The acronym “FACTS” is a blanket term used to describe a family of power electronic devices that can improve power quality and transmission capability of existing power transmission systems, without significant investment in infrastructure. Many of the most important issues in power engineering are simple to understand but complex to address, particularly since the system operates on a much larger scale than the simplified models studied in the classroom.
While initial investment in FACTS devices can number in the millions of US dollars due to their sheer size, the payback time is usually short due to the cost savings they can provide. For the utility, installation of FACTS devices to increase utilization of existing transmission line assets is preferable to the planning and deployment of additional lines, since the cost of building a new transmission line can be in the range of millions of dollars per kilometre and take several years to complete. Power utilities and consumers can realize the benefits of FACTS much more quickly, since planning through to deployment and testing only takes about a year.
In essence, FACTS devices can increase the efficiency of transmission lines up to their thermal limit, which can increase maximum power transfer from 50% to 100%. Evidently, the time and cost benefits are substantial, however, once transmission lines reach their thermal limit, new lines must be constructed. FACTS devices cannot offer any benefit once a line is operating at maximum efficiency and has reached the thermal limit.
This article was taken from a report which I co-authored. It was submitted to ECE3333: Power Systems I, taught by Professor Rajiv Varma at the University of Western Ontario in Spring 2009.