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 network meshing and cost-effective connection of distributed generation and intermittent renewable energy sources; while improving network stability and energy efficiency.

Two product lines are covering all market segments: (a) a pre-saturated core Fault Current Limiter (FCL) for medium-high voltage distribution and transmission networks; and (b) a solid-state Fault Current Limiting Interrupter (FCLi) for low-medium voltage DG connection and industrial applications. These cost-effective solutions significantly reduce capital expenditure and time consuming labor, required for network upgrades.

GridON’s FCLs have been operating flawlessly in live networks since early 2013 – proving extremely reliable, easy to operate and maintain, and very effective in limiting numerous faults. GridON’s FCL is based on combining industry-standard, proven transformer technology with unique and proprietary concept of electromagnetic flux alteration on a saturated iron core. This fail-safe system responds instantaneously to faults, suppresses fault current for its entire duration, and recovers immediately following fault clearance – being always ready for consecutive faults. The FCL is the first commercially available pre-saturated core fault current limiter currently available in the market. Being scalable to very high voltage and power ratings, this commercial, fail-safe product is well-suited for transmission and distribution network applications. GridON has partnered with Australian leading transformer manufacturer, Wilson Transformer Company, a shareholder and manufacturing partner, to offer a state-of-the-art portfolio of FCL products to the market. GridON's  transformer-like FCL systems are very easy to install and maintain, eliminating the costly, time and resource consuming network upgrade process.

GridON’s established technology has been further enhanced to offer an economical product with smaller footprint - specifically designed for industrial and power producing customers. GridON's cost-effective, compact FCLi limits and interrupts excessive fault current and mitigates arc-flash in low-to-medium voltage networks. Designed with relatively small footprint and low price tag, the FCLi is a perfect solution for grid operators, independent power producers and industrial customers. This solid-state based product limits excessive fault current in the network before it rises to high level, and acts to interrupt it before the first current peak. By controlling excessive fault currents, the FCLi enables fast and cost-effective connection of IPPs and distributed generators. It also allows increased power capacity in industrial plants, and sale of excess generation capacity to the grid. Return on investment in an FCLi is expected withing one year.

GridON's FCL/FCLi allow for continual uninterrupted operation, while preventing fault currents from propagating through the network and thus prevent power failures, disruptions and outages.

Placing an FCL in a transformer or generator feeder location offers great flexibility in reducing substation fault levels to accommodate switchgear ratings. One or more FCLs may be installed, depending on the fault reduction required, with minimal changes to existing protection settings. The FCL may be included in the transformer protection zone, with no additional relays or CTs required. The FCL may also be used to improve load-balancing between feeder transformers with different impedance and/or rated powers. The FCL enables capacity increase on existing grids.

Placing a FCL in a bus-tie location offers significant advantages in paralleling bus sections upon loss of one or more transformers in the substation. It also enables paralleling of bus sections in previously split substations, allowing interconnectivity, more flexible running arrangements and increased power quality. One or more FCLs may be installed, depending on the bus-bar topology and fault reduction required, with minimal changes to existing protection settings. The FCL may be paralleled with existing bus-tie circuit breakers, with no additional relays or CTs required.


Novel operating principles

GridON's product lines are based on novel technology concepts.

GridON’s variable-impedance FCL combines an electromagnetic alteration concept with conventional transformer technology. The unique and proprietary saturated-core based concept is utilizing the non-linear magnetic characteristic of iron core to introduce very high impedance to the grid during fault conditions. The FCL utilizes copper windings wound onto a DC biased, pre-saturated iron core, enabling it to present very low impedance during normal operation. When fault conditions occur, the iron core is driven instantaneously out of saturation, presenting much higher impedance to the grid, thereby suppressing the fault current for its entire duration. Upon fault clearing, the FCL immediately resumes its low impedance normal condition, ready to protect from any consecutive faults. The unique geometry of our design enables significant increase of impedance during fault, providing ample current limiting. GridON’s FCLs currently support all voltage levels and offer fault current reduction flexibility to suit the specific application and customer requirements.

GridON’s novel electronic FCLi is a series-connected solid-state based device which instantaneously interrupts the AC current upon detection of short circuit conditions. The FCLi limits and interrupts excessive fault infeed from the generator to the grid - before the first current peak. It also limits short circuit currents from the grid down to the generator. Once the short-circuit condition is cleared, the FCLi immediately returns to normal conduction.

A comprehensive monitoring and control system is provided with the FCL/FCLi to enable seamless integration with existing protection schemes and to provide a real-time view of the FCL operational parameters. GridON offers an optional DR-FCL monitoring system from Dynamic Ratings as part of its total solution.

Using standard technology and materials

Three main FCL paradigms have been developed in recent years; pre-saturated core, high temperature superconductor (HTS) and solid-state based technologies. HTS-based concepts are challenging technically and commercially. Not only does it require expensive, high-maintenance cryogenic system, the HTS system takes long time to cool-down and recovers following a fault. HTS-based FCLs are limited in their scalability and their ability to handle consecutive faults, hence yet to succeed commercially.

GridON has been focusing on two superconducting-free technologies:

The FCL product line is based on conventional transformer technology. It utilizes copper windings wound onto a DC biased, pre-saturated iron core. The FCL is being manufactured in a standard transformer production line, using transformer materials and manufacturing expertise. It is simple to manufacture, and is extremely reliable, easy to install, operate and maintain – like any power transformer.

The solid-state based FCLi is using standard power electronics components that have already extensive experience in commercial power systems.


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