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Fault Current Limiting/Interrupting Solutions

Utility network operators are investing hundreds of millions of dollars in upgrading and replacing existing equipment. They often have no choice other than segmenting the grid which negatively impacts the quality and availability of their network. Independent power producers are required to make significant investments and bear long delays, before receiving permits to connect distributed generation and renewable sources. Power disruptions in many industrial plants severely impact their business and financial losses.

GridON is offering grid operators, Independent Power Producers (IPP) and industrial customers cost-effective fault current limiting/interrupting solutions which enable increased capacity in meshed networks with growing load demand, and cost-effective connection of Distributed Generation (DG) and low carbon energy sources - while improving network stability and energy efficiency.

GridON offers two product lines that cover all market segments: (a) a saturated core Fault Current Limiter (FCL) for increased power capacity in medium-to-high voltage distribution and transmission networks; and (b) a power-electronics Fault Current Limiting Interrupter (FCLi) for low-to-medium voltage DG and industrial generators connections to distribution networks. These cost-effective solutions significantly reduce capital expenditure and time consuming labor, required for conventional network upgrades.

GridON's FCL/FCLi blocks fault currents from propagating through the network, thus preventing power failures, disruptions and network outages.

Power-electronics Fault Current Limiting Interrupter (FCLi)

The FCLi is a series-connected solid-state based device which interrupts network current and limits transient voltages to acceptable levels, instantly upon detection of short circuit conditions. The FCLi is using a proprietary detection algorithm to sense faults. It then limits and interrupts excessive fault infeed from the generator to the grid within micro-seconds – long before the first current peak. The FCLi also protects the private generator from fault current that come from the distribution network, and can also be utilized to rapidly disconnect the generator upon loss of mains. Once the short-circuit condition is cleared, the FCLi will immediately resumes to its normal conducting state. The use of power electronics enables fast recovery and return to service after each interruption operation, within seconds.

As fault current breaking elements, the solid-state based FCLi is using off-the-shelf power electronic devices (IGBT) that have accumulated extensive experience in commercial power systems. The FCLi technology is patent pending.

The FCLi was successfully tested at KEMA Labs, where it was subjected to multiple prospective fault currents – phase-to-earth, phase-to-phase and three-phase up to 25kA RMS, and fully interrupted the currents well before the first peak. The FCLi has undergone extensive factory acceptance tests such as functional tests, temperature rise tests and dielectric tests including lightning impulse test at 95kV.

Using FCLi to connect 5MW generator to 11kV network

Designed with relatively small footprint and affordable price tag, the FCLi is a perfect solution for cost-effective connection of distributed generators and for acquiring excess generation supply from industrial and commercial generators. Return on investment in an FCLi is expected within less than one year.

Saturated-core Fault Current Limiter (FCL)

The FCL is a passive, self-triggered system – imposing high impedance during fault condition. The FCL combines proprietary concept of electromagnetic flux alteration on a saturated core with conventional power transformer technology. The proprietary concept is utilizing the non-linear magnetic characteristic of iron core to introduce very high impedance to the grid during fault conditions. The unique geometry of the FCL enables significant increase of impedance during fault, providing ample current limiting. The FCL technology was granted several patents.

The FCL’s variable-impedance system responds instantaneously to current spikes long before the first peak, suppresses fault current for its entire duration, and recovers immediately following fault clearance – being always ready for consecutive faults.


Using FCL to enable connection of 4 parallel transformers

Being scalable to very high voltage and power ratings, this commercial, fail-safe product is well-suited for transmission and distribution network applications. The “transformer-like” FCL systems are very robust and easy to install and maintain.

Typical applications


FCLi enables cost-effective connection of distributed generators and low carbon energy sources from IPPs and industrial/commercial generators into low-medium voltage networks. It enables sale of excess generation capacity to the grid.

FCL/FCLi on a transformer feeder enables paralleling of multiple transformers on a single connected bus, reducing the overall substation fault levels to be within switchgear ratings.

FCL/FCLi in a bus-tie location enables paralleling bus sections during loss of power sources, improving network interconnectivity and power quality.

Please complete the request form in order to learn more about our FCL/FCLi solutions and their capabilities.