November 11, 2020
Sumitomo Electric Industries, Ltd.
*This press release was originally published in Japanese on October 26, 2020.

Sumitomo Electric Has Installed Over 10,000 PLC String
Monitoring Unites for Solar Power Plants
Sumitomo Electric Industries, Ltd. is pleased to announce that its sales of powerline communication (PLC) string monitoring units for solar power plants haveexceeded 10,000 units (as of the end of October 2020). The Company started tosell these units on a full scale in 2016 and has continued to expand its productlineup and services. The units have been introduced to 81 solar power plants(power generation capacity: 561 MW in total).
To enable solar power plants to maintain high power output over a long period (20 years)
under the feed-in tariff (FIT) scheme,*1 it is essential to predict and prevent failures basedon appropriate operational management and maintenance checkups. For preventive
purposes, it is effective and important to perform continuous monitoring to accurately
detect change points rather than gathering momentary and fractional information
obtained by I-V curve (Current-voltage characteristic) measurement and thermalmonitoring using drones. Sumitomo Electric’s PLC string monitoring units feature low
initial cost, stable transmission of monitoring data and high lightning resistance.
Continuous monitoring of solar power grid enables stable operation of plants over thelong term.
[Features of the PLC String Monitoring Units]
1. Achieve low-cost and stable transmission of monitoring data by using PLC
technology, and enable retrofitting to existing power plants
Sumitomo Electric’s PLC string monitoring units use power lines as communication lines.
Since the units can be introduced to existing power lines without the need for extraconstruction work to lay communication lines, they can reduce costs (by 70% comparedto other systems based on an estimate by Sumitomo Electric). The units are also
retrofittable to existing power plants. Wired connection ensures highly stable datatransmission.

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2. Enable continuous monitoring for each string, making it possible to detect
abnormalities and implement measures at an early stage
In power plant monitoring based on power conditioners, abnormalities cannot bedetected until they spread to a certain level. Sumitomo Electric’s units monitor eachstring*2 and can detect abnormalities before they become manifest in power conditioner
monitoring. This makes it possible to detect abnormalities quickly and implement
measures at an early stage.
3. Analyze the monitored data using AI and automatically determine the details of
the failure
In November 2019, Sumitomo Electric launched a service to analyze the data collectedby the string monitoring units using AI to provide daily, monthly and annual reports. The
details of failures are determined automatically by using AI and are notified together withthe locations of the failures. This supports accurate and efficient operationalmanagement and maintenance checkups. Introduction of this service can reduce manhours required for periodic checkups.
Sumitomo Electric remains committed to offering highly convenient string monitoring
units and auxiliary services to contribute to the widespread use and stable operation ofsolar power generation.
*1 Under this scheme, electricity utilities are required to purchase electricity generated
by renewable energy sources (e.g., solar power generation) for a certain period at a
price designated by the national government.
*2 A string is the minimum unit of solar panels that are connected in series.
■ Reference
Sumitomo Electric's Website
https://sumitomoelectric.com/

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