ABB has completed the delivery and energization of the world's first cross-linked polyethylene (XLPE) insulated 345-kV AC submarine cable system. Extruded in a single continuous length without factory joints, the new cable system brings 512 MW of power-generation capacity to the critical wholesale power market in New York City, New York, U.S.
The ABB extra-high-voltage (EHV) cable system is part of the Bayonne Energy Center (BEC) power generation and transmission project, a new facility that will provide cleaner, more reliable power for Manhattan and the New York City power transmission network.
BEC comprises a new high-efficiency natural-gas fired power plant in Bayonne, New Jersey, U.S., that will generate up to 512 MW of electricity for transfer via the ABB cable system to a Con Edison substation in Gowanus, Brooklyn, New York.
The cable system links the power plant to the substation and delivers the power at EHV (345 kV AC) across New York Harbor, close to Liberty Island and the famous Statue of Liberty. Completed and energized by ABB in December 2011, the system includes three single-core XLPE submarine cables, each 6.5 miles (10.4 km) in length, and two XLPE underground cable segments that connect the submarine cables to the power plant in Bayonne and the substation in Brooklyn, respectively.
In accordance with BEC's requirements, ABB manufactured each of the three 6.5-mile extruded cables in a single continuous length. Such a long extruded EHV AC cable without factory joints had never been attempted before. It requires exceptional levels of expertise at the cable factory, with no margin for error in the extrusion process which, for a cable of this length, takes more than 10 days.
Secondly, New York is a busy international seaport with freighters, cruise ships, ferries and tourist boats anchoring or operating in the harbor. To mitigate concerns about possible future dredging in the harbor and the risk of anchor damage, ABB was required to bury the cables at a depth of up to 15 ft (4.6 m), which is significantly deeper than the 3-ft to 6-ft (0.9-m to 1.8-m) burial required for most other submarine power cables. The water depth along the cable route in the harbor is on average about 66 ft (20 m).
ABB was responsible for delivering a turnkey cable system including design, engineering, manufacture, field construction at the landfall sites, laying and installation, and commissioning.
The work at the landfall sites included construction of in-water cofferdams and horizontal directional drilling in Brooklyn. The construction work at the landing sites and the laying of the cables were performed by a local New Jersey based firm (Caldwell Marine International) under a subcontract with ABB.
For more information, visit www.abb.com.