Field Evaluation of diverse Communication Methods for supporting smart Maintenance in remote hydroelectric Power Facilities

To address these issues, this study evaluated four communication technologies: single-pair high-speed digital subscriber line (SHDSL), very-high-bit-rate digital subscriber line 2

(VDSL2), power line communication (PLC), and Wi-Fi HaLow (based on the IEEE 802.11ah wireless standard). These standards were selected for their ability to utilize existing infrastructure or operate in harsh environments. Field tests were conducted to assess their transmission performance, environmental durability, and practical applicability.

• • SHDSL was applied to legacy metal telephone lines between power stations and remote facilities. It provided stable bidirectional communication over distances of up to 6.6 km, at rates of 3–4 Mbps. Wi-Fi access points were added to enable wireless connectivity between Internet of Things sensors and cameras. The system supported video streaming, voice calls, and cloud-based sensor-data transmission.

VDSL2 was tested within a power station using existing telephone lines. It enabled high-speed local-area network (LAN) construction and extended Wi-Fi coverage throughout the facility. The transmission rates varied with distance, reaching 300

Mbps at 250 m. • • High-speed PLC used power cables to establish LAN connections. Communication within the same distribution board was successful, achieving a rate of 25–26 Mbps.

In configurations using relay devices, the transmission rates decreased to approximately 6–8 Mbps owing to noise and retransmission effects; however, the performance was sufficient for video and audio transmissions.

Wi-Fi HaLow, operating in the 920 MHz band, was tested in vertical shafts and outdoor environments. Relay nodes enabled communication across multiple floors and extended horizontal coverage to 240 m. Although the signal strength and transmission rate were affected by the terrain and installation height, a low-bit-rate video transmission was successfully demonstrated. A decision-making flowchart was developed to guide technology selection based on sitespecific conditions such as terrain, existing cabling, and available power lines. SHDSL is most suitable when empty cable cores are available. VDSL2 is effective when the cable cores are occupied. PLC is viable when the power lines meet the regulatory conditions. Wi-Fi HaLow shows promise in areas with sufficient signal strength, and future regulatory changes may enhance its performance.

In conclusion, this study confirmed that these technologies offer practical and effective solutions for building communication infrastructures in remote hydroelectric facilities, enabling smart maintenance operations even in challenging environments.