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Flexible AC transmission systems (FACTS)

ABB pioneered FACTS technology in the 1950s and remains the market and technology leader to this day. In the past 50 years ABB has executed around 750 FACTS projects worldwide and has stood for the vast majority of technology breakthroughs.

About the same time that ABB was revolutionizing long-distance high-voltage DC power transmission in the 1950s with HVDC, it was also revolutionizing the transportation of AC power over long distances with flexible AC transmission systems (FACTS). 

FACTS is a generic term for a group of technologies that dramatically increase the capacity of the existing transmission network – by as much as 50 percent or more – while maintaining or improving voltage stability, grid reliability and energy security.

FACTS technologies have a small footprint and minimal impact on the environment. Project implementation times are considerably faster and investment costs substantially lower than the alternative of building more transmission lines or new power generation facilities.


It can take 15 years to negotiate the rights of way and complete a power line project; with FACTS the same project would take only 15 months.


In addition to their primary role of increasing transmission capacity and improving grid control, FACTS technologies are also used to reduce power losses in long-distance power transfer, relieve transmission bottlenecks quickly, minimize the risk of blackouts, and integrate renewable energy sources like wind power into the grid.

In industrial processes ABB FACTS innovations are widely used in steelmaking to raise productivity by several percentage points and stabilize the effects of the huge electric arc furnaces on the power network and surrounding grid by improving the power quality.

FACTS technologies are traditionally divided into the two categories of series compensation and shunt compensation. All four technologies that make up the two categories – fixed series compensation and thyristor-controlled series compensation in the former, SVC and STATCOM/SVC Light in the latter – are ABB innovations.

Among the 750 FACTS projects that ABB has delivered - which is more than 50 percent of the world total – are the following:

The world’s largest SVC

ABB delivered the world’s largest SVC (500 kV) in 2007 for Allegheny Power’s Black Oak substation in Maryland. The solution has raised reliability on a critical transmission line in the mid-Atlantic region of the United States and increased the line’s transmission capacity. ABB completed the project in only 14 months, a world record given the project’s size, complexity and scope.

Increasing transmission capacity by 30 percent

An ABB series compensation solution for the Saudi Electricity Company boosted the transmission capacity of a vital power transmission interconnector by 30 percent. The increased capacity is preventing power shortages in the Saudi capital, Riyadh, and has saved SEC a huge investment outlay in a new transmission corridor.

Exporting surplus energy across India

The ABB solution stabilizes one of India’s most important AC interconnections at Raipur and enables power to be reliably transferred from India’s eastern power grid (where there is a surplus) to the west and south (where there is a shortage). The solution has also provided a substantial increase in transmission capacity and is the largest installation of its kind in the country.

Boosting steel mill productivity

ABB has supplied more than 260 SVC and SVC Light solutions to steel mills all over the world. One of the most well known is Outokumpu’s Tornio Works steel mill in Finland, where ABB SVC Light and SVC solutions create a smooth and stable voltage for the huge melting shop, which has a capacity of around one million tons a year. The solutions also reduce harmonics and flicker to prescribed levels, thereby enabling the plant owner to meet the required grid codes.