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PLC / BPL –An Ideal Communication Platform For A More Intelligent Electric Grid ?. Gerd Bumiller. Application. Automatic meter reading Remote control of distribution network Loss and ground circuit detection Load balancing Automatic billing and prepayment Fraud detection
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PLC / BPL –An Ideal Communication Platform For A More Intelligent Electric Grid ? Gerd Bumiller
Application • Automatic meter reading • Remote control of distribution network • Loss and ground circuit detection • Load balancing • Automatic billing and prepayment • Fraud detection like in the USA • Energy management for efficient integration of alternative energy generation
Energy Management I • State of the Art: • Power plants produce on demand of customer high peak loads • Alternative power generation grows and shall be doubled until 2010 • Production of solar and wind power generators (Germany today: 18 GW) depends on availability of sun and wind Prediction of production is very difficult • Production of alternative power can vary over range of several GW (Germany) within one hour only • Regulation between consumption and production is still done only by traditional power plants Less production, high standby times, low efficiency • Costs for electrical energy grow dramatically
Energy Management II • Task for tomorrow: • Storage possibilities of consumer have to be used for regulation (e.g. air conditioner, heating, refrigerator, hot water generator, ...) • Alternative energy production has to be integrated in regulation(e.g. combined heat and power stations, biogas plant, ...) Real-Time Energy Management (EDISON, CRIS, ...) Distribution quality depends on it • Key: Reliable and secure communication • PLC is natural communication link (efficient and always available) • Very high requirements (existing systems do not fulfil) REMPLI offers the communication infrastructure
Attenuation [dB] Frequency [MHz] Narrow Band vs. Broadband • RequirementCoverage of large areas on existing infrastructure (MV- and LV-grid) • Frequency range < 500 kHz • Much lower attenuation longer distances • Reduced number of repeaters lower costs more redundancy • Narrow Band data rate between 100 kbps ... 1Mbps • Regulation: FCC 15 part B • No interference with SW radio • Independent and parallel use with BPLC (1.5-30MHz) on one Power-Line Length profile of the attenuation models for different cable lengths in LV access network Source:M. Zimmermann, Energieverteilnetze als Zugangsmedium für Telekommunikationsdienste, Shaker Verlag, Aachen, Germany 2000
Independent vs. Integrated • Requirements • Existing protocols (IEC 60870-5-10x, M-Bus, IEC 62056 (former 1107),...) • Request / response mechanism with small package size (typ. 20-50 Bytes) • Variable reaction time of connected equipment • Different real-time and QoS requirements (switching commands vs. metering data) • Application dependent redundancy requirements • Guaranteed reaction time on sensor events • BPLC • QoS mapped for Video and VoIP • Link oriented traffic • Package size adapted to IP-packets Integration in BPLC is difficult and not efficient
Distribution Network • Topological requirements • Use of MV- and LV-network bridges • Large number of participants(up to 60,000 meter/primary station) • No direct link to every client repeaters • Transfer quality changes over time dynamic channel estimation • Topology of LV-network is often unknown or changes dynamically automatic routing (inside and between networks) • Meshed MV-networks with variable switch configuration bridge routing • Guaranteed reaction time and other real-time requirements No time for reorganisation Typical structure of a 10 KV sub-stations grid, Netherlands
Solutions • Completely independent communication packages • Full dynamic range • Synchronisation • Channel equalisation without estimation • No adaptive bit loading possible Specialised Physical Layer • Add hoc networking • Single Frequency Network technology • Redundant networks • Time slots for multiple masters and redundant use • Time synchronisation (< 1ms) Specialised MAC and Network Layer • Transportation Layer for Dynamic Routing • Bridge / Access Point routing, redundancy handling Specialised Transportation Layer Only a complete system design fulfils requirements
Security • Security is key requirement for nearly all applications • Required Security Services • Authentication • Integrity • Availability • Requirements from PLC characteristics • High packet loss (up to 10%) • Small bandwidth (shared 30-100 kbit/s) • Limited payload (20 to 50 bytes) • Special Cryptography for PLC • Symmetric block ciphers (3-DES) on PLC • Security Token – Smart Card • Security services are integral part of communication stack
Conclusion • Fulfill requirements with technical innovation • Infrastructure for a lot of applications • Coexistence with BPL • Cost sensitive design Solution on Chip • Cheaper realization compared with other tech. • Make alternative power generation economical • REMPLI is a real innovation ! Field trial scheduled for Q4 / 2005
Contacts Gerd Bumiller iAd GmbH http://www.iad-de.com gerd.bumiller@iad-de.com
Interference / SNR Interferences at the receiver: • Coloured noise • Narrow band noise • Impulse noise Undisturbed transmission is not possible Powerful and efficient channel coding is required