  • KDF AES-CMAC for key derivation
  • 2 secure profiles to choose between higher security or
    performance
  • Individual keys for traffic with each meter and a subnetwork key
    known by all nodes
  • Non secure profile is still available

• PRIME 1.4 defines a method to reference temporal events
  • A header with time offset defining an event time
  • Time relative to a specific MAC frame start, frame is synchronized with beacons
  • Frame is selected with frame sequence
  • Switches are aware of this so the information is kept up to date if needed
  • 
    

• Three posible scenarios:
  • • Pure PRIME 1.3.6 Networks: PRIME 1.3.6
      meters are progressively replaced by 1.4
      meters in 1.3.6 mode. Once the
      replacement is completed the whole
      network is switched to PRIME 1.4
    • Hybrid PRIME 1.3.6 & PRIME 1.4 Networks:
      A new PRIME 1.4 network is deployed
      along the old 1.3.6 network
    • Pure PRIME 1.4 Networks: The old
      network is replaced at once
    • 
      

• Issues:
  • Coverage: In PRIME networks, coverage relies on service nodes (meters) acting as
    switches. Bottlenecks can occur when only one or a few nodes provide coverage to
    certain areas. If two networks are deployed simultaneously and these critical nodes are
    part of only one network, the other network may lose coverage in those areas
  • Collision: Two different communication channels are not electrically independent. When a
    node transmits a PLC signal, it lowers the network impedance across all frequencies,
    causing significant interference with other nodes transmitting at the same time, even on
    different frequency bands
  • 
    
• A deployment strategy is needed:
  • Initial bulk replacement is recommended
  • Try to group meters with the same version in service connections
  • Individual meters may need to be switched to address communication issues
  • 
    

• Meter renewal process over the next 15 years presents both a challenge and an opportunity
  challenge for utilities
• 
  
• Utilities have already started piloting the migration towards PRIME 1.4 meters
• 
  
• The coexistence of two communication networks on a single low-voltage grid can present
  issues. While it doesn't prevent migration from one version to another over several years, it
  can impact the meter replacement strategy
• 
  
• Pilot tests have demonstrated that PRIME 1.4 offers significant improvements in robustness
  and performance
• 
  
• Pilot tests also confirm that the coexistence of both networks is feasible and manageable
  during deployment

Contact us now for further information

ziv@zivautomation.com