The global drive towards renewable energy has significantly positioned solar power at the forefront of sustainable progress. As Photovoltaic (PV) systems grow in scale and complexity, a critical requirement emerges for advanced, efficient, and reliable communication infrastructure. Single Pair Ethernet (SPE) stands out as a potentially significant technology, poised to fundamentally alter how data is transmitted and devices receive power within these systems, promising simplified cabling, enhanced connectivity, and improved overall performance.
What is Single Pair Ethernet (SPE)?
Traditionally, Ethernet communication depends on multiple pairs of twisted wires – typically two pairs for Fast Ethernet at 100 Mbit/s or four pairs for Gigabit Ethernet and faster speeds. Single Pair Ethernet represents a fundamental shift, using only a single twisted pair for transmitting data. This distinct characteristic provides significant technical advantages and opens up possibilities for various applications, solar power being a notable example.
IEEE 802.3 defines SPE standards, which outline different transmission speeds and distances achievable over just one pair of wires. For instance, 10BASE-T1L facilitates speeds up to 10 Mbit/s across distance's reaching up to 1000 meters. In contrast, 1000BASE-T1 supports 1 Gbit/s communication, but only up to 40 meters. Other standards, like 100BASE-T1, operate up to 100 meters. The 10BASE-T1S standard was designed specifically for multidrop configurations, allowing multiple devices to share a single cable segment over shorter ranges, usually up to 25 meters supporting at least 8 nodes, or 50 meters supporting at least 16 nodes. It also supports remote power delivery.
A particularly noteworthy aspect of SPE is its capability for Power over Data Line (PoDL). PoDL allows both data and electric power to travel simultaneously over the same single twisted pair cable, thus doing away with the necessity for separate power lines for connected devices. PoDL can supply substantial power; IEEE 802.3cg specifies Class 15, enabling up to 52 W at the Power Source Equipment (PSE). While cable quality can impact power delivery, PoDL is recommended, specially for new installations. This integrated power and data capability is exceptionally beneficial for powering remotely located sensors, actuators, and IoT devices.
Why SPE is a Game Changer for Solar Systems
SPE's unique technical characteristics make it particularly well-suited for the specific requirements and the spread-out nature of solar power installations.
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Simplified Cabling and Reduced Cost: By decreasing the number of cable pairs from the traditional two or four down to just one, SPE dramatically simplifies the wiring infrastructure. This leads directly to considerable savings in material costs, primarily less copper, and minimizes the overall effort involved in cabling. This simplification offers a major advantage in expansive solar farms covering vast area's.
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Integrated Power and Data (PoDL): The capability to deliver both data and power over a single cable pair through PoDL simplifies installation and lowers the number of cables and connectors needed, thereby reducing installation and maintance costs. This is especially useful for powering devices like sensors or microinverters directly via the data cable.
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Seamless Ethernet Connectivity: SPE makes possible a continuous, standardized IP-based communication pathway from the edge devices, such as sensors or inverters, all the way through the network to higher-level system's and cloud services. This negates the requirement for complex and often proprietary gateways that would otherwise translate between different fieldbus protocol's and Ethernet. This simplification reduces network architecture complexity, lowers potential failure points, and decreases latency.
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Extended Reach: The ability of the 10BASE-T1L standard to transmit data up to 1000 meters at 10 Mbit/s presents a significant benefit in large solar installations. This extended reach often eliminates the need for supplementary repeaters or switches, which traditional Ethernet would require to cover comparable distances.
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Improved Suitability for Harsh Environments: SPE has been engineered for industrial applications, and its robust connection technology makes it appropriate for challenging environments. While not specifically detailed for solar settings in this context, the ability to integrate EMC (Electromagnetic Compatibility) compliance during device design is crucial in industrial use cases where electrical noise is common. This is a pertinent consideration in solar installations, which include power electronics. SPE also supports connectors that are designed for outdoor use, adhering to specific IP ratings like IP67.
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Enabling Enhanced Data Utilization: By offering higher data throughput and eliminating the data silos created by gateways, SPE facilitates the collection of significantly more real-time data from the system. This abundance of data supports advanced analytics, faster control loop operations, and opens up possibilities for AI/ML based optimizations in energy management and predictive maintance.
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Space and Weight Savings: SPE cabling and connectors are considerably smaller compared to conventional Ethernet using RJ45 connectors or other multi-pair industrial cables. This size reduction is valuable in components such as inverters or control cabinets where space is often limited.
Applications of SPE within Solar Power Systems
Single Pair Ethernet offers versatile application possibilities throughout a solar power installation.
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Inverters: As essential components, inverters are prime candidates to benefit from SPE interfaces. Microinverters and string inverters can leverage SPE for communication within arrays and back to monitoring systems. The Ingeteam INGECON® SUN 350TL M12 string inverter includes SPE communication as a standard feature, enabling communication up to 1,000 meters and supporting daisy-chaining connections for multiple inverters on a single line.
