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Laying of 132 kv hvac underwater power line within the Venice Lagoon

Nautilus has laid, during a period of three months, a new section (length of approx. 10.5 km) of 132 kV HVAC underwater power line connecting the island of Sacca Serenella (Murano) to Cavallino Treporti within the Lagoon of Venice.


M/s Terna Rete Italia - Terna Group


M/s Prysmian Powerlink

Site Area

Venice Lagoon, Italy.

Project scope brief

  • Underwater installation, in trench, of a triad of 150 kV HVAC power cables, to a depth of burial varying between 2.00 and 3.00 m from the lagoon bottom
  • Track length: 10.50 km, for an overall length of cables installed of 42 km.

The works consisted in the simultaneous laying of three single-core 150 kV HVAC power cables and one fiber-optic telecommunication cable, tied to form a bundle.

The laying activities were performed without causing any shutdown of the existing utilities as well as without interrupting the navigation within the waterways encountered along the route, and by constructing a single cables joint.

The submarine cables installation was executed within areas characterized by very shallow water and considerable environmental value.

Summary of activities carried out

  1. Onshore landing of cables at the starting / end points by means of a controlled pulling winch. The concerned activities consisted in the pulling of the head of each single cable through a dedicated HDPE conduit installed by HDD (Horizontal Directional Drilling) method.
  2. Underwater controlled laying of bundle of cables by means of the subsea wheel trencher MAC1.
  3. Construction of all complementary works such as infrastructures for crossing of existing utilities, marker posts, etc.

Cables characteristics

Single Core 150 kV HVAC Power Cables

  • Outside Diameter: 116 mm
  • Minimum Bending Radius: 2.5 m
  • Weight in air: 31 kg/m
  • Type of cables: XLPE 150 kV Cu 1x1000 mm2

Marine Fiber Optic Cable (48 fibers)

  • Outside Diameter: 35 mm
  • Weight in air: 3 kg/m
  • Type of fiber: ITU T G 652D