A fault current occurs when an excessive amount of current flows in an uncontrolled manner through the electrical system. These sudden, stronger-than-normal currents pulsing through the system are triggered by an unintended short-circuit or partial short-circuit in an electric circuit. Some of the causes of faults include lightning strikes, contact between power lines and tree branches, and downed or crossed power lines. Additionally, outages caused by fault currents increase as electricity demand and/or the number of contributing power sources increase.
Fault currents can create major problems because they interrupt the flow of power between electric utilities and customers. They can damage or degrade transmission and distribution equipment, requiring expensive and time-consuming repairs. Fault Current Limiters (FCLs) regulate the amount of current moving through the transmission and distribution systems under abnormal conditions. Therefore, FCLs enhance the safety, stability and efficiency of power delivery systems and extend the life of substation equipment, which in turn reduces maintenance and even replacement costs of transmission and distribution equipment.
Interest in advancing the use of FCLs is growing as utilities and the Department of Energy collaborate with manufacturers, national laboratories, and other stakeholders to modernize, expand and increase the capabilities of the nation's stretched-to-capacity electric grid. FCLs have the potential to play a pivotal role in transforming the current grid into the DOE's vision for a smart and more efficient grid.
FACT SHEETS AND REPORTS
- Fault Current Limiter Fact Sheet, November 2009
- An Assessment of Fault Current Limiter Testing Requirements, February 2009
FAULT CURRENT LIMITER TESTING WORKING GROUP, IEEE P37.302
The FCL testing task force which started in 2009 to address testing requirements was approved as an IEEE working group P37.302 in June 2010 to develop a "Guide for Fault Current Limiter (FCL) Testing". Review minutes from previous meetings and learn more about the task force.