Electricians in the water

Repair and modernization of power transmission lines is a complex and expensive job, especially in the system of large megacities, when work has to be done not only in dense urban areas, but even underwater, in river beds and historical canals. Rosseti Group enterprises operating in large cities such as Moscow and St. Petersburg have to annually engage special vessels and electrical divers to carry out such work. In 2024, Rosseti power divers spent almost 2 thousand hours underwater while performing unique work on power transmission lines laid along the bottoms of the Moscow and St. Petersburg rivers.

In 2024, Rosseti power divers spent almost 2,000 hours underwater while performing unique work on power transmission lines laid along the bottoms of the Moscow and St. Petersburg rivers

As noted by the Moscow City Hall, at the beginning of the year, Rosseti Moscow Region carried out work on the installation and relocation of four cable lines (10 kV) between Moskvoretskaya and Raushskaya embankments from the Raushskaya substation (110 kV), and in December 2024, three cable lines between Bolotnaya and Yakimanskaya embankments and two cable lines between the Kremlin and Sofiyskaya embankments were modernized. Divers worked on the bottom of the Moscow River near Zaryadye Park and the oldest operating power plant in the city, GES-1 on Raushskaya Embankment.

"These lines were laid seven decades ago and have exhausted their service life. We are replacing them with modern ones, with the necessary capacity. This will increase the reliability of power supply to consumers in the Central District and expand the opportunities for connecting new consumers, which is also important for the development of small and medium-sized businesses in the city," Moscow Mayor Sergei Sobyanin noted on his Telegram channel in January 2025. It was technically impossible to carry out work using horizontal directional drilling, given the dense historical development of the city. In this regard, specialists decided to wash out the riverbed, dismantle the old cables with a winch and lay new ones directly along the river bottom, using divers, tugboats, barges and towed barges with hydraulic monitors.

In Moscow, such work has not been carried out for more than 20 years. The cables were laid in the most difficult conditions with intensive navigation of the Moscow River.

In St. Petersburg, Rosseti Lenenergo specialists carried out diagnostics and repairs on more than 45 cable lines (6–110 kV) in the waters of the Bolshaya Neva, Malaya Nevka and Moika rivers. To do this, divers had to go underwater 174 times. In addition to severe weather and intensive navigation, the work was complicated by the strong current, the speed of which on the Neva exceeds 4 km/h, as well as the depth of the river, which in some places reaches 16 meters. For these works, a diving television complex for underwater filming and ventilated diving equipment were used, including a three-bolt shirt, a bib, weights, a pot and boots. The total weight of the equipment exceeds 80 kg.

The large number of rivers and canals has led to the company Rosseti Lenenergo even acquiring its own fleet, which includes 7 vessels: 2 cable installation vessels, 2 tugboats and 1 diving motor ship, 1 non-self-propelled vessel for developing underwater trenches for cable routes and 1 small-sized floating craft to support the work of divers on small rivers and canals.

The experience of Rossetti Group branches in laying, prompt repair and comprehensive modernization of underwater cables in the difficult conditions of Moscow and St. Petersburg is unique. Now the company actively applies the practice of diving operations in other regions of the country. To implement such technically complex tasks, training dives are regularly conducted, during which basic skills are practiced: exchange and transmission of signals, bottom survey, methods of searching for underwater cables and actions in emergency situations.