This abstract summarizes the growth of distributed photovoltaic (PV) systems—especially balcony-mounted applications—and the critical challenge of reverse power flow, along with Eastron's smart metering solutions that address this pain point.

Distributed PV Growth and Its Hidden Pain Point

In the global effort to tackle climate change and advance energy transition, distributed photovoltaic (PV) systems, especially balcony-mounted applications, have become a core driver of renewable growth. Across Europe, a surge in balcony PV installations is revolutionizing household energy use—Germany, for example, has seen a year-on-year market increase, with over 500,000 small-scale systems installed annually by 2024. This "small energy revolution" enables homes to generate their own electricity ("self-consumption") and feed excess power back to the grid, saving users about €132 per year in energy bills while contributing green power. However, the rapid adoption of distributed PV has revealed a critical industry challenge: reverse power flow.

Reverse power flow occurs when PV generation exceeds on-site demand, causing excess electricity to feed back into the public grid. This issue can lead to voltage fluctuations, harmonic pollution, and grid instability, increasing the risk of safety incidents. Consequently, European countries like Germany enforce strict regulations, limiting reverse power to under two seconds. Globally, grid operators are tightening requirements for anti-backflow measures in distributed PV systems. Meanwhile, traditional unidirectional meters fall short due to their inability to distinguish between generation and consumption, along with slow response times. Achieving precise measurement and rapid reverse power protection has thus emerged as a pervasive "hidden pain point" for PV professionals and end users alike.

Eastron's Wireless Smart Meters: Solving PV Measurement Challenges
Addressing this market need, Eastron—a leading smart metering solutions provider—has leveraged its technical expertise to launch the SEM1 and SEM3 series wireless smart meters, optimized for distributed PV scenarios. These products aren't just accurate PV meters; they integrate critical features like reverse power protection, high-speed data acquisition, and intelligent communication to ensure safe, reliable operation of balcony PV systems.

Eastron SEM1 Series: The Compact Powerhouse for Single-Phase Systems
Eastron SEM1-M-2: A DIN-rail mounted single-phase smart meter supporting 1P2W wiring. Its ultra-slim design occupies just one standard module width (1P), maximizing space efficiency in compact electrical enclosures. Featuring plug-and-play current transformers for easy installation, it enhances deployment speed. Data is transferred reliably via RS485 communication, enabling real-time system monitoring with refresh rates as fast as 50mS.
Eastron SEM1-WL-2: Building on the SEM1-M-2, this model adds Wi-Fi communication, eliminating the need for complex RS485 cabling. Users and maintenance staff can remotely access real-time data—such as power generation, consumption, and power levels—through apps, enabling smarter energy management. Its robust reverse power protection capability prevents electricity from flowing back into the grid, ensuring compliance with safety standards.

Eastron SEM3 Series: The Intelligent Manager for Three-Phase Systems
Eastron SEM3-M-2: A DIN-rail mounted three-phase smart meter designed for residential rooftops and small PV plants. Supporting 1P2W/3P3W/3P4W wiring configurations, it boasts a compact 1P width and plug-and-play current transformers for simple installation and space savings, ideal for balcony setups. RS485 communication allows effortless monitoring of power usage.
Eastron SEM3-WL-2: This Wi-Fi meter combines RS485 and wireless connectivity for versatile communication. With a 50-millisecond refresh rate, it delivers real-time data accuracy. Beyond excellent reverse power protection, it includes phase sequence error alerts: during installation, if incorrect phasing is detected, the meter triggers an alarm, allowing technicians to send automatic correction commands instantly. This reduces troubleshoting time and streamlines setup.
Furthermore, Eastron SEM1 and SEM3 series products are fully certified under EU standards, including:
Radio Equipment Directive (RED 2014/53/EU): Ensures spectrum compliance and RF safety.
Low Voltage Directive (LVD 2014/35/EU): Guarantees electrical safety for shock and fire prevention.
Electromagnetic Compatibility Directive (EMC 2014/30/EU): Validates interference resistance and emissions control.
Additionally, they carry the EN 18031:2021 cybersecurity certification, meeting international standards for data encryption and system protection. Covering all critical aspects—safety, wireless compliance, EMC, and cybersecurity—these certifications underscore the products' excellence, reliability, and global market readiness.

From Residential Balconies to Small Commercial Sites: Scalable Solutions for Diverse Needs
Home Balcony PV: The 'Energy Guardian' for Compact Spaces
In a pilot project in Berlin, Germany, homeowners adopted the Eastron SEM1-WL-2 radio meter. With limited balcony space, the 1P-width meter fit snugly into a DIN-rail enclosure, and plug-in current transformers enabled installation in under 10 minutes. Via Wi-Fi, users monitor real-time PV generation, household consumption, and grid interactions on their smartphones. When generation exceeds demand, the meter automatically triggers reverse power protection, preventing unwanted backflow to the grid.

Small Commercial Rooftops: The 'Reliability Enabler' for Industrial Operations
At a small manufacturing facility in Hamburg, Germany, the Eastron SEM3-WL-2 Wi-Fi meter played a pivotal role. Operating on three-phase power, the site had previously suffered from phase sequence errors during PV integration, causing inverter shutdowns and costly downtime. After deploying the SEM3-WL-2, phase errors immediately trigger alerts, allowing technicians to issue auto-correction commands and avert disruptions. Wi-Fi integration with energy management systems provides precise tracking of solar generation and grid purchases, delivering data-driven insights for energy savings.

Eastron: Empowering New Energy with Smart Metering Expertise
As a seasoned provider in the smart energy sector, Eastron focuses on metering and management solutions after over a decade of innovation. Its portfolio spans electric vehicle charging, PV storage, IoT, data centers, and prepaid systems. Committed to high-quality, reliable products, Eastron operates with a robust R&D team, advanced manufacturing, and strict quality control. Globally recognized certifications—such as EU MID, CE, German PTB (Eichrecht), UL, ETL, and SAA—facilitate distribution across 50+ countries, cementing Eastron's reputation in energy metering.
Amid energy transitions and shifting user demands, Eastron's SEM series represents a technological leap forward, empowering distributed PV—especially balcony applications—worldwide. Continuously investing in R&D, Eastron is dedicated to building a safer, smarter, and more efficient energy future.