Strengthening the power connection between mainland Italy and Sicily will ensure affordable and reliable energy supplies for Sicilians, and minimize the risk of power outages on the island by trebling the capacity of the existing connection. It also makes possible the export of around 700 MW of renewable power production to the mainland, fully utilizing the rapid expansion of renewable energy sources in Sicily, and improving the efficiency of electricity markets in southern Italy.
To ensure reliable power supplies over this new connection, Terna is installing innovative ABB Plug and Switch System (PASS) 420 kV hybrid switchgear modules in substations at Sorgente and Rizziconi, that is at both ends of the line.
Integrating the Sicilian and mainland power grids has always been an ambitious task. In 1955, two elecric pylons 233 meters high - the tallest in the world at the time - were built to carry a 220 kV transmission line across the Strait of Messina and connect the Sicilian and mainland grids for the first time. In 1985, the huge pylons were replaced with a submarine power cable, which is still in service.
To expand the line's capacity, Terna decided to connect Sicily and the mainland with another 380 kV alternating current (AC) power link terminating at substations in Sorgente on the Sicilian side and Rizziconi, on the mainland in Calabria.
Reliability of the energy supply is key to the project's success, an aspect greatly dependent on the switchgear being used to control and protect the line. Terna decided to enhance the capacity of the existing 420 kV air-insulated substation by adding a new high-voltage switching bay.
However, with extremely limited space available for the new bay, conventional equipment configurations were ruled out. In addition, the strategic importance of the line means Terna must be able to perform maintenance on the modules without power interruptions.
ABB's plug and switch modules satisfy every key requirement. Compact PASS hybrid modules combine the benefits of AIS and GIS technologies, providing all the functions of an entire switchgear bay in one compact, multi-functional unit that arrives on site factory assembled and tested, ready for rapid installation and energization.
Compact PASS modules provide customers with the utmost convenience in easy transportation and flexibility. The hybrid design deploys traditional air-insulated busbars to connect with other equipment in the existing substation while enclosing the main bay functions in a single-phase gas-insulated housing.
ABB even supplies PASS modules with special rollers that enable them to be moved to an area adjacent to the service bay for needed maintenance without creating substation service interruptions, ensuring full and proper functionality of the entire system. This also reduces the time and cost of servicing the equipment in addition to enhancing its reliability and availability.
The installation in Sorgente, in Sicily, has been already executed and the module is energized and now in service for the customer satisfaction.
With the introduction of the new 420 kV module the PASS product family now covers voltages from 72,5 kV to 420 kV with breaking current capability ranging from 31,5 to 63 kA. In addition to standard modules a special solution called the PASS M0 H offers a complete high voltage switchyard with an 'H' configuration as a single product.