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Sensor Networks and Monitoring: Solar farms employ numerous sensors to monitor environmental conditions, including temperature and solar radiation, as well as system performance. SPE allows these sensors to be integrated directly into the Ethernet network, removing the reliance on separate gateways. The Jumo hydroTRANS series serves as an example of sensors capable of direct communication with controllers and cloud service's using SPE interfaces (JUMO hydroTRANS S20 – SPE version). This direct connection capability enhances data collection for real-time monitoring, performance analysis, and optimization.
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Connection to Energy Management and Control Systems: SPE simplifies the communication pathway from inverters, sensors, and other field devices up to energy management systems. This enables better integration with Smart-Grid and Smart-Home solutions. Continuous IP-based communication allows for simpler monitoring and control systems, improves remote diagnosis capabilities, and facilitates easier maintenance procedures.
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Intra-System Communication: Within component's like inverters or control cabinets, SPE can simplify internal wiring and communication between various modules or sub-components.
Replacing Legacy and Conventional Technologies
SPE is positioned to replace several communication methods currently utilized in solar and other industrial applications, driving modernization and standardization.
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Proprietary Fieldbus Systems: Many existing solar installations, much like other industrial plants, currently use proprietary fieldbus system's for communication at the sensor and device level. SPE enables a transition to a uniform, IP-based Ethernet network that extends from one end to the other. This eliminates the complexity and the necessity for gateways associated with integrating different fieldbuses.
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Conventional Ethernet: Where standard Ethernet mandates multiple pairs of wires, SPE requires only one, leading to considerable savings in materials and space.
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Separate Data and Power Cabling: SPE's PoDL functionality eliminates the need for distinct cables dedicated solely to data transmission and power delivery. This simplifies wiring and reduces the effort required for installation.
Available Products and Ecosystem Development
While broad, publicly documented implementation of SPE specifically within solar farms is still in its early phase's, the technology is reaching maturity, and pertinent components are becoming available.
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Inverters: As previously mentioned, products like the Ingeteam INGECON® SUN 350TL M12 string inverter exemplify commercially available inverters that incorporate SPE, showcasing it's practical application.
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Sensors: Sensors can be equipped with SPE interfaces to facilitate direct integration. The Jumo hydroTRANS series illustrates how sensors can communicate directly utilizing SPE.
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Network Infrastructure: SPE networks necessitate compatible switches and routers. Weidmüller offers a suitable switch designed for 10BASE-T1L applications that fulfills SPE requirements, but alternatives emerge as well. Such switches can centralize data from various devices, potentially including components connected via SPE as the technology becomes more integrated.
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Standards and Connectors: The underlying SPE standards are defined by IEEE 802.3, including specifications like 802.3cg, 802.3bp, and 802.3bw. Connector standardization is vital for widespread adoption. Standards such as IEC 63171-2 (IP20) and IEC 63171-5 (IP67) define connectors suitable for different environments, including those appropriate for outdoor solar applications.
Challenges and the Path Forward
Despite its considerable advantages, the widespread adoption of SPE in solar power system's faces certain obstacles. The ecosystem of compatible components, including chips, connectors, and devices, along with established norms, is still evolving when compared to traditional Ethernet or fieldbuses. Connector standardization, while progressing, requires full industry alignment.
Ensuring robust electromagnetic compatibility (EMC) is also crucial for reliable communication, given the electrically noisy environment typical of solar installations.
Currently, successful, large-scale, publicly documented series projects specifically within solar farms are not yet widespread. However, the technology is technically ready and is being deployed in pilot and test setups across a variety of industrial applications.
The solar industry has demonstrated considerable interest. With the growing availability of SPE-enabled component's and the consolidation of standards, the initial large-scale reference installations are anticipated in the near future. A phased migration strategy, involving dual interfaces (both conventional and SPE) on key components and utilizing adapters or gateways during a transition period, could facilitate the broader introduction of SPE into existing product portfolios and brownfield installations. New installations, often referred to as greenfield projects, are more likely to adopt SPE from the outset at a faster pace.
Experts predict significant growth for SPE across diverse markets. While projections vary, estimates suggest millions of SPE nodes in factory automation alone by 2030, with even higher figures expected across all market's combined. This growth trajectory indicates a strong future for SPE, including it's increasing role in renewable energy sectors such as solar.
Conclusion
Single Pair Ethernet (SPE) holds transformative potential for solar power systems. By significantly simplifying cabling, enabling combined power and data transmission, providing long-distance IP communication, and enhancing noise immunity, SPE paves the way for solar installations that are more efficient, cost-effective, and simpler to maintain.
SPE's capacity to replace legacy fieldbuses and streamline complex network architectures with a unified, end-to-end Ethernet approach serves as a key driver for digitalization and modernization within the solar industry. Although the ecosystem is still in development and challenge's such as connector standardization are being addressed, the availability of initial SPE-enabled products like inverters and sensors underscores the technology's readiness for deployment.
As the solar industry continues its rapid expansion and increasingly relies on detailed monitoring, control, and integration with smart grids, the advantages offered by SPE position it as a crucial technology for realizing the full potential of solar energy. The anticipated acceleration in SPE adoption in greenfield projects and the gradual migration in brownfield installation's signals a clear path towards a future where SPE becomes a standard element in sustainable and efficient solar power system's.
