Flexible AC Transmissions Systems, or FACTS, as defined by the IEEE, are “alternating current transmission systems incorporating power-electronics based and other static controllers to enhance control ability and power transfer ability.” In more lay-friendly terms, one company defines FACTS as a group of resources frequently used to “overcome certain limitations in static and dynamic transmission capacity of electrical networks.”
FACTS help mitigate voltage drops on the power grid through electronic devices that manage acceptable voltage limits. The technology has evolved significantly in the last 40 years, driven, in part, as a reaction to the growth of large-scale renewable energy. This growth frequently employs intermittent power, which continues to drive the need for FACTS.
Here are some facts about FACTS that you should know:
Solutions like Static Var Compensators (SVC) and Static Synchronous Compensators (STATCOM) are addressing local transmission grid conditions in order to improve reliability and stability on the HV transmission grid.
SVC projects, which Beta Engineering frequently builds, use a high voltage system that manages network voltage, keeping it within acceptable limits to improve reliability. When system voltage lowers, the SVC generates reactive power. When system voltage fluctuates the other way, the SVC absorbs reactive power.
Control of Reactive Power Flow
Controlling reactive power flow goes hand in hand with improved reliability. Reactive power can cause an increase in transmission system losses, creating additional costs. It can also impact system voltage deviation, causing a degradation of load performance at under-voltage, as well as a risk of insulation breakdowns at over-voltage.
FACTS can help control reactive power flow, improving overall system stability and quality.
These features of FACTS give power companies the ability to optimize their existing transmission networks, increase the reliability and availability of their line networks, improve the quality of their supply, and ensure dynamic and transient network stability.
A Solution for Renewables
As mentioned previously, FACTS provide a sound solution in conjunction with the growth of renewables, such as wind and solar power. FACTS provide solutions for the intermittency of renewables, which can cause localized voltage sag and power factor fluctuations. As outlined earlier, SVCs can improve reliability, which can be particularly important with renewables.
FACTS is growing with the rise of renewable energy use. Navigant Research projects that cumulative FACTS investments by utilities and power grid operators will total $42.3 billion between 2014 and 2022.
The capital costs of new transmission grids and high voltage substations are high and can be cost-prohibitive. Utilities and transmission grid operators need to mitigate voltage drops, which is driving the demand for new FACTS deployments.
The report from Navigant shows that FACTS is projected to continue growing in the utilities sector. As Pandey and Kori note, “Better, faster, cheaper, and more reliable utilization of electrical energy is an important subject that electric power companies are concerned about.” FACTS is one solution for a growing field that provides an economical way to increase grid stability and reliability.